The History of Geothermal Energy Utilization

The first commercial geothermal power plant was commissioned in 1913 in the Valle del Diavolo near the Italian town of Larderello.

The earliest reports of geothermal energy utilisation come from China, around 300 BC, and relate to bathing in hot springs. In the first century AD, the Romans used hot springs in public baths at Aquae Sulis, now the English city of Bath. One of the earliest geothermal district heating systems was established in 1332 in the French town of Chaudes-Aigues, using hot water from around thirty thermal springs with temperatures between 40 and 80 °C.

In the early 20th century, the first attempts were made to use geothermal energy for electricity generation. In 1904, Piero Ginori Conti used geothermal steam at Larderello in Italy to drive a small turbine connected to an electric generator. The electricity produced lit five light bulbs. Nine years later, the first commercial geothermal power plant was built at Larderello. The Larderello geothermal field was gradually expanded, reaching an installed generating capacity of about 127 MW by 1942. Italy remained the world’s only industrial producer of geothermal electricity until 1958, when the Wairākei Power Station in New Zealand (map) began generating electricity.

The first heat pumps utilising geothermal energy were installed in the 1940s.

The world’s first geothermal binary-cycle power plant was commissioned at Paratunka on Russia’s Kamchatka Peninsula in 1967. Binary-cycle technology later enabled electricity generation from lower-temperature geothermal resources.

4 pictures

4 pictures

Direct Heat Utilization

The Blue Lagoon is a renowned spa in south-western Iceland that uses mineral-rich geothermal water from the nearby Svartsengi geothermal power plant.

Lower-temperature geothermal resources are generally better suited to direct heat use than to electricity generation, while residual heat from geothermal power plants can also be used directly.

One of the oldest forms of direct geothermal use is bathing in hot springs. Their hot and often mineralised water has been used since ancient times for bathing, relaxation and therapeutic purposes.

Geothermal heat is widely used for district and space heating. Direct geothermal applications, including geothermal heat pumps, were reported in 88 countries in the latest global survey. In some systems, geothermal water can be circulated directly through heating networks. More often, however, its heat is transferred through heat exchangers because geothermal fluids may contain high concentrations of dissolved minerals. Globally, geothermal heat pumps account for about 59% of direct geothermal heat use, followed by bathing and swimming at about 18% and space heating at about 16%.

Low-temperature geothermal heat can be used to heat greenhouses and agricultural land, allowing crops to be grown in colder climates. It can also be used in aquaculture to maintain suitable water temperatures for species such as shrimp and certain fish.

Reykjavík is supplied with geothermal hot water from several geothermal fields through one of the world’s largest district heating systems.

Industrial uses of geothermal heat include food drying and various processes that require thermal energy. Geothermal heat can also be used for water desalination.

Ground-source heat pumps allow shallow geothermal energy to be used even in regions without conventional high-temperature geothermal resources. Heat pumps operate on the same basic principle as vapour-compression refrigerators. Ground-source systems extract heat from the ground or groundwater and transfer it into buildings. Heat pumps require electricity to operate but can typically supply about three to five units of heat for each unit of electricity consumed. Geothermal heat pumps now represent the largest share of direct geothermal energy use worldwide.

13 pictures

13 pictures