A Johnson thermoelectric energy converter or JTEC is a type of solid-state heat engine that uses the electrochemical oxidation and reduction of hydrogen in a two-cell, thermal cycle that approximates the Ericsson cycle.[1] It is under investigation as a viable alternative to conventional thermoelectric conversion. Lonnie Johnson invented it and claims the converter exhibits an energy conversion efficiency of as much as 60%,[2] however, this claim is at a theoretical level based on comparison with a Carnot cycle and assumes a temperature gradient of 600 °C.[3] It was originally proposed for funding to the Office of Naval Research but was refused. Johnson obtained later funding by framing the engine as a hydrogen fuel cell. Johnson had been collaborating with PARC on development of the engine.[4]