that will address important societal issues regarding sustainability and climate change.
As one example, he discussed the carbohydrate supply chain. Today, if all of the global production of cereal grains were converted to ethanol, leaving nothing for food, the total output would be approximately 14 million barrels of oil equivalent per day. In contrast, current crude oil production is approximately 85 million barrels of oil equivalent per day. Clearly, conventional carbohydrates cannot make a significant impact on the world’s demand for petroleum-based fuels, chemicals, and materials. What can meet that demand is lignocellulose, both from waste and purposefully grown energy crops. Recent estimates from the DOE’s Billion-Ton study put the total U.S. biomass potential of lignocellulose in the range of 1.0 to 1.6 billion tons, which would be enough to meet the demands of the U.S. Renewable Fuels Standards (RFS2) as set out in the Energy Independence and Security Act of 2007 (EISA), and generate enough additional biomass for electricity generation and the production of chemicals and other materials.
Another obstacle is what Bryan calls the tyranny of distance. Although it is expensive to drill a well to collect crude oil or natural gas, a single well produces massive amounts of product that can be fed into a pipeline for distribution. Biomass, in contrast, is sparsely distributed, and even the highest yielding energy crop will require many times the area of an oil or natural gas field to produce the equivalent amount of energy. This will be a challenging problem to solve, one that DOE is addressing through its Uniform Feedstock Format. The idea is that small depots would convert biomass into a uniform, pellet-like material that could be handled as a quasi-liquid and easily transported to central storage or processing facilities. Seasonality is another significant issue, Bryan added, one that will require developing a mix of biomass sources that will together produce a steady supply of feedstock to a processing plant.
There is also the issue of process scale. Today, the world’s largest ethanol plant is rated at 175 million gallons per year, the energy equivalent of approximately 12,000 barrels of oil per day. The largest petroleum refining facility in operation today can process about 1 million barrels of oil per day, and the smallest economically efficient refinery handles 200,000 barrels per day.
After Bryan’s introductory remarks, the workshop consisted of two presentations on feedstocks and conversion technologies, followed by three presentations and corresponding breakout sessions on value chains for the production of fuels, chemicals, heat, and power from biomass. These presentations and discussions are summarized briefly below and in Chapters 2-6 of this workshop report. The workshop concluded with a panel discussion and an open comment period.
Feedstocks and Conversion Technologies
Bryce Stokes, senior advisor with CNJV, a contractor to DOE, summarized the main findings of DOE’s Billion-Ton Study update, for which he was a co-director, noting that the United States has the resources to produce a sufficient supply of renewable biomass to meet its 2030 goal of producing one billion tons of biomass for energy uses without impacting other vital U.S. farm and forest products. The 2011 report included county-level projections showing that necessary land use changes will occur slowly and that a significant amount of biomass will come from increased production of energy crops and increased use of corn stover and straws. The report noted that the woody portion of municipal solid waste can become a substantial contributor to biomass resources. Given the diffuse nature of biomass, collecting and distributing biomass on the billion-ton scale will be challenging. The report also outlines a vision for creating a uniform commodity feedstock from biomass.
Brian Duff, chief engineer and acting deployment team leader for the Office of Biomass Program at DOE, discussed the security, environmental, and economic reasons why the United States should develop biomass-based fuels, chemicals, and power industries. He noted that tapping into the enormous value of petrochemicals and specialty chemicals is a place where chemistry can play a huge role in realizing value from biomass conversion, particularly since these are high value added products that would use very little of the available biomass. He then introduced the two major sets of technologies—biological and thermochemical—for converting biomass into biofuels and chemicals and remarked that the list of building blocks, secondary chemicals, intermediates, and end products that can be made from biomass feedstocks is virtually limitless, just as it is with petroleum.
Chris Somerville, professor of alternative energy and director of the Energy Biosciences Institute at the University of California in Berkeley, gave a broad perspective on the challenges that need to be addressed to develop economically viable schemes for converting lignocellulosic biomass into fuels or intermediates that can be converted into other chemicals. The biggest challenge is to move from the current batch processing system to one that more closely resembles the continuous flow process used in producing fuels from oil. He discussed the potential advantages of continuous flow processing and explained that the development of such a system will require new separation and purification technologies. Attracting researchers with the necessary skills in chemistry and chemical engineering to this field represents a substantial challenge.
Robert Brown, founding director of the Bioeconomy Institute at the Iowa State University, discussed the pros and cons of the two routes for thermochemical conversion of