A new study from the US Geological Survey (USGS) shows that geothermal power plants have a potential to provide more than 40 percent of total U.S. electricity. The report, published in the February issue of Science Magazine, says that if all existing and planned geothermal projects were completed by 2030, they would generate nearly 1,000 terawatt-hours (TWh) of electric power annually — enough to supply about 5 percent of current U.S. electrical demand.
According to the U.S. Geological Survey, there may be up to 16,500 megawatts of untapped power potential from the already known geothermal sources alone. This amount is equal to 16 sizable nuclear power plants or numerous coal-fired power plants.
According to the USGS report, the power output could grow as much as five times over the next several decades as additional geothermal projects are built.
maakütte paigaldus (ground heating installation) generated within Earth’s crust through the natural processes of convection, conduction, or radioactive decay. Geothermal reservoirs vary widely in temperature and depth, but most contain liquid water at temperatures between 60 degrees Celsius (140 degrees Fahrenheit) and 200 C (392 F).
The report estimates that there are approximately 7,600 TWh of recoverable geothermal energy worldwide, with more than 2,200 TWh located in the United States alone. However, only about 8 percent of this energy has been developed for commercial use so far. The USGS research indicates that this rate of development can be increased significantly, if the right incentives are put into place.
“We found that the cost of producing electricity from geothermal resources is comparable to other forms of renewable energy,” said lead author Robert Giegengack of the USGS, “and our research suggests that many more geothermal resources will become available as we develop methods to extract them.”
In general, electricity production costs tend to reflect the price of fossil fuels used to generate it, rather than the actual generation process itself. This is because electricity generators typically pay taxes on their fuel costs; the higher the tax, the lower the price per kilowatt hour produced. By contrast, geothermal energy is usually considered free, since no fuel is needed to produce it. In fact, some companies actually charge customers a premium for using geothermal energy.
But the reality is that geothermal power is not without its challenges and drawbacks. In addition to environmental concerns, such as air pollution and greenhouse gas emissions, geothermal power also requires expensive initial equipment, which means that upfront investments may be substantial. Also, the availability of high quality sites suitable for the extraction of geothermal energy can be limited. It also takes time to build up steam pressure, which is necessary to start generating electricity.
Still, compared to other types of renewable energy, geothermal power does offer significant advantages. Unlike wind and solar, geothermal plants can operate almost continuously. And unlike nuclear power, there are no long-term storage issues when the sun goes down or the wind dies down.
Although it still remains an emerging technology, USGS researchers believe that geothermal power will continue to gain ground in the coming years. According to the report, recent advances in drilling and extraction technologies, combined with the increasing number of geothermal power plants being built around the world, show that geothermal energy production is becoming increasingly affordable and attractive.
For example, the authors point out that the average price per megawatt hour has declined from $50/MWh in 2000 to just under $26/MWh today, making it competitive with coal-fired electricity generation. Furthermore, they note that the cost of operating geothermal power plants has decreased dramatically over the past few years, largely due to improvements in drilling technology and the use of underground reservoirs instead of open surface wells.
The report cites several examples where geothermal power has already played a major role in providing energy security and economic growth. According to the authors, Iceland has been able to meet 90 percent of its electricity needs since 1996 with geothermal power, while China has recently begun to utilize geothermal energy to address its rapidly growing energy demands.
“Geothermal resources are abundant,” said co-author David Hughes of Oregon State University, “so the opportunity is certainly great. But geothermal power is a very young industry, so there are still plenty of opportunities to improve efficiency and reduce costs.”
The research team notes that there is a need for a comprehensive national policy framework to encourage the development of geothermal energy, as well as to facilitate access to capital for entrepreneurs interested in developing the resource. They also call upon federal agencies, such as the Department of Energy, to help fund further research aimed at improving the efficiency and reliability of geothermal power systems.
Accordingly, they recommend that Congress should enact legislation to promote geothermal energy development by establishing a dedicated source of funding to finance geothermal project feasibility studies. Such efforts would help ensure that entrepreneurs receive the information they need to make informed decisions regarding the viability of future geothermal projects.
Finally, the researchers suggest that the government should consider expanding the eligibility requirements of the Section 1603 Advanced Technology Vehicle Manufacturing Credit, a provision enacted as part of the American Recovery and Reinvestment Act of 2009, to include geothermal energy. This would allow more businesses to take advantage of the tax credit for purchasing vehicles designed to run on alternative fuel sources.