Biofuels as a Sustainable Source of Energy

The United States is facing the growing realization that sustainable sources of domestic energy production are necessary to the economic, strategic and environmental well being of our country.

Biofuels are now being developed as sustainable sources of energy because, unlike wind, solar or hydroelectric energy sources, biofuels can be converted into energy-dense, liquid fuels that are compatible with current energy distribution and consumption systems. In addition, oil-based biofuels are one of the few renewable, energy-dense fuels that can be used by the aviation and shipping transportation sectors.

Currently, the demands for food and environmental sustainability limit the use of food crops or plants for biofuel production. However, since biofuels have the potential to reduce our global environmental footprint, they are becoming an attractive part of the mix of sustainable energy solutions.

First and Second Generation Biofuel Production Systems

The U.S biofuel industry has primarily focused its efforts on ethanol production from corn starch. More recently, biodiesel has been produced from soybeans. Unfortunately, these first generation biofuels (ethanol and biodiesel) are produced from only a few crop systems, compete with food demands, and often utilize only a fraction of their total plant biomass for fuel production.

Inefficiencies in feedstock processing further reduce the recoverable fuel yields from these plants and reduce net carbon capture. Extensive crop land is also required to produce fuels from first generation biofuel crops. Therefore, first generation biofuel production systems typically have more negative impacts on the environment than later generation biofuel systems.

Second generation biofuel production systems are currently being developed, including high cellulosic producing biomass plants, such as Miscanthus and switch grass. These crops do not directly compete with food crops, have less agronomic and environmental impact and have the potential to convert nearly all the plant biomass into fuels (ethanol, butanol, and biodiesel), leading to both increased fuel production and reduced environmental impact.

The Center for Advanced Biofuel Systems (CABS) and the development of third generation Biofuel Production Systems

CABS's mission is to increase the thermodynamic and kinetic efficiency of light conversion into biochemically useful energy or green feedstocks. CABS scientists are also working to enhance the production of energy-rich bio-oils in both algae and Camelina for conversion to sustainable biofuels. Some of the improvements we are likely to see in advanced biofuel systems include:

  • A shift towards fuels with higher energy density (shift from alcohol-based fuels to oil-based fuels)
  • Enhanced photosynthetic energy conversion efficiency of biofuel production systems
  • Reduced energy and agronomic inputs for biofuel production and enhanced environmental control of production, thereby reducing environmental impact.
  • Reduced impact on food production and pricing.

The Center for Advanced Biofuel Systems is developing knowledge-based strategies for enhancing oil production efficiency using two model systems; a species of unicellular microalgae, Chlamydomonas, and a cruciferous oil seed plant related to canola, Camelina sativa.

Microalgae and Oilseed Plants

Each of these model systems have their own unique advantages and applications. Microalgae (e.g., Chlamydomonas) have significant potential as a clean, renewable, and economical fuel source for several reasons. It is an ideal organism to study the conversion of solar energy into biofuels, and can be highly controlled and optimized for fuel production. Temperature, light, pH, nutrient and CO2 concentrations can be readily monitored and optimized for maximum oil yields. This level of environmental control is difficult to achieve with land plants grown in field conditions.

Oilseed plants (Camelina Sativa) provide an attractive alternative and complementation to algal Biofuel production systems as it grows successfully in areas not suitable for microalgae, including latitudes greater than fifty degrees Celsius, mountainous areas, marginal crop lands, and areas with limited water availably. Camelina has reported high seed yields, moderate oil content of its seeds, and it responds well to marginal land crops and limited precipitation. In addition, Camelina has the potential to become a dedicated Biofuel/industrial crop because of the greater interest in established oilseeds (soybean, sunflower) for food use. It can also be grown as a spring or fall rotation crop so it does not compete with the summer food crops for existing land.

Additional Resources on Biofuel Research

The Donald Danforth Plant Science Center

The United States Department of Energy Department of Energy Algal Biofuels Roadmap

The National Alliance for Advanced Biofuels and Bioproducts

The Bio-Research & Development Growth (BRDG) Park at the Danforth Plant Science Center

For information on specific educational and outreach programs involving advanced biofuel production systems research, please free to contact Dr. Terry Woodford-Thomas at the Donald Danforth Plant Science Center, at TThomas@danforthcenter.org.