Harnessing the Earth's power – geothermal energy

The core of Planet Earth is seriously hot, as hot springs, geysers and volcanoes attest to. High temperatures can be found nearly everywhere at about 5,000 meters below ground. This heat can be harnessed as a source of energy.

The advantages of geothermal energy are numerous: the supply is more or less inexhaustible, it can be used for heat and electricity and it barely emits any greenhouse gases. Tapping this power from the Earth's depths is one of the greatest technical challenges of the 21st century.

GLOBAL IDEAS reporters traveled across the globe to explore the various ways in which this challenge is being met.

Geothermal energy in Europe

The Icelandic capital Reykjavik boasts the largest district heating grid in the world. Seven power plants produce electricity from geothermal energy. Iceland draws more than two thirds of its energy supply from renewable sources, 50 percent of which is geothermal energy. This electricity is used for households, public swimming pools and greenhouses.

After Iceland, Turkey has the second-highest potential for geothermal energy in Europe. But so far, only one percent of electricity generated in the country is drawn from geothermal energy. However, the government plans new laws to promote its use. Turkey is home to over 150 geothermal fields, all capable of producing electricity. GLOBAL IDEAS reporters visited the Izmir region, which leads the way in the use of geothermal energy.

Geothermal energy in Asia

Indonesia lies along what is known as the Ring of Fire. With over 150 active volcanoes, it has the world's highest geothermal potential but for now, uses only five percent of this resource. In order to reduce dependency on fossil fuels, the government plans to multiply tenfold its geothermal energy use. Germany is among the countries supporting Indonesia's exploratory drilling program.

China, meanwhile, is concentrating on tapping its shallow geothermal resources, especially in cities such as Beijing and Shanghai. Probes are sent 400 meters underground to extract energy and supply cities. GLOBAL IDEAS went to of the largest construction sites in Beijing, where 500 geothermal probes will one day supply 70,000 square meters of building space with energy.

Old pits, new uses

Disused mines can still serve an important function. With temperatures between 35 and 40 degrees, mine water is still available and can be used both to heat and cool buildings – as demonstrated by a futuristic building at the Zollverein coal mine in Germany's Ruhr Valley. Some 80 million cubic meters of mine water available in the region could heat an entire village – and inspire similar projects in former mining areas all over the world.

A film by Anne Hoffmann (jp)
Editor: Sonia Phalnikar