They already do that here (in the UK). Shanks McEwen run a facility at Brogborough (in Bedfordshire) which generates methane, that is used to heat a "digester" that generates more methane. At the moment the "spare" methane is being "flared off" but ultimately it is intended to introduce it into the domestic gas supply. This process will be introduced to a number of sites in the UK over the next 5 years. It is expected that "reclaimed" methane will make up to 6% of the domestic supply in the future.
