To some extent, it already is (See: https://bangordailynews.com/2019/05/23/business/maine-natural-gas-company-has-big-plans-to-turn-cow-manure-into-renewable-energy/).
Guilt-free home and industrial heating in the cold climates of Maine can be achieved by integrating anaerobic digestion more fully into municipal waste management systems (See: http://www.engineersjournal.ie/2018/01/09/sustainable-developments-anaerobic-digestion-wastewater/).
Natural gas has been called a "bridge fuel". This is the other side of that bridge.
See Eben Rose Webpage: https://www.ebenrose.com/
FACEBOOK: User must login