Turbo-expanders, also referred to as expansion turbines, provide a way to capture the energy lost in natural gas facilities and refineries. Turbo-expanders have a range of applications, but this template focuses on the use of turbo-expanders for energy recovery and power generation. Virtually any high-temperature or high-pressure gas is a potential resource for energy recovery. Generator-loaded expanders can be custom engineered to recover the maximum amount of useful energy available in the process.

The expander principle relies on converting kinetic energy to useful energy / electricity by using turbines and electrical generators. As the gas flows from the high pressure stream into the turbo-expander, the gas spins the turbine, which is coupled to a generator that produces electricity. Thus, by replacing a conventional control valve or regulator with a turbo-expander, the energy contained in the motive stream, that would otherwise be lost, can be converted to electricity. It is noted that energy output is proportional to pressure ratio, temperature and flow rate of the stream.