- Agent-based model for electricity consumption and storage to evaluate economic viability of tariff arbitrage for residential sector demand responseM. Zheng, C. J. Meinrenken, K. S. Lackner | Applied Energy, 2014-08-01 [+]
Demand response (DR) is one of many approaches to address temporal mismatches in demand and supply of grid electricity. More common in the commercial sector, DR usually refers to reducing consumption at certain hours or seasons, thus reducing peak demand from the grid. In the residential sector, where sophisticated appliance-level controls such as automatic dimming of lights or on-demand lowering of air conditioning are less common, building-based electricity storage to shift grid consumption from peak to off-peak times could provide DR without requiring consumers to operate their appliances on shifted or reduced schedules: Storage would be dispatched to appliances as needed while still shaving peaks on the grid. Technologically, storage and two-way-inverters are readily available to enable such residential DR. Economically, however, the situation is less clear. Specifically, are time-varying electricity tariffs available such that electricity cost reduction via arbitrage could offset manufacturing, financing, and installation costs of the required storage? To address this question we (i) devise an agent-based appliance-level stochastic model to simulate the electricity demand of an average U.S. household; (ii) loadshift the demand via simple dispatch strategies; and (iii) determine potential profits to the building owner, i.e. reduced electricity cost of the modified demand with realistic tariffs (Con Edison, NY) minus storage cost. We determine the economic viability for a range of traditional and advanced storage technologies as well as their optimum storage capacities to maximize profits. We find that (i) profits can range from <1% to 48% of annual electricity costs of a typical household; and (ii) optimum capacities, while approximately equal to households’ kWh consumption during peak hours, is affected by stochastic variations in daily and seasonal consumption. Future improvements to storage technology, arbitrage strategies, and tariffs are discussed. Details of the storage technologies, agent-based model, testing, and benchmarking are supplied as Supplementary Data.
- Electricity storage in buildings for residential sector demand response: Control algorithms and economic viability evaluationM. Zheng, C. J. Meinrenken, K. S. Lackner | National Institute of Standards and Technology, 2014-06-27 [+]
“Smart grid”-enabled demand response (DR) provides significant opportunities to improve today’s electricity grids’ reliability, efficiency, affordability and security. In contrast to conventional DR, electricity storage in buildings (residential or commercial) can provide essential, flexible and reliable DR service without requiring consumers to operate their appliances on shifted or reduced schedules. With a number of DR tariffs and DR-enabling technologies available (e.g., storage technologies and two-way inverters), one of the key current barriers for higher penetration of DR is consumers’ understanding of the cost-benefit issue. To address this question, and focusing on the residential sector, we (i) devised an agent-based appliance-level stochastic model to simulate the electricity demand of an average U.S. household; (ii) developed control strategies to shift loads from the peak periods to the off-peak periods (i.e., loadshifting strategy) and to shed the peaks of the power demand loads (i.e., peak reduction strategy); (iii) suggested the potential profits for the consumers, i.e., the reduced electricity cost of the modified demand with realistic tariffs (Con Edison, New York) minus storage costs. We optimized DR operation for the above two DR strategies to maximize the profits for consumers and determined the economic viabilities for a range of traditional and advanced storage technologies. We concluded that annual profits range from $61 to $1365 per year per household by utilizing the loadshifting strategy and from $161 to $1058 per year per household by using the peak reduction strategy. These profits can be achieved without changing the actual consumption patterns of appliances. Of the two DR strategies, the peak reduction strategy can render more storage technologies economically viable.
- Energy Investments under Climate Policy: A Comparison of Global Models climate change economicsMcCollum, D., Y. Nagai, K. Riahi, G. Marangoni, K. Calvin, R. Pietzcker, J. van Vliet, B.C.C. van der Zwaan | Climate Change Economics, 2014-06-04 [+]
The levels of investment needed to mobilize an energy system transformation and mitigate climate change are not known with certainty. This paper aims to inform the ongoing dialogue and in so doing to guide public policy and strategic corporate decision making. Within the framework of the LIMITS integrated assessment model comparison exercise, we analyze a multi-IAM ensemble of long-term energy and greenhouse gas emissions scenarios. Our study provides insight into several critical but uncertain areas related to the future investment environment, for example in terms of where capital expenditures may need to flow regionally, into which sectors they might be concentrated, and what policies could be helpful in spurring these financial resources. We find that stringent climate policies consistent with a 2°C climate change target would require a considerable upscaling of investments into low-carbon energy and energy efficiency, reaching approximately $45 trillion (range: $30–$75 trillion) cumulative between 2010 and 2050, or about $1.1 trillion annually. This represents an increase of some $30 trillion ($10–$55 trillion), or $0.8 trillion per year, beyond what investments might otherwise be in a reference scenario that assumes the continuation of present and planned emissions-reducing policies throughout the world. In other words, a substantial "clean-energy investment gap" of some $800 billion/yr exists — notably on the same order of magnitude as present-day subsidies for fossil energy and electricity worldwide ($523 billion). Unless the gap is filled rather quickly, the 2°C target could potentially become out of reach.
- Emission Certificate Trade and Costs under Regional Burden-Sharing Regimes for a 2˚C Climate Change Control TargetT. Kober, B. C. C. Van Der Zwaan, H. Rösler | Climate Change Economics
, 2014-05-01 [+]
In this article we explore regional burden-sharing regimes for the allocation of greenhouse gas emission reduction obligations needed to reach a 2°C long-term global climate change control target by performing an integrated energy-economy-climate assessment with the bottom–up TIAM-ECN model. Our main finding is that, under a burden-sharing scheme based on the allowed emissions per capita, the sum of merchandized carbon certificates yields about 2000 billion US$/yr worth of inter-regional trade around 2050, with China and Latin America the major buyers, respectively Africa, India, and other Asia the main sellers. Under a burden-sharing regime that aims at equal cost distribution, the aggregated amount of transacted carbon certificates involves less than 500 billion US$/yr worth of international trade by 2050, with China and other Asia representing the vast majority of selling capacity. Restrictions in the opportunities for international certificate trade can have significant short- to mid-term impact, with an increase in global climate policy costs of up to 20%.
- Experimental Design and Data Analysis for Accurate Estimation of Reaction Kinetics and Conversion for Carbon MineralizationG. Gadikota, E.J. Swanson, H. Zhao, A.-H. A. Park. | American Chemical Society, 2014-03-24 [+]
Silicate minerals such as olivine (Mg2SiO4) and serpentine [Mg3(OH)4(Si3O5)] can react with CO2 to form mineral carbonates to permanently store CO2. Despite significant advancements in carbon mineralization, major discrepancies in the reported kinetics exist because of inconsistencies among various experimental methodologies, the heterogeneity and aging of the minerals, and inadequate fast kinetics and morphological data to probe the reaction mechanisms. In this work, it was found that aged and freshly ground olivine produce very different carbonation yields. A new mineral cleaning protocol to remove fines (<5 μm) was developed. Fast and slow serpentine dissolution regimes were distinguished using a custom-built differential-bed reactor. Mineral carbonate formation using a bubble-column reactor was described. Different carbon analyses were evaluated for accurate estimation of the extent of carbon mineralization. Therefore, this study focused on the development of an experimental framework and a data analysis method for the systematic investigation of mineral dissolution and carbonation behaviors.
- Electricity versus Hydrogen for Passenger Cars under Stringent Climate Change ControlRösler, H., B.C.C. van der Zwaan, I.J. Keppo and J.J.C. Bruggink | Sustainable Energy Technologies and Assessments, 2014-03-01 [+]
In this article we analyze how passenger car transportation in Europe may change this century under permanent high oil prices and stringent climate control policy. We focus on electricity and hydrogen as principal candidate energy carriers, because these two options are increasingly believed to become the long-term competitors in the transport sector. We complement a concise stylistic analysis with an in-depth investigation performed with the energy system optimization model TIAM-ECN, which we ran only for the European regions for this study. This bottom-up model, belonging to the TIMES family, has been adapted for the purpose of researching – amongst others – the transport sector. We particularly inspect the use of passenger cars and find that, if oil prices amount to 100–150 $/bl during the remainder of the century, the transport sector could be little affected in the sense that it may continue to rely predominantly on (liquid or gaseous) fossil fuels: our model suggests that it could be optimal to start replacing gasoline and diesel by natural gas around the middle of the century if sufficient oil and gas reserves are available within this price range. If the European Commission achieves implementing its ambitious carbon mitigation plan, however, a massive restructuring of the transport sector away from fossil fuels could take place, which in three decades would transform it to broadly rely on hydrogen as main energy carrier according to our model runs. Under a broad set of sensitivity scenarios with varying assumptions regarding our most important modeling parameters, we find that if battery costs are reduced by at least 60% in comparison to our reference cost decline path, the passenger car sector could predominantly run on electricity from around 2050.
- Morphological changes during enhanced carbonation of asbestos containing material and its comparison to magnesium silicate mineralsG. Gadikota, C. Natali, C. Boschi, A.-H. A. Park. | Journal of Hazardous Materials, 2014-01-15 [+]
The disintegration of asbestos containing materials (ACM) over time can result in the mobilization of toxic chrysotile ((Mg, Fe)3Si2O5(OH)4)) fibers. Therefore, carbonation of these materials can be used to alter the fibrous morphology of asbestos and help mitigate anthropogenic CO2 emissions, depending on the amount of available alkaline metal in the materials. A series of high pressure carbonation experiments were performed in a batch reactor at PCO2 of 139 atm using solvents containing different ligands (i.e., oxalate and acetate). The results of ACM carbonation were compared to those of magnesium silicate minerals which have been proposed to permanently store CO2 via mineral carbonation. The study revealed that oxalate even at a low concentration of 0.1 M was effective in enhancing the extent of ACM carbonation and higher reaction temperatures also resulted in increased ACM carbonation. Formation of phases such as dolomite ((Ca, Mg)(CO3)2), whewellite (CaC2O4·H2O) and glushinskite (MgC2O4·2H2O) and a reduction in the chrysotile content was noted. Significant changes in the particle size and surface morphologies of ACM and magnesium silicate minerals toward non-fibrous structures were observed after their carbonation.
- Relative Permeability Experiments of Carbon Dioxide Displacing Brine and Their Implications for Carbon SequestrationJ.S. Levine, D.S. Goldberg, K.S. Lackner, J.M. Matter, M.G. Supp, and T. S. Ramakrishnan | Environment Science & Technoogy, 2013-11-25 [+]
To mitigate anthropogenically induced climate change and ocean acidification, net carbon dioxide emissions to the atmosphere must be reduced. One proposed option is underground CO2 disposal. Large-scale injection of CO2 into the Earth’s crust requires an understanding of the multiphase flow properties of high-pressure CO2 displacing brine. We present laboratory-scale core flooding experiments designed to measure CO2 endpoint relative permeability for CO2 displacing brine at in situ pressures, salinities, and temperatures. Endpoint drainage CO2 relative permeabilities for liquid and supercritical CO2 were found to be clustered around 0.4 for both the synthetic and natural media studied. These values indicate that relative to CO2, water may not be strongly wetting the solid surface. Based on these results, CO2 injectivity will be reduced and pressure-limited reservoirs will have reduced disposal capacity, though area-limited reservoirs may have increased capacity. Future reservoir-scale modeling efforts should incorporate sensitivity to relative permeability. Assuming applicability of the experimental results to other lithologies and that the majority of reservoirs are pressure limited, geologic carbon sequestration would require approximately twice the number of wells for the same injectivity.
- Small Modular InfrastructureE. Dahlgren, C. Göçmen, K. Lackner, & G. van Ryzin | The Engineering Economist, 2013-11-13 [+]
In this article we argue that advances made in automation, communication, and manufacturing portend a dramatic reversal of the “bigger is better” approach to cost reductions prevalent in many basic infrastructure industries; for example, transportation, electric power generation, and raw material processing. We show that the traditional reductions in capital costs achieved by scaling up in size are generally matched by learning effects in the mass production process when scaling up in numbers instead. In addition, using the U.S. electricity generation sector as a case study, we argue that the primary operating cost advantage of large unit scale is reduced labor, which can be eliminated by employing low-cost automation technologies. Finally, we argue that locational, operational, and financial flexibilities that accompany smaller unit scale can reduce investment and operating costs even further. All of these factors combined imply that with current technology, economies of numbers may well dominate economies of unit scale. Yet realizing the full potential of small unit scale will require technologists and business leaders to develop a new ability to “think small.”
- A Multi-Model Analysis of the Regional and Sectoral Roles of Bioenergy in Near- and Long-Term CO2 Emissions ReductionCalvin, K., M. Wise, D. Klein, D. McCollum, M. Tavoni, B.C.C. van der Zwaan, D.P. van Vuuren | Climate Change Economics , 2013-11-01 [+]
This paper examines the near- and the long-term contribution of regional and sectoral bioenergy use in response to both regionally diverse near-term policies and longer-term global climate change mitigation policies. The use of several models provides a source of heterogeneity in terms of incorporating uncertain assumptions about future socioeconomics and technology, as well as different paradigms for how different regions and major economies of the world may respond to climate policies. The results highlight the heterogeneity and versatility of bioenergy itself, with different types of resources and applications in several energy sectors. In large part due to this versatility, the contribution of bioenergy to climate mitigation is a robust response across all models. Regional differences in bioenergy consumption, however, highlight the importance of assumptions about trade in bioenergy feedstocks and the influence of energy and climate policies. When global trade in bioenergy is possible, regional patterns of bioenergy use follow global patterns. When trade is assumed not to be feasible, regions with high bioenergy supply potential tend to consume more bioenergy than other regions. Energy and climate policies, such as renewable energy targets, can incentivize bioenergy use, but specifics of the policies will dictate the degree to which this is true. For example, renewable final energy targets, which include electric and non-electric renewable sources, increase bioenergy use in all models, while electric-only renewable targets have a mixed effect on bioenergy use across models.
- "Fast LCA" to Apply Life Cycle Methodologies and Supply Chain Management at ScaleC. J. Meinrenken, A. N. Garvan, & K. S. Lackner │7th International Society for industrial Ecology Biennial Conference , 2013-06-26 [+]
Tools in Industrial Ecology such as Life Cycle Assessment (LCA) of goods and services lend themselves to better understand, measure, and potentially reduce the material consumption and cradle-to-grave environmental impact of goods and services. Owing to modern enterprise resource planning (ERP), many companies making such products have much of the required primary inventory data required for product-level LCA already available. To deal with inevitable data imperfections or missing data, LCA offers, via the concepts of secondary data, proxies, and immaterial contributions, a framework to arrive at approximated LCA results that, while informative in their own right, also form a basis for gradual, future improvement. Such iterative processes (e.g., “data screening” as per ) are best carried out while carefully monitoring compound uncertainty of the resulting LCA and using this as a guide for further research into some rather than all inventory materials and processes (e.g., [2, 3]).
In practice, however, above approach faces significant obstacles when to be carried out in real world situation because
practitioners (here: companies that produce such goods or services) become overwhelmed by the deluge of data and the strategy of screening is impossible to implement when dealing with tens of thousands of underlying inventory data items, each potentially contributing materially to the LCA result and its error margin . Recognizing that recent standards on carbon footprinting, a sub-discipline of LCA, propel LCA to the mainstream [1, 5-15], we recently developed a novel methodology that enable companies to calculate thousands of “mass-produced” product carbon footprints and use these
for their inner operations and business decision making . Working with a global consumer goods company, we have since applied this methodology to quantify the carbon footprints of ~3000 different products across 5 countries.
Here, we focus on three sets of results from this work: (i) Using real-life feeds from ERP data warehouses, we demonstrate how common data limitations and inaccuracies in LCA inventory data can be overcome by employing intelligent data filtering, cleaning, and flagging algorithms. (ii) Despite tens of thousands of underlying inventory inputs, in real life data sets, only a few of these determine most of the error margin in a particular, monitored environmental impact (such as GHG) or life cycle stage. We give benchmarks for such data. (iii) Carbon footprinting is a prime example for a
common dilemma at the intersection of Industrial Ecology-based methodologies and their actual use by practitioners. Complexity of analytics and data structure can deter wide-spread use of LCA, thus preventing many of its benefits. By the same token, overly simplified approaches risk not capturing important aspects of the LCA and thus yielding misleading sustainability information. Focusing on the educational aspect of the novel methodology and presenting results from pilot tests, we discuss how explicit inclusion of uncertainty and a uniform yet flexible data structure (e.g., primary/secondary; LCA assemblies) can facilitate immediate access to the methodology on the one hand while still allowing expert users to evaluate sophisticated GHG-affecting product scenarios on the other.
- A Cross-Model Comparison of Global Long-Term Technology Diffusion under a 2˚C Climate Change Control TargetB.C.C. van der Zwaan, H. Rösler, T. Kober, T. Aboumahboub, K.V. Calvin, D.E.H.J. Gernaat, G. Marangoni & D. McCollum │Climate Change Economics, 2013-06-14 [+]
This article investigates the long-term global energy technology diffusion patterns required to reach a
stringent climate change target with a maximum average atmospheric temperature increase of 2˚C.
One of our main findings in this cross-model energy system integrated assessment exercise is that
many different technology deployment pathways exist to reach such ambitious climate change control.
If the anthropogenic atmospheric temperature increase is to be limited to at most 2˚C, total CO2
emissions have to be reduced massively, so as to reach substantial negative values during the second
half of the century. Particularly power sector CO2 emissions should become deeply negative from
around 2050 onwards in order to compensate for GHG emissions in other sectors where abatement is
more costly. The annual additional capacity deployment intensity (expressed in GW/yr) for solar and
wind energy until 2030 needs to be around that recently observed for coal-based power plants, and
will have to be several times higher in the period 2030-2050. In all energy transformation pathways,
CCS constitutes a significant part of the climate mitigation technology mix, but applies, according to
different models, to varying forms of primary energy (coal, gas and biomass) and types of energy
carrier production (electricity, hydrogen and liquid fuels). Uncertainty abounds regarding both type
and extent of low-carbon technology deployment, as well as concerning individual technology costs,
but relatively high agreement exists in terms of the aggregated total low-carbon energy system cost
requirements on the supply side until 2050, amounting to about 50 trillion US$ (that is, well over
1 trillion US$/yr) in order to stay within the limits of 2˚C temperature increase.
- Effect of water on the physical properties and carbon dioxide capture capacities of liquid-like Nanoparticle Organic Hybrid Materials and their corresponding polymersC. Petit, S. Bhatnagar & A.-H. A. Park │Journal of Colloid and Interface Science, 2013-06-11 [+]
Binary systems composed of liquid-like Nanoparticle Organic Hybrid Materials (NOHMs) and the secondary fluid (i.e., water) were prepared, and their thermal stabilities, densities, viscosities, and CO2 absorption capacities were investigated. Recent work has suggested NOHMs as an alternative CO2 capture media with interesting chemical and physical tunability. Anhydrous CO2 capture solvents often degrade when they are exposed to water, while flue gas generally contains about 8–16% water. Thus, this study was conducted to investigate the effect of water on the NOHMs’ properties relevant to CO2 capture as well as the chemical and thermal stabilities of H2O-loaded NOHMs. It was found that water acted as an antisolvent of NOHMs, and therefore, caused a decreased CO2 capture capacity. On the other hand, the results indicated that while water did not affect the NOHMs’ thermal stability, it significantly helped lowering their density and viscosity. In order to investigate the effect of intermolecular interactions among two fluids on the density and viscosity, the excess volumes and viscosity deviations were calculated and correlated with Redlich–Kister equations. The trends revealed the existence of strong intermolecular interactions between water molecules and the poly(ethlyne glycol) component of NOHMs, which may have caused the drastic decrease in the NOHMs’ viscosity with the addition of water.
- Potential for Renewable Energy Jobs in the Middle East B.C.C. van der Zwaan, L. Cameron & T. Kober │Energy Policy, 2013-05-8 [+]
Based on employment factors derived from a recent review of publications investigating opportunities for work associated with the diffusion of renewable energy technology, we here present an analysis of the potential for renewable energy jobs in the Middle East. We use energy system optimisation results from the regionally disaggregated TIAM-ECN model as input to our study. This integrated assessment model is utilised to inspect the energy technology requirements for meeting a stringent global climate policy that achieves a stabilisation of greenhouse gas concentrations in the atmosphere with a maximum additional radiative forcing of 2.9 W/m2. This climate control target implies a massive deployment of renewable energy in the Middle East, with wind and solar power accounting for approximately 60% of total electricity supply in 2050: 900 TWh of an overall level of 1525 TWh would be generated from 210 GW of installed renewable energy capacity by the middle of the century. For this pervasive renewables diffusion scenario for the Middle East we estimate a total required local work force of ultimately about 155,000 direct and 115,000 indirect jobs, based on assumptions regarding which components of the respective wind and solar energy technologies can be manufactured in the region itself. All jobs generated through installation and O&M activities are assumed to be domestic.
- How to Decarbonize the Transport Sector?B.C.C. van der Zwaan, I.J. Keppo & F. Johnsson│Energy Policy, 2013-05-30 [+]
This article investigates possible evolution pathways for the transport sector during the 21st century, globally and in Europe, under a climate change control scenario. We attempt to shed light on the question how the transport sector should best be decarbonized. We perform our study with the global bottom-up energy systems model TIAM-ECN, a version of the TIAM model that is broadly used for the purpose of developing energy technology and climate policy scenarios, which we adapted for analyzing in particular the transport sector. Given the global aggregated perspective of TIAM-ECN, that in its current version yields at every point in time a single CO2 price for different forms of energy use across geographic regions and economic sectors, it generates a decarbonization process that for the transport sector occurs later in time than for the power sector. This merely reflects that emission reductions are generally cheaper for electricity production than for transportation, and that it is thus cost-minimizing to spend limited financial resources available for CO2 emissions abatement in the power sector first. In our scenarios the use of hydrogen in internal combustion engines and fuel cells, rather than electricity as energy carrier and batteries to store it, gradually becomes the dominant transport technology. This outcome is in agreement with some recent publications but is at loggerheads with the current popularity of the electric car. Based on sensitivity analysis we conclude that even if the establishment of a hydrogen infrastructure proves about an order of magnitude more costly than modeled in our base case, electricity based transportation only broadly emerges if simultaneously also the costs of electric cars go down by at least 40% with respect to our reference costs. One of the explanations for why the electric car is today, by e.g. entrepreneurs, often considered the supposed winner amongst multiple future transportation options is that the decision horizon of many analysts is no more than a few decades, instead of a full century. Electric cars fit better the current infrastructure than hydrogen fueled vehicles, so that from a short time perspective (covering the next decade or two) investments are not optimally spent by establishing an extensive hydrogen distribution network. Hence the path-dependency created by the present existence of a vast power transmission and distribution network can make electricity the most efficient choice for transportation, but only if the time frame considered is short. Electric transportation generally proves the more expensive alternative in our long-term perspective, except when electric car costs are assumed to drop substantially.
- Effect of SO2 on CO2 Capture Using Liquid-like Nanoparticle Organic Hybrid MaterialsK.-Y. A. Lin , C. Petit & A.-H. A. Park│American Chemical Society, 2013-05-13 [+]
Liquid-like nanoparticle organic hybrid materials (NOHMs), consisting of silica nanoparticles with a grafted polymeric canopy, were synthesized. Previous work on NOHMs has revealed that CO2 capture behaviors in these hybrid materials can be tuned by modifying the structure of the polymeric canopy. Because SO2, which is another acidic gas found in flue gas, would also interact with NOHMs, this study was designed to investigate its effect on CO2 capture in NOHMs. In particular, CO2 capture capacities as well as swelling and CO2 packing behaviors of NOHMs were analyzed using thermogravimetric analyses and Raman and attenuated total reflectance (ATR) Fourier transform infrared (FTIR) spectroscopies before and after exposure of NOHMs to SO2. It was found that the SO2 absorption in NOHMs was only prominent at high SO2 levels (i.e., 3010 ppm; Ptot = 0.4 MPa) far exceeding the typical SO2 concentration in flue gas. As expected, the competitive absorption between SO2 and CO2 for the same absorption sites (i.e., ether and amine groups) resulted in a decreased CO2 capture capacity of NOHMs. The swelling of NOHMs was not notably affected by the presence of SO2 within the given concentration range (Ptot = 0–0.68 MPa). On the other hand, SO2, owing to its Lewis acidic nature, interacted with the ether groups of the polymeric canopy and, thus, changed the CO2 packing behaviors in NOHMs.
- Electricity demand and storage dispatch modeling for buildings and implications for the smartgrid M. Zheng & C. Meinrenken│April Meeting of the American Physical Society, 2013-04-15 [+]
As an enabler for demand response (DR), electricity storage in buildings has the potential to lower costs and carbon footprint of grid electricity while simultaneously mitigating grid strain and increasing its flexibility to integrate renewables (central or distributed). We present a stochastic model to simulate minute-by-minute electricity demand of buildings and analyze the resulting electricity costs under actual, currently available DR-enabling tariffs in New York State, namely a peak/offpeak tariff charging by consumed energy (monthly total kWh) and a time of use tariff charging by power demand (monthly peak kW). We then introduce a variety of electrical storage options (from flow batteries to flywheels) and determine how DR via temporary storage may increase the overall net present value (NPV) for consumers (comparing the reduced cost of electricity to capital and maintenance costs of the storage). We find that, under the total-energy tariff, only medium-term storage options such as batteries offer positive NPV, and only at the low end of storage costs (optimistic scenario). Under the peak-demand tariff, however, even short-term storage such as flywheels and superconducting magnetic energy offer positive NPV. Therefore, these offer significant economic incentive to enable DR without affecting the consumption habits of buildings' residents. We discuss implications for smartgrid communication and our future work on real-time price tariffs.
- Effect of H2O on Mg(OH)2 carbonation pathways for combined CO2 capture and storageK. Fricker & A.-H.A. Park | Chemical Engineering Science, 2012-12-21 [+]
Abstract: Mg-bearing sorbents, derived from silicate minerals and industrial wastes, can act as combined carbon capture and storage media in various energy conversion systems. Mg(OH)2 carbonation in the slurry phase occurs spontaneously and recent results show improved gas–solid carbonation with comparable materials in the presence of H2O vapor; however, the reaction mechanism is still poorly understood at high temperature and pressure conditions. This study investigated the pathways of H2O enhanced Mg(OH)2 carbonation at elevated temperatures and CO2 pressures (up to 673 K and 1.52 MPa) in the presence of steam and in the slurry phase. For a given reaction temperature, carbonation conversion showed dramatic increase with increasing H2O loading. Comprehensive solid analyses via thermogravimetric analysis, X-ray diffraction, and UV-Raman allowed for qualitative and quantitative compositional characterization of reacted solids. The results suggest that a hydrated environment facilitates the formation of intermediate hydrated magnesium carbonate species. The hydrated carbonates form relatively quickly and can transform into anhydrous carbonates while subjected to greater H2O loading, higher temperature, and/or longer reaction time.
- The Role of Nuclear Power in Mitigating Emissions from Electricity GenerationB.C.C. van der Zwaan │ Energy Strategy Reviews, 2012-12-16 [+]
This article presents an updated overview of recent literature on the role of nuclear power in mitigating greenhouse gas (GHG) and particulate matter (PM) emissions from electricity generation. Emission intensities are strongly dependent on the country of operation and type of technology used in each category of power production options, but robust observations can be made with regards to the average emission intensity of each main alternative. The majority of emissions from nuclear energy is associated with parts of its overall life cycle other than the operation of nuclear power plants. Technological progress in especially uranium enrichment has recently yielded energy intensity reductions that have significantly lowered the GHG footprint of nuclear power, which at present amounts to 5–17 gCO2eq/kWh. As a result, average GHG emissions are today around two orders of magnitude lower for nuclear energy than for conventional coal-based power production. This article also addresses the feasibility of potential deployment scenarios for nuclear power and their implications in terms of global GHG emissions mitigation.
- Moisture-swing sorption for carbon dioxide capture from ambient air: a thermodynamic analysisT. Wang, K.S. Lackner, & A.B. Wright | Physical Chemistry Chemical Physics, 2012-11-05 [+]
An ideal chemical sorbent for carbon dioxide capture from ambient air (air capture) must have a number of favourable properties, such as environmentally benign behaviour, a high affinity for CO2 at very low concentration (400 ppm), and a low energy cost for regeneration. The last two properties seem contradictory, especially for sorbents employing thermal swing adsorption. On the other hand, thermodynamic analysis shows that the energy cost of an air capture device need only be slightly larger than that of a flue gas scrubber. The moisture swing separation process studied in this paper provides a novel approach to low cost CO2 capture from air. The anionic exchange resin sorbent binds CO2 when dry and releases it when wet. A thermodynamic model with coupled phase and chemical equilibria is developed to study the complex H2O–CO2–resin system. The moisture swing behaviour is compatible with hydration energies changing with the activity of water on the resin surfaces. This activity is in turn set by the humidity. The rearrangement of hydration water on the resin upon the sorption of a CO2 molecule is predicted as a function of the humidity and temperature. Using water as fuel to drive the moisture swing enables an economical, large-scale implementation of air capture. By generating CO2 with low partial pressures, the present technology has implications for in situ CO2 utilizations which require low pressure CO2 gas rather than liquid CO2.
- The urgency of the development of CO2 capture from ambient airK.S. Lackner., S. Brennan, J. Matter, A.-H.A. Park, A. Wright, & B.C.C. van der Zwaan | Proceedings of the National Academy of Sciences, 2012-07-27 [+]
Abstract: CO2 capture and storage (CCS) has the potential to develop into an important tool to address climate change. Given society’s present reliance on fossil fuels, widespread adoption of CCS appears indispensable for meeting stringent climate targets. We argue that for conventional CCS to become a successful climate mitigation technology—which by necessity has to operate on a large scale—it may need to be complemented with air capture, removing CO2 directly from the atmosphere. Air capture of CO2 could act as insurance against CO2 leaking from storage and furthermore may provide an option for dealing with emissions from mobile dispersed sources such as automobiles and airplanes.
- Novel Approach to Hydrogen Production with Suppressed COx Generation from a Model Biomass FeedstockT.E. Ferguson, Y. Park, C. Petit, & A.-H.A. Park | Energy Fuels, 2012-06-28 [+]
Abstract: The alkaline thermal treatment of biomass has recently been proposed as a novel method for producing high purity H2 with suppressed COx formation under moderate reaction conditions (i.e., 523 K and ambient pressure). This technology has a great potential for sustainable bioenergy production because it can handle a wide range of feedstocks including biomass and biogenic wastes with high water content. Unfortunately, due to the complexity of the reactions involved, the alkaline thermal treatment of biomass is still poorly understood. In this study, using a model biomass system of glucose, a series of noncatalytic kinetic and mechanistic studies was performed to investigate the effects of reaction temperature and reactant ratios in terms of H2 conversion, purity, and formation rates of H2 as well as gaseous products such as CH4, CO, and CO2. The CO concentration is one of the important factors for the utilization of the product gas because CO is generally poisonous to catalytic systems such as those found in proton exchange membrane (PEM) fuel cells. Thus, high CO concentration would require additional gas cleanup processes. This study found that NaOH does play an important role in suppressing CO and CO2 formation while facilitating H2 production and promoting CH4 formation. The noncatalytic alkaline thermal treatment of glucose resulted in a maximum H2 conversion of about 27% at 523 K with a stoichiometric mixture of NaOH and glucose. While the H2 conversion was limited in the absence of catalyst, the moderate reaction conditions, low COx concentration, and solid–solid reaction scheme give advantages over conventional biomass conversion technologies. The solids analysis confirmed the presence of Na2CO3 in the solid product, indicating the inherent carbon management potential of the alkaline thermal treatment process.
- Fast Carbon Footprinting for Large Product PortfoliosC.J. Meinrenken, S.M. Kaufman, S. Ramesh, & K.S. Lackner | Journal of Industrial Ecology, 2012-05-08 [+]
Abstract: Publicly Available Specification 2050‐2011 (PAS 2050), the Green House Gas Product Protocol
(GHGPP) standard and forthcoming guideline 14067 from the International Organization for
Standardization (ISO) have helped to propel carbon footprinting from a subdiscipline of life
cycle assessment (LCA) to the mainstream. However, application of carbon footprinting to large
portfolios of many distinct products and services is immensely resource intensive. Even if
achieved, it often fails to inform company‐wide carbon reduction strategies because footprint
data are disjointed or don't cover the whole portfolio. We introduce a novel approach to
generate standard‐compliant product carbon footprints (CFs) for companies with large
portfolios at a fraction of previously required time and expertise. The approach was developed
and validated on an LCA dataset covering 1,137 individual products from a global packaged
consumer goods company. Three novel techniques work in concert in a single approach that
enables practitioners to calculate thousands of footprints virtually simultaneously: (i) a uniform
data structure enables footprinting all products and services by looping the same algorithm; (ii)
concurrent uncertainty analysis guides practitioners to gradually improve the accuracy of only
those data that materially impact the results; and (iii) a predictive model generates estimated
emission factors (EFs) for materials, thereby eliminating the manual mapping of a product or
service's inventory to EF databases. These autogenerated EFs enable non‐LCA experts to
calculate approximate CFs and alleviate resource constraints for companies embarking on large‐
scale product carbon footprinting. We discuss implementation roadmaps for companies,
including further road‐testing required to evaluate the effectiveness of the approach for other
product portfolios, limitations, and future improvements of the fast footprinting methodology.
- Gasoline-powered serial hybrid cars cause lower life cycle carbon emissions than battery carsC.J. Meinrenken & K.S. Lackner |March Meeting of The American Physical Society, 2012-02-27 [+]
Abstract: Battery cars powered by grid electricity promise reduced life cycle green house gas (GHG) emissions from the automotive sector. Such scenarios usually point to the much higher emissions from conventional, internal combustion engine cars. However, today's commercially available serial hybrid technology achieves the well known efficiency gains from regenerative breaking, lack of gearbox, and light weighting - even if the electricity is generated onboard, from conventional fuels. Here, we analyze emissions for commercially available, state-of the-art battery cars (e.g. Nissan Leaf) and those of commercially available serial hybrid cars (e.g., GM Volt, at same size and performance). Crucially, we find that serial hybrid cars driven on (fossil) gasoline cause fewer life cycle GHG emissions (126g CO2e per km) than battery cars driven on current US grid electricity (142g CO2e per km). We attribute this novel finding to the significant incremental life cycle emissions from battery cars from losses during grid transmission, battery dis-/charging, and larger batteries. We discuss crucial implications for strategic policy decisions towards a low carbon automotive sector as well as relative land intensity when powering cars by biofuel vs. bioelectricity.
- Nuclear Versus Coal plus CCS: a Comparison of Two Competitive Base-Load Climate Control OptionsM. Tavoni & B.C.C van der Zwaan│Note Di Lavoro, 2011-3-11 [+]
In this paper we analyze the relative importance and mutual behavior of two competing base-load electricity generation options that each are capable of contributing significantly to the abatement of global CO2 emissions: nuclear energy and coal-based power production complemented with CO2 capture and storage (CCS). We also investigate how, in scenarios from an integrated assessment model that simulates the economics of a climate-constrained world, the prospects for nuclear energy would change if exogenous limitations on the spread of nuclear technology were relaxed. Using the climate change economics model WITCH we find that until 2050 the resulting growth rates of nuclear electricity generation capacity become comparable to historical rates observed during the 1980s. Given that nuclear energy continues to face serious challenges and contention, we inspect how extensive the improvements of coal-based power equipped with CCS technology would need to be if our model is to significantly scale down the construction of new nuclear power plants.
- Cost Reductions for Offshore Wind Power: Exploring the Balance between Scaling, Learning and R&DB.C.C. van der Zwaan, R. Rivera-Tinoco, S. Lensink, & P. van den Oosterkamp | Renewable Energy, 2011-12-3 [+]
Abstract: Offshore wind electricity generation is prospected to increase substantially in the near
future at a number of locations, like in the Baltic, Irish and North Sea, and emerge at
several others. The global growth of offshore wind technology is likely to be
accompanied by reductions in wind park construction costs, both as a result of scaling
and learning effects. Since 2005, however, significant cost increases have been
observed. A recent surge in commodity prices proves to constitute one of the main
drivers of these cost increases. This observation begs the question whether wind
turbine manufacturers should return to the laboratory for undertaking R&D that explores
the use of alternative materials and bring offshore wind energy closer to
competitiveness. It is demonstrated that if one abstracts from material price fluctuations,
in particular for metals such as copper and steel, turbine production plus installation
cost data publicly available for a series of offshore wind park projects (realized in
several European countries since the 1990s) show a cost reduction trend. Hence
various other sources of cost increases, such as due to the progressively larger
distances from the shore (and correspondingly greater depths at sea) at which wind
parks have been (and will be) built, are outshadowed by cost reduction effects.
When one expresses the overall cost development for offshore wind energy capacity as
an experience curve, a learning rate is found of 3%, which reflects a mixture of
economies-of-scale and learning-by-doing mechanisms. Also the impact is quantified on
offshore wind power construction costs from the recent tightness in the market for
turbine manufacturing and installation services: without the demand-supply response
inertia at the origin of this tightness it is estimated that the learning rate would be 5%.
Since these learning rates are relatively low -- in comparison to those observed for other
technologies, and in view of the high current capacity costs of offshore wind in
comparison to onshore w
- Spectroscopic Investigation of the Canopy Configurations in Nanoparticle Organic Hybrid Materials of Various Grafting Densities during CO2 CaptureC. Petit, Y. Park, K.A. Lin, & A.-H.A. Park | Journal of Physical Chemistry, 2011-12-12 [+]
Abstract: Novel liquid-like nanoparticle organic hybrid materials (NOHMs) made of polyetheramine chains tethered onto functionalized silica nanoparticles were synthesized and characterized before and after exposure to CO2 using NMR, Raman, and ATR FT-IR spectroscopies in order to investigate the effect of the grafting densities on the NOHM canopy structure. Considering the promising tunable properties for CO2 capture of NOHMs, this study was conducted to provide important structural information to better design NOHMs for CO2 capture. In order to minimize the CO2 absorption via enthalpic effect and provide a more accurate assessment of the structural effects, the NOHMs were synthesized without task-specific groups. A greater chain ordering and decreased intermolecular interactions were observed in NOHMs compared to the unbound polymer. This was attributed to the specific structural arrangement of the frustrated canopy. The distinct configuration of grafted polymer chains caused different CO2 packing and CO2-induced swelling behaviors between the NOHMs and the unbound polymer. The grafting density influenced the ordering and coupling of the polymer chains and CO2-induced swelling. Its effect on the CO2 packing behavior was less pronounced.
- Learning Curves for Solid Oxide Fuel CellsR. Rivera-Tinoco, K. Schoots, & B.C.C. van der Zwaan | Energy Conversion and Management, 2011-11-25 [+]
In this article we present learning curves for solid oxide fuel cells (SOFCs). With data from fuel cell manufacturers we derive a detailed breakdown of their production costs. We develop a bottom-up model that allows for determining overall SOFC manufacturing costs with their respective cost components, among which material, energy, labor and capital charges. The results obtained from our model prove to deviate by at most 13% from total cost figures quoted in the literature. For the R&D stage of development and diffusion, we find local learning rates between 13% and 17% and we demonstrate that the corresponding cost reductions result essentially from learning-by-searching effects. When considering periods in time that focus on the pilot and early commercial production stages, we find regional learning rates of 27% and 1%, respectively, which we assume derive mainly from genuine learning phenomena. These figures turnout significantly higher, approximately 44% and 12% respectively, if also effects of economies-of-scale and automation are included. When combining all production stages we obtain lr = 35%, which represents a mix of cost reduction phenomena. This high learning rate value and the potential to scale up production suggest that continued efforts in the development of SOFC manufacturing processes, as well as deployment and use of SOFCs, may lead to substantial further cost reductions.
- CO2 Capture Capacity and Swelling Measurements of Liquid-like Nanoparticle Organic Hybrid Materials via Attenuated Total Reflectance Fourier Transform Infrared SpectroscopyY. Park, D. Shin, Y.N. Jang, & A.-H.A. Park | Journal of Chemical & Engineering Data, 2011-10-28 [+]
Abstract: Novel nanoparticle organic hybrid materials (NOHMs), which are comprised of organic oligomers or polymers tethered to an inorganic nanosized cores of various sizes, have been synthesized, and their solvating property for CO2 was investigated using attenuated total reflectance (ATR) Fourier transform infrared (FT-IR) spectroscopy. Simultaneous measurements of CO2 capture capacity and swelling behaviors of polyetheramine (Jeffamine M-2070) and its corresponding NOHMs (NOHM-I-PE2070) were reported at temperatures of (298, 308, 323 and 353) K and CO2 pressure conditions ranging from (0 to 5.5) MPa. The polymeric canopy, or polymer bound to the nanoparticle surface, showed significantly less swelling behavior with enhanced or comparable CO2 capture capacity compared to pure unbound polyetheramine.
- Investigation of CO2 Capture Mechanisms of Liquid-like Nanoparticle Organic Hybrid Materials via Structural CharacterizationY. Park, J. Decatur, K.A. Lin, & A.-H.A. Park | Physical Chemistry Chemical Physics, 2011-10-28 [+]
Abstract: Nanoparticle organic hybrid materials (NOHMs) have been recently developed that comprise an oligomeric or polymeric canopy tethered to surface-modified nanoparticles via ionic or covalent bonds. It has already been shown that the tunable nature of the grafted polymeric canopy allows for enhanced CO(2) capture capacity and selectivity via the enthalpic intermolecular interactions between CO(2) and the task-specific functional groups, such as amines. Interestingly, for the same amount of CO(2) loading NOHMs have also exhibited significantly different swelling behavior compared to that of the corresponding polymers, indicating a potential structural effect during CO(2) capture. If the frustrated canopy species favor spontaneous ordering due to steric and/or entropic effects, the inorganic cores of NOHMs could be organized into unusual structural arrangements. Likewise, the introduction of small gaseous molecules such as CO(2) could reduce the free energy of the frustrated canopy. This entropic effect, the result of unique structural nature, could allow NOHMs to capture CO(2) more effectively. In order to isolate the entropic effect, NOHMs were synthesized without the task-specific functional groups. The relationship between their structural conformation and the underlying mechanisms for the CO(2) absorption behavior were investigated by employing NMR and ATR FT-IR spectroscopies. The results provide fundamental information needed for evaluating and developing novel liquid-like CO(2) capture materials and give useful insights for designing and synthesizing NOHMs for more effective CO(2) capture.
- Historical variation in the capital costs of natural gas, carbon dioxide and hydrogen pipelines and implications for future infrastructureK. Schootsa, R. Rivera-Tinocoa., G. Verbong & B.C.C. van der Zwaan│International Journal of Greenhouse Gas Control, 2011-09-29 [+]
The construction of large pipeline infrastructures for CH4, CO2 and H2 transportation usually constitutes a major and time-consuming undertaking, because of safety and environmental issues, legal and (geo)political siting arguments, technically un-trivial installation processes, and/or high investment cost requirements. In this paper we focus on the latter and present an overview of both the total costs and cost components of the transmission of these three gases via pipelines. Possible intricacies and external factors that strongly influence these costs, like the choice of location and terrain, are also included in our analysis. Our cost breakdown estimates are based on transportation data for CH4, which we adjust for CO2 and H2 in order to account for the specific additional characteristics of these two gases. Our main finding is that the economics of CH4, CO2 and H2 transportation through pipelines are volatile. In particular for CH4 and CO2 the overall trend seems that pipeline construction costs have not decreased over recent decades or, at least, that possible reductions in overall costs have been outshadowed by the variability in the costs of key inputs. We speculate on the reasons why we observe limited learning-by-doing effects and expect that negligible construction cost reductions for future CH4 and CO2 pipeline projects will materialize. Cost data of individual pipeline projects may strongly deviate from the global average because of national or regional effects, such as related to varying costs of labor and fluctuating market prices of components like steel. We conclude that only in an optimistic scenario we may observe learning effects for H2 pipeline construction activity in the future, but there are currently insufficient data to fully support the limited evidence for this claim, so that the uncertainty of this prediction for now remains large.
- Inorganic Nanofibers with Tailored Placement of Nanocatalysts for Hydrogen Production via Alkaline Hydrolysis of GlucoseN. Hansen, T.E. Ferguson, J.E. Panels, A.-H.A. Park, & Y.L. Joo | Nanotechnology, 2011-08-12 [+]
Abstract: Monoaxial silica nanofibers containing iron species as well as coaxial nanofibers with a pure silica core and a silica shell containing high concentrations of iron nanocrystals were fabricated via electrospinning precursor solutions, followed by thermal treatment. Tetraethyl-orthosilicate (TEOS) and iron nitrate (Fe(NO(3))(3)) were used as the precursors for the silica and iron phases, respectively. Thermal treatments of as-spun precursor fibers were applied to generate nanocrystals of iron with various oxidation states (pure iron and hematite). Scanning electron microscopy (SEM), x-ray diffraction (XRD), and transmission electron microscopy (TEM) were used to probe the fiber morphology and crystal structures. The results indicated that the size, phase, and placement of iron nanocrystals can be tuned by varying the precursor concentration, thermal treatment conditions, and processing scheme. The resulting nanofiber/metal systems obtained via both monoaxial and coaxial electrospinning were applied as catalysts to the alkaline hydrolysis of glucose for the production of fuel gas. Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and bulk weight change in a furnace with residual gas analysis (RGA) were used to evaluate the performance of the catalysts for various ratios of both Fe to Si, and catalyst to glucose, and the oxidation state of the iron nanocrystals. The product gas is composed of mostly H(2) (>96 mol%) and CH(4) with very low concentrations of CO(2) and CO. Due to the clear separation of reaction temperature for H(2) and CH(4) production, pure hydrogen can be obtained at low reaction temperatures. Our coaxial approach demonstrates that placing the iron species selectively near the fiber surface can lead to two to three fold reduction in catalytic consumption compared to the monoaxial fibers with uniform distribution of catalysts.
- Effects of Bonding Types and Functional Groups on CO2 Capture using Novel Multiphase System of Liquid-like Nanoparticle Organic Hybrid MaterialsK.A. Lin & A.-H.A. Park | Environmental Science and Technology, 2011-08-01 [+]
Abstract: Novel liquid-like nanoparticle organic hybrid materials (NOHMs) which possess unique features including negligible vapor pressure and a high degree of tunability were synthesized and their physical and chemical properties as well as CO(2) capture capacities were investigated. NOHMs can be classified based on the synthesis methods involving different bonding types, the existence of linkers, and the addition of task-specific functional groups including amines for CO(2) capture. As a canopy of polymeric chains was grafted onto the nanoparticle cores, the thermal stability of the resulting NOHMs was improved. In order to isolate the entropy effect during CO(2) capture, NOHMs were first prepared using polymers that do not contain functional groups with strong chemical affinity toward CO(2). However, it was found that even ether groups on the polymeric canopy contributed to CO(2) capture in NOHMs via Lewis acid-base interactions, although this effect was insignificant compared to the effect of task-specific functional groups such as amine. In all cases, a higher partial pressure of CO(2) was more favorable for CO(2) capture, while a higher temperature caused an adverse effect. Multicyclic CO(2) capture tests confirmed superior recyclability of NOHMs and NOHMs also showed a higher selectivity toward CO(2) over N(2)O, O(2) and N(2).
- Modeling Uncertainty and the Economics of Climate Change: Recommendations for Robust Energy PolicyA. Haurie, M. Tavoni, & B.C.C. van der Zwaan | Environmental Modeling and Assessment, 2011-07-15 [+]
Abstract: Economic analysis of climate change has become a fundamental instrument for the
multidisciplinary research of this global environmental challenge and is increasingly
used for informing the ongoing discussion between climate scientists and policy makers.
The formulation of climate policy is increasingly becoming reliant on the adequacy of
economic analysis, yet many of its aspects are left poorly understood. Both the scientific
and policy-making communities therefore agree that economic studies of climate
change ought to be perfected. Among the subjects that deserve further in-depth
investigation, the issue of uncertainty emerges as, perhaps, the most prominent.
- Moisture Swing Sorbent for Carbon Dioxide Capture from Ambient AirT. Wang, K.S. Lackner, & A. Wright | Environmental Science & Technology, 2011-06-20 [+]
Abstract: An amine-based anion exchange resin dispersed in a ﬂat sheet of polypropylene was prepared in alkaline forms so that it would capture carbon dioxide from air. The resin, with quaternary ammonium cations attached to the polymer structure and hydroxide or carbonate groups as mobile counterions, absorbs carbon dioxide when dry and releases it when wet. In ambient air, the moist resin dries spontaneously and subsequently absorbs carbon dioxide. This constitutes a moisture induced cycle, which stands in contrast to thermal pressure swing based cycles. This paper aims to determine the isothermal performance of
the sorbent during such a moisture swing. Equilibrium experiments show that the absorption and desorption process can be described well by a Langmuir isothermal model. The equilibrium partial pressure of carbon dioxide over the resin at a given loading state can be increased by 2 orders of magnitude by wetting the resin.
- Co-electrolysis of CO2 and H2O in Solid Oxide Cells: Performance and DurabilityC. Graves, S.D. Ebbesen, & M. Mogensen | Solid State Ionics, 2011-06-16 [+]
Abstract: This study examines the initial performance and durability of a solid oxide cell applied for co-electrolysis of CO2 and H2O. Such a cell, when powered by renewable/nuclear energy, could be used to recycle CO2 into sustainable hydrocarbon fuels. Polarization curves and electrochemical impedance spectroscopy were employed to characterize the initial performance and to break down the cell resistance into the resistance for the specific processes occurring during operation. Transformation of the impedance data to the distribution of relaxation times (DRT) and comparison of measurements taken under systematically varied test conditions enabled clear visual identification of five electrode processes that contribute to the cell resistance. The processes could be assigned to each electrode and to gas concentration effects by examining their dependence on gas composition changes and temperature.
This study also introduces the use of the DRT to study cell degradation without relying on a model. The durability was tested at consecutively higher current densities (and corresponding overpotentials). By analyzing the impedance spectra before and after each segment, it was found that at low current density operation (− 0.25 A/cm2 segment) degradation at the Ni/YSZ electrode was dominant, whereas at higher current densities (− 0.5 A/cm2 and − 1.0 A/cm2), the Ni/YSZ electrode continued to degrade but the serial resistance and degradation at the LSM/YSZ electrode began to also play a major role in the total loss in cell performance. This suggests different degradation mechanisms for high and low current density operation.
- The cost of pipelining climate change mitigation: An overview of the economics of CH4, CO2 and H2 transportationK. Schootsa, R. Rivera-Tinocoa., G. Verbong & B.C.C. van der Zwaan│Applied Energy, 2011-05-02 [+]
Gases like CH4, CO2 and H2 may play a key role in establishing a sustainable energy system: CH4 is the cleanest and least carbon-intensive among the fossil energy resources (that is, natural gas versus oil and coal); CO2 capture and storage can significantly reduce the climate footprint of especially fossil-based electricity generation; and the use of H2 as energy carrier could enable carbon-free automotive transportation. Yet the establishment of extensive distribution networks, required to transport these gases, is challenging. For instance the construction of large pipeline infrastructures usually constitutes a major and time-consuming undertaking, because of safety and environmental issues, legal and (geo)political siting arguments, technically un-trivial installation processes, and/or high investment cost requirements. In this paper we focus on the latter and present an overview of both the total costs and cost components of the distribution of these three gases via pipelines. Possible intricacies and external factors that strongly influence these costs, like the choice of location and terrain, are also included in our analysis. Our distribution cost breakdown estimates are based on transportation data for CH4, which we adjust for CO2 and H2 in order to account for the specific additional characteristics of these two gases. For CH4 and CO2 in any case the overall trend is that pipeline construction costs have more or less stabilized. For the purpose of designing energy policy and climate strategy we therefore know in principle with great reliability what the distribution cost components of future energy systems will be that rely on pipelining these gases. We speculate on the reasons why we observe limited learning-by-doing effects and expect that negligible construction cost reductions for future CH4 and CO2 pipeline projects will materialize. Cost data of individual pipeline projects may strongly deviate from the global average because of national or regional effects, such as related to varying costs of labor and fluctuating market prices of components like steel. We conclude that only in an optimistic scenario we may observe learning effects for H2 pipeline construction activity in the future, with a learning rate of around 20% – but the uncertainty of this prediction is large.
- US Tactical Nuclear Weapons in Europe after NATO’s Lisbon Summit: Why Their Withdrawal is DesirableT. Sauer & B.C.C. van der Zwaan | Belfer Center for Science and International Affairs, Harvard Kennedy School, 2011-05 [+]
Abstract: In this paper we describe how, over the past two decades, the usefulness of U.S.
tactical nuclear weapons that are forward-deployed in Europe has gradually declined,
and we explain the logic behind their decreased importance. We then list the main
arguments in favor of the continuation of this trend until they are completely eliminated
over the next couple of years, while subsequently investigating what the reasons are for
NATO’s desire to prolong its reliance on these weapons in the future. In the final part of
this paper, we analyze the political feasibility of their complete withdrawal, explain what
the political practicalities of such a withdrawal would be, and end with several
- Evaluating Uncertain CO2 Abatement over the Very Long TermR. Gerlagh & B.C.C. van der Zwaan | Environmental Modeling and Assessment, 2011-04-01 [+]
Abstract: Climate change research with the economic methodology of cost–benefit analysis is
challenging because of valuation and ethical issues associated with the long delays
between CO2 emissions and much of their potential damages, typically of several
centuries. The large uncertainties with which climate change impacts are known today
and the possibly temporary nature of some envisaged CO2 abatement options
exacerbate this challenge. For example, potential leakage of CO2 from geological
reservoirs, after this greenhouse gas has been stored artificially underground for climate
control reasons, requires an analysis in which the uncertain climatic consequences of
leakage are valued over many centuries. We here present a discussion of some of the
relevant questions in this context and provide calculations with the top–down energyenvironment-economy model DEMETER. Given the long-term features of the climate
change conundrum as well as of technologies that can contribute to its solution, we
considered it necessary extending DEMETER to cover a period from today until the
year 3000, a time span so far hardly investigated with integrated assessment models of
- The Impact of Uncertainty in Climate Targets and CO2 Storage Availability on Long-Term AbatementI. Keppo & B.C.C. van der Zwaan | Environmental Modeling and Assessment, 2011-04-01 [+]
Abstract: A major characteristic of our global interactive climate-energy system is the large
uncertainty that exists with respect to both future environmental requirements and the
means available for fulfilling these. Potentially, a key technology for leading the
transition from the current fossil fuel-dominated energy system to a more sustainable
one is carbon dioxide capture and storage. Uncertainties exist, however, concerning the
large-scale implementability of this technology, such as related to the regional
availability of storage sites for the captured CO2. We analyze these uncertainties from
an integrated assessment perspective by using the bottom-up model TIAM-ECN and by
studying a set of scenarios that cover a range of different climate targets and
technology futures. Our study consists of two main approaches: (1) a sensitivity analysis
through the investigation of a number of scenarios under perfect foresight decision
making and (2) a stochastic programming exercise that allows for simultaneously
considering a set of potential future states-of-the-world. We find that, if a stringent
climate (forcing) target is a possibility, it dominates the solution: if deep CO2 emission
reductions are not started as soon as possible, the target may become unreachable.
Attaining a stringent climate target comes in any case at a disproportionally high price,
which indicates that adaptation measures or climate damages might be preferable to
the high mitigation costs such a target implies.
- Moving Forward on Product Carbon Footprint StandardsL. Draucker, S. Kaufman, R. ter Kuile, & C.J. Meinrenken | Journal of Industrial Ecology, 2011-04 [+]
Abstract: Life cycle assessment (LCA) has come a long way, evolving from a niche activity
carried out by academics and a few forward-thinking businesses to a mainstream
practice talked about publicly by Fortune 500 companies. During this evolution, the
focus has shifted from multi-impact assessments to carbon footprints. Although other
impacts are equally important, the world's focus on greenhouse gases—and their
relative ease of calculation from an LCA perspective—will only increase the demand for
product carbon footprints (PCFs) in the coming years (Weidema et al. 2008).
This growth in PCF activity has fuelled a need for global standards that allow for greater
reliability of footprints. Although the ISO 14040/44 standards remain foundational for
LCA, they lack the prescriptiveness and carbon-specific accounting guidance needed to
produce consistent PCFs. Furthermore, for practitioners who are not classically trained,
these ISO standards are difficult to understand and correctly implement.
The ultimate aim of PCF is to identify and inform reduction opportunities for greenhouse
gases (GHGs). But without equipping real-world practitioners with the right tools and
guidance, we cannot facilitate measurable progress toward this goal. The result is an
increased risk of leaked emissions and other unintentional accounting inaccuracies that
limit the global ability to achieve real reductions—hence the need for PCF standards.
But what are these standards best suited to address? As organizations around the
world revise and publish new PCF standards, we have identified two loosely defined
types of issues whose solution requires interaction and understanding among standard
developers, business practitioners, and the scientific community.
- Layer Inversion and Mixing of Binary Solids in Two- and Three-Phase Fluidized BedsB.S. Chun, D.H. Lee, N. Epstein, J.R. Grace, A.-H.A. Park, S.D. Kim, J.K. Lee | Chemical Engineering Science, 2011-03-09 [+]
Abstract: Water fluidization in a 210 mm diameter semi-cylindrical acrylic column of a binary
solids mixture of 3.2 mm polymer beads (ρs=1280 kg/m3) and 0.385 mm glass beads
(ρs=2500 kg/m3) at superficial liquid velocities from 18.1 to 43.1 mm/s is shown to
generate layer inversion at a superficial liquid velocity, UL, of 33.1 mm/s. Introduction of
air with a superficial velocity, Ug, of 1.92 mm/s yielded a layer inversion velocity
at UL=30.4 mm/s. The latter is explainable if it is assumed that the determinant of layer
inversion is the interstitial liquid velocity and that therefore the main function of the gas
in this respect is to occupy space.
Mixing of the binary solids, as quantified by a mixing index applied to measured particle
compositions at different levels of the fluidized bed, is shown to be greatest at the layer
inversion velocity for liquid fluidization and, in general, to increase as co-current gas
flow increases at a fixed value of UL.
- Enhancing serpentine dissolution kinetics for mineral carbon dioxide sequestrationS.C.M. Krevor & K.S. Lackner | International Journal of Greenhouse Gas Control, 2011-01-20 [+]
Abstract: The current low-cost process for mineral carbonation involves the direct carbonation of
a slurry of magnesium or calcium silicate mineral with supercritical CO2. The process is
currently limited by the slow reaction kinetics of the carbonation reactions, and in
particular the slow dissolution rates of the silicates in weakly acidic conditions.
Enhancing the dissolution rate in weakly acidic conditions has been identified as one of
the main opportunities for lowering the costs of a direct mineral carbonation process.
Serpentine has been identified by its reactivity and abundance as a potential mineral for
use in a mineral carbonation process. In this paper we discuss the results of dissolution
experiments in which ground serpentine was reacted in weakly acidic aqueous systems
containing NH4Cl, NaCl,, sodium citrate, sodium EDTA, sodium oxalate, and sodium
acetate. All experiments are carried out at 120 C and under 20 bars of CO2 in a batch
autoclave. It was found that the sodium salts of citrate, oxalate, and EDTA significantly
enhance the dissolution of serpentine under weakly acidic conditions.
- Sustainable Hydrocarbon Fuels by Recycling CO2 and H2O with Renewable or Nuclear EnergyC. Graves, S.D. Ebbesen, M. Mogensen, & K.S. Lackner | Renewable and Sustainable Energy Reviews, 2011-01 [+]
Abstract: To improve the sustainability of transportation, a major goal is the replacement of conventional petroleum-based fuels with more sustainable fuels that can be used in the existing infrastructure (fuel distribution and vehicles). While fossil-derived synthetic fuels (e.g. coal derived liquid fuels) and biofuels have received the most attention, similar hydrocarbons can be produced without using fossil fuels or biomass. Using renewable and/or nuclear energy, carbon dioxide and water can be recycled into liquid hydrocarbon fuels in non-biological processes which remove oxygen from CO2 and H2O (the reverse of fuel combustion). Capture of CO2 from the atmosphere would enable a closed-loop carbon-neutral fuel cycle.
This article critically reviews the many possible technological pathways for recycling CO2 into fuels using renewable or nuclear energy, considering three stages—CO2 capture, H2O and CO2 dissociation, and fuel synthesis. Dissociation methods include thermolysis, thermochemical cycles, electrolysis, and photoelectrolysis of CO2 and/or H2O. High temperature co-electrolysis of H2O and CO2 makes very efficient use of electricity and heat (near-100% electricity-to-syngas efficiency), provides high reaction rates, and directly produces syngas (CO/H2 mixture) for use in conventional catalytic fuel synthesis reactors. Capturing CO2 from the atmosphere using a solid sorbent, electrolyzing H2O and CO2 in solid oxide electrolysis cells to yield syngas, and converting the syngas to gasoline or diesel by Fischer–Tropsch synthesis is identified as one of the most promising, feasible routes.
An analysis of the energy balance and economics of this CO2 recycling process is presented. We estimate that the full system can feasibly operate at 70% electricity-to-liquid fuel efficiency (higher heating value basis) and the price of electricity needed to produce synthetic gasoline at U.S.D$ 2/gal ($ 0.53/L) is 2–3 U.S. cents/kWh. For $ 3/gal ($ 0.78/L) gasoline, electricity at 4–5 cents/kWh is needed. In some regions that have inexpensive renewable electricity, such as Iceland, fuel production may already be economical. The dominant costs of the process are the electricity cost and the capital cost of the electrolyzer, and this capital cost is significantly increased when operating intermittently (on renewable power sources such as solar and wind). The potential of this CO2 recycling process is assessed, in terms of what technological progress is needed to achieve large-scale, economically competitive production of sustainable fuels by this method.
- Hydrogen permeability of Pd–Ag membrane modules with porous stainless steel substratesD. Xie, J. Yu, F. Wang, N. Zhang, W. Wang, , H. Yu, F. Peng, & A.-H.A. Park | International Journal of Hydrogen Energy, 2011-01 [+]
Abstract: Palladium-based membranes are attractive for their nearly perfect permselectivity to hydrogen. Membrane modules, consisting of a membrane foil, porous stainless steel substrate, test frame and flange were assembled and tested in an electrically heated vessel. Instantaneous hydrogen permeation flux was measured. Influences of operation conditions on the membrane performance were examined. Microstructure and morphology of the membrane surface and the cross-sectional surface of the substrate and membrane foil were characterized by scanning electron microscopy. It was observed that for an operation temperature higher than 755 K, the hydrogen permeation flux through the membrane module with 0.2 μm grade porous 316L stainless steel substrate decayed continuously due to the inter-metallic diffusion between the membrane and the substrate. For a temperature of around 869 K–943 K, a stable hydrogen permeation flux through the membrane module with 0.5 μm grade stainless steel substrate was observed. Pretreatment of the 0.5 μm grade substrate with polishing and etching helped to smooth the membrane foil surface. However, it changed the surface structure of the material and led to a decrease in hydrogen permeability. Under the conditions investigated, the permeation factor of the module increased by raising the hydrogen pressure in the vessel side and decreasing the membrane module temperature. By decreasing the hydrogen exit partial pressure by sweep gas, the membrane module permeation flux increased, while the permeation factor decreased.
- Two phase brine-CO2 flow experiments in synthetic and natural mediaJ. Levine, J. Matter, D. Goldberg, K.S. Lackner, M. Supp, & T.S. Ramakrishnan | Energy Procedia, 2011 [+]
Abstract: Industrial scale injection of anthropogenic carbon dioxide into the crustal lithosphere has
been proposed to reduce atmospheric accumulation. Much of this injection is expected
to occur in saline reservoirs. An understanding of two-phase brine- CO2 flow is
necessary for predicting storage capacity, fluid migration, and injectivity in geologic
reservoirs. Additionally, the chemical reactivity of the rock matrix with CO2(l) affects the
transport properties of the rock. A flow system for measuring two-phase transport of
CO2 and brine is presented in this paper. The system is capable of displacing brine with
either liquid or supercritical CO2. Special effort was taken to circumvent capillary end-effects in these experiments. Drainage end point relative permeability of CO2 displacing
brine is found to be in the range of 0.34–0.44, much lower than what is expected for a
nonwetting fluid. Such low relative permeabilities would tend to decrease injectivity
while increasing displacement efficiency.
- The Case for Carbon Capture and StorageK.S. Lackner | Process engineering for CCS Power Plants, 2011 [+]
Abstract: For a world of 10 billion people to achieve a decent standard of living, a prerequisite for
political stability and a requirement for curbing population growth, society will need
access to far more energy than it has today. Efficiency and conservation can reduce the
growth in energy demand, but they cannot stop it. However, concerns over climate
change will limit the use of fossil fuels. Fossil fuel consumption is the most important
contributor to climate change because of the associated carbon dioxide emissions.
While the oxidation of carbon is the unavoidable consequence of extracting energy from
fossil carbon, the subsequent emission could be avoided by capturing the carbon
dioxide and storing it permanently.
- Storage of Fossil CarbonK.S. Lackner | Process engineering for CCS Power Plants, 2011
- Composite electrolyte membranes for high temperature CO2 separationJ.L. Wade, C. Lee, A.C. West, & K.S. Lackner | Journal of Membrane Science, 2010-11-03 [+]
Abstract: A membrane device that can selectively separate CO2 at temperatures exceeding 600
°C has been demonstrated. The membrane can be made from a composite material
made of a molten carbonate electrolyte that fills the pore space in a solid oxide
electrolyte (e.g. yttria doped zirconia (YSZ), or gadolinia doped ceria (CGO)). The
experimental evidence points to a transport mechanism based on opposing ionic
currents of carbonate and oxide ions. The flux of CO2 across these membranes has
been shown to increase with temperature, reaching permeabilities of 10−11 mol m−1
s−1 Pa−1 (or permeance of 3 × 10−8 mol m−2 s−1 Pa−1) at 850 °C. The use of a nonion conducting solid oxide, Al2O3, does not result in strong CO2 permeability or
selectivity, supporting a facilitated dual-ion transport mechanism.
- High Efficiency Nanocomposite Sorbent for CO2 Capture based on Amine-Functionalized Mesoporous CapsulesG. Qi, Y. Wang, L. Estavez, X. Duan, N. Anako, A.-H.A. Park, W. Li, C.W. Jones, & E.P. Giannelis | Energy & Environmental Science, 2010-10-18 [+]
Abstract: A novel high efficiency nanocomposite sorbent for CO2 capture has been developed based on oligomeric amine (polyethylenimine, PEI, and tetraethylenepentamine, TEPA) functionalized mesoporous silica capsules. The newly synthesized sorbents exhibit extraordinary capture capacity up to 7.9 mmol g−1 under simulated flue gas conditions (pre-humidified 10% CO2). The CO2 capture kinetics were found to be fast and reached 90% of the total capacities within the first few minutes. The effects of the mesoporous capsule features such as particle size and shell thickness on CO2 capture capacity were investigated. Larger particle size, higher interior void volume and thinner mesoporous shell thickness all improved the CO2 capacity of the sorbents. PEI impregnated sorbents showed good reversibility and stability during cyclic adsorption–regeneration tests (50 cycles).
- Novel Applications of Chemical Looping TechnologiesA.-H.A. Park, P. Gupta, F. Li, D. Sridhar, & L.-S. Fan | Chemical Looping Systems for Fossil Energy Conversions, 2010-08-27
- A review of emerging technologies for sustainable use of coal for power generationT.M. Yegulalp, K.S. Lackner, & H.-J. Ziock | International Journal of Surface Mining, Reclamation and Environment, 2010-08-09 [+]
Abstract: Concerns about climate change and environmental consequences of increased levels of atmospheric CO 2 will require the power generation industry to reduce CO 2 emissions from current levels. Unfortunately, for reductions to have the desired effect they will have to be large. While the schedule of the Kyoto Protocol may appear daunting, in the long term mere compliance with the protocol will hardly change the rate of increase of atmospheric CO 2. There are, however, technical, economical and practical choices that will allow the industry to meet the requirements of protocol and ultimately stop the increase in atmospheric CO 2 without eliminating coal from the fuel mix. In this paper, we present a review of current and emerging technologies for CO 2 sequestration. We provide a summary of the underlying scientific principles and discuss the practical and economic aspects of sequestration technologies, which will allow continuing use of global coal resources with minimum or no impact on CO 2 levels in the atmosphere.
- Washing Carbon out of the AirK.S. Lackner | Scientific American, 2010-06 [+]
--Machines with filters made from sorbent materials can bind carbon dioxide, extracting it from the air.
--With mass production,machines might capture CO2 at $30 a ton, less than the $100 or more charged for commercial CO2 supply.
--With improved sorbents, 10 million machines across the planet could reduce CO2 concentration by five parts per million a year, more than the rate of global increase right now.
- Durability testing modified compression ignition engines fueled with straight plant oilM. Basinger, T. Reding, F.S. Rodriguez-Sanchez, K.S. Lackner, & V. Modi | Energy, 2010-05-10 [+]
Abstract: Many short-run studies point to the potential for direct fueling of compression ignition
engines with plant oil fuels. There is a much smaller body of work that examines the
potential for these fuels in long-run tests that illuminate engine endurance and longevity
issues. Generally, longevity studies involving direct fueling of engines with straight plant
oils have shown significant impact to the life of the engine, though test results vary
widely depending on the oil, engine type, test conditions, and measurement approach.
This study utilizes a previously designed modification kit to investigate the longevity
implications of directly fueling straight plant oil in an indirect injection (IDI) listeroid type,
slow speed stationary engine common in agro-processing applications in developing
countries. Specifically this study focuses on the lubrication oil by developing a model to
characterize the engine wear and estimate lube oil change frequency. The model is
extended to an analysis of the piston rings. Cylinder liner wear, emissions, engine
performance, and a visual investigation of several critical engine components are also
The 500 hour test with waste vegetable oil fuel resulted in several important findings.
The engine break-in period was identified as taking between 200 and 300 h. Emissions
analysis supported the break-in definition as smoke opacity and carbon monoxide
values fell from 9% and 600 ppm (respectively) during the first few hundred hours, to
5% and 400 ppm in the final 200 h. Lubrication oil viscosity was found to be the limiting
degradation factor in the lube oil, requiring oil to be changed every 110 h. Piston ring
mass loss was found to correlate very closely with chromium buildup in the lubrication
oil and the mathematical model that was developed was used to estimate that piston
ring inspection and replacement should occur after 1000 h. Cylinder ovalisation was
found to be most sever at top dead center (TDC) at 53 microns of averaged increased
- Compression ignition engine modifications for straight plant oil fueling in remote contextsM. Basinger, T. Reding, C. Williams, K.S. Lackner, & V. Modi | Fuel, 2010-05-04 [+]
Abstract: Though many plant oils have a similar energy density to fossil diesel fuel, several
properties of plant oils are considerably different from those of diesel. Engine
modifications can overcome some of these differences. An engine modification kit has
been designed and tested for a slow speed, stationary, indirect-injection diesel engine –
the Lister-type CS 6/1, common throughout the developing world. The kit allows waste
vegetable oil fueling with similar performance to that of diesel fueling. The kit’s simple
yet robust design is targeted for use as a development mechanism, allowing remote
farmers to use locally grown plant oils as a diesel substitute.
The modification kit includes a preheating system and the tuning of the injector pressure
and timing to better atomize given the unique properties of straight plant oils. The
design methodology for the modifications is detailed and a suite of performance test
results are described including fuel consumption, efficiency, pre-combustion chamber
pressure, and various emissions. The results of the study show how a combination of
preheating the high pressure fuel line, advancing the injector timing and increasing the
injector valve opening pressure allows this engine to efficiently utilize plant oils as a
diesel fuel substitute, potentially aiding remote rural farmers with a lower cost,
sustainable fuel source – enabling important agro-processing mechanization in parts of
the world that needs it most.
- Air Capture and Mineral Sequestration: Tools for Fighting Climate ChangeK.S. Lackner | Testimony for the US House of Representatives Committee on Science and Technology, 2010-03-18
- Large scale disposal of waste sulfur: From sulfide fuels to sulfate sequestrationT.A. Rappold & K.S. Lackner | Energy, 2010-03 [+]
Abstract: Petroleum industries produce more byproduct sulfur than the market can absorb.
As a consequence, most sulfur mines around the world have closed down, large
stocks of yellow sulfur have piled up near remote operations, and growing
amounts of toxic H2S are disposed of in the subsurface. Unless sulfur demand
drastically increases or thorough disposal practices are developed, byproduct
sulfur will persist as a chemical waste problem on the scale of 10^7 tons per year.
We review industrial practices, salient sulfur chemistry, and the geochemical
cycle to develop sulfur management concepts at the appropriate scale. We
contend that the environmentally responsible disposal of sulfur would involve
conversion to sulfuric acid followed by chemical neutralization with equivalent
amounts of base, which common alkaline rocks can supply cheaply. The
resulting sulfate salts are benign and suitable for brine injection underground or
release to the ocean, where they would cause minimal disturbance to
ecosystems. Sequestration costs can be recouped by taking advantage of the
fuel-grade thermal energy released in the process of oxidizing reduced
compounds and sequestering the products. Sulfate sequestration can eliminate
stockpiles and avert the proliferation of enriched H2S stores underground while
providing plenty of carbon-free energy to hydrocarbon processing.
- Comparative Impacts of Fossil Fuels and Alternative Energy SourcesK.S. Lackner | Carbon Capture: Sequestration and Storage, 2010
- Closing the Carbon Cycle: Liquid Fuels from Air, Water and SunshineK.S. Lackner, C.J. Meinrenken, E. Dahlgren, C. Graves, & T. Socci, 2010 [+]
This document was originally written as an application for the U.S. DOE funding opportunity
“Energy Innovation Hub – Fuels from Sunlight” (DE-FOA-0000214).
Abstract: This paper outlines proposed advancements of a coherent set of technologies for a solar-powered system that uses water and CO2 from ambient air to provide sustainable fuels to the world. These fuels would be synthetic liquid hydrocarbons that could power cars, trucks, aircraft, diesel-electric trains and generators, and heat residential and commercial buildings, without changes to current engine
technology or fuel distribution infrastructure, and at costs competitive with fossil-based fuels. The
explicit goal is to deliver an end-to-end solution for a complete sunlight-to-fuels system, including
associated technologies for cost-efficient construction, operation and maintenance. This focus will aid
cost-effectiveness and accelerate the transition to market. If desired, the system could also produce
electricity, fresh water, and non-fuel hydrocarbons (e.g., plastics), thus further strengthening its
economic viability. Fully developed, such a system could satisfy global demand for convenient fuel –
yet would operate entirely on carbon recycled from the air, locally-available water, and sunlight.
- Tailored Synthesis of Precipitated Magnesium Carbonates as Carbon-Neutral Filler Materials during Carbon Mineral SequestrationH. Zhao, N. Dadap, & A.-H.A. Park | Fluidization XIII, 2010 [+]
Abstract: Predictions of global energy usage and demand trends suggest that fossil fuels will remain as the main energy source for the foreseeable future. Unfortunately, the increased amount of anthropogenic carbon emitted during the energy production leads to environmental issues, including climate change. Thus, reducing carbon dioxide emissions in order to stabilize atmospheric CO2 levels is crucial, and this would not be achieved without significant changes in the energy conversion processes and the implementation of carbon capture and storage (CCS) technologies. Currently, the geological storage of carbon dioxide is considered to be the most economical method of carbon sequestration, while mineral carbonation is a relatively new and less explored method of sequestering CO2. The advantage of carbon mineral sequestration is that it is the most permanent and safe method of carbon storage, since the gaseous carbon dioxide is fixed into a solid matrix of Mg-bearing minerals (e.g., serpentine) forming a thermodynamically stable solid product. The current drawback of carbon mineral sequestration is its relatively high cost. Therefore, this study focuses on tailored synthesis of high purity precipitated magnesium carbonate (PMC) to mimic commercially available CaCO3-based filler materials, while sequestering CO2. The effects of pH, reaction time and reaction temperature on the mean particle size, particle size distribution, and particle morphological structures, have been investigated for the synthesis of magnesium carbonates as carbon-neutral filler materials.
- Synthesis of Iron-based Chemical Looping Sorbents Integrated with pH Swing Carbon Mineral SequestrationH.R. Kim, D.H. Lee, L.-S. Fan, & A.-H.A. Park | Journal of Nanoscience and Nanotechnology, 2009-12-09 [+]
Abstract: The previously developed pH swing carbon mineral sequestration immobilizes the gaseous CO2 into a thermodynamically stable solid, MgCO3, using Mg-bearing minerals such as serpentine. This mineral carbonation technology is particularly promising since it generates value-added solid products: high surface area silica, iron oxide, and magnesium carbonate, while providing a safe and permanent storage option for CO2. By carefully controlling the pH of the system, these solids products can be produced with high purity. This study focuses on the synthesis of iron oxide particles as a chemical looping sorbent in order to achieve the integration between carbon capture and storage technologies. Since the solubility of Fe in aqueous phase is relatively low at neutral pH, the effect of the weak acid and chelating agents on the extraction of Fe from serpentine was investigated. The synthesized iron-based chemical looping sorbent was found to be as effective as commercially available iron oxide nanoparticles at converting syngas into high purity H2, while producing a sequestration-ready CO2 stream.
- Production of Synthetic Fuels by Co-Electrolysis of Steam and Carbon DioxideS.D. Ebbesen, C. Graves, & M. Mogensen | International Journal of Green Energy, 2009-12-09 [+]
Co-electrolysis of H2O and CO2 was studied in solid oxide cells (SOCs) supported by nickel-/yittria-stabilized zirconia (Ni/YSZ) electrode. Polarization characterization indicates that electrochemical reduction of both CO2 and H2O occurs during co-electrolysis. In parallel with the electrochemical reactions, the equilibrium of the water–gas shift reaction is reached, and moreover, CO is produced via the water–gas shift reaction. The degradation observed when performing co-electrolysis in these SOCs occurs mainly at the Ni/YSZ cathode and may be a consequence of impurities in the gas stream, adsorbing on active sites in the SOC. The low degradation is most likely acceptable for long-time operation.
- Envisioning carbon capture and storage: expanded possibilities due to air capture, leakage insurance, and C-14 monitoringK.S. Lackner & S. Brennan | Climatic Change, 2009-10 [+]
In order to meet the challenge of climate change while allowing for continued economic development, the world will have to adopt a net zero carbon energy infrastructure. Due to the world’s large stock of low-cost fossil fuels, there is strong motivation to explore the opportunities for capturing the CO2 that is produced in the combustion of fossil fuels and keeping it out of the atmosphere. Three distinct sets of technologies are needed to allow for climate neutral use of fossil fuels: (1) capture of CO2 at concentrated sources like electric power plants, future hydrogen production plants and steel and cement plants; (2) capture of CO2 from the air; and (3) the safe and permanent storage of CO2 away from the atmosphere. A strong regime of carbon accounting is also necessary to gain the public’s trust in the safety and permanence of CO2 storage. This paper begins with an extensive overview of carbon capture and storage technologies, and then presents a vision for the potential implementation of carbon capture and storage, drawing upon new ideas such as air capture technology, leakage insurance, and monitoring using a radioactive isotope such as C-14. These innovations, which may provide a partial solution for managing the risks associated with long-term carbon storage, are not well developed in the existing literature and deserve greater study.
- Capture of carbon dioxide from ambient airK.S. Lackner | The European Physical Journal, 2009-09 [+]
Abstract: Carbon dioxide capture from ambient air could compensate for all carbon dioxide emissions to the atmosphere. Such capture would, for example, make it possible to use liquid, carbon-based fuels in cars or airplanes without negatively impacting the climate. We present a specific approach based on a solid sorbent in the form of an anionic exchange resin, that absorbs carbon dioxide when dry and releases it when exposed to moisture. We outline a particular implementation of such a moisture swing and discuss the scale of the collectors, the energy consumption, and the indirect carbon dioxide emissions related to the operation of carbon dioxide capture devices.
- Water–rock interactions during a CO2 injection field-test: Implications on host rock dissolution and alteration effectsN. Assayag, J.M. Matter, M. Ader, D. Goldberg, & P. Agrinier | Chemical Geology, 2009-07-15 [+]
Abstract: We investigated the nature and rates of in-situ CO2–fluid–rock reactions during an aqueous phase CO2 injection test. Two push–pull test experiments were performed at the Lamont–Doherty Earth Observatory test site (New York, USA): a non reactive control test without CO2 addition and a reactive test with CO2 equilibrated with the injected solution at a partial pressure of 1.105 Pa. The injected solution contained chemical and isotopic conservative tracers (NaCl and 18O) and was injected in an isolated and permeable interval at approximately 250 m depth. The injection interval was located at the contact zone between the Palisades sill (chilled dolerite) and the underlying metamorphic Newark Basin sediments and the injected solution incubated within this interval for roughly 3 weeks. Physico-chemical parameters were measured on the surface (pH, temperature, electrical conductivity) and water samples were collected for chemical (Dissolved Inorganic Carbon — DIC, major ions) as well as for isotopic (δ13CDIC, δ18O) analyses.
For the control test, post-injection chemical and isotopic compositions of recovered water samples display mixing between the background water and the injected solution. For the reactive CO2 test, observed δ13CDIC and DIC both increase, and enrichment in Ca2+, Mg2+, K+ allow for quantification of the chemical pathways through which aqueous CO2 and subsequent H2CO3 were converted into HCO3−. Dissolution of carbonate minerals was the dominant H2CO3 neutralization process (≈ 52 ± 7%), followed by cation exchange and/or dissolution of silicate minerals (≈ 45 ± 10%, for both processes), and to a minor extent, mixing of the injected solution with the formation water (≈ 3 ± 1%). The results confirm the rapid dissolution kinetics of carbonate minerals compared to those of basic silicate minerals. However, our results remain marked by uncertainties due to the natural variability of the background water composition, in mass balance calculations. These experiments imply that the use of accurate DIC measurements can quantify the relative contribution of CO2–fluid–rock reactions and evaluate the geochemical trapping potential for CO2 storage in reactive reservoir environments.
- CO2 capture and storage with leakage in an energy-climate modelB.C.C. van der Zwaan & K. Smekens | Environmental Modeling and Assessment, 2009-04 [+]
Abstract: Geological CO2 capture and storage (CCS) is among the main near-term
contenders for addressing the problem of global climate change. Even in a
baseline scenario, with no comprehensive international climate policy, a
moderate level of CCS technology is expected to be deployed, given the
economic benefits associated with enhanced oil and gas recovery. With stringent
climate change control, CCS technologies will probably be installed on an
industrial scale. Geologically stored CO2, however, may leak back to the
atmosphere, which could render CCS ineffective as climate change reduction
option. This article presents a long-term energy scenario study for Europe, in
which we assess the significance for climate policy making of leakage of CO2
artificially stored in underground geological formations. A detailed sensitivity
analysis is performed for the CO2 leakage rate with the bottom-up energy
systems model MARKAL, enriched for this purpose with a large set of CO2
capture technologies (in the power sector, industry, and for the production of
hydrogen) and storage options (among which enhanced oil and gas recovery,
enhanced coal bed methane recovery, depleted fossil fuel fields, and aquifers).
Through a series of model runs, we confirm that a leakage rate of 0.1%/year
seems acceptable for CCS to constitute a meaningful climate change mitigation
option, whereas one of 1%/year is not. CCS is essentially no option to achieve
CO2 emission reductions when the leakage rate is as high as 1%/year, so more
reductions need to be achieved through the use of renewables or nuclear power,
or in sectors like industry and transport. We calculate that under strict climate
control policy, the cumulative captured and geologically stored CO2 by 2100 in
the electricity sector, when the leakage rate is 0.1%/year, amounts to about
45,000 MtCO2. Only a little over 10,000 MtCO2 cumulative power-generation related emissions are captured and stored underground by the end of the century when the leakage rate is 1%/year. Overall marginal CO2 abatement costs
- Gravitational trapping of carbon dioxide in deep ocean sediments: hydraulic fracturing and mechanical stabilityJ.S. Levine, J. M. Matter, D. Goldberg, & K.S. Lackner | Energy Procedia, 2009-02 [+]
Abstract: Gravitational trapping of carbon dioxide in deep ocean sediments is attractive both for the long term stability provided by gravity as well as the large volume and hence storage capacity of deep ocean sediments at necessary depths. Unfortunately, most pelagic sediments suffer from extremely low permeability and are not expected to have an overlying mechanical seal, making emplacement of CO2 contingent upon large scale hydraulic fracturing and some mechanism of arresting fracture growth before reaching the seafloor. An experimental design is presented with the capability of testing a variety of proposed fracture arrest mechanisms.
- Enhancing process kinetics for mineral carbon sequestrationS.C. Krevor & K.S. Lackner | Energy Procedia, 2009-02 [+]
Abstract: The current low-cost process for mineral carbonation involves the direct carbonation of
a slurry of magnesium or calcium silicate mineral with supercritical CO2. The process is
currently limited by the slow reaction kinetics of the carbonation reactions, and in
particular the slow dissolution rates of the silicates in weakly acidic conditions.
Enhancing the dissolution rate in weakly acidic conditions has been identified as one of
the main opportunities for lowering the costs of a direct mineral carbonation process.
Serpentine has been identified by its reactivity and abundance as a potential mineral for
use in a mineral carbonation process. In this paper we discuss the results of dissolution
experiments in which ground serpentine was reacted in weakly acidic aqueous systems
containing NH4Cl, NaCl,, sodium citrate, sodium EDTA, sodium oxalate, and sodium
acetate. All experiments are carried out at 120 C and under 20 bars of CO2 in a batch
autoclave. It was found that the sodium salts of citrate, oxalate, and EDTA significantly
enhance the dissolution of serpentine under weakly acidic conditions.
- Permanent carbon dioxide storage into basalt: The CarbFix pilot project, IcelandJ. M. Matter, W.S. Broecker, M. Stute, S.R. Gislason, E.H. Oelkers, A. Stefansson, et al. | Energy Procedia, 2009-02 [+]
The storage of large volumes of industrial CO2 emissions in deep geological
formations is one of the most promising climate mitigation options. The long-term
retention time and environmental safety of the CO2 storage are defined by the
interaction of the injected CO2 with the reservoir fluids and rocks. Finding a
storage solution that is long lasting, thermodynamically stable and
environmentally benign would be ideal. Storage of CO2 as solid magnesium or
calcium carbonates in basaltic rocks may provide such a long-term and
thermodynamically stable solution. Basaltic rocks, which primarily consist of
magnesium and calcium silicate minerals, provide alkaline earth metals
necessary to form solid carbonates. In nature, the carbonization of basaltic rocks
occurs in several well-documented settings, such as in the deep ocean crust,
through hydrothermal alteration and through surface weathering. The goal of the
CarbFix pilot project is to optimize industrial methods for permanent storage of
CO2 in basaltic rocks. The objective is to study the in-situ mineralization of CO2
and its long term fate. The project involves the capture and separation of flue
gases at the Hellisheidi Geothermal Power Plant, the transportation and injection
of the CO2 gas fully dissolved in water at elevated pressures at a depth between
400 and 800 m, as well as the monitoring and verification of the storage. A
comprehensive reservoir characterization study is on-going prior to the CO2
injection, including soil CO2 flux measurements, geophysical survey and tracer
injection tests. Results from the tracer tests show significant tracer dispersion
within the target formation, suggesting large surface area for chemical reactions.
The large available reservoir volume and surface area in combination with
relatively rapid CO2-water-rock reactions in basaltic rocks may allow safe and
permanent geologic storage of CO2 on a large scale.
- Economic dimensions of geological CO2 storage: Key factors in an assessment of sub-seafloor and continental sequestration optionsS. Capalbo, C. Wu, D. Goldberg, J. Matter, & A. Slagle | Energy Procedia, 2009-02 [+]
Abstract: Geological sequestration offers long term storage opportunities that differ in terms of technical capacity and characteristics, and in terms of economic costs and benefits. In this paper we outline a simple economic framework that reflects the planning problem for sequestering CO2 in alternative geological sinks and highlights the differences in the environmental risks and the economic costs of alternative sinks. The marginal costs of alternative geological sequestration options must be compared to measures of marginal benefits that take into account the probability of local and global environmental risks and other regulatory requirements. We direct our discussion of an application of this framework to the case of geological sequestration in deep-sea basalts and provide an initial assessment of how this framework could be implemented to quantify the long-term economic costs relative to other continental geological storage options.
- Mapping the mineral resource base for mineral carbon-dioxide sequestration in the conterminous USS.C. Krevor, C. Graves, B.S.V. Gosen, and A.E. McCafferty | U.S. Geological Survey, 2009 [+]
Abstract: This database provides information on the occurrence of ultramafic rocks in the conterminous United States that are suitable for sequestering captured carbon dioxide in mineral form, also known as mineral carbon-dioxide sequestration.
Mineral carbon-dioxide sequestration is a proposed greenhouse gas mitigation technology whereby carbon dioxide (CO2) is disposed of by reacting it with calcium or magnesium silicate minerals to form a solid magnesium or calcium carbonate product. The technology offers a large capacity to permanently store CO2 in an environmentally benign form via a process that takes little effort to verify or monitor after disposal. These characteristics are unique among its peers in greenhouse gas disposal technologies.
The 2005 Intergovernmental Panel on Climate Change report on Carbon Dioxide Capture and Storage suggested that a major gap in mineral CO2 sequestration is locating the magnesium-silicate bedrock available to sequester the carbon dioxide. It is generally known that silicate minerals with high concentrations of magnesium are suitable for mineral carbonation. However, no assessment has been made in the United States that details their geographical distribution and extent, nor has anyone evaluated their potential for use in mineral carbonation.
Researchers at Columbia University and the U.S. Geological Survey have developed a digital geologic database of ultramafic rocks in the conterminous United States. Data were compiled from varied-scale geologic maps of magnesium-silicate ultramafic rocks. The focus of our national-scale map is entirely on ultramafic rock types, which typically consist primarily of olivine- and serpentine-rich rocks. These rock types are potentially suitable as source material for mineral CO2 sequestration.
- Conceptual design of a sulfur sequestration process using alkaline mineralsT. A. Rappold and K. S. Lackner | International Petroleum Technology Conference, 2008-12-03
- In situ carbonation of peridotite for CO2 storageP. Kelemen, & J.M. Matter | Proceedings of the National Academy of Sciences, 2008-11-11 [+]
Abstract: The rate of natural carbonation of tectonically exposed mantle peridotite during
weathering and low-temperature alteration can be enhanced to develop a
significant sink for atmospheric CO2. Natural carbonation of peridotite in the
Samail ophiolite, an uplifted slice of oceanic crust and upper mantle in the
Sultanate of Oman, is surprisingly rapid. Carbonate veins in mantle peridotite in
Oman have an average C14 age of ≈26,000 years, and are not 30–95 million
years old as previously believed. These data and reconnaissance mapping show
that ≈10^4 to 10^5 tons per year of atmospheric CO2 are converted to solid
carbonate minerals via peridotite weathering in Oman. Peridotite carbonation can
be accelerated via drilling, hydraulic fracture, input of purified CO2 at elevated
pressure, and, in particular, increased temperature at depth. After an initial
heating step, CO2 pumped at 25 or 30 °C can be heated by exothermic
carbonation reactions that sustain high temperature and rapid reaction rates at
depth with little expenditure of energy. In situ carbonation of peridotite could
consume >1 billion tons of CO2 per year in Oman alone, affording a low-cost,
safe, and permanent method to capture and store atmospheric CO2.
- Field observations and theoretical studies relevant to enhance in situ carbonation of peridotiteP.B. Kelemen, J. Matter, & L. Streit | International Conference on Accelerated Carbonation for Environmental and Materials Engineering, 2008-10-01 [+]
Abstract: Veins formed by carbonation of peridotite in the large thrust sheet of mantle peridotite in the Sultanate of Oman are ~ 1000 times younger than previously believed, occurring mainly in a relatively shallow weathering horizon (Kelemen & Matter, 2008). Accelerating this process via drilling and rock fracture, plus heating, could provide a globally significant sink for atmospheric CO2. Exothermic carbonation of olivine can reach a self-heating condition, in which heating due to reaction balances cooling due to advection and diffusion, maintaining temperature at an optimum value for rapid carbonation, ~ 10^6 faster than at 25°C (Kelemen & Matter, 2008). Volume changes due to carbonation can cause fracture that in turn exposes unreacted olivine and enhances permeability. We review work on natural peridotite carbonation, including recent observations of carbonate vein mineralogy and crack geometry in peridotites, relevant to evaluating and extending these hypotheses.
- Mineral carbonation of CO2E.H. Oelkers, S.R. Gislason, & J. Matter | Elements, 2008-10 [+]
Abstract: A survey of the global carbon reservoirs suggests that the most stable, long-term
storage mechanism for atmospheric CO2 is the formation of carbonate minerals
such as calcite, dolomite and magnesite. The feasibility is demonstrated by the
proportion of terrestrial carbon bound in these minerals: at least 40,000 times
more carbon is present in carbonate rocks than in the atmosphere. Atmospheric
carbon can be transformed into carbonate minerals either ex situ, as part of an
industrial process, or in situ, by injection into geological formations where the
elements required for carbonate-mineral formation are present. Many challenges
in mineral carbonation remain to be resolved. They include overcoming the slow
kinetics of mineral-fluid reactions, dealing with the large volume of source
material required and reducing the energy needed to hasten the carbonation
process. To address these challenges, several pilot studies have been launched,
including the CarbFix program in Iceland. The aim of CarbFix is to inject CO2 into
permeable basaltic rocks in an attempt to form carbonate minerals directly
through a coupled dissolution-precipitation process.
- Learning curves for hydrogen production technology: an assessment of observed cost reductionsK. Schoots, F. Ferioli, G.J. Kramer, & B.C.C. van der Zwaan | International Journal of Hydrogen Energy, 2008-06 [+]
Abstract: At present three key energy carriers have the potential to allow a transition towards a sustainable energy system: electricity, biofuels and hydrogen. All three offer great opportunity, but equally true is that each is limited in different ways. In this article we focus on the latter and develop learning curves using cost data observed during the period 1940–2007 for two essential constituents of a possible ‘hydrogen economy’: the construction of hydrogen production facilities and the production process of hydrogen with these facilities. Three hydrogen production methods are examined, in decreasing order of importance with regards to their current market share: steam methane reforming, coal gasification and electrolysis of water. The fact that we have to include data in our analysis that go far back in time, as well as the uncertainties that especially the older data are characterized by, render the development of reliable learning curves challenging. We find only limited learning at best in a couple of cases, and no cost reductions can be detected for the overall hydrogen production process. Of the six activities investigated, statistically meaningful learning curves can only be determined for the investment costs required for the construction of steam methane reforming facilities, with a learning rate of 11±6%, and water electrolysis equipment, with a learning rate of 18±13%. For past coal gasification facility construction costs no learning rate can be discerned. The learning rates calculated for steam methane reforming and water electrolysis equipment construction costs have large error margins, but lie well in the range of the learning reported in the literature for other technologies in the energy sector.
- Nuclear waste repository case studies: the NetherlandsB.C.C. van der Zwaan | Bulletin of the Atomic Scientists, 2008-05-19
- Carbon sequestrationA.-H.A. Park, K.S. Lackner, & L.-S. Fan | Hydrogen Fuel: Production, Transport and Storage, 2008
- Prospects for nuclear energy in EuropeB.C.C. van der Zwaan | International Journal of Global Energy Issues, 2008 [+]
Abstract: The aim of this paper is to add to the current debate about the role of nuclear power in
sustainable energy development, through an overview of its current status and future
prospects in Europe. In three time frames – until 2025, 2050, and 2100, respectively – the
main socio-economic and environmental concerns are analysed that nuclear energy could
contribute to alleviate, among which energy supply dependency, local air pollution, and
global climate change. Particular attention is paid to the five ‘classic’ problematic features of
nuclear energy, as applied to Europe, i.e. in terms of the challenges associated with
radioactive waste, proliferation security, operation safety, economic competitiveness, and
public acceptance. The main conclusion is that the coming couple of decades the installed
nuclear capacity in Europe is unlikely to change significantly, while the relative weights
associated with the benefits and drawbacks of nuclear power, as well as broader long-term
sustainability arguments related to the ensemble of all energy resources, will determine its
prospects beyond 2025.
- The importance of controlling carbon, not emissions or mpgK. S. Lackner & R. Wilson | Toxicology and Industrial Health, 2008 [+]
Abstract: In management of carbon dioxide concentrations in the atmosphere, the authors
argue that it is far superior to control upstream where the carbon leaves the
ground in a limited number of places than further downstream as carbon dioxide
is released in a myriad of locations. The authors note that none of the proposals
being discussed politically assure this, and they control sector by sector, allowing
undesirable room for special interests to be excluded from control.
- Particle TechnologyA.-H.A. Park, C. Zhu, & L.-S. Fan | Kirk-Othmer Encyclopedia of Chemical Technology, 2008
- Gravitational trapping of carbon dioxide in deep sea sediments: Permeability, buoyancy, and geomechanical analysisJ.S. Levine, J.M. Matter, D.M. Goldberg, A. Cook, & K.S. Lackner, 2007-12-21
- Investigation of electrostatic charging phenomenon in multiphase flows using the ECVT systemQ. Marashdeh, F. Wang, A.-H. A. Park & L.-S. Fan | American Institute of Chemical Engineers, 2007-11-04 [+]
Presentation given at the 2007 AIChE Annual Meeting.
- Validation of a population balance model for olivine dissolutionM. Hanchen, S. Krevor, M. Mazzotti, & K.S. Lackner | Chemical Engineering Science, 2007-11 [+]
The dissolution of silicate minerals, among them olivine, in water enables its
subsequent reaction with carbon dioxide to form magnesium carbonate, a
process called aqueous mineral carbonation. A general model for the dissolution
of olivine, based on a population balance approach, has been developed. For
this purpose, the dissolution rate of olivine has been measured as a function of
varying particle size and pH at 120º C. Three separate particle populations in
three different size ranges were used: a sub 90, a 90–180, and a 180–355 μm
size fraction. The pH was varied between 2 and 4.75 using HCl. Experiments
were carried out in a flow-through reactor under a nitrogen atmosphere of 20 bar.
The dissolution extent varied from 12% up to complete dissolution, depending on
experimental conditions. Particle size distributions of the different size fractions
were measured with a Coulter Multisizer®. Using the assumption of a surface
controlled reaction, the solution to the population balance equation was coupled
with a reactor model. Data were fitted to the model to obtain a shape modulated
dissolution rate. Including earlier published dissolution experiments an overall correlation for the dissolution rate was regressed. Using the general model, the limitations of the simplified model
employed in an earlier publication are illustrated.
- Transport model for a high temperature, mixed conducting CO2 separation membraneJ.L. Wade, K.S. Lackner, & A.C. West | Solid State Ionics, 2007-11 [+]
High temperature membranes for CO2 separation could lead to more efficient
energy conversion systems and more effective means of CO2 capture in power
plants. One concept for a membrane that can separate CO2 at high temperatures
from a gas mixture is described here. A theoretical model is presented to
describe the steady state flux of CO2 through a mixed conducting, dual-phase
membrane consisting of solid oxide and molten carbonate phases. An analytical
flux solution is derived for the case in which only ionic conduction is present. The
limiting factor dominating the flux of CO2 is the oxide ion conductivity. To take
advantage of solid oxide materials with higher ionic conductivities, the additional
presence of n-type electronic conductivity under low oxygen atmospheres is also
investigated. Using numerical and perturbation techniques we show that the
presence of electronic conduction will never be great enough to overwhelm the
CO2 separation mechanism.
- Pilot-Scale Demonstration of the OSCAR Process for High-Temperature Multipollutant Control of Coal Combustion Flue Gas, Using Carbonated Fly Ash and Mesoporous Calcium CarbonateH. Gupta, T. J. Thomas, A.-H. A. Park, M. Iyer, P. Gupta, R. Agnihotri, R. A. Jadhav, & L.-S. Fan | Industrial & Engineering Chemistry Research, 2007-06
- The road to clean energy starts hereJ.D. Sachs | Scientific American, 2007-04-15
- Electrostatic charging phenomenon in gas-liquid-solid flow systemsA.-H.A. Park & L.-S. Fan | Chemical Engineering Science, 2007-01 [+]
Abstract: During the operation of multiphase systems such as fluidized beds, electrostatic charges are generated when the materials involved are dielectric in nature. The accumulation of electrostatic charges within the system can be operationally hazardous. Work on understanding and, hence, preventing the electrostatic charging phenomena has mostly focused on gas–solid media. Relatively little study has been performed on particulates and multiphase systems with non-conductive liquids as the medium. In this study, electrostatic charging in gas–liquid–solid fluidized beds with liquid as the continuum phase under different operating conditions was explored. Two different charge-reducing methods were also evaluated. Based on experimental studies, it was found that the superficial gas and liquid velocities have a significant effect on the rate of charge generation and transfer in a three-phase fluidized bed because of variation in the frequency and the intensity of the particle collisions. The local number density of the particles also affected the distribution of the electrostatic signal obtained. Two methods of reducing electrostatic charge accumulation were also investigated: adding fine powder and adding an anti-static agent such as Larostat 264A. When 15 wt% of fine glass powder was added to an air-Norpar15-HDPE (high density polyethylene) fluidized bed, the charge inside the fluidized bed was reduced by 72%. When, on the other hand, as little as 0.5 wt% of the anti-static agent, Larostat 264A in a liquid form, was added to the air-Norpar15-HDPE, the electrostatic level was quickly reduced by 83% and within 1 h the electrostatic charge was completely eliminated from the system.
- Coal: research and development to support national energy policyC. L. Brierley et al. [including K.S. Lackner] | The National Academies Press, 2007
- Development of Electrical Capacitance Volume Tomography (ECVT) and Electrostatic Tomography (EST) for 3D Density Imaging of Fluidized Bed SystemD. Bing, Q. Marashdeh, A.-H. A. Park, & L.-S. Fan | 2007 ECI Conference on The 12th International Conference on Fluidization, 2007 [+]
Abstract: In this paper, Electrical Capacitance Volume Tomography (ECVT) is
used to study a gas-solid ﬂuidized bed system of .1 m ID. The interior ﬂow
structures (including the dynamic bed expansion, bubble/void breakage and
particle movement) and the charge distribution in a gas-solid ﬂuidized bed
are illustrated based on the 3D images obtained from the ECVT.
- Permanent carbon dioxide storage in deep-sea sedimentsK.Z. House, D.P. Schrag, C.F. Harvey, & K.S. Lackner | Proceedings of the National Academy of Sciences, 2006-11-10 [+]
Abstract: Stabilizing the concentration of atmospheric CO2 may require storing enormous
quantities of captured anthropogenic CO2 in near-permanent geologic reservoirs.
Because of the subsurface temperature profile of terrestrial storage sites, CO2
stored in these reservoirs is buoyant. As a result, a portion of the injected CO2
can escape if the reservoir is not appropriately sealed. We show that injecting
CO2 into deep-sea sediments <3,000-m water depth and a few hundred meters
of sediment provides permanent geologic storage even with large geomechanical
perturbations. At the high pressures and low temperatures common in deep-sea
sediments, CO2 resides in its liquid phase and can be denser than the overlying
pore fluid, causing the injected CO2 to be gravitationally stable. Additionally, CO2
hydrate formation will impede the flow of CO2(l) and serve as a second cap on
the system. The evolution of the CO2 plume is described qualitatively from the
injection to the formation of CO2 hydrates and finally to the dilution of the CO2(aq)
solution by diffusion. If calcareous sediments are chosen, then the dissolution of
carbonate host rock by the CO2(aq) solution will slightly increase porosity, which
may cause large increases in permeability. Karst formation, however, is unlikely
because total dissolution is limited to only a few percent of the rock volume. The
total CO2 storage capacity within the 200-mile economic zone of the U.S.
coastline is enormous, capable of storing thousands of years of current U.S. CO2
- Nearly reversible heat engines for thermal storage of excess electric powerJ.S. Levine, K.S. Lackner, and V. Modi | International Mechanical Engineering Congress and Exposition, 2006-11-05
- Ion conducting membranes for separation of moleculesK.S. Lackner, A.C. West, & J.L. Wade | U.S. Patent, 2006-10-26
- The conundrum of sustainable energy: clean coal as one possible answerK.S. Lackner | Asian Economic Papers, 2006-06-06 [+]
Abstract: Access to clean, cheap, and copious energy would allow the entire world to enjoy a standard of living taken for granted in developed countries. This paper identifies technologies for sustainable energy infrastructures, emphasizing that fossil fuels are amply sufficient for the next 100–200 years. However, today's fossil fuel technology will be inadequate to sustain a future world population of 10 billion. Pollution and greenhouse gases from unfettered fossil fuel use far exceed the environment's capacity to cope. Alternative forms of energy are presently either expensive or unsuitable for largescale energy production. Reliance on coal, in combination with carbon capture, carbon storage, and zero-emission technology, could break the world's dependence on petroleum and natural gas while providing environmentally acceptable energy for centuries. By also developing nuclear energy and renewable energy sources, it is possible to pursue a path characterized by plentiful and sustainable energy.
- Zero emission kilnF.S. Zeman & K.S. Lackner, 2006-05 [+]
Abstract: The global consensus on climate change, its anthropogenic source, and the need for a regulatory framework, typified by the Kyoto Accord, is strengthening. Whether the Kyoto accord or similar national frameworks come into force, the pressure on all carbon dioxide (CO2) producers to reduce emissions is likely to increase. Furthermore, the Intergovernmental Panel on Climate Change (IPCC) Special Report on Carbon Capture and Storage (CCS) has identified the cement industry as an early candidate for emission reductions. Regulatory mechanisms, such as emissions trading, provide a financial incentive by allowing industries that can exceed their target reduction to sell the excess for profit. The cement industry, because of its large size and the production of a highly concentrated stream of CO2, is well positioned to take advantage of these trading mechanisms.
- Thermodynamic optimization of hydrogen production for a coal based power plant with zero emissionsBelova, A., and Yegulalp, T. | Society of Manufacturing Engineers Annual Meeting, 2005-01-01 [+]
Abstract: This paper expands on the ZECA (Zero Emission Coal Alliance) technology, which is aimed at making coal a sustainable source of clean energy in the near future. The technology proposed immediate capture of carbon dioxide and other pollutants upon generation, thus alleviating their negative effects in the Earth’s atmosphere. ZECA proposes using chemical energy of coal to produce hydrogen; the latter is then used to produce electricity via fuel cells or Hyrogen-Oxygen turbines. In this study, a chemical engineering package, AspenPlus 12.1, is used to simulate the reactor (reformer) in which hydrogen is produced from methane water and lime as part of the zero emission power plant. Thermodynamic conditions, pressure and temperature, are optimized with respect to molar hydrogen production. Under the proposed conditions, molar conversion efficiency, carbon to hydrogen, of 95% is achieved. Further studies are required to model the complete power plant and to optimize it for efficiency.
- A robust strategy for sustainable energyK.S. Lackner & J. D. Sachs | Brookings Papers on Economic Activity, 2005
- Mineral carbonation and industrial uses of carbon dioxideM. Mazzotti, J.C. Abanades, R. Allam, K.S. Lackner, F. Meunier, E. Rubin, J.C. Sanchez, K. Yogo, & R. Zevenhoven | Carbon Dioxide Capture and Storage, 2005
- Development of a coal-based solid-oxide fuel cell systemJ.L. Wade & K.S. Lackner | Paper presented at 30th International Technical Conference on Coal Utilization & Fuel Systems, 2005
- Coal-based clean energy systems and CO2 sequestrationT.M. Yegulalp & K.S. Lackner | Mining Engineering (Colorado), 2004-10
- Capturing carbon dioxide directly from the atmosphereF.S. Zeman & K.S. Lackner | World Resource Review, 2004 [+]
Abstract: The increasing concern over rising CO2 levels in the atmosphere and their
potential climate effects is fuelling research aimed at carbon management. One
area of research focuses on capturing the CO2 after combustion and
sequestering it underground. Capture schemes would operate at the site of
generation taking advantage of the elevated concentrations of CO2 in the
effluent. Here, however, we propose an indirect method of carbon capture that
removes CO2 from the atmosphere. This process combines existing technologies
with recent technological innovations into a novel carbon capture concept termed
air extraction. The process uses dissolved sodium hydroxide to remove the CO2
from ambient air. The resultant sodium carbonate solution is causticized using
calcium hydroxide to regenerate the sodium hydroxide solution and precipitate
calcite. The calcite is then thermally decomposed to produce lime and CO2. The
lime is hydrated to complete the process. These latter stages are used routinely
in the paper industry and the calcination of limestone is central to the cement
industry. This paper reviews the process and highlights pertinent research to
develop a likely cost-effective process. It is shown that the proposed process is
well defined and technically feasible. The wide parameter space and potential for
improvements suggest that further efficiency improvements are attainable. The
most significant improvements will be derived from efficient heat management.
- CO2 Mineral Sequestration: Physically Activated Aqueous Carbonation of Serpentine and pH Swing processA.-H.A. Park & L.-S. Fan | Chemical Engineering Science, 2004 [+]
Abstract: The effect of the physical activation on the dissolution of serpentine was investigated and a pH swing scheme was developed to improve the overall conversion of the CO2 mineral sequestration process. Various methods of the surface agitation such as ultrasound, acoustic, and internal (in-situ) grinding were examined for their effectiveness in removing the diffusion limiting SiO2 layer in order to promote further dissolution of the inner MgO layer of serpentine. It was found that the ﬂuidization of the serpentine slurry with 2 mm glass
beads was most effective in refreshing the surface of the serpentine particles during the dissolution process. Unlike the external attrition
grinding, this method could be much less energy intensive. It was also found that the mechanical agitation via the internal grinding alone
did not enhance the dissolution of serpentine, while the combination of the internal grinding and Mg leaching solvent resulted in rapid
serpentine dissolution. Using the proposed pH swing scheme, the overall conversion of the mineral carbonation radically improved. By
controlling the pH of the system, three solid products were generated from the mineral carbonation process: SiO2-rich solids, iron oxide
and MgCO3 3H2O. Since the iron oxide and MgCO3
produced were highly pure, these value-added products could eventually reduce the overall cost of the carbon sequestration process.
- A guide to CO2 sequestrationK.S. Lackner | Science, 2003-06-13
- Drag Coefficients for Settling Sphere with Microbubble Drag Reduction EffectsZ. Cui, J. Fan, A.-H.A. Park | Powder Technology, 2003 [+]
Abstract: Experiments are conducted to study the microbubble effects on drag reduction of settling particles in liquid. In this study, microbubbles
are generated from Alka-Seltzer(R) powder coated on the surface of the particle. The particle Reynolds number range examined varies from
20,000 to 70,000. The reduction of drag force in terms of drag coefficient is found to decrease to about 15% with microbubble generation
compared to that without microbubble generation.
- Comment on Efficient Photochemical Water Splitting by a Chemically Modified n-TiO2 (III)K.S. Lackner | Science, 2003
- Clean energy from coal—emission-free power generation with option for CO2 sequestrationT.M. Yegulalp, K.S. Lackner, & P.F. Duby | Proceedings of the 19th World Mining Congress, pp. 955–996, 2003
- CO2 Mineral Sequestration: Chemically Enhanced Aqueous Carbonation of SerpentineA.-H.A. Park, R. Jadhav, & L.S. Fan | Canadian Journal of Chemical Engineering, 2003
- Can fossil carbon fuel the 21st century?K.S. Lackner | International Geology Review, 2002-10 [+]
Abstract: Fossil fuels, despite their drawbacks, have been fueling the world economy for
the last two centuries. They have proven abundant, easy to use, and low in cost.
Contrary to common belief, fossil fuels are not likely to run out any time soon. For
the foreseeable future, fossil fuels may continue to be the most cost-effective
energy resource, even as concerns over climate change will force the
implementation of technologies to capture and dispose of the carbon dioxide
generated in their use. With a successful implementation of the carbon
management technologies that are under development today, the use of fossil
carbon could be sustained for at least another century.
- Advanced Technology Paths to Global Climate Stability: Energy for a Greenhouse PlanetHoffert, Cladeira, Benford, Criswell, Green, Herzog, Jain, Kheshgi, K.S. Lackner, J. Lewis, H. Lightfoot, et. al | Science, 2002 [+]
Abstract: Stabilizing the carbon dioxide–induced component of climate change is an energy problem. Establishment of a course toward such stabilization will require the development within the coming decades of primary energy sources that do not emit carbon dioxide to the atmosphere, in addition to efforts to reduce end-use energy demand. Mid-century primary power requirements that are free of carbon dioxide emissions could be several times what we now derive from fossil fuels (∼1013 watts), even with improvements in energy efficiency. Here we survey possible future energy sources, evaluated for their capability to supply massive amounts of carbon emission–free energy and for their potential for large-scale commercialization. Possible candidates for primary energy sources include terrestrial solar and wind energy, solar power satellites, biomass, nuclear fission, nuclear fusion, fission-fusion hybrids, and fossil fuels from which carbon has been sequestered. Non–primary power technologies that could contribute to climate stabilization include efficiency improvements, hydrogen production, storage and transport, superconducting global electric grids, and geoengineering. All of these approaches currently have severe deficiencies that limit their ability to stabilize global climate. We conclude that a broad range of intensive research and development is urgently needed to produce technological options that can allow both climate stabilization and economic development.
- Characterization of Electrostatic Charges in Freely Bubbling Fluidized Beds with Dielectric ParticlesL. Yao, H.T. Bi, & A.-H.A. Park | Journal of Electrostatics, 2002 [+]
Abstract: Experiments were conducted in an 89 mm inner diameter Plexiglas fluidized bed with polyethylene resin particles to study the local instantaneous electrostatic charges using a miniature collision ball probe installed inside the column. Local differential pressure fluctuations were also measured to monitor the local fluidization quality. The power spectrum and probability density distributions from both the differential pressure fluctuations and the local instantaneous electric voltage signals were similar, confirming that the amplitude of voltage signals from a ball probe is mainly induced by passing bubbles. The standard deviation of voltages from the ball probe increased with increasing superficial gas velocity, probably due to an increase in the charge density on particles surrounding the rising bubble and increasing bubble rise velocity. The net charge transfer rate, however, showed no clear change with increasing superficial gas velocity because of the balance between the increase in particle velocity and the decrease in dense phase fraction. As the relative humidity increased at a given gas velocity, the standard deviation of the voltage signals and the differential pressure fluctuations both decreased, indicating that the charge buildup in the vicinity of the bubble decreased as the bubble size decreased. The net charge transfer rate, however, increased with increasing relative humidity at RH>50%, likely due to an increase in the charge dissipation rate due to increased electrical conductivity of the fluidizing media. At relative humidities below 50%, the net charge transfer rate was insensitive to the relative humidity because the increase in conductivity was offset by the decrease in charge buildup on particle surfaces. The addition of antistatic powders was effective in reducing the electrostatic charge buildup in the polyethylene resin bed. One hour after the addition of 1 wt% Larostat powders, both the standard deviation of voltage signals and the net charge transfer rate were reduced to insignificant levels.
- Carbonate chemistry for sequestering fossil carbonK.S. Lackner | Annual Review of Energy and the Environment, 2002 [+]
Abstract: Fossil fuels play a crucial role in satisfying growing world energy demands, but their continued use could cause irreparable harm to the environment. Unless
virtually all anthropogenic carbon dioxide is captured, either at the source or subsequently from the air, and disposed of safely and permanently, fossil fuels may have to
be phased out over the next few decades. Sequestration of waste carbon dioxide will
require methods that can safely store several trillion tons of carbon dioxide. Long-term
storage of a gaseous substance is fraught with uncertainty and hazards, but carbonate chemistry offers permanent solutions to the disposal problem. Carbonates can be
formed from carbon dioxide and metal oxides in reactions that are thermodynamically
favored and exothermic, which result in materials that can be safely and permanently
kept out of the active carbon stocks in the environment. Carbonate sequestration methods require the development of an extractive minerals industry that provides the base
ions for neutralizing carbonic acid.
- Reduction of Electrostatic Charges in Gas-Solid Fluidized BedA.-H.A. Park, X. Bi, & J.R. Grace | Chemical Engineering Science, 2002 [+]
Abstract: Reduction of electrostatic charge accumulation by increasing the humidity of fluidizing gas was investigated using single bubble injection in two- and three-dimensional fluidized beds. Both glass beads and polyethylene particles were found to be charged positively when fluidized by air. Electrostatic charges increased as the bubble size increased. Increasing the relative humidity of the fluidizing air to 40–80% reduced the accumulation of electrostatic charge by increasing the surface conductivity, thereby enhancing charge dissipation.
- Free Market Approaches to Controlling Carbon Dioxide Emissions to the AtmosphereK.S. Lackner, R. Wilson, & H-J. Ziock | Global Warming and Energy Policy Conference, 2001
- Stability of Hydrogen Peroxide in Sodium Carbonate SolutionsH. Lee, A.-H.A. Park, & C. Oloman | TAPPI Journal, 2000
- Multi-scale linear solvers for very large systems derived from PDEsK.S. Lackner & R. Menikoff | SIAM journal on scientific computing, 2000 [+]
Abstract: We present a novel linear solver that works well for large systems obtained from
discretizing PDEs. It is robust and, for the examples we studied, the
computational effort scales linearly with the number of equations. The algorithm
is based on a wavelength decomposition that combines conjugate gradient,
multi-scaling and iterative splitting methods into a single approach. On the
surface, the algorithm is a simple preconditioned conjugate gradient with all the
sophistication of the algorithm in the choice of the preconditioning matrix. The
preconditioner is a very good approximate inverse of the linear operator. It is
constructed from the inverse of the coarse grained linear operator and from
smoothing operators that are based on an operator splitting on the fine grid. The
coarse graining captures the long wavelength behavior of the inverse operator
while the smoothing operator captures the short wavelength behavior. The
conjugate gradient iteration accounts for the coupling between long and short
wavelengths. The coarse grained operator corresponds to a lower resolution
approximation to the PDEs. While the coarse grained inverse is not known
explicitly, the algorithm only requires that the preconditioner can be a applied to a
vector. The coarse inverse applied to a vector can be obtained as the solution of
another preconditioned conjugate gradient solver that applies the same algorithm
to the smaller problem. Thus, the method is naturally recursive. The recursion
ends when the matrix is sufficiently small for a solution to be obtained efficiently
with a standard solver. We have tested our solver on the porous flow equation.
On a workstation we have solved problems on grids ranging in dimension from
10^3 to 10^6, and found that the linear scaling holds.
- The importance of and a method for disposing of carbon dioxide in a thermodynamically stable formD.P. Butt, K.S. Lackner, C.H. Wendt, K. Nomura, & Y. Yanagisawa | World Resource Review, 1999-06 [+]
In this paper we argue for the importance of methods for sequestering carbon
dioxide. We first discuss the importance of energy to society and the role that
fossil fuels play. This leads us to outline a set of constraints that we propose
should be considered or imposed upon any sequestration technology. Due to the
importance of fossil fuels, coal in particular, in the energy mix for most nations,
and objective of sequestration and our research is to maintain the viability of
carbon-based fuels. Toward this end, we outline a process to bind carbon dioxide
as a mineral carbonate. We describe experimental results and process concepts
that could allow us to economically dispose of carbon dioxide in a
thermodynamically stable form.
- Carbon dioxide extraction from air: is it an option?K.S. Lackner, H-J. Ziock, & P. Grimes | 24th Annual Technical Conference on Coal Utilization & Fuel Systems, 1999-03-08 [+]
Abstract: Controlling the level of carbon dioxide in the atmosphere without limiting access
to fossil energy resources is only possible if carbon dioxide is collected and
disposed of away from the atmosphere. While it may be cost-advantageous to
collect the carbon dioxide at concentrated sources without ever letting it enter the
atmosphere, this approach is not available for the many diffuse sources of
carbon dioxide. Similarly, for many older plants a retrofit to collect the carbon
dioxide is either impossible or prohibitively expensive. For these cases we
investigate the possibility of collecting the carbon dioxide directly from the
atmosphere. We conclude that there are no fundamental obstacles to this
approach and that it deserves further investigation. Carbon dioxide extraction
directly from atmosphere would allow carbon management without the need for a
completely changed infrastructure. In addition it eliminates the need for a
complex carbon dioxide transportation infrastructure, thus at least in part
offsetting the higher cost of the extraction from air.
- Carbon dioxide sequestering using ultramafic rocksF. Goff & K.S. Lackner | Environmental Geosciences, 1998-09 [+]
Abstract: Fossil fuels continue to provide major sources of energy to the modern world
even though global emissions of CO 2 are presently at levels of ≥19 gigatons/yr.
Future antipollution measures may include sequestering of waste CO 2 as
magnesite (MgCO3) by processing ultramafic rocks. Common ultramafic rocks
react easily with HCl to form MgCl2 which is hydrolyzed to form Mg(OH)2. CO2
would be transported by pipeline from a fossil fuel power plant to a sequestering
site and then reacted with Mg(OH)2 to produce thermodynamically stable
magnesite. Huge ultramafic deposits consisting of relatively pure Mg-rich silicates
exist throughout much of the world in ophiolites and, to a lesser extent, in layered
intrusions. Peridotites and associated serpentinite are found in discontinuous
ophiolite belts along both continental margins of North America. Serpentinites
and dunites comprise the best ores because they contain the most Mg by weight
(35 to 49 wt-% MgO) and are relatively reactive to hot acids such as HCl. Small
ultramafic bodies (∼1 km3) can potentially sequester ∼1 gigatons of CO2 or ∼20%
of annual U.S. emissions. A single large deposit of dunite (∼30 km3) could
dispose of nearly 20 years of current U.S. CO 2 emissions. The sequestering
process could provide Mg, Si, Fe, Cr, Ni, and Mn as by products for other
industrial and strategic uses. Because "white" asbestos (chyrsotile) is a
serpentine mineral, CO 2 sequestering could dispose of some waste asbestos.
The cost and environmental impact of exploiting ultramafic deposits must be
weighed against the increased costs of energy and benefits to the atmosphere
- Exponential growth of large self-reproducing machine systemsK.S. Lackner & C.H. Wendt | Mathematical and Computer Modelling, 1995-05 [+]
Abstract: We address quantitatively the major issues involved in the design of self-reproducing machine systems that are capable of both rapid growth to a very
large scale and the accomplishment of correspondingly large tasks. A minimal
system that satisfies the growth requirement would consist of a large solar cell
array and a colony of diverse and specialized machines. With solar energy, raw
dirt, and air as its input, the collective purpose of the colony is to expand the
solar cell array and build more machines largely without the aid of man. Once the
desired size is attained, the entire production capacity of the system may be
diverted to useful applications such as large scale energy collection, control of
greenhouse gases in the atmosphere, and fresh water production. We consider
the issues of resource availability, the suitability of current automation
technology, and the required investment in land area. In the discussion of
resources, we propose a high-temperature, metallurgical process for separating
useful elements from raw dirt without the use of rare elements. Automation
technology is judged by a formal productivity requirement in the production chain
of each machine type, which must be satisfied to achieve a given overall growth
rate. We estimate the time scale for exponential growth to be on the order of
months, so that such a system could reach continental size in less than a
decade. An area of 10^6 km2 is enough to provide the key elements of a
sustainable world economy. At ten percent efficiency, a solar cell array of this
size can collect energy at three times the rate of today's global energy
- Carbon dioxide disposal in carbonate mineralsK.S. Lackner, C.H. Wendt, D.P. Butt, E.L. Joyce, & D.H. Sharp | Energy (Oxford), 1995-03-24 [+]
Abstract: We introduce a safe and permanent method of CO2 disposal based on combining
CO2 chemically with abundant raw materials to form stable carbonate minerals.
Substantial heat is liberated in the overall chemical reaction so that cost will be
determined by the simplicity and speed of the reaction rather than the cost of
energy. Preliminary investigations have been conducted on two types of
processes, involving either direct carbonation of minerals at high temperature or
processing in aqueous solution. Promising raw materials are identified in both
cases. For aqueous processing, a chemical cycle employing well-known
reactions is proposed for digesting and carbonating the raw material. Cost
estimates, based on comparison with standard industrial and mining practice, are
encouraging. Necessary raw materials are surveyed and vast quantities are
found to be easily accessible. Amounts are sufficient to allow utilization of the
large known fossil-fuel reserves while avoiding build-up of atmospheric CO2.