Mainly, geothermal energy is energy from the sun that has been stored in the ground. Today there are efficient and environmentally friendly ways to extract this energy, both on a small scale, such as for individual dwellings, and on a larger scale for industrial premises, department stores or complete residential areas.
The method is based on using a heat pump. As a rule, three times more energy is extracted than is used to drive the pump. Once the initial installation has been paid for, in an estimated 4 to 9 years, one only needs to pay for the heat pump electricity consumption and the technology depreciation. The operational life of the system is estimated to be 25 years, but in practice is often longer. Bedrock heat storage can last for over 50 years.
With a geothermal energy plant you can also reverse the process and cool a property by returning heat to the ground. The most efficient installations are used for taking out heat during the winter and cooling during the summer.
From an international perspective, Sweden is way ahead in the utilisation of geothermal energy. More than 300,000 detached houses (2010) are heated by geothermal energy, as are many large facilities (Arlanda airport, IKEA, Akademiska Hus and others). Geothermal energy replaces (2010) over a million cubic metres of heating oil, which is equivalent to a reduction of 2.3 million tonnes of carbon dioxide emissions. Every year more than 30,000 new geothermal energy wells are drilled. Installation involves only a limited and restricted environmental effect, and operation has an extremely small influence on climatic changes.