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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 451 records · Page 25
All sourcesNASA NTRSDOE OSTI
DOE OSTI2011

Well-to-Wheels Analysis of Fast Pyrolysis Pathways with GREET

The pyrolysis of biomass can help produce liquid transportation fuels with properties similar to those of petroleum gasoline and diesel fuel. Argonne National Laboratory conducted a life-cycle (i.e., well-to-wheels [WTW]) analysis of various pyrolysis pathways by expanding and employing the Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) model. The WTW energy use and greenhouse gas (GHG) emissions from the pyrolysis pathways were compared with those from the baseline petroleum gasoline and diesel pathways. Various pyrolysis pathway scenarios with a wide variety of possible hydrogen sources, liquid fuel yields, and co-product application and treatment methods were considered. At one extreme, when hydrogen is produced from natural gas and when bio-char is used for process energy needs, the pyrolysis-based liquid fuel yield is high (32% of the dry mass of biomass input). The reductions in WTW fossil energy use and GHG emissions relative to those that occur when baseline petroleum fuels are used, however, is modest, at 50% and 51%, respectively, on a per unit of fuel energy basis. At the other extreme, when hydrogen is produced internally via reforming of pyrolysis oil and when bio-char is sequestered in soil applications, the pyrolysis-based liquid fuel yield is low (15% of the dry mass of biomass input), but the reductions in WTW fossil energy use and GHG emissions are large, at 79% and 96%, respectively, relative to those that occur when baseline petroleum fuels are used. The petroleum energy use in all scenarios was restricted to biomass collection and transportation activities, which resulted in a reduction in WTW petroleum energy use of 92-95% relative to that found when baseline petroleum fuels are used. Internal hydrogen production (i.e., via reforming of pyrolysis oil) significantly reduces fossil fuel use and GHG emissions because the hydrogen from fuel gas or pyrolysis oil (renewable sources) displaces that from fossil fuel natural gas and the amount of fossil natural gas used for hydrogen production is reduced; however, internal hydrogen production also reduces the potential petroleum energy savings (per unit of biomass input basis) because the fuel yield declines dramatically. Typically, a process that has a greater liquid fuel yield results in larger petroleum savings per unit of biomass input but a smaller reduction in life-cycle GHG emissions. Sequestration of the large amount of bio-char co-product (e.g., in soil applications) provides a significant carbon dioxide credit, while electricity generation from bio-char combustion provides a large energy credit. The WTW energy and GHG emissions benefits observed when a pyrolysis oil refinery was integrated with a pyrolysis reactor were small when compared with those that occur when pyrolysis oil is distributed to a distant refinery, since the activities associated with transporting the oil between the pyrolysis reactors and refineries have a smaller energy and emissions footprint than do other activities in the pyrolysis pathway.

02 PETROLEUM↗
DOE OSTI2011

Geologic carbon sequestration as a global strategy to mitigate CO2 emissions: Sustainability and environmental risk

Fossil fuels are abundant, inexpensive to produce, and are easily converted to usable energy by combustion as demonstrated by mankind's dependence on fossil fuels for over 80% of its primary energy supply (13). This reliance on fossil fuels comes with the cost of carbon dioxide (CO{sub 2}) emissions that exceed the rate at which CO{sub 2} can be absorbed by terrestrial and oceanic systems worldwide resulting in increases in atmospheric CO{sub 2} concentration as recorded by direct measurements over more than five decades (14). Carbon dioxide is the main greenhouse gas linked to global warming and associated climate change, the impacts of which are currently being observed around the world, and projections of which include alarming consequences such as water and food shortages, sea level rise, and social disruptions associated with resource scarcity (15). The current situation of a world that derives the bulk of its energy from fossil fuel in a manner that directly causes climate change equates to an energy-climate crisis. Although governments around the world have only recently begun to consider policies to avoid the direst projections of climate change and its impacts, sustainable approaches to addressing the crisis are available. The common thread of feasible strategies to the energy climate crisis is the simultaneous use of multiple approaches based on available technologies (e.g., 16). Efficiency improvements (e.g., in building energy use), increased use of natural gas relative to coal, and increased development of renewables such as solar, wind, and geothermal, along with nuclear energy, are all available options that will reduce net CO{sub 2} emissions. While improvements in efficiency can be made rapidly and will pay for themselves, the slower pace of change and greater monetary costs associated with increased use of renewables and nuclear energy suggests an additional approach is needed to help bridge the time period between the present and a future when low-carbon energy is considered cheap enough to replace fossil fuels. Carbon dioxide capture and storage (CCS) is one such bridging technology (1). CCS has been the focus of an increasing amount of research over the last 15-20 years and is the subject of a comprehensive IPCC report that thoroughly covers the subject (1). CCS is currently being carried out in several countries around the world in conjunction with natural gas extraction (e.g., 2, 3) and enhanced oil recovery (17). Despite this progress, widespread deployment of CCS remains the subject of research and future plans rather than present action on the scale needed to mitigate emissions from the perspective of climate change. The reasons for delay in deploying CCS more widely are concerns about cost (18), regulatory and legal uncertainty (19), and potential environmental impacts (21). This chapter discusses the long-term (decadal) sustainability and environmental hazards associated with the geologic CO{sub 2} storage (GCS) component of large-scale CCS (e.g., 20). Discussion here barely touches on capture and transport of CO{sub 2} which will occur above ground and which are similar to existing engineering, chemical processing, and pipeline transport activities and are therefore easier to evaluate with respect to risk assessment and feasibility. The focus of this chapter is on the more uncertain part of CCS, namely geologic storage. The primary concern for sustainability of GCS is whether there is sufficient capacity in sedimentary basins worldwide to contain the large of amounts of CO{sub 2} needed to address climate change. But there is also a link between sustainability and environmental impacts. Specifically, if GCS is found to cause unacceptable impacts that are considered worse than its climate-change mitigation benefits, the approach will not be widely adopted. Hence, GCS has elements of sustainability insofar as capacity of the subsurface for CO{sub 2} is concerned, and also in terms of whether the associated environmental risks are acceptable or not to the public.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2014

Greenhouse gas emissions from production chain of a cigarette manufacturing industry in Pakistan

This study quantified greenhouse gas (GHG) emissions from the Pakistan Tobacco Company (PTC) production using a life cycle approach. The PTC production chain comprises of two phases: agricultural activities (Phase I) and industrial activities (Phase II). Data related to agricultural and industrial activities of PTC production chain were collected through questionnaire survey from tobacco growers and records from PTC manufacturing units. The results showed that total GHG emissions from PTC production chain were 44,965, 42,875, and 43,839 tCO{sub 2}e respectively in 2009, 2010, and 2011. Among the agricultural activities, firewood burning for tobacco curing accounted for about 3117, 3565, and 3264 tCO{sub 2}e, fertilizer application accounted for 754, 3251, and 4761 tCO{sub 2}e in 2009, 2010, and 2011, respectively. Among the industrial activities, fossil fuels consumption in stationary sources accounted for 15,582, 12,733, and 13,203 tCO{sub 2}e, fossil fuels used in mobile sources contributed to 2693, 3038, and 3260 tCO{sub 2}e, and purchased electricity consumed resulted in 15,177, 13,556, and 11,380 tCO{sub 2}e in 2009, 2010, and 2011, respectively. The GHG emissions related to the transportation of raw materials and processed tobacco amounted to 6800, 6301, and 7317 respectively in 2009, 2010, and 2011. GHG emissions from energy use in the industrial activities constituted the largest emissions (i.e., over 80%) of GHG emissions as PTC relies on fossil fuels and fossil fuel based electrical power in industrial processes. The total emissions of carbon footprint (CFP) from PTC production were 0.647 tCO{sub 2}e per million cigarettes produced in 2009, 0.675 tCO{sub 2}e per million cigarettes in 2010 and 0.59 tCO{sub 2}e per million cigarettes in 2011. Potential strategies for GHG emissions reductions for PTC production chain include energy efficiency, reducing reliance on fossil fuels in non-mobile sources, adoption of renewable fuels including solar energy, energy from crop residues, and promotion of organic fertilizers. - Highlights: • We quantified greenhouse gas (GHG) emissions from the Pakistan Tobacco Company (PTC). • PTC production chain comprises of two phases: agricultural and industrial activities. • GHG emissions accounts to 44,965, 42,875 and 43,839 tCO{sub 2}e in 2009, 2010, and 2011, respectively. • GHG emissions from energy use in the industrial activities constituted the largest emissions i.e. 80%. • Implications for GHG emissions mitigation strategies for PTC are also discussed in detail.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2017

Biospheric feedback effects in a synchronously coupled model of human and Earth systems

Fossil fuel combustion and land-use change are the first and second largest contributors to industrial-era increases in atmospheric carbon dioxide concentration, which is itself the largest driver of present-day climate change1. Projections of fossil fuel consumption and land-use change are thus fundamental inputs for coupled Earth system models (ESM) used to estimate the physical and biological consequences of future climate system forcing2,3. While empirical datasets are available to inform historical analyses4,5, assessments of future climate change have relied on projections of energy and land use based on energy economic models, constrained using historical and present-day data and forced with assumptions about future policy, land-use patterns, and socio-economic development trajectories6. Here we show that the influence of biospheric change – the integrated effect of climatic, ecological, and geochemical processes – on land ecosystems has a significant impact on energy, agriculture, and land-use projections for the 21st century. Such feedbacks have been ignored in previous ESM studies of future climate. We find that synchronous exposure of land ecosystem productivity in the economic system to biospheric change as it develops in an ESM results in a 10% reduction of land area used for crop cultivation; increased managed forest area and land carbon; a 15-20% decrease in global crop price; and a 17% reduction in fossil fuel emissions for a low-mid range forcing scenario7. These simulation results demonstrate that biospheric change can significantly alter primary human system forcings to the climate system. This synchronous two-way coupling approach removes inconsistencies in description of climate change between human and biosphere components of the coupled model, mitigating a major source of uncertainty identified in assessments of future climate projections8-10.

climate change↗
DOE OSTI2019

Hagfish from the Cretaceous Tethys Sea and a reconciliation of the morphological–molecular conflict in early vertebrate phylogeny

Hagfish depart so much from other fishes anatomically that they were sometimes considered not fully vertebrate. They may represent: ( i ) an anatomically primitive outgroup of vertebrates (the morphology-based craniate hypothesis); or ( ii ) an anatomically degenerate vertebrate lineage sister to lampreys (the molecular-based cyclostome hypothesis). This systematic conundrum has become a prominent case of conflict between morphology- and molecular-based phylogenies. To date, the fossil record has offered few insights to this long-branch problem or the evolutionary history of hagfish in general, because unequivocal fossil members of the group are unknown. Here, we report an unequivocal fossil hagfish from the early Late Cretaceous of Lebanon. The soft tissue anatomy includes key attributes of living hagfish: cartilages of barbels, postcranial position of branchial apparatus, and chemical traces of slime glands. This indicates that the suite of characters unique to living hagfish appeared well before Cretaceous times. This new hagfish prompted a reevaluation of morphological characters for interrelationships among jawless vertebrates. By addressing nonindependence of characters, our phylogenetic analyses recovered hagfish and lampreys in a clade of cyclostomes (congruent with the cyclostome hypothesis) using only morphological data. This new phylogeny places the fossil taxon within the hagfish crown group, and resolved other putative fossil cyclostomes to the stem of either hagfish or lamprey crown groups. These results potentially resolve the morphological–molecular conflict at the base of the Vertebrata. Furthermore, assessment of character nonindependence may help reconcile morphological and molecular inferences for other major discords in animal phylogeny.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2016

The terrestrial carbon budget of South and Southeast Asia

Accomplishing the objective of the current climate policies will require establishing carbon budget and flux estimates in each region and county of the globe by comparing and reconciling multiple estimates including the observations and the results of top-down atmospheric carbon dioxide (CO 2 ) inversions and bottom-up dynamic global vegetation models. With this in view, this study synthesizes the carbon source/sink due to net ecosystem productivity (NEP), land cover land use change (E LUC ), fires and fossil burning (E FIRE ) for the South Asia (SA), Southeast Asia (SEA) and South and Southeast Asia (SSEA = SA + SEA) and each country in these regions using the multiple top-down and bottom-up modeling results. The terrestrial net biome productivity (NBP=NEP - E LUC - E FIRE ) calculated based on bottom-up models in combination with E FIRE based on GFED4s data show net carbon sinks of 217 ± 147, 10 ± 55, and 227 ± 279 TgC yr -1 for SA, SEA, and SSEA. The top-down models estimated NBP net carbon sinks were 20 ± 170, 4 ± 90 and 24 ± 180 TgC yr -1 . In comparison, regional emissions from the combustion of fossil fuels were 495, 275, and 770 TgC yr -1 , which are many times higher than the NBP sink estimates, suggesting that the contribution of the fossil fuel emissions to the carbon budget of SSEA results in a significant net carbon source during the 2000s. When considering both NBP and fossil fuel emissions for the individual countries within the regions, Bhutan and Laos were net carbon sinks and rest of the countries were net carbon source during the 2000s. The relative contributions of each of the fluxes (NBP, NEP, E LUC , and E FIRE , fossil fuel emissions) to a nation’s net carbon flux varied greatly from country to country, suggesting a heterogeneous dominant carbon fluxes on the country-level throughout SSEA.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2013

Climate policy implications for agricultural water demand

Energy, water and land are scarce resources, critical to humans. Developments in each affect the availability and cost of the others, and consequently human prosperity. Measures to limit greenhouse gas concentrations will inevitably exact dramatic changes on energy and land systems and in turn alter the character, magnitude and geographic distribution of human claims on water resources. We employ the Global Change Assessment Model (GCAM), an integrated assessment model to explore the interactions of energy, land and water systems in the context of alternative policies to limit climate change to three alternative levels: 2.5 Wm-2 (445 ppm CO2-e), 3.5 Wm-2 (535 ppm CO2-e) and 4.5 Wm-2 (645 ppm CO2-e). We explore the effects of two alternative land-use emissions mitigation policy options—one which taxes terrestrial carbon emissions equally with fossil fuel and industrial emissions, and an alternative which only taxes fossil fuel and industrial emissions but places no penalty on land-use change emissions. We find that increasing populations and economic growth could be anticipated to almost triple demand for water for agricultural systems across the century even in the absence of climate policy. In general policies to mitigate climate change increase agricultural demands for water still further, though the largest changes occur in the second half of the century, under both policy regimes. The two policies examined profoundly affected both the sources and magnitudes of the increase in irrigation water demands. The largest increases in agricultural irrigation water demand occurred in scenarios where only fossil fuel emissions were priced (but not land-use change emission) and were primarily driven by rapid expansion in bioenergy production. In these scenarios water demands were large relative to present-day total available water, calling into question whether it would be physically possible to produce the associated biomass energy. We explored the potential of improved water delivery and irrigation system efficiencies. These could potentially reduce demands substantially. However, overall demands remained high under our fossil-fuel-only tax policy. In contrast, when all carbon was priced, increases in agricultural water demands were smaller than under the fossil-fuel-only policy and were driven primarily by increased demands for water by non-biomass crops such as rice. Finally we estimate the geospatial pattern of water demands and find that regions such as China, India and other countries in south and east Asia might be expected to experience greatest increases in water demands.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2014

Geothermal Power Production: Alternative Scenarios and Critical Issues

This is the last in a series of reports that completes the life cycle analyses (LCAs) of geothermal power production technologies conducted by Argonne National Laboratory. It addresses the remaining critical issues pertaining to the LCAs of geothermal electricity production: the relative contributions from plant operations and maintenance (O&M), from decommissioning (dcm), from well field exploration, and from plant operational greenhouse gas (GHG) emissions to the total life cycle performance of geothermal power plants. Contributions from O&M and dcm to the performance of other power generating technologies are also discussed. Also included in this study are LCA results for a new series of scenarios for geothermal power production. Our analysis uses fossil fuel energy consumption and GHG emissions per unit of lifetime electricity output (referred to as the fossil energy and GHG ratios, respectively) as the life cycle metrics for quantifying life cycle stage contributions to their corresponding totals, which were subsequently used for comparing the environmental performance of geothermal and other electric power production plants. Based on literature results, we concluded that the contribution from dcm to both ratios is negligible for power plants in general. Further, we found that the contribution from O&M to both ratios is generally significant for facilities with no fuel cycle (fuel production and use) burdens. In the case of geothermal power production, O&M contributes about 20% to the total for enhanced geothermal power plants, 10% for geothermal binary plants, and about 25% of the energy ratio for geothermal flash and dry steam plants. However, due to operational GHG emissions that are unique among geothermal power plants, O&M contributes only about 1% of total GHG ratios for flash and dry steam plants. These GHG emissions arise when the geofluids of these plants become exposed to the atmosphere, thus releasing dissolved GHGs. The amount of GHG emissions from these plants had a wide range. However, we found that 85% of California’s running capacity in flash and dry steam plants released 160 grams or less per kilowatt-hour of electricity produced. We developed an exploration model to account for core hole, slim hole, and confirmation well drilling that includes a probability of success for confirmation well drilling. The model shows that well field exploration represents about 20% of the total life cycle burden for large geothermal plants with numerous wells and 32% of the burden for small plants with few wells. We also analyzed a set of geothermal scenario pairs. The objective was to identify geothermal scenarios with a lower levelized cost of electricity and lower life cycle burdens. A comparison of reference with improved cases within each pair revealed that the improved cases demonstrated a lower levelized cost of electricity and lower fossil energy consumption and GHG metrics. The scenario pairs covered a range of plant capacities, well numbers and depths, resource temperatures, and plant lifetimes. Finally, we found that compared to fossil-fuel generation of electricity, both flash and dry steam geothermal electricity generation result in fewer GHG emissions: on average, only one-fifth of the GHG emissions per kilowatt-hour from a natural gas combined-cycle plant, and one-tenth of those from a coal-fired plant. Moreover, these fractions were much smaller when the fossil plants were compared with plants that use geothermal binary technology.

Sullivan, J. L.↗
DOE OSTI2017

Montana BioDiesel Initiative

This initiative funding helped put Montana State University (MSU) in a position to help lead in the development of biodiesel production strategies. Recent shortages in electrical power and rising gasoline prices have focused much attention on the development of alternative energy sources that will end our dependence on fossil fuels. In addition, as the concern for environmental impact of utilizing fossil fuels increases, effective strategies must be implemented to reduce emissions or the increased regulations imposed on fossil fuel production will cause economic barriers for their use to continue to increase. Biodiesel has been repeatedly promoted as a more environmentally sound and renewable source of fuel and may prove to be a highly viable solution to provide, at the least, a proportion of our energy needs. Currently there are both practical and economic barriers to the implementation of alternative energy however the advent of these technologies is inevitable. Since many of the same strategies for the storage, transport, and utilization of biodiesel are common with that of fossil fuels, the practical barriers for biodiesel are comparatively minimal. Strategies were developed to harness the CO 2 as feedstock to support the growth of biodiesel producing algae. The initiative funding led to the successful funding of highly rated projects in competitive national grant programs in the National Science Foundation and the Department of Energy. This funding put MSU in a key position to develop technologies to utilize the CO 2 rich emissions produced in fossil fuel utilization and assembled world experts concerning the growth characteristics of photosynthetic microorganisms capable of producing biodiesel.

09 BIOMASS FUELS↗
DOE OSTI2024

Coupling of the Electricity and Transportation Sectors - Part II: Risk Assessment

This comprehensive report explores the intricate interplay through “sector coupling” between the Transportation Sector, Energy Sector, and the critical infrastructure challenges faced by the United States. Aligned with the ambitious federal goal of reducing greenhouse gas emissions, the report analyzes the present vulnerabilities in the fossil fuel supply chain, highlighting instances where the dependence on this industry has been susceptible to local and global disruptions. With a focus on risk assessment, this report establishes a framework to compare the fossil fuel-based transportation sector with the burgeoning electrified sector, considering the evolving technologies in electric vehicles (EVs) and the nascent charging infrastructure. This study delves into the historical reliability of fossil fuel-based transportation and identifies opportunities for strengthening sector coupling between transportation and the electric sector. Assessments of the gasoline-diesel supply chain provide insights into both opportunities and threats, offering a roadmap for creating a more reliable and resilient electrified transportation system. We modeled sectoral coupling scenarios for the current internal combustion engine (ICE)-based and future EV-dominant landscapes, leveraging qualitative sector attributes to identify relative strengths and weaknesses in Part 1 of the report. In this report (Part 2) we continue to understand the role of the electricity sector on transportation and develop a semi-quantitative methodology is employed to evaluate and compare the risks associated with the fossil fueled and electric transportation sector during emergency scenarios, drawing from real-world events like hurricanes and geopolitical disruptions. Different operational scenarios for the fossil fuel and electrified sectors have been developed to understand the risks associated with them. This report concludes with recommendations for the architectural designs of electric charging infrastructure, underlining the need for informed decisions in the transition towards a sustainable and resilient transportation future.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2025

Systems Analysis of Biomass and Coal Co-firing Power Plants with Deep Carbon Capture Toward Net-zero Emissions

Achieving a net-zero emission economy in the United States requires integrating diverse low-carbon and negative-emission technologies into the existing fossil fuel-dominant power fleet. Potential technologies from the low-carbon portfolio include renewable power, fossil power with carbon capture and storage (CCS), bioenergy with CCS (BECCS), and direct air capture (DAC). Renewable power is a clean energy source but has to pair with costly battery storage to provide dispatchable electricity. Fossil power with CCS offers dispatchable electricity yet still relies on DAC to offset residual emissions, even when deploying deep CCS with more than 90% CO2 capture. Coal-biomass co-firing with CCS, a subset of BECCS, is a reliable energy production technology that can be retrofitted from existing electricity generation units (EGUs). Power plant retrofit maximizes the use of the current U.S. coal power fleet without the need for large-scale deployment of new renewable power, battery storage, or DAC. Retrofitting coal-biomass co-firing with deep CCS in EGUs is a promising option, but not a universal solution. Biomass co-firing at a power plant introduces economic challenges and indirectly poses pressure on land and water resources. Meanwhile, retrofitting deep CCS affects plant efficiency and raises electricity generation costs. Overall, the technical feasibility and economic viability of plant retrofits vary across EGUs, as they are contingent upon the regional availability of biomass, unit-specific characteristics, site-specific fuel supply costs, and adjacent CO2 storage potential. Government incentives like 45Q can improve the retrofit viability, though the impact requires further quantification. A comprehensive analysis at the unit level is essential to address the question regarding the fate of the U.S. coal-fired electricity generation fleet toward the net-zero emission goal. This study conducts a systematic techno-economic-environmental assessment of EGUs to identify the viability of biomass co-firing and deep CCS retrofits in the U.S. coal-fired power fleet. Specifically, it characterizes the techno-economic performance of deep carbon capture, estimates life cycle greenhouse gas (GHG) emissions, and conducts a fleet-level assessment on retrofit viability. The key objectives are (1) to estimate the unit-specific performance and retrofitted cost under various biomass co-firing levels and CO2 capture rates; (2) to determine the possibility of reaching net-zero emission at the fleet level; (3) to quantify the cumulative capacities that are suitable for plant retrofits under current and future biomass supply scenarios; and (4) to improve the understanding of policy impacts on such retrofits to help the power sector’s transition to a net-zero economy. Techno-economic Model of Deep Carbon Capture. This study develops the performance and economic models for Monoethanolamine-based post-combustion CO2 capture at 95–99% capture rates. The process is simulated in Aspen Plus, analyzing the performance of carbon capture technology by varying the plant sizes, solvent lean loading, CO2 concentrations, and flue gas inlet temperature. Based on the key inputs and output parameters of CO2 capture, a reduced-order performance model of deep carbon capture is formulated. In addition, an engineering-economic model integrating the performance metrics is developed to estimate the capital as well as operation and maintenance (O&M) costs. Capital cost estimations follow the framework of the Integrated Environmental Control Model (IECM) and incorporate data regressions from three technical reports by IECM, the National Energy Technology Laboratory (NETL), and the National Renewable Energy Laboratory. The O&M cost estimation utilizes the actual inventory consumption rate and labor requirements. Both performance and cost models are embedded into IECM v13.0-beta, a fossil-fuel power plant modeling tool. Life Cycle Assessment of Power Plants. This study estimates the GHG emissions of power plants through life cycle assessment (LCA). The LCA scope includes fuel supply, combustion-based power generation, and CO2 transport and storage. The fuel-based life cycle module is designed following the framework of the NETL Unit Process Library and CO2U LCA Guidance Toolkit. The module is then incorporated into IECM v13.0-beta. The process-based LCA is applied to estimate the GHG emissions of coal and biomass supply, coal- and coal-biomass co-firing power plant operation, as well as CO2 pipeline transport and geographical sequestration. An uncertainty analysis is conducted to quantify the variability and uncertainty associated with the LCA using the Latin Hypercube Sampling (LHS) method. Fleet-level Assessment. This study evaluates the technical and economic feasibility of selected coal-fired EGUs, examines the role of tax credits in retrofit viability, and assesses the competitiveness of retrofitted units against other low-carbon options. Unit screening identifies EGUs for the study, focusing on new, efficient baseload units with air pollution controls. The power plant databases are then established to organize unit-specific information on performance and operating conditions from the relevant public databases. Biomass for co-firing retrofits is selected based on home and neighboring county availability, ensuring sustained operation with at least a 5% co-firing level. The CO2 storage site is determined by state-level storage potential, with ArcGIS Pro and NETL CO2 Saline Storage Cost Model used to identify the optimal balance between the nearest transport distances and affordable storage costs. The latest IECM v13.0-beta is then employed to configure and evaluate the eligible EGUs with or without the deployment of deep CCS and biomass co-firing. A supply curve is established to illustrate the cumulative installed capacity suitable for retrofits at different cost levels. A sensitivity analysis on tax credits for carbon sequestration is performed. Finally, a unit-level cost comparison is conducted among retrofitted plants, renewable power with battery storage, and abated fossil fuels with DAC. Expected Results. This study evaluates the technical, economic, and environmental metrics of each EGU across an array of CO2 capture rates and biomass co-firing level scenarios. Unit-level comparisons will identify critical factors influencing technical performance. The supply curves with and without tax incentives will provide insights into the impact of tax credits on biomass co-firing and CCS deployment. The cost comparisons with renewables and DAC-retrofit will assess the competitiveness of the retrofitted units. Life cycle emissions from each unit will be assessed to identify the scenarios under which net-zero emissions can be achieved. These analyses are expected to determine the total coal-fired capacity suitable for serving as a low-carbon energy source with or without tax incentives. The study results are novel in identifying optimal unit-specific strategies for producing carbon-neutral power, whether through retrofitting EGUs with deep CCS, biomass co-firing, DAC, or installing renewable power with battery. The findings will provide insight into nationwide efforts to ensure reliable, affordable, and low-carbon electricity. It also will inform investment decisions and policies in the deployment of deep carbon capture and negative emission technologies for a net-zero energy future.

Biomass Co-firing↗
DOE OSTI2016

Energy economic evaluation of hydrogen production by HTGR and solar tower - 18554

Changing the high temperature heat supply of energy intensive industries from today's mostly fossil sources to nuclear or renewable sources offers the opportunity of massive reductions of greenhouse gas emissions. Even though the HTGR as well as the solar tower are technically capable to supply heat at the required high temperature level, it is uncertain whether these technologies can compete with the fossil energy supply. Therefore, the aim of this paper is the assessment of the economic competitiveness of process heat supply by HTGR or solar tower to fossil fired processes using steam methane reforming as industrial example process. Applying a self-developed optimization model, energy economic analyzes are conducted for nuclear, solar and fossil energy supply systems. The results are benchmarked with the IAEA software HEEP and compared to literature values. The analyzes show that hydrogen generation costs of the solar tower system are higher than those of the HTGR system. Both technologies benefit from the support of a fossil heater, as the hydrogen generation costs can be significantly reduced even with a small amount of burned natural gas. Nevertheless, a steam methane reforming process run by HTGR or by solar tower is not yet competitive to the natural gas fired hydrogen production. (authors)

08 HYDROGEN↗
DOE OSTI2011

The potential environmental gains from recycling waste plastics: Simulation of transferring recycling and recovery technologies to Shenyang, China

Research highlights: {yields} Urban symbiosis creates compatibility of industrial development and waste management. {yields} Mechanical technology leads to more CO{sub 2} emission reduction. {yields} Energy recovery technology leads to more fossil fuel saving. {yields} Clean energy makes recycling technologies cleaner. {yields} Demand management is crucial for realizing potential environmental gains of recycling. - Abstract: With the increasing attention on developing a low-carbon economy, it is necessary to seek appropriate ways on reducing greenhouse gas (GHG) emissions through innovative municipal solid waste management (MSWM), such as urban symbiosis. However, quantitative assessments on the environmental benefits of urban symbiosis, especially in developing countries, are limited because only a limited number of planned synergistic activities have been successful and it is difficult to acquire detailed inventory data from private companies. This paper modifies and applies a two-step simulation system and used it to assess the potential environmental benefits, including the reduction of GHG emissions and saving of fossil fuels, by employing various Japanese plastics recycling/energy-recovery technologies in Shenyang, China. The results showed that among various recycling/energy-recovery technologies, the mechanical waste plastics recycling technology, which produces concrete formwork boards (NF boards), has the greatest potential in terms of reducing GHG emissions (1.66 kg CO{sub 2}e/kg plastics), whereas the technology for the production of refuse plastic fuel (RPF) has the greatest potential on saving fossil fuel consumption (0.77 kgce/kg-plastics). Additional benefits can be gained by applying combined technologies that cascade the utilization of waste plastics. Moreover, the development of clean energy in conjunction with the promotion of new waste plastics recycling programs could contribute to additional reductions in GHG emissions and fossil fuel consumption.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2015

Absorption and Phase Contrast X-Ray Imaging in Paleontology Using Laboratory and Synchrotron Sources

X-ray micro-computed tomography (CT) is commonly used for imaging of samples in biomedical or materials science research. Owing to the ability to visualize a sample in a nondestructive way, X-ray CT is perfectly suited to inspect fossilized specimens, which are mostly unique or rare. In certain regions of the world where important sedimentation events occurred in the Precambrian geological time, several fossilized animals are studied to understand questions related to their origin, environment, and life evolution. This article demonstrates the advantages of applying absorption and phase-contrast CT on the enigmatic fossil Corumbella werneri, one of the oldest known animals capable of building hard parts, originally discovered in Corumba (Brazil). Different tomographic setups were tested to visualize the fossilized inner structures: a commercial laboratory-based CT device, two synchrotron-based imaging setups using conventional absorption and propagation-based phase contrast, and a commercial X-ray microscope with a lens-coupled detector system, dedicated for radiography and tomography. Based on our results we discuss the strengths and weaknesses of the different imaging setups for paleontological studies.

Corumbella werneri↗
DOE OSTI2019

Experimental Preservation of Muscle Tissue in Quartz Sand and Kaolinite

Siliciclastic sediments of the Ediacaran Period contain exceptionally preserved fossils of macroscopic organisms, including three-dimensional casts and molds commonly found in sandstones and siltstones and some two-dimensional compressions reported in shales. The sporadic and variable associations of these exceptionally preserved macroscopic fossils with pyrite, clay minerals, and microbial fossils and textures complicate our understanding of fossilization processes. This hinders inferences about the evolutionary histories, tissue types, original morphologies, and lifestyles of the enigmatic Ediacara biota. In this work, we investigate the delayed decay of scallop muscles buried in quartz sand or kaolinite for 45 days. This process occurs in the presence of microbial activity in mixed redox environments, but in the absence of thick, sealing microbial mats. Furthermore, microbial processes that mediate organic decay and release the highest concentrations of silica and Fe(II) into the pore fluids are associated with the most extensive tissue decay. Delayed decay and the preservation of thick muscles in sand are associated with less intense microbial iron reduction and the precipitation of iron oxides and iron sulfides that contain Fe(II) or Fe(III). In contrast, muscles buried in kaolinite are coated only by <10 μm-thick clay veneers composed of kaolinite grains and newly formed K- and Fe(II)-rich aluminosilicate phases. Muscles that undergo delayed decay in kaolinite lose more mass relative to the muscles buried in sand and undergo vertical collapse. These findings show that the composition of minerals that coat or precipitate within the tissues and the vertical dimension of the preserved features can depend on the type of sediment that buries the muscles. Similar processes in the zone of oscillating redox likely facilitated the formation of exceptionally preserved macrofossils in Ediacaran siliciclastic sediments.

58 GEOSCIENCES↗
DOE OSTI2011

Waste-to-Wheel Analysis of Anaerobic-Digestion-Based Renewable Natural Gas Pathways with the GREET Model

In 2009, manure management accounted for 2,356 Gg or 107 billion standard cubic ft of methane (CH 4 ) emissions in the United States, equivalent to 0.5% of U.S. natural gas (NG) consumption. Owing to the high global warming potential of methane, capturing and utilizing this methane source could reduce greenhouse gas (GHG) emissions. The extent of that reduction depends on several factors - most notably, how much of this manure-based methane can be captured, how much GHG is produced in the course of converting it to vehicular fuel, and how much GHG was produced by the fossil fuel it might displace. A life-cycle analysis was conducted to quantify these factors and, in so doing, assess the impact of converting methane from animal manure into renewable NG (RNG) and utilizing the gas in vehicles. Several manure-based RNG pathways were characterized in the GREET (Greenhouse gases, Regulated Emissions, and Energy use in Transportation) model, and their fuel-cycle energy use and GHG emissions were compared to petroleum-based pathways as well as to conventional fossil NG pathways. Results show that despite increased total energy use, both fossil fuel use and GHG emissions decline for most RNG pathways as compared with fossil NG and petroleum. However, GHG emissions for RNG pathways are highly dependent on the specifics of the reference case, as well as on the process energy emissions and methane conversion factors assumed for the RNG pathways. The most critical factors are the share of flared controllable CH 4 and the quantity of CH 4 lost during NG extraction in the reference case, the magnitude of N 2 O lost in the anaerobic digestion (AD) process and in AD residue, and the amount of carbon sequestered in AD residue. In many cases, data for these parameters are limited and uncertain. Therefore, more research is needed to gain a better understanding of the range and magnitude of environmental benefits from converting animal manure to RNG via AD.

02 PETROLEUM↗
DOE OSTI2013

Energy transitions in the early 21st Century

We are in the early stages of a long and complex transition from a global economy based on fossil energy to an economy based on low carbon renewable energy. However, fossil fuel resources are abundant and widely distributed, and they will remain the dominant source of primary energy for at least the next quarter century. In the United States, displacement of coal by natural gas for electric power generation has done more to reduce CO2 emissions than all new renewables combined, and this may occur globally for the next decade or two, even if the European Union does not take advantage of its large unconventional natural gas resources. Greater energy efficiency (not including the efficiencies associated with displacement of coal by gas) will also be more important than new renewables. Cost/benefit ratios are important for sustainability of the transition, and some energy efficiency technologies and displacement of coal by natural gas have lower cost/benefit ratios than wind power, solar power or biofuels. Money spent on the large scale deployment of wind, solar and especially biofuels would be better spent on research, development and demonstration of a broader suite of technologies that would support the energy transition, with a focus on improving the cost benefit ratios of already deployed technologies and developing alternatives. Advanced nuclear reactors, engineered geothermal systems, fossil fuel recovery coupled with CO2 sequestration and pre-combustion or post-combustion decarbonation of fossil fuels with geological CO2 sequestration are among the technologies that might be more cost effective than wind, solar or biofuels, and biofuels have serious adverse societal and environment consequences.

58 GEOSCIENCES↗