I'm looking at building a sustainable energy project that will convert biogas (methane) into electricity. I haven't found any biogas or methane electric generators for sale. It seems that there are some projects that are using generators to convert the methane gas into electricity, however, I can't tell if this is special kind of generator and I just don't know what it's called or if it is a natural gas or propane generator.
So will off the shelf natural gas or propane generators also run off of methane?
Also, how would I go about trying to calculate how much methane it would take to run the generator to produce enough electricity to say charge a cell phone or another small appliance?