Magma Boosts Geothermal Energy
An accident of nature could lead to more energy efficient geothermal power plants.
Many energy companies would love to double their production. Now, researchers have discovered a way, not to double, but triple production in some geothermal wells. These wells, which are built in regions with high tectonic activity that may produce volcanoes, hot springs and earthquakes, tap into naturally heated water and steam deep in Earth and use it to generate electricity.
The hotter the steam, the more energy a geothermal well generates. So when molten rock, or magma, unexpectedly seeped into a research well in Iceland, researchers realized the well could be a model for future drilling projects around the world.
"It is producing super-heated steam at about 400 degrees Celsius (750 degrees Fahrenheit), and it has about three times the energy content of traditional wells," said Peter Schiffman, UC Davis geology professor and researcher on the project.
Geothermal wells currently supply energy to 60 million people in 24 countries, and are growing in popularity, according to the Geothermal Energy Association. Geothermal well installations in the United States alone have been increasing 15 percent each year, the group says.
But geothermal energy can only be exploited in regions with high tectonic activity such as California, the Philippines and Iceland, for example. In 2009, Reykjavik, Iceland-based Landsvirkjun Power Company partnered with a research team to study the nature of the fluids deep beneath Earth's surface. The company began drilling a geothermal well in the Krafla Caldera, a large land basin that is part of an active volcanic system in the northeast of the country. Landsvirkjun planned to drill about 2.5 miles deep, but was forced to stop after only 1.24 miles because magma, molten rock from the Earth's core, began seeping into the well.
The researchers tested the well, known as the IDDP-1, and discovered it produced enough energy to power between 25,000 and 30,000 homes. They were amazed.
"We were months behind schedule and really frustrated by all of the drilling problems. Then we suddenly have this major discovery," UC Davis geology professor and researcher Robert Zierenberg said.
By drilling closer to magma in areas with higher volcanic activity, energy companies could create a well that produces as much steam as three to four wells, saving millions of dollars in drilling costs and making geothermal energy a more valuable energy source. Zirenberg warns that with all the benefits, there are still some risks involved.
"Wherever magma is close to the surface, there is potential for producing high temperature geothermal fluids," Zierenberg said. "But building power plants in active volcanic areas does come with some risk due to the potential for future eruptions."
The wells themselves could also create problems. Conventional turbines used to convert steam into energy cannot withstand the high temperatures and pressures coming out of the IDDP-1 well.
Landsvirkjun's head of power projects Bjarni Pálsson said in an email that he is confident engineers can develop new turbines that can do just that.
"Higher pressure and temperature are known from nuclear and fossil fuel power generation," he said. "We believe turbine manufacturers would be able to combine knowledge and experience from these two industries."
Pálsson said the company plans to build a new power plant to tap into the IDDP-1 well's energy.
"Landsvirkjun and the Iceland Deep Drilling Project will continue experiments this year with the aim of finding an optimum way of utilizing the potentially erosive and corrosive steam," he said.
Once this research is complete, Pálsson said, the company will decide whether or not to move ahead its plans for the power plant and the drilling of more triple-power wells.