Down with Greenhouse Gas

Way, way down. LBL's Sally Benson leads an effort to fight global warming by hiding CO2 deep underground.

In a book-lined office at the Lawrence Berkeley National Lab, Sally Benson describes her upcoming experiment, as wound up as a kid at a science fair. A sensible woman in a cardigan and spectacles, she is about to embark on a pilot project that could be the model for a sweeping new system to combat global warming. It’s no wonder she thumps on the table as she illustrates a point. “We’re very excited,” she says for the sixth time.

Benson is designated as lead author of a report, already two years in the making, that will represent the international consensus on an emerging technology awkwardly named carbon sequestration, or carbon capture and storage. In the next year, her own research team will buy two thousand to four thousand tons of carbon dioxide, the heat-trapping gas largely responsible for global warming, truck it to Solano County, and send it down through a pipe to a layer of sandstone five thousand feet beneath the Earth’s surface. There, she hopes, the gas will fill up tiny spaces in the rock and stay put for thousands of years — never to bother us again. “For all intents and purposes, it’s permanent storage,” she says.

While researchers elsewhere struggle to develop alternatives to fossil fuels, this technology, by tucking carbon dioxide emissions from power plants deep into the earth, could help keep the problem from getting worse. Over the past few years, oil companies, business leaders, and even a reluctant Bush administration have largely ceased their blustering suggestions that global warming is all an illusion. With backing from these recent allies, scientists like Benson are quietly preparing for a new world, defined by the need to cope with our carbon dioxide excesses. “This is not a silver bullet, but this technology could ease the transition away from fossil fuels,” she says.

Already, global warming’s effects are being documented worldwide. Enormous Arctic ice shelves that have been stable for three thousand years are cracking up. Average ocean temperatures are one degree Fahrenheit warmer than they were a century ago, leading to a higher probability of devastating storms like Katrina.

While the federal government has balked at regulating carbon emissions from power plants, a major source, the states aren’t waiting around. A group of states in the Northeast has set goals for reducing emissions from power plants starting in 2009. This past June, Governor Arnold Schwarzenegger followed suit with an executive order that set bold reduction targets. Citing issues of water supply, air quality, and coastal erosion, it mandates that state emissions must be at or below 2000 levels by 2010, with increasingly sharp cuts thereafter; state officials expect carbon capture and storage will figure into the long-term plan.

It may come as a surprise that this technology stems from work done by oil companies over the past thirty years. In 1972, engineers at a rig in Scurry County, Texas, tried a new way of coaxing recalcitrant drops of oil from the ground. They injected carbon dioxide into a reservoir, which forced so-called “stranded oil” to flow toward a well where it could be pumped up. The idea caught on, with a typical industrial operation injecting a million tons of carbon dioxide a year into the ground. It wasn’t until the late 1990s that scientists seriously considered using it to slow global warming.

Benson first started working on the problem in 1998, while working at a Department of Energy lab at LBL. Her boss suggested she look into a few of the key questions: Will the CO2 stay underground? Can you monitor its movements? Is it safe? Benson and her collaborators are laying those fears to rest. Potential safety hazards, such as faulty injection wells that could allow the gas to blast back out of the ground, she says, are certainly no worse than those faced by natural-gas drillers, and the companies know how to handle them.

To prevent carbon dioxide from leaking out gradually, meanwhile, you simply need a good site — one with an impermeable rock layer that caps the storage zone. Researchers cite natural-gas reservoirs that have held methane below the surface for millions of years as proof that the process can work. “If you’re doing your job, [leaking] won’t be a problem,” Benson says. “It’s not like people are going to just drill a hole anywhere and cram the CO2 down there.”

Next year’s pilot projects, designed to test the technology under real-world conditions, will be overseen by the West Coast Regional Carbon Sequestration Partnership (WESTCARB), one of seven regional partnerships set up by the DOE in 2003. The total effort will cost $29.9 million over the next four years, with the feds contributing $14.3 million. The remaining money comes from a consortium of oil companies, electric utilities, and state agencies from participating Western states. They’ll also work on terrestrial sequestration — the natural storage of carbon dioxide through forest management and conservation, but it’s Benson’s upcoming project in Solano County’s Rio Vista gas fields that has the experts most excited.

“The Central Valley in general is a very attractive place to think about the storage of CO2 in the subsurface,” says Larry Myer, WESTCARB’s technical director. Estimates show the area’s rock formations could hold eighty billion to five hundred billion tons of carbon dioxide, the equivalent of hundreds of years of emissions from California’s power plants and industrial sources.

The Rio Vista project, the first attempt to store carbon dioxide in a natural-gas reservoir, will be conducted with the financial support of Calpine, an independent power producer based in San Jose that operates a host of gas-fired power plants nationwide. “First, we recognize that global warming is a significant environmental challenge facing this country,” says Peggy Duxbury, Calpine’s vice president of government and environmental affairs. “Second, we operate in regions of the country where states have already taken steps to regulate CO2, and we feel more states will continue to do this, and it won’t be too long before the federal government regulates carbon. So we want to be prepared.”

Finally, the technology may boost natural-gas recovery from nearly depleted fields, pushing out stranded methane the same way it has pushed out oil. Using this process, Benson says, a given well could yield 30 percent more natural gas. That’s good business for Calpine. “I think the ideal situation is if you can both sequester carbon, take it out of upper atmosphere, and at the same time be able to recover some natural gas or oil in the process,” Duxbury says. “Then you’d really see something that could both make economic sense, and help us all deal with this significant environmental challenge.”

By focusing on natural gas and oil recovery, the researchers hope to jump-start a larger environmental effort, with the recovered fuels offsetting initial costs. Myer hopes federal regulations will eventually compel companies to adopt the technology and bring it to its full potential. “It is a very large-scale undertaking,” he says. “The full-scale implementation of geological sequestration would involve infrastructure on the scale of the oil and gas industry today,” with pipelines that run from power plants to suitable injection sites. This new “carbon-constrained” world is fast approaching, experts say. The energy bill President Bush signed in August put money and support behind so-called clean coal power plants, which will emit pure carbon dioxide ready to be compressed and piped to an injection site.

Many environmental groups were initially skeptical, worried that the technology would divert funding from research on alternative power sources. But many key environmentalists now agree with Myer. “If we’re going to address this problem, we need to get started as soon as possible,” notes Antonia Hertzog, a staff scientist at the climate center of the National Resources Defense Council. “We want to move away from fossil fuels and develop alternative energy, but we are pragmatic. Fossil fuels are here to stay for a long time, and we need to address that.”

Time is indeed of the essence, Myer cautions. “This is not a problem that we can put off for fifty years while we develop some unseen, unknown adaptive technique,” he says. “When you’re faced with the magnitude of the problem that we have at present, I think it’s very justified to look at multiple techniques.” Benson, sitting across the table from him, nods in sober agreement. “I think we need everything we can possibly dream up,” she says.

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