The operations at the biogas and heating plants bring in cash, because farms and factories pay fees to dispose of their waste and the plants sell the heat, electricity and car fuel they generate.

经营沼气供热厂很赚钱，因为农场和工厂要处理他们的废料就得向这些工厂交钱，而这些工厂又出售生产出的热、电以及汽车燃料。