Mark Finkelstein, Luca’s vice president of bioscience, says that the company has tested its methods in coal beds where wells had been drilled to collect natural gas (about 10 percent of the natural gas mined in the United States comes from coal beds). Many of these wells had stopped producing natural gas, or produced too little to be profitable. After treatment, production increased, and the wells became profitable again, Finkelstein says. The new funding will allow Luca to apply its techniques to more wells and continue research to understand the microorganisms involved, with the goal of further increasing methane production.
Finkelstein says that based on initial results, the company’s process could extend the lifetime of natural-gas wells. Conventional techniques for extracting natural gas from coal kill the gas-producing organisms found naturally in these coal beds, first, by removing the water that they need, and second, by exposing them to oxygen, which is deadly to them. By carefully maintaining conditions favorable to the microorganisms, the company allows them to continue digesting the coal and producing methane. The company could also employ its techniques to collect useful fuel from coal that’s inaccessible to conventional mining, Finkelstein says.
Scott says that it’s still unclear how much of the coal reserves in the United States can be converted into methane. Much depends on the nature of the coal bed, including factors such as the surface area of the coal that the microbes feed on. Eventually, for example, waste produced by the microbes could cause them to die off. Scott is also concerned about public reaction to the use of microbes, even though they occur naturally in coal beds, especially in areas where the coal beds are the source of drinking water. (However, he says, the microbes aren’t harmful to humans.)
Ultimately, Stiegel says, the success of the company will depend on the costs of Luca’s process and the price of natural gas. But he says that as a way to reduce carbon emissions and develop more sources of domestic energy, “it’s an intriguing approach.”