This is crazy. The volcanic rock beneath Lake Kivu in Rwanda emits carbon dioxide. A lot of it. Bacteria in turn converts the CO2 into methane. The lake contains 256 cubic kilometers of CO2 and 65 cubic kilometers of methane.
Rwanda is going to suck the methane out of the lake and convert it into 100 megawatts of energy. That's equal to half of the country's current generating capacity. Wow.