DARPA Eyes Cheaper, Greener Fuel from Coal

DARPA Eyes Cheaper, Greener Fuel from Coal

(NSI News Source Info) September 14, 2008: The U.S. Defense Advanced Research Projects Agency has unveiled an "aggressive" program to demonstrate economical and environmentally friendly conversion of coal-to-liquid (CTL) fuels. DARPA has issued a broad agency announcement (BAA) soliciting research proposals and plans to award 12-month contracts totaling $4.56 million to demonstrate the feasibility of alternative coal to liquid (CTL) technologies. Already investigating biofuels, the agency says its CTL program is intended to demonstrate processes that could meet Defense Department demand for JP-8 jet fuel from U.S. coal reserves at a cost-competitive price compared with petroleum-based fuels. DARPA says existing direct and indirect coal liquefaction processes are "extremely expensive to implement, consume large amounts of water and produce unacceptable amounts of atmospheric carbon dioxide (CO2) and other pollutants." Indeed, several lawmakers have noted the potential greenhouse gas consequences and in recent years and demurred on coal lobbyists' initial efforts at pushing friendly legislation (Aerospace DAILY, May 5, 2007). The indirect method of producing CTL fuels is to first gasify the coal then convert it to hydrocarbon fuel using Fischer-Tropsch synthesis. Each kilogram of coal converted uses a kilogram of water and produces 1.3 kg of CO2 and 0.27 kg of oil, says DARPA. Using existing technologies, DARPA says, a 100,000 barrel per day (bpd.) CTL plant will cost $6 billion to build, four-times that of a similar-capacity crude oil refinery, while the end-user fuel cost is expected to exceed $4.50/gal. DARPA's goals for its CTL program equate to a capital cost of less than $1.5 billion for a 100,000bpd plant with zero CO2 emissions, less than $3/gal for JP-8 jet fuel, and less than 0.5 kg. of water consumed for every kilogram of coal converted . Because of their environmental impact, the agency says "incremental improvements to existing Fischer-Tropsch or other existing CTL technologies are not appropriate for consideration" under its demonstration program. Fuels from coal produce 80 percent more CO2 than petroleum-based fuel, but DARPA believes CTL concepts may exist that avoid the production of CO2. The need for water as a source of hydrogen is also an issue with existing methods. As a result, new CTL processes "should consider utilizing the hydrogen available in the coal feedstock, alternative hydrogen sources, and/or recycling part of the water consumed during the process," according to the BAA.