Renewables

Reykjavik, Iceland

The world's largest geothermal heating system saves up to 4m tons CO2 annually

What is it?

Reykjavik has the world's largest and most sophisticated geothermal district heating system, which has used natural hot water to heat its buildings and homes since 1930. Today, geothermal powers the entire city - with an electricity distribution network harnessing 750 MW thermal power from steam, and a water distribution system generating 60 million cubic meters of hot water.

The use of this natural resource has massively reduced the City's dependence on fossil fuels – making it one of the cleanest cities in the world. CO2 emissions have been reduced from 1944 to 2006 by up to 110,000,000 tons, delivering savings of up to 4 million tons CO2 every year. Geothermal has also contributed to Iceland's transformation from one of the poorest nations to one that enjoys a very high standard of living.

How does it work?

Geothermal heat comes from the Earth's core, where temperatures may reach 4,000-7,000°C (7,200 to 12,600°F) and comes to the surface with water through fissures, cracks and permeable rock. A number of countries and continents, including Iceland, sit over these naturally occurring heat supplies.

The special geological situation of Iceland with its high concentration of volcanoes means it has an obvious opportunity to use geothermal energy. Iceland gets its heating and electricity from this natural resource via five geothermal power/heating plants, which turn the heat into clean energy for the entire country – half of whose residents live in the City of Reykjavik.

Reykjavik Energy company uses both water from low temperature fields (temperature below 150°C at 1000 m depth) for direct heating of houses and energy from high temperature fields (temperature higher than 200°C at 1000 m depth) for generating electricity and hot water for house heating. The system serves around 170,000 people using 63 million cubic metres of water, of which 7 million is recycled backflow water.

Key results

• Total CO2 reductions are between 2.5 and 4 million tons annually
• The calculation of CO2 saving is based on other possible alternatives - in the case of Reykjavik this would have been the use of fossil fuels such as gas, oil or coal. Fossil fuels have to be imported to Iceland, therefore the CO2 saving is much higher.
• There are five geothermal plants in Iceland – producing 26.5% of the country's electricity and 87% of the housing and building heating needs (2005).
• Financial savings were calculated in 1995 for the period 1944 to 1995 to be just below 3,000M USD, compared to the cost of heating by oil.
• The total financial savings from 1944 to 2006 would amount to about 4,290M USD.

Application

Geothermal heat can be used by countries that sit over Magma hot spots, including the following:

• Volcanic regions that border the Pacific Ocean (known as the Ring of Fire) such as the USA, Mexico, Central America, Japan, Phillipines, Indonesia and New Zealand;
• Volcanic chains that form along mid-ocean or continental rift zones: Iceland and Kenya;
• Hot spots where magma plumes continuously ascending from deep in the mantle, such as the Hawaiian Islands and Yellowstone.

There are also low temperature geothermal resources, which can be used for direct applications, such as heating houses, recreation, green houses and industry. Geothermal heat pumps are increasingly used for house heating where there are no geothermal manifestations.

UNU Geothermal Training Program

The United Nations University Geothermal Training Program and Iceland's National Energy authority established a training program in 1968 to help developing countries with considerable geothermal potential build specialists on geothermal exploration and sustainable development. The program annually offers specialised training in various fields of geothermal studies. In 2005, 338 scientists and engineers from 39 countries had completed training. UNU-GTP graduates are, in many countries, among the leading specialists in geothermal research and development. Source: www.or.is/media/files/nesjavellir_eng.pdf Reykjavík Energy, June 2003