Geothermal energy technology is moving beyond volcanos, and popping up in unexpected spots like oilfields.
The technology developed in the last century to tap the earth’s heat has been most productive in regions where hotter layers are closer to the earth’s surface, like hot springs and active volcanic formations. Steam produced in those layers is used to generate electricity.
More recently, lower temperature geothermal applications have been developed so homes or communities can sink wells to tap the earth’s heat for building heating and cooling.
Now, innovators are branching out to adapt technology to utilize heat from sources other than the earth.
Classic geothermal energy was still the centerpiece at the Geothermal Energy Association (GEA) conference in Washington DC May 23.
Wealth of Potential for Resource Poor Nations
Speakers from countries seeking more indigenous energy sources told of projects in operation or under way in Nicaragua, the Philippines, Indonesia, New Zealand, Iceland, Romania, Germany, Chile, Colombia and much of East Africa, where the Rift Valley offers huge resources.
Ernesto Martinez Tiffer, President of the National Electric Co. of Nicaragua, said his nation currently gets 70% of its annual 3,000 gigawatt-hours from petroleum fuels and 30% from renewables. With new wind, hydropower, and geothermal plants being built, he said, “in five years we hope to invert that.”
Karl Gawell, GEA Executive Director, said geothermal still costs more, at least initially. But Martinez and experts from other nations said with the high price of oil, domestic geothermal is economic.
Mike Allen, Chair of Geothermal New Zealand, said geothermal in his nation is used for both electricity and industrial process heat, in a “totally deregulated” power market with “absolutely no government incentives.”
By contrast, Friedo Sielemann, Counselor, Energy and Environment, German Embassy, said his country has put in place above-market feed-in tariffs guaranteeing power prices for 20 years as it seeks to encourage renewables, including geothermal, and replace fossil generation.
Jonathan Weisgall, Vice President, MidAmerican Energy Holdings Co., said US tax incentives, usually lasting 1-3 years, don’t work well because geothermal projects take 4-8 years to plan, permit and build.
Technology Helping Reduce Cost
Drilling test wells to prove a site require “15-20% of the capital expenditure” of a project up front, said Pierre Audinet, Clean Energy Program Team Leader, World Bank, making them high risk ventures to investors.
But technical advances are making geothermal more efficient and economical, said Paul Von Hirtz of the International Geothermal Association, and increasing ability to tap lower-temperature environments.
For instance, many sites with underground water not hot enough for electricity generation can power district heating and cooling systems, said Halley Dickey of TAS Energy.
That technology to extract useful energy from water below the boiling point is key to Electratherm’s oilfield cogeneration technology, said CEO John Fox. Oil and gas wells coproduce hot water that is now considered a nuisance by drillers. His company’s modular units are “bolted on” to wells and utilize the water’s heat to make electricity for the well pumps, substituting for diesel fuel.
The technology, developed with support from the US Department of Energy, can use any source of heat and work on a small scale, Fox said. It was tested out in Mississippi, but the first commercial customer is in Romania, for a town district heating plant.
That kind of innovation is opening up a “new dynamic” for geothermal, said Gawell, with distributed as well as utility-scale applications, if only people “begin to think that way.”