Posted on 01 March 2012

Geothermal replaces coal for heating and electricity

Of all the cities in the world, Reykjavik, the capital of Iceland, is the one which best utilises geothermal energy. Some 95% of buildings are connected to a district heating system, which has a geothermal power station as a source of energy. The electricity is produced almost entirely by renewables. Geothermal energy has helped Iceland to both largely eliminate coal power, and reduce oil to 25% of primary energy use.



Keywords: geothermal energy, district heating, green electricity, volcanoes, coal

Iceland has been extending its geothermal energy system since the 1930s. Today it makes up more than one-third of Iceland's total energy consumption. It constitutes 53% of the total energy mix, and together with hydropower, has almost entirely ousted coal. The percentage of oil has also progressively diminished from 70% in the 1960s to a current 25%.

Heats almost all houses
Five large geothermal power plants produce almost 90% of Iceland's residential heating and more than one quarter of its electricity, with hydropower supplying the remaining 10%. Reykjavik Energy uses both water from low temperature geothermal fields (below 150 C at a depth of 1,000 metres) for direct heating and high temperature fields (above 200 C at a depth of 1,000 metres) for the production of electricity and its district heating systems (see also Danish towns). In late 2010, it opened a new plant, which eventually will become one of the world's largest, with 300 MW of electric and 400 MW of thermal capacity.

Iceland’s geothermal plants have reduced both carbon dioxide emissions and energy expenses, since heating with geothermal energy is one-third the cost of oil heating. In 1968, together with the UN, the Icelandic authorities started a programme of education in order to help developing countries with geothermal potential develop their energy production.

Geothermal energy worldwide
Geothermal energy is one of the renewable sources of energy that has the highest longterm potential. The heat in the first ten km of the earth's crust contains 50,000 times as much energy as found in all the world’s oil and gas reserves combined. The potential for geothermal energy is greatest in those countries which have high volcanic activity or which are located close to the edges of continental plates.

The world’s collective capacity of geothermal electricity production is just over 11 GW (2010), with the US and the Philippines on top of the list, followed by Indonesia, Mexico, Italy and Iceland. Geothermal power plants constitute a large part of the electricity production in Iceland (26%), El Salvador (23%) and the Philippines (18%). Significantly more geothermal power is used as an immediate source of heating, approximately 51 GW worldwide in 2010. When counted per capita, Iceland has the highest capacity of both electric and direct geothermal energy.


References
Lester R. Brown, Earth Policy Institute, 2009, Plan B 4.0: Mobilizing to Save Civilization, First edition, W. W. Norton & Company, http://www.earth-policy.org/images/uploads/book_files/pb4book.pdf

"Reykjavik: The ground heats the city", Sustainable Cities, http://sustainablecities.dk/en/city-projects/cases/reykjavik-the-ground-heats-the-city

“Renewable energy in Iceland”, Wikipedia, http://en.wikipedia.org/wiki/Renewable_energy_in_Iceland

REN21 Renewable Energy Policy Network for the 21st Century, 2011, Renewables 2011 Global Status Report, Paris: REN21 Secretariat, http://www.ren21.net/Portals/97/documents/GSR/REN21_GSR2011.pdf

Key data are retrieved from the UN Demographic Yearbook 2011, http://unstats.un.org/unsd/demographic/products/dyb/dyb2011.htm

Text by: Martin Jacobson