Aaron Smith, a leading expert on the economics of manure digesters, discusses how large concentrated animal feeding operations (CAFOs) in the US are increasingly turning waste into fuel and what the future holds for this nascent industry.
California regulators broke state environmental laws by allowing polluters to buy clean fuel credits from large farms that are extracting gas from manure, a policy that harms poor communities and perverts the state’s clean air program, four advocacy groups allege in a lawsuit.