Geothermal energy is derived from underground water heated naturally by contact or close proximity to molten rock, deep beneath the earth’s surface.
Supported by Alcoa, the Iceland Deep Drilling Project (IDDP) consortium will collaborate on a deep drilling pilot project which will investigate the economic feasibility of producing energy and useful chemicals from geothermal systems at what are known as “supercritical conditions”. Essentially, these are natural systems where underground water becomes super-heated by close proximity to almost molten rocks.
Supercritical (high-temperature) geothermal systems could potentially produce up to ten times more electricity than the geothermal wells typically in service around the world today.
In signing the agreement with the research consortium, Bernt Reitan, Alcoa Executive Vice President, said, “We are drilling towards the future. Geothermal energy is exactly what the world needs to tap into almost limitless, clean, natural energy and to substantially reduce greenhouse emissions.
For Alcoa’s part, if we could connect supercritical geothermal energy to our world class aluminum smelting expertise, and the metal’s unrivaled ability to reduce greenhouse gas emissions generated by such things as transportation, then we are really beginning to make a difference that will be beneficial all over the world.
The technology we hope to develop in Iceland should be applicable where ever there is high temperature geothermal potential,” he said.
The IDDP consortium is composed of three leading Icelandic power companies: Hitaveita Sudurnesja Ltd.; Landsvirkjun; and Orkuveita Reykjavikur; together with Orkustofnun (National Energy Authority) and Alcoa.
To produce energy from supercritical fluids, requires drilling to depths of 4 to 5 km (13,000-16,000 ft) in order to reach fluid temperatures of 400–600°C. (750 -1100° F). Today, typical geothermal wells are about 2 km deep, (8,000 ft), produce steam at about 300°C, (570°F) -- a rate sufficient to generate about 5 megawatts of electricity. It is estimated that producing steam from a well penetrating a reservoir at or above 450°C (840°F) temperature and at a rate of 0.67 cubic meters (24 cubic feet) a second, could generate 40-50 megawatts of electricity.
Each of the power companies, who financed the pre-feasibility study completed in 2003, have committed to drill at their own costs one 3.5-4.0 km deep well in a geothermal field they operate. These wells will be designed for deepening to 4.5-5.0 km. One of the wells selected for further deepening is a joint IDDP-project funded by the consortium with additional funds from the International Continental Scientific Drilling Program, an international foundation based in Germany that supports drilling on land for scientific research, as well as the U.S. National Science Foundation.
The first wells will be drilled in 2008 at Krafla in north-east Iceland and tested the following year. Two new wells, 4 km deep, will then be drilled at Hengill and Reykjanes geothermal fields during 2009-2010, and, subsequently, deepened. Pilot plant testing is expected to be completed in 2015.