Is there a fix for global warming under our feet?
By Sandi Doughton (Seattle Times) - July 26, 2013
Scientists at Pacific Northwest National Laboratories are conducting an experiment near the Columbia River in southeastern Washington to see if greenhouse gases from power plants could be captured and stored underground in porous rocks.
The long-delayed test started on July 17 and will continue for another two or three weeks, said project leader Pete McGrail. The goal is to inject 1,000 tons of liquefied carbon dioxide about half a mile below the surface.
PNNL will monitor the well and its environs for at least 14 months, to track the carbon dioxide and watch for any leakage.
The experiment is the first of its kind to focus on basalt — the volcanic rock that underlies much of the Columbia Basin — as a possible repository for the heat-trapping air pollutant that is the main driver of global warming.
“This is the only one in the world,” McGrail said.
An earlier analysis estimated that the Northwest’s basalt deposits are vast enough to hold 20 years’ worth of U.S. power plant emissions — though it’s not likely that carbon dioxide would ever be piped here from other parts of the country.
But the results from the experiment should be relevant to basalt deposits elsewhere in the U.S. and in countries like India, where a growing demand for energy is fueling an increase in greenhouse gas emissions, McGrail said.
Far-fetched though it sounds, burying carbon dioxide emissions offers a way to slow global warming while continuing to build power plants that burn coal, a more polluting fuel than natural gas.
The approach is a spinoff from the oil industry, which has long injected carbon dioxide into rock formations to force out more petroleum.
Lab tests at PNNL show that liquefied carbon dioxide solidifies quickly when it’s pumped into porous basalt, forming carbonate minerals. If laboratory results translate into the field, that should ensure that none of the CO2 leaks back into the atmosphere, McGrail said.
“But the things you see in the lab don’t always translate that well into the field,” he cautioned. “That’s why there’s no substitute for doing a field experiment like this.”
Layers of impermeable rock above and below the injection zone will serve as additional barriers to keep the CO2 from migrating.
The experiment poses no risk to sources of drinking or irrigation water, said Grant Pfeifer, regional director for the Washington Department of Ecology. The zone of permeable rock where the gas will be injected is far deeper than any wells, and the ground water in the area is naturally high in iron, fluoride and other minerals that make it unsuitable for human consumption, he said.
When the experiment is done, the researchers hope to get additional funding to extract rock cores from the site and determine whether the carbon dioxide solidified as expected.
The $12 million project is part of the DOE-funded Big Sky Carbon Sequestration Partnership, one of seven regional projects to explore carbon storage technology.
The experiment has been in the works for nearly a decade, but was postponed repeatedly due to bureaucratic hurdles and budget woes. In the intervening years, the energy landscape in the United States has shifted dramatically and interest in underground storage has waned.
Thanks to abundant supplies of cheap, cleaner-burning natural gas, coal-fired plants have fallen out of favor. And Congress shows no signs of forcing industry to curb carbon dioxide emissions.
“I am far less optimistic about where carbon sequestration is going today.” McGrail said. “There just aren’t any drivers that would push us in that direction.”