The Process

Naturally occurring heat from the earth is a massive, environmentally friendly energy resource. As the earth is constantly generating heat, the energy is classified as a renewable resource.

Conventional geothermal systems tap, for power generation purposes, the heat contained in natural volcanic structures such as hydrothermal springs, and have been operating commercially for many years. Engineered Geothermal Systems (EGS/also known as enhanced geothermal or hot dry/fractured rock)) require a man-made fluid reservoir to be created in hot rock. The EGS resource base is very large and is only just beginning to be commercially exploited.

This involves the circulation of water down an injection well, through deep (2 to 5 km) hot rocks with temperatures typically around 200°C. In order to allow the flow of water, tiny fractures are engineered creating an underground heat exchanger. As the water passes through the heat exchanger, it is rapidly heated to a high temperature by contact with the hot rock. The superheated water, is then returned via a production well to surface where the heat energy is converted to electricity.