As petroleum supplies dwindle and prices seesaw wildly, many attempts to create new-age fuel substitutes are slowed by a variety of barriers. Batteries tend to be expensive, require long periods to charge, are heavy and promise only a limited range. Hydrogen presents major challenges in energy generation, storage, transport, use and overall efficiency, while converting corn to ethanol triggers public concerns about the impact on food prices and greenhouse gas emissions. Wind and sun, the two most abundant sustainable energy technologies, are not available 24 hours a day, seven days a week, and would require storage in batteries or conversion to hydrogen fuel to meet current energy needs.  All options have their pros and cons and will have to be considered.

AAA asked Charles Wyman, Ford Motor Co. chair in Environmental Engineering at the University of California’s Department of Chemical and Environmental Engineering in Riverside, Calif., to explain biofuels and how they might contribute to helping solve the nation’s energy challenges.

AAA: In layman’s terms, explain biomass and how it’s produced.

CW: Biomass is a broad category of living materials that can include a range of organisms and plants. Our focus is on cellulosic biomass, which is the material that forms the structural portion of plants. It could be an excellent fuel source due to its abundance, low cost and limited value for other uses. Common examples are poplar trees and switchgrass, along with agricultural and forestry residues, such as corn plants and sawdust, respectively, and substantial portions of municipal solid waste, such as yard and paper materials.

AAA: How much biomass material would it take to produce a gallon of gas? 

CW: That depends on the process and technologies employed for both making and using the fuel. In simple terms, we can refine the equivalent of about 70 gallons of gasoline from one ton of dry biomass. An acre of land could yield about 10 tons a year, so about 700 gallons of fuel could be produced per acre of land. Replacing the 140 billion gallons of gasoline we use each year in the U.S. would require something like 200 million acres of land, but if we combine use of more efficient vehicles and biomass technology, we can cut the land requirement to something like 50 million to 70 million acres.  For comparison purposes, about 450 million acres of land are used for agriculture in the U.S. today.

AAA: Would a gallon of biofuel cost more, less or about the same as a gallon of gasoline?

CW: Again, this depends on the process, technology and location. In general terms, biomass costing about $60 a ton could produce about 60 to 70 gallons of gasoline equivalent fuel resulting in a cost of less than $1 a gallon. However, adding in other factors, such as refining, personnel, transportation and facilities costs could add up to about $2.50 per gallon of gasoline equivalent with current technology, although this will drop with experience.

AAA: Where would biofuels be produced, and how would they be made available to consumers? Do we have the infrastructure in place?

CW: Biofuels would be produced near the source of biomass. Generally speaking, this means where land and water are available. Unfortunately, the fuel would have to be moved by truck and rail from manufacturing facilities to the pump because there are no pipelines available for its use, but such pipelines could be implemented.

AAA: How would biofuels impact today’s vehicle fleet?

CW: Cellulosic biomass can be converted into diesel-like fuel, jet fuel, biodiesel and ethanol that all are compatible for use in existing vehicles. Each has advantages and disadvantages. For example, cellulosic ethanol has a somewhat lower energy content per gallon than gasoline and presents some challenges for cold starting. However, it burns more efficiently due to its high octane (that is why it is used in Indy cars), is not carcinogenic like gasoline, produces less evaporative pollutants, has a low carbon footprint for greenhouse gas emissions, can be blended with gasoline and used in nearly pure form for flexible fuel vehicles. Ultimately, the choice of fuel type should come down to cost, customer preferences and environmental impacts.