Sustainability and Biomass Energy Systems

In the late 1970’s when oil supply disruptions caused the U.S. Government to begin to support research on biomass feedstocks for fuels and chemicals, the renewability of the bioenergy resources was the most important criteria. All of the projects initiated as a result of the U.S. Department of Energy’s (DOE’s) first biomass solicitation in 1977 were directed toward evaluating the potential for wood production and harvest scenarios that would supply renewable bioenergy resources. Much debate at the time centered around the environmental soundness of various feedstock technology choices and the energy input versus output ratios (eg Braunstein et al, 1981) but sustainability was not yet a term in poplar usage. It was with a high level of environmental and social sensitivity that the herbaceous crops program solicitation in 1984 sought crops that would “increase the production of biomass for energy without significantly reducing food production” (ORNL, 1984). This goal lead to a decision to solicit research on crops suitable for marginal cropland. However, because marginal croplands are often sloping or have poor quality (low nutrient) soils, crops that could minimize erosion, be productive with minimal fertilizer inputs and increase soil carbon were also given higher priority.

Although many crop and soil management techniques now considered essential elements of sustainable agriculture were researched and published during the 1945 to 1979 time period (Gold and Gates , 2007) the term sustainability did not come into popular usage until after a definition of sustainable development was published in the 1987 Bruntland Commission Report. It defined sustainable developments as those that “meet the present needs without compromising the ability of future generations to meet their needs” (United Nations,1987). In the US the first legislation to specifically promote “sustainable” agriculture was the 1985 Farm Bill, but it was not officially defined until the 1990 Farm Bill. The 1990 Farm Bill definition of sustainable agriculture was: “An integrated system of plant and animal production practices having a site-specific application that over the long term will: (1) satisfy human food and fiber needs, (2) enhance environmental quality and the natural resource base upon which the agricultural economy depends, (3) make the most efficient use of nonrenewable resources and on-farm resources and integrate, where appropriate, natural biological cycles and controls, (4) sustain the economic viability of farm operations, and (5) enhance the quality of life for farmers and society as a whole”.

Most sustainability definitions, however, seem to stimulate debate, rather than provide guidance regarding the types of crop management systems that should be used for biomass production. A 1995 Doane’s Agricultural Report on the 1995 Farm Bill debate (Vol. 58, No.7-5), noted there were two contrasting viewpoints on what constituted sustainable agriculture. One view argued that sustainable agricultural policy should encourage the use of fewer and lower levels of pesticides and fertilizers in producing crops. The other view argued that the goal should be to produce more food (or biomass) on fewer acres using high-yield techniques, including pesticide and fertilizer use (and genetically modified crops). A similar debate still rages today for biomass production systems with some researchers proposing low-input, high-diversity grasslands as the most environmentally desirable approach (Tilman et al, 2006) while others show that at the low yields obtained, the land area required is prohibitive and moderate input, low-diversity, high-yield biomass crops are environmentally sound and more likely to be economically viable (Mitchell and Vogel, in press 2009). Some convergence is occurring as several researchers are evaluating the possibility of attaining high yield in polyculture systems including mixed grasses, mixed trees, and even mixtures of grasses or forbs and trees.

The first attempt at developing a set of principals and guidelines for environmentally sound bioenergy systems began in 1992. The Electric Power Research Institute and the National Audubon Society (with help from DOE) collaborated to conduct several roundtable discussions across the nation and to produce a report entitled “Principles and Guidelines for the Development of Biomass Energy Systems (National Biofuels Roundtable, 1994). The principles developed included the concepts of environmental soundness, economic viability, and social fairness, very similar to many definitions of sustainability though the word sustainability was purposely omitted from the report. A large range of environmental impacts were addressed in developing guidelines, but of particular interest at that time was the potential impacts (positive and negative) of biomass energy systems on greenhouse gas emissions on a full life cycle basis, and on the impacts of scale of technology implementation.

In 2008 a Roundtable on Sustainable Biofuels was initiated by an international group with many industry leaders and representatives from developing as well as developed countries on the steering board. Stakeholder meetings have been held around the world, including two in the US in spring 2009. A draft statement of global principals and criteria for sustainable biofuels production called “Version Zero” is currently circulating and available for comment through the website www.bioenergywiki.net . The draft contains 12 principals including more in the area of social fairness than any previous statement of sustainability principals. The issue of effects of bioenergy energy system implementation on direct and indirect land use change (recently highlighted by Searchinger et al, 2008) are incorporated within the principal pertaining to greenhouse gas emissions.

The Ecological Society of America (ESA), held a workshop on Biofuels in March 2008 to address sustainability issues. Reports generated by working groups at that workshop will be published in the near future. Meanwhile, the ESA policy statement on biofuel sustainability can be found at http://www.esa.org/pao/policyStatements/Statements/biofuel.php . As expected it focuses on ecological principals, with the three key principals being “systems thinking, conservation of ecological services, and scale alignment”.

The Department of Energy’s Biomass Program continues to be committed to developing the technologies, processes and systems needed to sustainably convert a broad range of cellulosic feedstocks into clean, abundant biofuels. Program literature states that the DOE Biomass Program aims to develop processes and products that reduce carbon emissions, protects human health and the environment, and add value to the biofuel life cycle.

References:

Gold, M and Gates, JP. Tracing the Evolution of Organic/Sustainable Agriculture; A Selected and Annotated Bibliography. Bibliographies and Literature of Agriculture, no. 72. USDA, National Agricultural Library, Alternative Farming Systems Information Center. Updated and expanded May 2007. Available at http://www.nal.usda.gov/afic/pubs/tracing/tracing.shtml

Braunsetin HM, Kanciruk P, Roop RD, Sharples FE, Tatum JS, Oakes KM. Biomass Energy Systems and the Environment. Pergamon Press. 1981.

Mithchell, R and Vogel, K. Biomass Production from native warm-season grass monocultures and polycultures managed for bioenergy. Presented August 2008 at the Biofuels, Bioenergy, and Bioproducts from Sustainable Agricultural and Forest Crops International Conference; publication currently in press (2009).

National Biofuels Roundtable. Principals and Guidelines for the Development of Biomass Energy Systems. Circulated widely as a Draft Final Report in May, 1994, now available at www.bioenergy.ornl.gov (select tabs, “environment”, “others”, “reports”.

Oak Ridge National Laboratory (ORNL). Request for Proposal No. 19-6233 Entitled “Selection of Herbaceous Species for Energy Crops”. Released by Oak Ridge National Laboratory’s Bioenergy Feedstock Development program approximately March 1984 with proposals due July 17, 1984.

Searchinger T, Heimlich R, Haughton RA., Dong F, Elobeid A, Fabiosa J, Tokgoz,S, Hayes D, Yu,Tun-Hsiang. Use of U.S. Croplands for Biofuels Increases Greenhouse Gases through Emissions from Land Use Change. ScienceExpress online publication 7 February 2008;10.1126/Science.1151861. available at: www.sciencemag.org

United Nations. Our Common Future, Report of the World Commission on Environment and Development. Oxford University Press, 1987. Available at http://www.worldinbalance.net/agreements/1987-brundtland.php