An integrated combustor-thermoelectric generator and method for producing electrical power and/or for operating a pneumatic or electric device. The apparatus includes a burner tube, a tubular heat exchanger extending along and around the burner tube, a plurality of thermoelectric generators disposed along sides of the heat exchanger, and a heat sink on an opposite side of the thermoelectric generators from the burner and heat exchanger. The thermoelectric generators can be paired with an electric valve or a DC air compressor for operating a pneumatic device by directing heated gases from the combustor through the heat exchanger to thermoelectric couples and/or modules for powering the air compressor. The thermoelectric generator and DC compressor can be installed to a natural gas source at a well pad for operating a pneumatic device at the well pad.