U.S. Department of Energy - Energy Efficiency and Renewable Energy

Geothermal Technologies Office

Text Version of a How a Geothermal Power Plant Works (Simple)

The below is a text version of the animation How a Geothermal Power Plant Works.

This animation is meant to convey in simple terms what happens in the operation of a geothermal power plant. Aspects such as exploration, resource verification, site preparation, construction, geothermal fluid processing, and power conditioning are not shown or described in the interest of simplicity, and so the viewer can more readily grasp the basic operating concepts.

Wells Are Drilled

A production well is drilled into a known geothermal reservoir. Typically, an injection well is also drilled to return used geothermal fluids to the geothermal reservoir. Hot geothermal fluids flow through pipes to a power plant for use in generating electricity.

Steam Turns the Turbine

Hot, pressurized geothermal fluid, or a secondary working fluid, is allowed to expand rapidly and provide rotational or mechanical energy to turn the turbine blades on a shaft.

The Turbine Drives the Electric Generator

Rotational energy from the turning turbine shaft is used directly to spin magnets inside a large coil and create electrical current. The turbine and generator are the primary pieces of equipment used to convert geothermal energy to electrical energy.

Transmission - Power Lines Deliver Electricity

Electrical current from the generator is sent to a step-up transformer outside the power plant. Voltage is increased in the transformer and electrical current is transmitted over power lines to homes, buildings, and businesses.