Closed-loop geothermal

Closed-loop geothermal systems (also known as “advanced geothermal systems” or “AGS”) are a type of engineered geothermal energy system containing subsurface working fluid that is heated in a hot rock reservoir without direct contact with rock pores and fractures.: Instead, the subsurface working fluid stays inside a closed loop of deeply buried pipes that conduct Earth’s heat. Closed-loop geothermal systems are one of the prominent categories of next-generation geothermal systems in development today.

Like all geothermal systems, closed-loop geothermal systems provide renewable energy, and primarily operate as baseload resources that produce energy at a constant rate. Unlike conventional geothermal energy plants, closed-loop geothermal plants can be placed anywhere in the world, depending only on the depth of the hot rock resource.

Closed-loop geothermal projects are under development in the United States, Canada, Japan, and Germany.