Carbon sequestration may reduce emissions linked to global warming
June 22, 2008
By Katie Burford | Herald Staff Writer

This month researchers will begin pumping carbon dioxide deep into the ground in a test that could yield a valuable new method for keeping the greenhouse gas out of the atmosphere while also increasing methane production.

The Pump Canyon test pilot, located near Navajo Dam in New Mexico, is part of nationwide, public-private push to advance a technology known as carbon sequestration, which aims to lock the gas away where it can't contribute to global warming.

And the Four Corners has plenty of emissions it could stand to get rid of.

Recently, San Juan County, N.M., with two large coal-fired power plants, was listed as the sixth-worst carbon-dioxide emitter in the country by a major university study. Southwest Colorado, in the same airshed, could exceed federal air-quality standards this summer.

If the results from the test are positive, the San Juan Basin, which stretches into Southwest Colorado, could be among the first places in the world where the process is put into widespread use.

But many questions have to be answered first. Is sequestration feasible, both technically and economically, on a large scale? Will the gas, once it has been injected into a geologic formation, stay where it is put?

And the biggest unknown - will the technology have any real impact on reducing emissions?

Some environmental groups fear it will serve only as a crutch, keeping us dependent on dirty fuels. But researchers hope it will be a bridge, ferrying us between the fossil-fuel present and the renewable-energy future.

Big potential, with a catch

One thing is clear: The federal government sees considerable potential in carbon sequestration.

Currently, there are 26 field tests going on around the country, all funded by the Department of Energy's National Energy Technology Laboratory. Three of these, including the Pump Canyon test, are in the Southwest.

The test near Navajo Dam will inject 20,000 tons of carbon dioxide into the Fruitland coal layer. Because coal has a strong affinity for carbon dioxide, the two are expected to bond, pushing the methane out. Just as the coal held the methane for millennia, it is predicted to hold the carbon dioxide.

Coal beds are just one of the potential options for storing carbon dioxide; others include depleted or marginal oil fields and deep saline aquifers. The gas can also be stored in surface vegetation and in a solid, mineralized form. All of these methods are being tested.

Under the DOE's initiative, each region is assessing its emissions and storage capacity.

A 490-page report on Colorado's carbon-sequestration potential estimated the state's storage capacity at more than 700 billion tons, providing several hundred years of carbon storage. Of this, an estimated 19 billion tons could be stored in coal-bed methane reservoirs and 668 billion tons could be stored in deep saline aquifers.

The state's emissions, meanwhile, were more than 92 million tons, of which 46 percent was from power plants. These emissions, which are from 2000 estimates, are projected to increase 2.4 percent per year through 2025.

The potential to capture and store carbon in the San Juan Basin is especially appealing because the area has two large carbon-dioxide producing sources: The San Juan power plant, which produced 14.5 million tons of carbon dioxide in 2000, and the Four Corners power plant, which produced 17 million tons.

Plans for a third coal-fired plant, Desert Rock, are on hold pending permit approval by the U.S. Environmental Protection Agency, which expects to make a decision by the end of July.

The catch to capturing and storing the plants' carbon dioxide is the cost.

Brian McPherson, associate professor in civil and environmental engineering at the University of Utah and principal investigator for Southwest's three projects, said that separating the plants' carbon dioxide from its other emissions, including mercury, is an expensive process - around $40 per ton. For the Fours Corners plant, this would mean around $680 million a year.

"That must wait necessarily until the cost comes down," he said.

Frank Maisano, spokesman for the Desert Rock project, said the technology could eventually be integrated into the proposed plant.

"They're building the project so that it can be retrofitted for carbon-sequestration technologies should they become affordable and available," he said.


Academics and DOE experts don't expect that to happen for another 10 years or more.

"Right now, it does look rather far off," Maisano said.

He added that the plant would use other, currently available technologies that would reduce its emissions by 20 percent compared with other plants its size.

Many believe it will take government-mandated emissions caps to move the technology along. Such a system was part of a sweeping climate bill debated earlier this month by the U.S. Senate.

The legislation, the most ambitious response to global warming ever taken up in Congress, garnered a majority of votes but not the 60 necessary to avoid a Republican filibuster. Supporters have vowed to revisit the topic next year in what they hope will be a more favorable political environment after November elections.

Maisano disputed that regulation is the best impetus for advancing the technology.

"What regulations tend to do is push too fast, so that people will just switch fuels," he said. "There can be a regulatory push, but if the regulation is, for instance, what environmentalists want, there wouldn't be a technology, there would be just a full switch away from using coal."

Burying the problem - or our heads?

A switch away from coal is exactly what some environmental groups are saying needs to happen. They say carbon sequestration will only delay the process.

"Despite being unproven and expensive, coal and power companies are advertising the scheme as a solution to global warming in order to justify building new coal-fired power plants," Greenpeace said in a new release last month.

Gwen Lachelt, director of the Durango-based Oil and Gas Accountability Project, had similar concerns.

"We need to proceed really cautiously and not look at it as a fix-all for just being able to use dirty energy like coal," she said.

McPherson and other researchers on the Pump Canyon pilot say sequestration isn't intended to reverse human-made emissions, but rather temper them while sustainable alternatives are developed.

"I very much think of it as a potential bridge technology," he said. "Sequestration is something that we can do right now."

But Lachelt said it is that kind of reasoning that has kept us hooked on fossil fuels for far too long.

"We've been talking about using natural gas and all as a bridge fuel for over 30 years. I just think we keep burying our heads in the sand," she said.