An energy converter system, preferably including one or more thermionic energy converters (TECs), and optionally including an electrical power converter. A TEC, preferably including a collector body, an emitter body, and a seal. A method of operation for an energy converter system, preferably including providing a heat source; converting thermal energy to electrical energy; and/or providing one or more electrical energy outputs.

An energy converter system, preferably including one or more thermionic energy converters (TECs), and optionally including an electrical power converter. A TEC, preferably including a collector body, an emitter body, and a seal. A method of operation for an energy converter system, preferably including providing a heat source; converting thermal energy to electrical energy; and/or providing one or more electrical energy outputs.