Experience in developing and utilizing geothermal resources in iceland

Geothermal energy plays a larger role in the energy economy of Iceland than in any other country-Iceland is The Geothermal Country. This development dates back to 1930, when the first district heating system was started in Reykjavik, and since then geothermal water and steam have been utilized for a broad range of applications. Iceland has seen an unprecedented activity of geothermal projects over the past decade; geothermal district heating systems being installed wherever possible in cities and rural areas, a 30 MW_e, electric power plant at Krafla, small scale production of salt and carbon dioxide, heat extracted from the newly erupted lava in the Westman Islands for district, heating, increased use in industry and agriculture, and now recently an explosive development in fish farming. For a number of years the investment in geothermal projects represented 1.5% of the gross national product of Iceland.The largest use of geothermal energy in Iceland is for space heating and domestic use. At the moment 85% of all houses in the country are heated with geothermal water. This is of great importance in a country where heating is required practically throughout the year. The climate is rather temperate ranging from −15 to +20°C, and with the building codes now in effect that call for double and triple glazing and 150–200 mm of roof insulation, heating demand is 20 W/m³ and the annual usage 60–80 kWh/m³. Heating of greenhouses, industrial drying, fish farming, swimming pools, chemical production and electric power generation also make use of this energy source.This development has on the whole been very successful from the economic and technical standpoint, and has contributed to the wellbeing of the population of some 240,000 persons.This review paper will focus on some of the engineering experience gained in harnessing this “unconventional” energy source.