PbSnTe based thermoelectric power modules are manufactured and contained in a hermetically sealed stainless steel casing to reduce oxidation to near zero.This is critical for long extended life applications up to 15 years. The modules are a Lead Telluride based thermoelectric module that can work at temperatures of 600°C (1110˚F) continuous heat source. The thermoelectric power module generates DC power as long as there is a temperature difference across the module but are optimized when the hot side is above 350˚C (662˚F) and below 600˚C . As DT (Delta Temperature) from hot side to cold side (heat removal side) increases, so does power generated. Peak efficiency for this material is delivered when the hot side junction temperature is at 500°C (932˚F) to 600°C (1110˚F) using liquid cooling on the cold removal side to maximize power output and heat flow.