Reciprocating engines Small electricity generators are often powered by reciprocating engines burning diesel, biogas or naturalgas.

Biogas is often combusted where it is produced, such as alandfill or wastewater treatment plant, with a reciprocating engine or a microturbine, which is a small gas turbine.

An increasing number of commercial buildings use a combined cycle with cogeneration to provide heating, often water heating, from the output of a natural gas reciprocating engine, gas turbine or stirling electric generator.