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Can We Lock Greenhouse Gases
Away in Rocks?

by Sandi Doughton, staff reporter
Seattle Times, November 24, 2006

RICHLAND -- Pete McGrail knelt at the base of a towering basalt cliff, picked up a chunk of rock and tilted it to catch the sunlight.

"That's what we're interested in," he said, pointing to a Swiss-cheese network of tiny holes. "That porosity."

The cavities are the remnants of gas bubbles trapped in lava that flooded the Pacific Northwest millions of years before humans appeared on Earth.

Now, McGrail hopes these rocks will help solve a man-made problem of global proportions: reducing greenhouse-gas emissions.

Next year, he and fellow scientists from Pacific Northwest National Laboratory (PNNL) in Richland will test their notion that carbon dioxide injected deep into the region's basalt formations will seep into cracks and pores in the rock -- and stay there.

A proposed power plant in Cowlitz County is being designed to take advantage of the technology, if it pans out. Researchers are also studying a coal mine near Centralia as a possible reservoir for emissions from the state's only coal-fired power plant.

The idea of burying heat-trapping air pollutants, such as carbon dioxide, may sound far-fetched, but it has emerged as a leading strategy to combat global warming. Commercial-scale operations are already under way in Canada, Norway and Algeria. The PNNL project is one of dozens of small-scale tests planned across the United States.

The technology isn't new. For decades, the oil industry has been injecting carbon dioxide underground to force more petroleum out of fields where production has dropped.

An international review panel concluded last year that carbon dioxide from power plants can be locked up underground without leaking, contaminating groundwater or posing a risk to people, if projects are carefully designed.

"There's no single, silver bullet for addressing climate change," said Jim Dooley, senior staff scientist for PNNL's Joint Global Climate Change Research Institute. "But this could be 30 to 40 percent of the solution."

While some critics say carbon storage is only a stop-gap measure that could actually hinder the shift to cleaner energy sources, most environmental groups are backing the approach.

"While we would prefer to see more emphasis on energy efficiency and renewable-energy sources like wind, solar and biomass, there are a lot of coal plants being built and proposed, and they should be equipped with carbon capture and storage," said David Hawkins, director of the Natural Resources Defense Council's Climate Center.

Nearly 150 new power plants, mostly coal-burning, are on the drawing board in the United States, threatening to boost greenhouse gases at a time when scientists say drastic cuts are needed to avoid climate upheaval.

The U.S. Department of Energy (DOE) and private companies are spending $85 million this year to study underground storage, also called carbon sequestration. That's nearly triple the budget five years ago.

The $4 million Richland basalt project, funded by DOE, is a long-shot candidate.

A good storage site needs two key components, explained Julio Friedmann, head of the carbon-management program at Lawrence Livermore National Laboratory in California. Porous rock deep underground acts like a sponge to absorb the carbon dioxide, which behaves like a liquid at those depths. Impermeable rock overlying the porous layer acts as a lid.

Most of the attention so far has focused on the vast basins of highly permeable, sedimentary rock around the world where people have long drilled for oil and natural gas. The fact that they held fossil-fuel deposits for millions of years means the cap rocks are sturdy and bodes well for containing carbon dioxide, Friedmann said.

But Northwest basalts also have porous sections and thick cap rocks, said McGrail, who heads PNNL's carbon capture and storage programs.

More than 77,000 square miles of the volcanic rock covers much of central and eastern Washington -- including the Columbia River corridor -- and parts of Idaho and Oregon. In some places the layers are nearly 3 miles thick. The DOE spent $500 million to examine the basalts as a possible nuclear-waste repository before picking a site in Nevada instead.

"No other basalt formation in the world has been studied as intensively," McGrail said.

Laboratory experiments also show a potentially big advantage to basalt: When carbon dioxide is injected into the pores, it reacts with the rock to form solid calcium carbonate -- the same crusty white deposit that builds up on your shower stall.

"It completely converts to solid rock ... so leakage is not a concern," McGrail said.

In next year's test, the scientists plan to pump 3,000 tons of carbon dioxide -- equivalent to a few hours' output from a coal-fired power plant -- about two-thirds of a mile below the surface. That's far below any aquifers used for drinking or irrigation water.

The scientists will then track the way the gas moves underground and watch for leaks.

Can be deadly

Carbon dioxide is a natural component of the atmosphere, but in large concentrations it can be deadly.

Three ski patrol members suffocated on Mammoth Mountain in California this spring after they were overcome by carbon dioxide and other gases venting from volcanic fissures. An entire village in the African nation of Cameroon was wiped out in 1986 when the waters in a volcanic lake overturned, releasing a massive cloud of carbon dioxide that smothered everyone in its path.

Such accidents couldn't happen with a carbon-sequestration site -- even in the worst-case scenario of an earthquake -- because the gas is pressurized deep underground and trapped inside pores in the rocks, experts say.

They are more worried about slow leaks, through old oil and gas wells, that undo the benefits of sequestration.

"If we have 1 percent a year coming back to the surface, the technology is a complete failure," McGrail said.

McGrail estimates Northwest basalts can hold 20 years' worth of U.S. power-plant emissions. But the region isn't likely to become a major dumping ground because it's so remote from the nation's power-producing centers.

The eastern United States, where coal-fired plants are concentrated, also has large basalt deposits. And PNNL researchers plan to collaborate on a pilot project in India, where enormous basalt fields cover much of the country and where power-plant construction is booming.

One possible local target for underground carbon storage is a $1 billion power plant proposed for Kalama, Cowlitz County. The plant would "cook" petroleum coke, a waste product of oil refining, and burn the resulting gas for energy production, said Brad Peck, spokesman for Energy Northwest, the public consortium behind the idea.

Energy Northwest is spending an extra $35 million to design the plant so it could eventually be retrofitted to capture carbon-dioxide emissions and stash them in underlying basalt or sedimentary rocks.

"It's an investment we're making to ensure that if sequestration becomes technically viable and affordable ... the design of this plant would be compatible," Peck said.

Is it affordable?

Affordability is the rub that has kept carbon storage largely theoretical so far.

Using the technology on new power plants could boost the cost of electricity production 15 to 40 percent. Until nations adopt caps or taxes on carbon emissions, few power companies will spend that extra money.

The world's longest-running carbon-sequestration project, off the coast of Norway, exists because the government there imposed a tax on carbon-dioxide emissions.

The Sleipner project is a natural-gas-mining operation in the North Sea. Most natural-gas deposits also contain carbon dioxide, which must be removed before the gas can be burned. Normally, that CO2 is simply vented to the air. But at Sleipner, about a million tons per year are injected into sandstone deposits deep under the sea floor.

British Petroleum, the first oil company to acknowledge global warming, is involved in a similar project in a gas field in Algeria. The company also plans to build a power plant in California that will pump its carbon-dioxide emissions into a nearby oil field.

The Weyburn project in Saskatchewan, started six years ago, pipes carbon dioxide 200 miles from a coal-gasification plant in North Dakota and injects it into an oil field. The primary motive was to boost oil production. But the companies also teamed up with the Canadian government to monitor injection sites and develop technology for future sequestration projects.

So far, there has been no leakage, said Ray Knudsen, who oversees the project.

At the Centralia coal mine, scientists are drilling and coring to see if it would be feasible to inject carbon dioxide from the nearby power plant into areas too deep to mine. The procedure could have the added benefit of forcing usable natural gas out of the coal.

The power industry is closely tracking carbon-storage projects but not making many commitments. Puget Sound Energy, which gets nearly a quarter of its electricity from a coal-fired power complex in Montana, is part of the DOE-sponsored consortium mounting the basalt test in Eastern Washington.

Most observers say federal carbon regulations are inevitable, but it's hard to say how soon they will come.

"The energy companies are waiting for carbon policy -- some optimistically, some with fear and trepidation," said Friedmann, of Lawrence Livermore National Laboratory. "When they get the signal, they all know what they have to do ... and a lot of it will involve working with carbon capture and storage."

Sandi Doughton
Can We Lock Greenhouse Gases Away in Rocks?
Seattle Times, November 24, 2006

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