Disclosed is a non-polluting high temperature combustion system which comprises in combination a graphite-lined combustion chamber fueled by a controlled-burn thermite fuel, wherein the fuel burns a temperature of up to 6000 degrees Fahrenheit, wherein the resulting gases are essentially pollution free; the system also include a means of passing a substrate into and out of the combustion chamber and/or a turbine powered by gases from the combustion products, means of injecting a working fluid into the combustion gases upstream of the turbine, a heat recovery means that comprises a geo-thermal hot rock bed, a steam generator utilizing heat from the geo-thermal hot rock bed, a working fluid separation means which comprises a condenser, and means of liquefying the remaining gases for commercial use.