Geothermal

The technologies used to generate and distribute electricity will be radically transformed during the coming decade. Amid that change, the power industry must continue to meet customer reliability, safety, and cost-of-service expectations. Achieving the right balance among these often-conflicting goals is the primary focus of every utility. The Electric Power Research Institute is helping utilities achieve that balance with R&D programs for many new and emerging technologies.

Geothermal power and conventional fossil fuel–powered technologies have similar power production cycles, and both generation types can be dispatched. Geothermal power’s primary advantage is its renewable fuel. Its primary disadvantage is that its fuel requires large investments over many years to characterize uncertain sources. Enhanced recovery techniques that use fracking may be the future of this renewable resource.

Acoustic pulse reflectometry (APR) is a tube inspection method that has been gradually gaining acceptance as a tool for heat exchanger inspection. Different types of heat exchangers operating in different operating environments have different failure mechanisms, making some of them more suited than others for inspection by APR. Finned tube heat exchangers are a typical example of heat exchangers particularly conducive to APR inspection.

At the close of 2009, the U.S. geothermal industry had seen seven new geothermal power plants come online in the previous 12 months. In 2010, only one new power plant was completed.

Geologists drilling an exploratory well in Iceland’s Krafla volcano in search of supercritical geothermal resources in 2009 unexpectedly uncovered a new way to harness energy from deep within Earth’s crust. It involves accessing shallow bodies of molten rock, which the geologists say could likely be found elsewhere in Iceland and around the world, wherever young volcanic rocks occur.

Completed in 2009 and partially funded under the American Reinvestment and Recovery Act, the 50-MW Blue Mountain Faulkner 1 Geothermal Power Plant is harnessing large amounts of renewable energy by tapping into an underground geothermal reservoir in northern Nevada. This subterranean source of heat allows the binary plant to generate pollution-free baseload electricity.

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In 2010 investment in wind power continued to accelerate, particularly in California and Texas. California also entered several solar projects in the race for financing. The finish line that renewable power developers and their partners are racing to meet is a December 31 deadline to qualify for federal cash grants.

Most countries are trying to increase the percentage of their electricity supply that comes from renewable sources. But because capital costs for renewable generation still, in most cases, are higher per kilowatt-hour than for fossil-fueled power, governments are looking at all options for encouraging the development of greater renewable capacity. Feed-in tariffs (FITs) are one policy tool that has been used, most notably in Europe. Now North America is testing FITs as well.

One of the world’s largest geothermal power stations was officially opened this May on New Zealand’s North Island. A joint venture between Mighty River Power and Tauhara North No. 2 Trust, the new 140-MW Nga Awa Purua Geothermal Power Station increases geothermal’s share of power in New Zealand to around 14%—a proportion that has more than doubled since 2005.