Tapping energy from heat stored in the Earth | Global Ideas | DW | 09.03.2010
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Global Ideas

Tapping energy from heat stored in the Earth

The Earth is an oven with 99 percent of our planet hotter than 1000 degrees Celsius. This natural heat can be harnessed for eco-friendly electricity production. What is more, poor countries can profit from it.

A volcano on the island of Sumatra

Volcanic regions are a great source of thermal energy

The ancient Romans knew how to live the good life. They turned hot springs with sulfurous water into thermal baths, creating health spas for the rich and powerful. This knowledge of the Earth's heat was passed on to their descendants: modern-day Italians who set up the first geothermal power plant Italy in 1913, paving the way for a new form of energy production.

Today, geothermal energy is used in numerous countries. It works especially well in places where volcanic activity is high and the crust of the Earth is thin. Drilled tunnels several kilometers long release steam with a temperature of more than 200 degrees Celsius (392 degrees Fahrenheit), which is then easily turned into electricity at special power plants around the world from New Zealand to the Philippines to the West Coast of the United States.

Clean energy worldwide

The Enel geothermal plant in Italy

The world's first geothermal plant was set up in Italy

A warm climate is not a prerequisite for geothermal energy. Sweden, for example, with its cool temperatures, is a world leader in heating buildings with heat pumps. This near-surface geothermal energy, as it is known, involves drilling shafts up to 400 meters deep, and inserting pipe-shaped heat exchanging devices to channel the heat to the surface.

Experts believe that geothermal energy could satisfy the world's energy needs in the long term - and this could be done in an eco-friendly way. According to Stefan Dietrich from Germany's Geothermal Energy Association (GtV), "geothermal energy is one hundred percent clean to produce."

This is the reason why this kind of energy is publicly financed in many European countries - an important factor, considering that deeper drilling is necessary to reach the required temperatures there.

Iceland: heated streets

"Without public subsidies, geothermal energy is not cost-effective in Central Europe," said Horst Kreuter from the NGO International Geothermal Association (IGA). However, he is confident that this situation is not permanent and that geothermal energy will be profitable in the future.

The Hell's Gate National Park in Kenya

The Hell's Gate National Park in Kenya is home to an important geothermal plant

Iceland is a prime example of the implementation and cost-effectiveness of geothermal energy. Over half of the country's energy needs are covered with this method. Even one fifth of the electricity supply stems from geothermal power plants. Geothermal power is so affordable there that even some streets in the capital city, Reykjavik, are heated in winter.

Indonesia: hope for affordable electrcity

Just like Iceland, Indonesia is a volcanic region. The country has very good geological conditions for using geothermal energy in electricity production. Despite this, less than half of Indonesians have access to electricity, and for those who do, power outages are a common occurrence. It's for countries like this one that geothermal energy offers the hope of a cheap, accessible-to-all power supply. However, electricity from coal-fired plants is still more affordable in Indonesia than geothermal electricity.

"Geothermal energy can contribute significantly to solving the problem of supply deficits," said Thorsten Schneider from the German KfW development bank, which supports the construction of a power plant in Indonesia's Aceh province. According to him, geothermal energy's advantage over solar and wind energy is its reliability and the fact that it is not affected by weather.

"As well as this, the geothermal plant would reduce Indonesia's CO2 emissions by around 230,000 tons per year," added Schneider.

Kenya: geothermal energy instead of water energy

The risk of earthquakes is higher in places where tectonic plates meet. But these regions also frequently have the perfect conditions for the utilization of geothermal energy.

Kenya, which straddles the Great Rift Valley, is a prime example of this. The country is largely dependent on hydro power, but due to ongoing drought, alternative sources of energy are being sought. Geothermal energy is one possibility. At the moment, Kenya has eight geothermal power plants, including the Olkaria power plant in the Hell's Gate National Park north-west of Nairobi.

Many opportunities, few risks

"Geothermal energy makes a lot of sense in developing countries that have no nationwide electricity network," said Stefan Dietrich. "Geothermal energy's big advantage compared to ordinary energy sources like nuclear and coal-fired plants is its decentralized organization."

However, despite all the opportunities and eco-friendliness it offers, geothermal energy is not completely risk-free. There are fears that drilling in geographically delicate regions could trigger earthquakes.

"When humans are active underground, there are risks," said Horst Kreuter. "But with geothermal energy, they are very low."

Author: Nele Jensch (ew)
Editor: Mark Mattox

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