World War II saw the development of a remarkable technology, the gas turbine. Air is compressed, a hydro-carbon fuel is sprayed into the pressurized air, ignited and that causes a turbine to rotate. The early machines were inefficient and somewhat unpredictable, but over the past 50 years these devices have evolved into large powerful, reliable and efficient machines.

About 1/2 of the gas turbine's power is used to compress air.