Wednesday, May 27, 2009
Enhanced Geothermal Systems - EGS
EGS stands for Enhanced Geothermal Systems, sometimes called Engineered Geothermal Systems as well. This title represents the scale of a new type of geothermal technologies, enabling to exploit geothermal potential in areas without underground natural hot water streams or natural hot water reservoirs. In other words, if natural conditions do not allow to use hot water streams in economic viable way, EGS technology brings solution by pumping cold water down the well, under high pressure, in order to be warmed in rock pores underground and after it delivered above the surface, all in closed loop. Therefore we call this procedure “Hot Dry Rock” (HDR).
Efficiency and viability depends on depth of well. As we wrote in previous article, in fact, geothermal wells nowadays are rarely deeper than 3 kilometers. It is caused by the costs of ultra deep drilling. Just for information, drilling into 5-10 km represents tens of million dollars in general.
Exploiting geothermal energy via EGS/HDR can be established anywhere on the Earth, but always regarding to financial limits of drill depth. In areas where there are present so called tectonic plate boundaries - in areas where magma and its heat come together closer to Earth's surface, using EGS becomes cheaper. On the other hand, if distance between surface and magma is longer, drilling effective wells becomes more and more expensive.
Under various estimations, if EGS should be competitive to other renewable energy sources really anywhere, it needs huge R&D (research and development) progress. Experts say that in next 15 years, there need to be 1 billion USD invested into geothermal EGS research in order to be able to install 100 GW of electricity only in United States by 2050.
Nowadays, EGS and HDR technologies are being tested in axis France – Switzerland – Germany as well as in the middle of Australia, in Japan and in the West side of United States (notice: in next articles we will try to show some concrete examples of EGS installation in Europe via case studies from Germany and France).
Enhanced Geothermal Systems and Hot Dry Rock technologies offer unique opportunity to find new energy solutions. Information technology giant Google also considers this huge opportunity. The reason according to Google.org is very simple and clear: „EGS is a utility-scale, base-load, and renewable energy source that could produce electricity cheaper than coal. Since EGS builds the geothermal reservoir by design, EGS projects can be made large enough to produce as much power as a typical natural gas or coal power plant (500 - 1,000 MW). Everywhere on Earth, the deeper you go, the hotter it gets, meaning EGS can be developed in many areas across the world. EGS is a base-load resource, meaning it can run 24 hours a day regardless of weather.“ Therefore also the leading web search engine decided to invest into EGS research heavily as well as to inform public with creation of US geothermal potential digital map for Google Earth's users.