Trends: Making Fuel from Trash

Forget the food-for-fuel argument. It's over. Done. Finished. Cellulosic ethanol made from biomass sources other than food stocks is a reality and on the fast track to commercial viability. Underscoring the point is a process that can even make fuel from garbage, or more specifically biowaste, that typically clogs our landfills. Trash-to-fuel could well be the ultimate in recycling since it provides a fully renewable fuel source.

Cellulosic ethanol doesn't rely on sugars from corn or other food sources to produce ethyl alcohol, but rather from lignocelluloses, which makes up the structure and much of the mass of the plants. The beauty of cellulosic ethanol is that it can be processed from abundant bio sources. The end product is chemically identical to ethanol from corn or sugarcane.

Irvine, California-based BlueFire Ethanol was recently granted a conditional use permit by the County of Los Angeles Department of Regional Planning to construct the nation's first commercial biowaste-to-ethanol production facility. The plant will be built in Antelope Valley near the Mojave Desert city of Lancaster, California. The Lancaster plant alone receives an estimated 170 tons of biowaste everyday. Each ton of waste can produce up to 70 gallons of ethanol. By locating the facility adjacent to a landfill operation, BlueFire can collect incoming biowaste material before it goes into the landfill without the need for additional transportation. As an added benefit, the landfill is also a source of methane gas from decomposing waste, which can power the production facility with clean energy.

A fully operational plant is projected to produce as much as 3.2 million gallons of cellulosic ethanol per year. The Lancaster plant is designed to reclaim water and a byproduct of BlueFire's production process called lignin, with the latter used to produce its own electricity and steam. While all this may sound expensive, BlueFire is estimating production costs below the magic $1/gallon price point.

The potential cellulosic feedstocks are quite diverse. From municipal waste, the process can use material like non-recyclable paper, grass clippings, wood chips, landscaping residue, lumber, and the woody portion of construction and demolition debris. Other potential sources include paper mill sludge and saw mill waste, harvesting slash, and agricultural residues such as corn stover, sugar cane bagasse, and high-yield energy crops such as switch grass and miscanthus.

BlueFire Ethanol is using a patented method of commercially transforming cellulose waste to ethanol using Arkenol Process Technology. The company uses a well-known acid hydrolysis conversion technology with proprietary improvements to make it economically viable. The process essentially converts cellulosic biomass into inexpensive simple sugars for fermentation. Interestingly, the cellulose-to-ethanol process isn't new. In fact, Germany and Russia used it in both World Wars in the first half of the last century to produce fuel and other essential chemicals. There was also a similar plant in Oregon. Those early efforts using wood to produce alcohol fuels were very wasteful, however, and couldn't compete with the low cost of petroleum.

A major advantage of the process is moving ethanol production away from low population density corn-belt states located in the center of the country to the outer coastal and perimeter states. Here, abundant urban residue, as well as forest and agricultural wastes generated from these areas, can be converted into fuel. Thus, ethanol will be produced where it will be used, greatly cutting transportation costs and increasing overall efficiencies.

End products from the concentrated acid hydrolysis process can be pure ethanol, which can be a volumetric extender for both gasoline and diesel, as well as n-butanol, ethyl citrate, ethyl lactate, and ethyl levulinate. The process has been validated by JGC Corporation at a third-party production facility in Izumi, Japan. Even as BlueFire has its first plant permitted and ready for the beginning of construction in California, a second facility is in the preliminary engineering and design phase with up to 20 future plants currently being sited.

Ethanol as a 'green' transportation fuel has been the subject of much public debate and misinformation of late. Moving away from the use of food feedstocks with greatly increased production efficiency at a lower per-gallon cost should quiet many of those critics. And, of course, converting trash and biowaste to clean fuel may well be the game-changer ethanol has needed.