Environmental life cycle impacts of cellulosic ethanol in the Southern U.S. produced from loblolly pine, eucalyptus, unmanaged hardwoods, forest residues, and switchgrass using a thermochemical conversion pathway

The production of six regionally important cellulosic biomass feedstocks, including pine, eucalyptus, unmanaged hardwoods, forest residues, switchgrass, and sweet sorghum, was analyzed using consistent life cycle methodologies and system boundaries to identify feedstocks with the lowest cost and environmental impacts. Supply chain analysis models were created for each feedstock calculating costs and supply chain requirements for the production 453,592 dry tonnes of biomass per year. Cradle-to-gate environmental impacts from these supply systems were quantified for nine mid-point indicators using SimaPro 7.2 LCA software. Conversion of grassland to managed forest for bioenergy resulted in large reductions in GHG emissions, due to carbon sequestration associated with direct land use change. However, converting forests to energy cropland resulted in large increases in GHG emissions. Production of forest-based feedstocks for biofuels resulted in lower delivered cost, lower greenhouse gas (GHG) emissions and lower overall environmental impacts than the studied agricultural feedstocks. Forest residues had the lowest environmental impact and delivered cost per dry tonne. Using forest-based biomass feedstocks instead of agricultural feedstocks would result in lower cradle-to-gate environmental impacts and delivered biomass costs for biofuel production in the southern U.S.

This paper examines the changes in land use in the U.S. likely to be induced by biofuel and climate policies and the implications of these policies for GHG emissions over the 2007-2022 period. The policies considered here include a modified Renewable Fuel Standard (RFS) by itself as well as combined with a cellulosic biofuel tax credit or a carbon price policy. We use a dynamic, spatial, multi-market equilibrium model, Biofuel and Environmental Policy Analysis Model (BEPAM), to endogenously determine the effects of these policies on cropland allocation, food and fuel prices, and the mix of first- and second-generation biofuels. We find that the RFS could be met by diverting 6% of cropland for biofuel production and would result in corn prices increasing by 16% in 2002 relative to the business-as-usual baseline. The reduction in GHG emissions in the U.S. due to the RFS is about 2%; these domestic GHG savings can be severely eroded by emissions due to indirect land use changes and the increase in gasoline consumption in the rest of the world. Supplementing the RFS with a carbon price policy or a cellulosic biofuel tax credit induces a switch away from corn ethanol to cellulosic biofuels and achieves the mandated level of biofuel production with a smaller adverse impact on crop prices. These supplementary policies enhance the GHG savings achieved by the RFS alone, although through different mechanisms; greater production of cellulosic biofuels with the tax credit but larger reduction in fossil fuel consumption with a carbon tax.

This paper examines the extensive and intensive margin changes in land use in the U.S. likely to be induced by biofuel policies and the implications of these policies for GHG emissions over the 2007-2022 period. The policies considered here include the Renewable Fuel Standard (RFS) by itself as well as combined with current biofuel tax credits or a carbon price policy. We use a dynamic, spatial, multi-market equilibrium model, Biofuel and Environmental Policy Analysis Model (BEPAM), to endogenously determine the effects of these policies on cropland allocation, food and fuel prices, and the mix of first and second-generation biofuels. We find that the increase in crop prices under the RFS is likely to be less than 20% in most cases and this increase is much smaller when the RFS is accompanied by volumetric subsidies or a carbon price policy since these policies induce a switch away from corn ethanol to cellulosic biofuels. The impact of the RFS on GHG emissions reduction in the U.S. is fairly modest in size but increases when the RFS is accompanied by volumetric subsidies or a carbon price policy. However, domestic savings in GHG emissions achieved by the RFS can be severely eroded by the indirect land use changes and the rebound effect on global gasoline consumption. The net reductions in global GHG emissions are largest when the RFS is accompanied by a carbon price policy.

The Renewable Fuel Standard (RFS) and state-level Renewable Portfolio Standards (RPS) have the potential to interact in complex ways because they will both rely on biomass for cellulosic biofuels and bio-electricity. This interaction could be synergistic or competitive; while the implementation of the RFS could divert biomass from electricity generation for biofuels it would also generate electricity as a co-product of the cellulosic biofuel production process. This paper examines the welfare costs and greenhouse gas (GHG) emissions effects of the RFS and RPS implemented jointly and compares them with those of implementing each of these policies by itself over the 2007-2030 period using an integrated, dynamic, price endogenous model of the electricity, transportation and agricultural sectors for the US. We also compare the cost effectiveness of these policies implemented jointly with those of a carbon tax that achieves the same level of cumulative reduction in domestic GHG emissions over 2007-2030 period. We find that the implementation of the RFS will raise the welfare costs of implementing the RPS for the electricity sector by 10% and lower its GHG benefits by 7% relative to those with the RPS implemented by itself. We also find that the global welfare costs of the jointly implemented RFS and RPS policies are significantly higher than those of a carbon tax. However, the former induces a larger shift to renewable energy than the carbon tax alone and thus would achieve larger reductions in domestic GHG emissions in the long run than a constant carbon tax policy.

This paper examines the changes in land use in the U.S. likely to be induced by biofuel and climate policies and the implications of these policies for greenhouse gas (GHG) emissions over the 2007–2022 period. The policies considered here include a modified Renewable Fuel Standard (RFS) by itself as well as combined with a cellulosic biofuel tax credit or a carbon price policy. We use a dynamic, spatial, multi-market equilibrium model, Biofuel and Environmental Policy Analysis Model (BEPAM), to endogenously determine the effects of these policies on cropland allocation, food and fuel prices, and the mix of first- and second-generation biofuels. We find that the RFS could be met by diverting 6% of cropland for biofuel production and would result in corn prices increasing by 16% in 2002 relative to the business-as-usual baseline. The reduction in GHG emissions in the U.S. due to the RFS is about 2%; these domestic GHG savings can be severely eroded by emissions due to indirect land-use changes and the increase in gasoline consumption in the rest of the world. Supplementing the RFS with a carbon price policy or a cellulosic biofuel tax credit induces a switch away from corn ethanol to cellulosic biofuels and achieves the mandated level of biofuel production with a smaller adverse impact on crop prices. These supplementary policies enhance the GHG savings achieved by the RFS alone, although through different mechanisms; greater production of cellulosic biofuels with the tax credit but larger reduction in fossil fuel consumption with a carbon tax.

Ethanol production from cellulosic material is considered one of the most promising options for future biofuel production contributing to both the energy diversification and decarbonization of the transport sector, especially where electricity is not a viable option (e.g., aviation). Compared to conventional (or first generation) ethanol production from food and feed crops (mainly sugar and starch based crops), cellulosic (or second generation) ethanol provides better performance in terms of greenhouse gas (GHG) emissions savings and low risk of direct and indirect land-use change. However, despite the policy support (in terms of targets) and significant R&D funding in the last decade (both in EU and outside the EU), cellulosic ethanol production appears to be still limited. The paper provides a comprehensive overview of the status of cellulosic ethanol production in EU and outside EU, reviewing available literature and highlighting technical and non-technical barriers that still limit its production at commercial scale. The review shows that the cellulosic ethanol sector appears to be still stagnating, characterized by technical difficulties as well as high production costs. Competitiveness issues, against standard starch based ethanol, are evident considering many commercial scale cellulosic ethanol plants appear to be currently in idle or on-hold states.

The production of six regionally important cellulosic biomass feedstocks, including pine, eucalyptus, unmanaged hardwoods, forest residues, switchgrass, and sweet sorghum, was analyzed using consistent life cycle methodologies and system boundaries to identify feedstocks with the lowest cost and environmental impacts. Supply chain analysis was performed for each feedstock, calculating costs and supply requirements for the production of 453,592 dry tonnes of biomass per year. Cradle-to-gate environmental impacts from these modeled supply systems were quantified for nine mid-point indicators using SimaPro 7.2 LCA software. Conversion of grassland to managed forest for bioenergy resulted in large reductions in GHG emissions due to carbon uptake associated with direct land use change. By contrast, converting forests to cropland resulted in large increases in GHG emissions. Production of forest-based feedstocks for biofuels resulted in lower delivered cost, lower greenhouse gas (GHG) emissions, and lower overall environmental impacts than the agricultural feedstocks studied. Forest residues had the lowest environmental impact and delivered cost per dry tonne. Using forest-based biomass feedstocks instead of agricultural feedstocks would result in lower cradle-to-gate environmental impacts and delivered biomass costs for biofuel production in the southern U.S.

Sweetness and Power - Public Policies and the ‘Biofuels Frenzy’

The Renewable Fuel Standard (RFS) program specifies a greenhouse gas (GHG) reduction threshold for cellulosic biofuels, while the Low Carbon Fuel Standard (LCFS) program in California does not. Here, we investigate the effects of the GHG threshold under the RFS on projected GHG savings from two corn stover-based biofuel supply chain systems in the United States Midwest. The analysis is based on a techno-economic framework that minimizes ethanol selling price. The GHG threshold lowers the lifecycle GHG of ethanol: 34.39 ± 4.92 gCO2 MJ-1 in the RFS-compliant system and 46.30 ± 10.05 gCO2 MJ-1 in the non RFS-compliant system. However, hypothetical biorefinery systems complying with the RFS will not process the more GHG-intensive corn stover, and thus much less biofuel will be produced compared to the non RFS-compliant system. Thus, taken as a whole, the non RFS-compliant system would achieve more GHG savings than an RFS-compliant system: 10.7 TgCO2 year-1 in the non RFS-compliant system compared with 4.4 TgCO2 year-1 in the RFS-compliant system. These results suggest that the current RFS GHG reduction threshold may not be the most efficient way to carry out the purposes of the Energy Security and Independence Act in the corn stover-based biofuel system: relaxing the threshold could actually increase the overall GHG savings from corn stover-based biofuels. Therefore, the LCFS-type regulatory approach is recommended for the corn stover-based cellulosic biofuel system under the RFS program. In addition, our calculation of the GHG balance for stover-based biofuel accounts for SOC losses, while the current RFS estimates do not include effects on SOC.

Co-firing in coal power plants and its impact on biomass feedstock availability

The present research is aimed at contributing to the Latvian national climate policy development by projecting total GHG emissions up to 2030, by evaluating the GHG emission reduction path in the non-ETS sector at different targets set for emissions reduction and by evaluating the obtained results within the context of the obligations defined by the EU 2030 policy framework for climate and energy. The method used in the research was bottom-up, linear programming optimisation model MARKAL code adapted as the MARKAL-Latvia model with improvements for perfecting the integrated assessment of climate policy. The modelling results in the baseline scenario, reflecting national economic development forecasts and comprising the existing GHG emissions reduction policies and measures, show that in 2030 emissions will increase by 19.1 % compared to 2005. GHG emissions stabilisation and reduction in 2030, compared to 2005, were researched in respective alternative scenarios. Detailed modelling and analysis of the Latvian situation according to the scenario of non-ETS sector GHG emissions stabilisation and reduction in 2030 compared to 2005 have revealed that to implement a cost effective strategy of GHG emissions reduction first of all a policy should be developed that ensures effective absorption of the available energy efficiency potential in all consumer sectors. The next group of emissions reduction measures includes all non-ETS sectors (industry, services, agriculture, transport, and waste management).

This paper develops a conceptual framework and a numerical simulation model of the fuel and agricultural sectors in the US to analyze the effects of the existing Renewable Fuels Standard (RFS) that mandates the blending of specific volumes of low carbon biofuels with liquid fossil fuels and a proposed national Low Carbon Fuel Standard (LCFS) that imposes a limit on the GHG intensity of the blended fuel on fuel mix, GHG emissions and social welfare in an open economy and to compare them to those with a carbon price policy. The conceptual framework illustrates that, unlike a carbon price policy, the RFS and LCFS have an ambiguous effect on GHG emissions. The numerical analysis shows that all three policies reduce US GHG emissions and increase domestic social welfare relative to a no-policy, business-as usual scenario, with the RFS leading to a lower reduction in GHG emissions than the LCFS. However, the RFS leads to higher social welfare among the policies examined here than the LCFS and the carbon tax.

This study by the U.S. Department of Energy (DOE) estimates the worldwide potential to produce biofuels including biofuels for export. It was undertaken to improve our understanding of the potential for imported biofuels to satisfy the requirements of Title II of the 2007 Energy Independence and Security Act (EISA) in the coming decades. Many other countries biofuels production and policies are expanding as rapidly as ours. Therefore, we modeled a detailed and up-to-date representation of the amount of biofuel feedstocks that are being and can be grown, current and future biofuels production capacity, and other factors relevant to the economic competitiveness of worldwide biofuels production, use, and trade. The Oak Ridge National Laboratory (ORNL) identified and prepared feedstock data for countries that were likely to be significant exporters of biofuels to the U.S. The National Renewable Energy Laboratory (NREL) calculated conversion costs by conducting material flow analyses and technology assessments on biofuels technologies. Brookhaven National Laboratory (BNL) integrated the country specific feedstock estimates and conversion costs into the global Energy Technology Perspectives (ETP) MARKAL (MARKet ALlocation) model. The model uses least-cost optimization to project the future state of the global energy system in five year increments. World biofuels production was assessed over the 2010 to 2030 timeframe using scenarios covering a range U.S. policies (tax credits, tariffs, and regulations), as well as oil prices, feedstock availability, and a global CO{sub 2} price. All scenarios include the full implementation of existing U.S. and selected other countries biofuels policies (Table 4). For the U.S., the most important policy is the EISA Title II Renewable Fuel Standard (RFS). It progressively increases the required volumes of renewable fuel used in motor vehicles (Appendix B). The RFS requires 36 billion (B) gallons (gal) per year of renewable fuels by 2022. Within the mandate, amounts of advanced biofuels, including biomass-based diesel and cellulosic biofuels, are required beginning in 2009. Imported renewable fuels are also eligible for the RFS. Another key U.S. policy is the $1.01 per gal tax credit for producers of cellulosic biofuels enacted as part of the 2008 Farm Bill. This credit, along with the DOE's research, development and demonstration (RD&D) programs, are assumed to enable the rapid expansion of U.S. and global cellulosic biofuels production needed for the U.S. to approach the 2022 RFS goal. While the Environmental Protection Agency (EPA) has yet to issue RFS rules to determine which fuels would meet the greenhouse gas (GHG) reduction and land use restrictions specified in EISA, we assume that cellulosic ethanol, biomass-to-liquid fuels (BTL), sugar-derived ethanol, and fatty acid methyl ester biodiesel would all meet the EISA advanced biofuel requirements. We also assume that enough U.S. corn ethanol would meet EISA's biofuel requirements or otherwise be grandfathered under EISA to reach 15 B gal per year.

Alternative transportation fuel standards: Welfare effects and climate benefits

This paper examines the economic and GHG implications of stacking a low carbon fuel standard (LCFS) with and without a carbon price policy on the Renewable Fuel Standard (RFS). We compare the performance of various policy combinations for food and fuel prices, fuel mix and fuel consumption. We also analyze the economic costs and benefits of alternative policy combinations and their distributional effects for consumers and producers in the transportation and agricultural sector in the US. Using a dynamic, multi-market equilibrium, nonlinear mathematical programming model of the transportation and agricultural sectors, we find that combining the RFS with an LCFS policy leads to a reduction in first generation biofuels and an increase in second generation biofuels compared to the RFS alone. This policy combination also achieves greater reduction in GHG emissions even after considering offsetting market mediated effects. Imposition of a carbon price with the RFS and LCFS policy primarily induces fuel conservation and achieves larger GHG emissions reduction compared to the other policy scenarios. All of these policy combination lead to higher net economic benefits for the transportation and agricultural sectors relative to the no policy baseline because they improve the terms of trade for these sectors.