A project to learn more about extracting energy from hot rocks on land should give clues about "black smokers," hydrothermal vents that belch superheated water and minerals deep below the ocean. The project's aim is to drill deep boreholes to learn more about processes in deep, hot rocks, with the goal of producing more energy from a single geothermal well.
A project to learn more about extracting energy from hot rocks on land should give clues about "black smokers," hydrothermal vents that belch superheated water and minerals deep below the ocean.
As part of the Iceland Deep Drilling Project, researchers from UC Davis, UC Riverside, Stanford University and the University of Oregon plan to sink a deep borehole into a site on land where seawater circulates through deep, hot rock. Most such sites on land have circulating fresh water, with very different chemistry.
“We hope to understand the process of heat transfer when water reacts with hot volcanic rocks and how that changes the chemistry of fluids circulating at depth," says Robert Zierenberg, professor of geology at UC Davis. "We know very little about materials under these conditions. It's the dry land version of a deep-sea hydrothermal vent. It's the first opportunity to look at rocks and fluid together and in situ."
Deep ocean hydrothermal vents support unique communities of living things that, unlike most ecosystems on Earth, draw no energy from the sun. The vents also generate unusual, and possibly valuable, deposits of copper, zinc and other minerals.
Zierenberg says that it is technically challenging to drill into rocks that are under high pressure and bathed in corrosive fluids at 840 degrees F, but it is easier than trying to drill deep below the sea floor in the deepest parts of the ocean. The university team, funded by the National Science Foundation, will drill up to 2.5 miles into the rock. It will be one of three boreholes sunk as part of the Iceland Deep Drilling Project, which is supported largely by Icelandic power companies.
The Project aims to drill deep boreholes to learn more about processes in deep, hot rocks, with the goal of producing more energy from a single geothermal well. Iceland already gets half of its electrical power and meets much of its needs for space heating and hot water from geothermal energy.
The United States also has lots of potential for geothermal energy generation, Zierenberg says. There are several plants in California, including the Geysers region in the north and at Mammoth Lakes. Although its share of energy generation in the state is small, the Geysers is the largest geothermal field in the world, Zierenberg explains. There also are numerous abandoned oil and gas boreholes around the country – including in the Central Valley – that could potentially access hot water that could be used for space heating.
That would, however, require something of a cultural change. In Iceland, geothermal heating is used at a community level: Hot water is pumped up and circulated around a town or neighborhood. Americans are more accustomed to individual power delivery, Zierenberg notes.
The researchers expect to start drilling in the summer of 2008.
Deep Drilling for "Black Smoker" Clues
November 16, 2007