The energy from beneath

The global potential for geothermal energy is enormous. In the United States alone there is enough energy for the next 30 000 years. On Iceland access to all this free energy is bringing the country one step closer towards energy independence every day.

Full steam ahead. By harnessing geothermal energy Iceland can heat its homes without being dependent on imported fuels (Photo: Lydurs/Flickr)

Massachusetts Institute of Technology has estimated that the amount of accessible geo thermal energy in the U.S. corresponds to approximately 2000 times the annual American energy consumption. The United States is the second largest producer of geothermal energy, but geothermal still produces less than one per cent of American electricity.

On Iceland geothermal energy produces 90 % of the heat and around 25 % of all electricity. Generating electricity with geothermal energy has increased significantly in recent years. As a result of a rapid expansion in Iceland's energy intensive industry, the demand for electricity has increased considerably.

During the course of the 20th century, Iceland has gone from what was one of Europe's poorest countries, dependent upon peat and imported coal for its energy, to a country with a high standard of living where practically all stationary energy is derived from renewable resources. In 2007, roughly 81% of primary energy use in Iceland came from indigenous renewable resources. Thereof 66% was from geothermal.

The figure above shows the development from 1970-2008.

The installed generation capacity of geothermal power plants in Iceland totalled 575 MWe in 2008 and the production was 4,038 GWh, or 24.5% of the country's total electricity production. But Iceland is working on a project that could squeeze even more energy out of ther geothermal resources. By exploiting the supercritical fluids, the power output of geothermal wells increase significantly, some say output will increase by 5 – 10 times. But you have to go deep to find these fluids. Very deep.

The Deep Drilling Project

Ten years ago, in 2000, the so called Deep Drilling Project was announced.  A consortium from the Icelandic energy industry was established to fund the project, and five years later they were ready to deepen a 3082 m deep well at the Reykjanes high temperature system.

The goal was to drill for 400-600 C supercritical fluid. Supercritical water is a fluid that is so hot and under so much pressure that it exists somewhere between water and steam.  Put simply, it is basically just very, very hot water under pressure. In coal power plants or nuclear power plants they use heat energy to heat water in pressurized tanks until it reaches a supercritical state. The supercritical water then runs through a heat exchanger, creating more steam that drives a turbine creating electricity. In other words, you use  energy to create energy.  But 4-5 kilometers below ground, heated by lava and captured in a pocket in the bedrock, this supercritical water exists in a natural form, and it keeps most of its energy when you bring it to the surface.  By tapping straight into the source, you don't have to use energy to bring water into a supercritical state.

Reykjanes is a peninsula and a volcanic system situated at the south-western end of Iceland, and was the location for the Deep Drilling Project's first drilling attempt (Photo: Debivort / Wikimedia) 

A challenging operation

Unfortunately the first the Deep Drilling Project’s first attempt in Reykjanes failed. This made the project move on to another promising site, Krafla. Here the drilling was menat to be completed late in the summer of 2009, but yet again the operation was terminated. This time because they struck molten rock, or lava. In spite of these setbacks, the project is intent on moving forward, and new wells are planned in 2010-2012.

Krafla is a caldera of about 10 km in diameter with a 90 km long fissure zone, in the north of Iceland in the Mývatn region. Krafla includes one of the best-known Víti craters of Iceland. The Icelandic word "víti" means "hell". This was the site for the project's second attempt at drilling for supercritical water. (Photo: Michael Ryan / Wikimedia )

Not giving up

It won’t be easy, but if they succeed in tapping into the supercritical reserves the reward would be unimaginable amounts of energy: Iceland’s energy output  would be five times that of the United States, the world’s largest producer of geothermal energy!

The companies behind the project are Landsvirkjun (Iceland’s National Power Company), HS Orka hf, Reykjavik Energy, the National Energy Authority, Alcoa Inc and Statoil New Energy AS.

Funding for the research part of the project came from the International Continental Scientific Drilling Program (ICDP) and the National Science Foundation. Iceland Drilling (Jarðboranir hf.) drilled the well and most engineering assistance is provided by ISOR, Iceland Geosurvey and Mannvit engineering, as well as a number of other players.
 

Further reading

• Read more about Iceland wish to utilize their renewable energy resources to produce hydrogen and become a carbon free nation.
• Learn about how Icelandic companies are involved in geothermal projects all over the world, and how Reykjavik makes maximum use of renewable energy.
• See professor Martyn Poliakoff demonstrate supercritical fluids in his office at the University of Nottingham
• Iceland Deep Drilling Project (IDDP) - 10 Years Later – Still an Opportunity for International Collaboration
• An article about deep drilling in Poular Science