The sound of oil tread

Millions of years ago the world’s oceans were filled with plants and plankton. When these died they fell to the bottom of the seas. Over millions of years, these remains were buried under layers of sand and mud. Heat and pressure turned the remains into oil and natural gas. The oil is burned to heat water and produce steam. This steam propels the blades of a turbine. This is attached to a generator, which produces electricity.