Every day dozens of tanker trucks, many laden with pig manure and other kinds of agricultural waste, rumble through the gateway of an imposing steel-and-concrete plant in northeast Netherlands.This pungent cargo will be mixed together into a slurry and pumped into massive tanks, where hungry bacteria will within weeks turn it into methane gas that will ultimately be sold to the energy grid to heat homes and generate electricity.The gas is a biofuel — similar to the natural gas pumped out of offshore wells in the North Sea but, because of its biological origins, considered carbon neutral.The recipe for success, said Fritz Ullrich, the plant manager, is keeping the microbes nourished with a steady stream of …
