Gas turbines, also known as combustion turbines, are mainstays of electricity generation in the United States, and will continue to be a reliable alternative even as renewable energy steadily gains in popularity. Westinghouse, which is no longer in the business, was for many years a driver of gas turbine technology development, until a decline in its fortunes required outsourcing of some of its manufacturing operations to Japan by Mitsubishi Heavy Industries (MHI), a long-time licensee of Westinghouse’s gas turbine engines.