SCOPE Biofuels Project Releases Assessment on Environmental Effects of Biofuel Technologies
3 April 2009
The SCOPE (Scientific Committee on Problems of the Environment) International Biofuels Project, has published the full proceedings of its Rapid Assessment workshop on the environmental effects of biofuel technologies, 22-25 September 2008. SCOPE is part of the International Council for Science.
While noting that most recent studies based on lifecycle analysis show that even first generation biofuels can result in “a substantial reduction” in net greenhouse gas emissions (80% to greater than 100% for sugarcane ethanol, 30% to 50% for corn ethanol), papers in the study express concerns over what they contend are potentially undercalculated N2O greenhouse gas effects; the exacerbation of hypoxia from run-off; the need for inclusion of indirect land use effects in greenhouse gas assessments; water use and quality; and other environmental and social effects.
Key findings of the rapid assessment, as collected in the Executive Summary paper (with Robert Howarth of Cornell the lead author) partially include:
Many of the adverse effects of biofuels on the environment could be reduced by using best agricultural management practices, if production is kept below sustainable production limits, although choice of feedstocks and the overall demand for biofuel and level of production remain critical.
In general, biofuels made from organic waste are environmentally more benign than those from energy crops. Using biomass primarily for material purposes, reusing and recycling it, and then recovering its energy content can gain multiple dividends.
Low-input cultivation of perennial plants, e.g. from short-rotation forestry and grasslands, may be an effective source of cellulosic biomass and provide environmental benefits (reduced pollution and lower greenhouse gas emissions). Careful attention to maintaining the longterm productivity of these systems through nutrient additions (particularly potassium) is required.
New liquid hydrocarbon fuels (BtL) produced from cellulosic biomass are under development, and seem likely to offer several advantages over producing ethanol from cellulose in terms of more efficient yields and less environmental impact. The economic viability of this technology still needs to be proven, and potential conflicts with traditional wood-based industries should be considered.
Increasing evidence suggests that biomass can be used much more efficiently (and therefore with less environmental impact) through direct combustion to generate electricity and heat, rather than being converted to liquid fuels such as ethanol.
On the production side, options exist for improving technologies in terms of new feedstocks and conversion technologies as well as more efficient use of biomass. Policies to enhance performance of biofuel production comprise: guidelines for sustainable biofuel production and tools to monitor their implementation; and product-oriented certification of biofuels.
The utility of guidelines for sustainable biofuel production and certification programs may be reduced if they are based only on product life-cycle and farming standards, as these cannot address the difficult issue of indirect land use resulting from growing demand. Criteria that account for the effects of land-use change, or that restrict the types of biofuel feedstocks, could have greater utility. The development of such criteria is a difficult challenge, but a necessary one if biofuels are to be environmentally sustainable.
Current mandates and targets for liquid biofuels should be reconsidered in light of the potential adverse environmental consequences, potential displacement or competition with food crops, and difficulty of meeting these goals without large-scale land conversion.
The first steps towards sustainable energy and resource management should aim for significant reductions on the demand side, with greater conservation and improved efficiency. Government mandates and economic incentives aimed at expanding biofuel production should be coupled with policies that manage the overall demand for energy.
Policy instruments are needed to help adjust the overall demand for (non-food) biomass at levels which can be supplied by sustainable production such as: effective incentives to increase efficient use of biomass and mineral resources; incentives to reduce fuel consumption for transportation.
Comprehensive land-use guidelines are needed that target biofuel production on marginal and degraded lands and preserve areas for agriculture, forestry, settlements/ infrastructure, and nature conservation on the regional, national, and international levels to avoid unintended consequences. This requires a spatial inventory of land resources and their potential competing uses at scales appropriate to crop production and nature conservation.
National programs for sustainable resource management will also have to consider the global land use associated with the domestic consumption of biomass products (agriculture, forestry) in order to limit the shift of environmental pressure to other regions.
Biofuels based on low input cultivation of non-food crops offers promise in developing countries as a source of energy, in part because energy use is often very low at present. Biofuel markets can serve as an opportunity to trigger additional investments that could lead to increased production of food as well as biofuel crops by small-scale farmers. Further research on the use of indigenous non-food crops should be encouraged.
The distribution of wealth is very uneven in many countries, and a high potential exists for the benefits of biofuels to accrue largely to those with wealth. Policies should be established to assure that rural poor populations would benefit from biofuel developments.
Opportunities for biofuel production that maximize social benefits while minimizing environmental impacts exist, but the extent of these win-win situations is limited, and their contribution to society’s energy budget will be very small. As total biofuel production grows, the environmental costs increasingly overshadow societal benefits.
Lifecycle analysis. In their paper on lifecycle analysis, Emanuela Menichetti and Martina Otto reviewed and assessed 30 LCA studies particularly those relating to the energy balance and greenhouse gas (GHG) emissions of biofuels produced from a range of crops and other biomass feedstocks using various conversion technologies.
Among their general observations were that while the number of full LCA studies continues to increase, it is still relatively small, and that most studies focus on traditional first generation feedstocks such as corn, sugarcane, rapeseed and wheat. Other observations included:
Most studies only include energy consumption (sometimes only non-renewable energy, sometimes total energy) and CO2 emissions. A few studies also include other relevant impact indicators as acidification potential, eutrophication potential, ozone depletion potential and various toxicity potentials. However very few studies include water use impacts.
Methodologies to develop biodiversity quality indicators are still under discussion. No study in the review presents results in terms of biodiversity.
Very few studies take into account land use impacts driven by biofuel crop production. More specifically, only one third of the studies define an alternative land use reference system and calculate the carbon stock. Potential impacts in terms of indirect land use change driven by increased bioenergy demand are not considered in the sample analyzed.
The transparency level of reports is quite heterogeneous with respect to hypothesis and assumptions, yields, heating values, emission factors, and other background methodological choices. Very few studies include a data quality review according to the requirements of the ISO standards for LCA.
Heterogeneity observed in terms of treatment of co-products and allocation methods followed.
Social issues are very often overlooked in the studies. “This is not surprising, given the purely environmental focus of LCA technique.”
Many databases and LCA softwares are used to model data. In particular, some of the life cycle inventory databases used in the studies appear relatively old. This affects the quality of results, regardless of the quality of the primary data collected.
LCA per se does not assess absolute impacts of large-scale deployment of a certain technology or product, but it can be combined with other assessment tools to do so (e.g. agro-economic market models). The very recent estimates of indirect-land use changes due to biofuels diffusion are an important step in this direction. However, further research on agro-economic modeling looking at worldwide impacts of large scale biofuel diffusion is needed to properly address this challenging issue.
At the same time, LCA models need to be improved and further developed to treat future technologies with a minimized level of uncertainty. We recommend the land use change GHG contribution to be always presented in a transparent and disaggregated way from the rest of the life cycle; and all the assumptions about new and former land use to be clearly reported.
...There is a clear need to reach consensus on how to carry out LCAs on biofuels, driven by national and international legislation which include GHG emission reduction goals. This implies reaching agreement on of key parameters (e.g. allocation rules of impacts on co-products, N2O emission rates, land use carbon stock, technology progress, etc). Ideally this should happen in a multi-stakeholder process at international level.—Menichetti and Otto
Ravindranath et al. in their paper conclude that, when factoring in land use change, “when biofuel cropping is associated with the conversion of native ecosystems, the net GHG balance is negative, implying no net immediate climate benefits from shifting to biofuels.”
The critical issues for both GHG emissions and food production are; which land types will be converted to biofuel crops; which biofuel crops will be grown and what biofuel crop yields will be. If forest land or wetlands or productive pasture lands are used, the implications are likely to be negative for GHG emissions as well as food production. Alternatively, if biofuel production is targeted towards lands previously converted to agriculture, but not currently being used for crop production, such as degraded pasture or abandoned farmland, the GHG and biodiversity consequences will be much more favorable than if biofuel production causes the direct or indirect conversion of natural ecosystems.—Ravindranath et al.
Nitrogen effects: N2O and run-off. Nitrous oxide (N2O), a potent greenhouse gas, is formed as a byproduct of bacterial processing of nitrogen in soils, sediments, and waters. In the introductory paper to the collection, Howarth et al. argue that the UN IPCC assessment approach is underestimating the importance of N2O, and reference the much higher estimates produced by Crutzen et al., while noting that the analysis “...has been controversial, particularly with regard to their allocation to specific fuel crops... and that the Gallagher Report...concludes that the findings of Crutzen et al. (2007) may not be robust.”
In their paper on the impact of ethanol production on nutrient cycles and water quality, Simpson et al. conclude that increased corn acreage and increased fertilizer application rates due to corn prices will increase N and P losses to streams, rivers, lakes, and coastal waters, particularly the Northern Gulf of Mexico and Atlantic coastal waters downstream of expanding production areas, with resulting increases in hypoxia (dead zones).
Future harvest of corn stover for cellulosic ethanol production would increase erosion (i.e. sedimentation) and nutrient loads from corn land, they said.
We conclude that continuing the current direction in ethanol production, particularly with the focus remaining on grain and sugar crops as primary feedstocks, has serious implications for coastal water quality and will almost certainly worsen, already serious hypoxic conditions in many locations around the world.—Simpson et al.
Renewable Fuels Association Response. The US Renewable Fuels Association (RFA) released a brief response to a few of the main points contained in the SCOPE report. These include:
The RFA contends that there is no empirical evidence positively establishing causation of indirect land use changes; nor is there any peer-reviewed research that undeniably and defensibly links biofuels expansion to indirect land conversions.
Analysis of the indirect effects associated with any product’s supply chain is highly uncertain and fraught with unknowns. In the case of predicting biofuels-related indirect land use changes, even the best available methodologies and models have proven to be significantly imprecise. The methodology used by Searchinger et al. to estimate land use changes resulting from biofuels expansion has been roundly rejected by broad array of experts, including the author of the GREET lifecycle model, Department of Energy officials, university professors and others.
While existing tools are instructive in determining the location and degree of land use changes, the RFA argues, they cannot positively assign the cause of those land conversions. According to a recent paper published by the National Academies of Sciences, the complex factors that drive land use change “…tend to be difficult to connect empirically to land outcomes, typically owing to the number and complexity of the linkages involved.” (Turner et al., 2007)
A recent study by Air Improvement Resources, Inc. (AIR), found that expansion of US corn ethanol production to 15 billion gallons per year in 2015 is unlikely to result in the conversion of nonagricultural lands in the US or abroad. Increasing crop yields and growing supplies of nutrient-dense feed co-products are likely to nullify the need to expand global cropland to meet the corn ethanol requirements of the Renewable Fuels Standard, the study found.
In 2007/08, 0.9% of world major cropland was needed (on a gross basis) to meet the grain requirements of the US ethanol industry. When the ethanol industry’s production of feed co-products are factored in, the net use of global cropland for US ethanol production was 0.6%, or an area roughly the size of the state of West Virginia. According to America’s Farmland Trust, more than 16 million acres of farmland have come out of production in the last 10 years.
Despite increases in the amount of coarse grains used for ethanol, the amount of land dedicated to coarse grains (corn, grain sorghum, barley, oats, rye, and millet) globally has decreased over the past 30 years. Global area for coarse grains has decreased 8% since 1980, while world grain ethanol production has increased dramatically. Despite a reduction in land dedicated to coarse grains, annual world coarse grain production has increased nearly 50% since 1980.
The methodology employed by Crutzen and that of the IPCC are very different and cannot be directly compared. The Crutzen approach has been described as a “top down” method and the IPCC is very much a “bottom up” approach. The Crutzen “top down” approach estimated the global N2O emissions from the atmospheric concentrations of N2O and estimated the portion that was attributable to agricultural soils by eliminating the estimated contributions from other sources. Top down approaches that are based on elimination can be very sensitive to the accuracy of the values being eliminated. It has been suggested by other experts that the Crutzen paper missed some sources such as biomass combustion, livestock, and even transportation.
Hypoxia in the Gulf of Mexico is a complex issue that is not fully understood by the scientific community. In its “Gulf Hypoxia Action Plan 2008,” the Mississippi River/Gulf of Mexico Watershed Nutrient Task Force acknowledged that “uncertainties remain in the ability to characterize the spatial and temporal dynamics of hypoxia and the biological, chemical, and physical properties that contribute to it.”
The task force also suggested that, “Additional analysis of detailed nutrient pollution contributions from multiple sectors, including point sources and non-agricultural contributions needs to be undertaken.”
The Task Force also found that, “Net anthropogenic nitrogen inputs (NANI) and net phosphorus inputs for the Mississippi/Atchafalaya River Basin have declined in the last decade, because of more efficient use of fertilizer (as evidenced by increasing corn harvest and constant or declining fertilizer application rates).”
SCOPE symposium on finance, food and energy crisis. SCOPE is holding its 13th General Assembly meeting 9-12 June in London, hosted by the Royal Society along with the UK Committee of SCOPE. Within the framework of the General Assembly, SCOPE is holding a one-day symposium on 12 June on “Finance, Food and Energy Crises: Consequences for the Environment and Land Use Change?”
The purpose of the symposium is to make a “rapid, critical and opportune appraisal and review” of how the current problems affect our environmental priorities and what they will mean for land use and land cover, and thus for future trends in climate.
Howarth, R.W., S. Bringezu, M. Bekunda, C. de Fraiture, L. Maene, L. Martinelli, O. Sala. 2009. Rapid assessment on biofuels and environment: overview and key findings. Pages 1-13 in R.W. Howarth and S. Bringezu (eds), Biofuels: Environmental Consequences and Interactions with Changing Land Use. Proceedings of the Scientific Committee on Problems of the Environment (SCOPE) International Biofuels Project Rapid Assessment, 22-25 September 2008, Gummersbach Germany.
Howarth, R.W., S. Bringezu, L.A. Martinelli, R. Santoro, D. Messem, O.E. Sala. 2009. Introduction: biofuels and the environment in the 21st century. Pages 15- 36, in R.W. Howarth and S. Bringezu (eds) Biofuels: Environmental Consequences and Interactions with Changing Land Use.
Menichetti E., and M. Otto. 2009. Energy balance and greenhouse gas emissions of biofuels from a life-cycle perspective. Pages 81-109 in R.W. Howarth and S. Bringezu (eds) Biofuels: Environmental Consequences and Interactions with Changing Land Use.
Ravindranath, N.H., R. Manuvie, J. Fargione, J.G. Canadell, G. Berndes, J. Woods, H. Watson, J. Sathaye. 2009. Greenhouse gas implications of land use and land conversion to biofuel crops. Pages 111-125 in R.W. Howarth and S. Bringezu (eds) Biofuels: Environmental Consequences and Interactions with Changing Land Use.
Simpson, T.W., L.A. Martinelli, A.N. Sharpley, R.W. Howarth. 2009. Impact of ethanol production on nutrient cycles and water quality: the United States and Brazil as case studies. Pages 153-167 in R.W. Howarth and S. Bringezu (eds) Biofuels: Environmental Consequences and Interactions with Changing Land Use.
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