---

The global demand for energy continues to rise as the world economy expands. In this matter, renewables like wind power, hydropower, photovoltaic, biofuels and geothermal energy will grow rapidly with 6.6% per year. Geothermal energy is recovered by using the heat of the earth and it requires only small footprint facilities (if you use already existing wellbores of the oil and gas industry). Moreover, extraction is carbon dioxide- and waste-free and independent of weather conditions. Although the geothermal share of global power generation remains very small (0.3%), it plays a significant role in the United States and Indonesia. With geothermal power it would theoretically be possible to supply the actual world s energy consumption for 100.000 years. But at the moment there is only a little part of these resources technologically exploitable. The aim of this book is to explain how drilling in ultra-hard formations can be done more efficiently. Technical inventions and economic analysis will be presented. Technical inventions and economic analysis will be presented.

---

Simmer, Marc Constantin
Marc Constantin Simmer, BSc.: International Study Program in Petroleum Engineering, Montanuniversitaet Leoben.

---