02/04/2014 - 13:27
Renewable Energy Development Institute - REDI

Cars running on geothermal fuel? Homes heated up with energy from Earth's interior? It is not science-fiction, it is everyday reality for many Icelanders, where usage of geothermal energy, e.g. heat pumps, is the standard of living since many years.

Iceland is world pioneer in handling subterranean natural resources. In 1930, Reykjavík was the first city to construct municipal geothermal central heating system. This breakthrough gained a lot of supporters among Icelanders, who started to explore new applications for releasing heat source. Geothermal is used in a variety of ways across Iceland today, from geothermal power plants, to geothermal hot water systems.

Geothermal energy is thermal energy generated and stored in the Earth. Current technology allows taking advantage of subterranean power to generate hydrogen that on Iceland is used as e.g. car fuel. If you need to fill up your tank in Reykjavík - just drive to one of few "green" liquid-hydrogen tank stations.

Iceland is not the only country that supports geothermal energy development. It is reckoned, that projects undergo in Western United States generate enough energy for 6 million homes. Heat pump technology is the most widespread in household appliances across the world and is still gaining in popularity. It represents 49% of global geothermal usage, followed by thermal treatment hydrotherapy and balneotherapy (less than 25%).

Heat pumps have the ability to move thermal energy against a thermal gradient. They absorb heat from a colder space and release it to a warmer one. Usually they use heat stored in ground or water (often of temperature not higher than few Celsius). There are also devices absorbing energy from the air. However their efficiency is limited to temperature ranging from -15 °C to +25 °C. An additional heat source, e.g. boilers, is often advised to accompany air-to-water heat pumps. Water-to-water heat pumps absorb energy from the ground and ground water what results in their higher efficiency. Mass production, price decrease and wider availability of the devices encourage to try them out at your own home.

On the world scale, geothermal energy can be used as a heat source for domestic hot water, central heating and floor heating systems, space heating or as a heat source in agriculture, gardening or recreation. A growing interest in geothermal energy is based on need of finding energy that is renewable, reduces greenhouse gas emissions and is independent of climate and weather conditions.

People are forever trying to find new sources of renewable energy, so it isn’t surprising that they are especially interested in water and its versatility. Accordingly, much effort has been directed into obtaining energy from tidal and wave power, which are defined as circular movements of water molecules caused by wind that moves water surface through friction.