A carbon stash
Colorado studies carbon sequestration near Craig

Three coal-fired power plants built near Craig in the late 1970s and early 1980s remain Colorado’s largest single source of carbon dioxide emissions. Colorado is currently studying ways to sequester the greenhouse gas./Photo by Allen Best

by Allen Best

Any sober reckonings of our energy future ultimately come down to a very smudgy realization: the United States may be stuck with coal for a long time.

In fact, Colorado gets 72 percent of its electricity by burning coal. In Utah, it’s even higher, 86 percent, and in Wyoming 95 percent.

Wind energy? You bet. The industry has surged in wind-rich Colorado.

Still, wind and solar together provided only 6 percent of Colorado’s electrical supply as of 2007, while hydroelectricity delivered another 5 percent.

Natural gas also has promise. Advocates – including media mogul Ted Turner, former U.S. senator Tim Wirth, and energy activist Randy Udall – all argue that we need to produce more electricity by burning natural gas, which produces only half the carbon dioxide of coal.

But can natural gas fill the void if we abandon coal?

Not likely, says Vincent Matthews, the Colorado state geologist. He says that’s why technology to sequester carbon dioxide from coal-burning power plants must be developed.

To that end, the Colorado Geological survey has applied for a $5 million federal grant to test geological sequestration near Craig, adjacent to Colorado’s largest array of power plants. Oil-shale developer Royal Dutch Shell, oil field services operator Schlumberger, and Tri-State Generation & Transmission collectively chipped in another $1 million.

The three power plants at Craig together generate 1,274 megawatts of electricity, of which Tri-State gets 624 megawatts.

Colorado proposes to drill a well 8,500 deep into a coal-bearing ridge adjacent to the power plants. Geologists want to know whether the carbon dioxide can be sealed within the underlying sandstone formation, so it won’t escape into the atmosphere. Geologists also want to understand whether minerals within the sandstone might react to the carbon dioxide in a way that blocks integration of the gas into the microscopic pores.

The project would be consistent with the Colorado Climate Action Plan of 2007. That plan calls for sequestration of carbon through such techniques as revised farming practices, but also by injecting it underground, as may be tested near Craig.

The state several years ago compiled a 500-page report that identifies the most promising geological formations in Colorado. Already, Colorado has participated in three partnerships, including an experiment conducted just 20 miles south of Durango in New Mexico.

The federal government is also pushing research into testing carbon capture and sequestration. President Barack Obama had pledged support of coal, and the stimulus package included substantial allocations for sequestration studies.

Some aspects of carbon sequestration are well understood. For example, drillers have long used carbon dioxide to dislodge oil from geological formations. In fact, a major source of carbon dioxide exists in Southwest Colorado, near the community of Montezuma. Carbon dioxide from that underground deposit, plus another source near Walsenburg, has been piped to oil fields in West Texas.

“People say, ‘Can you do this safely?’” says Matthews, a long-time oil and gas geologist. “Nature has been doing this safely for 100 million years.”

But can carbon sequestration be done on a massive scale as needed to justify continued burning of coal? Anti-coal activists see carbon sequestration as a giant gamble. They paint pictures of carbon dioxide, an asphyxiant, boiling to the surface, as has sometimes happened naturally.

Nancy LaPlaca, a Denver-based activist, points to the injection of 165 million gallons of toxic waste deep underground at the Rocky Mountain Arsenal, just east of Denver, from 1962-67. She noted that the experiment was accompanied by 1,500 seismic events, three of them higher than 5 on the Richter scale. When pumping ended, so did the earthquakes.

“This is folly,” LaPlaca says of carbon sequestration. “It is very risky. The cost is enormous on the scale at which we would have to do this. It is absolutely staggering.”

LaPlaca and others believe the money would better be invested in efficiency and renewables.

Vacliv Smil, a professor of energy at the University of Manitoba, has argued that carbon sequestration of the magnitude needed will be difficult. Last year he told the New York Times that capturing and burying just 10 percent of the carbon dioxide emitted during a year from4 coal-fired plants would require moving volumes of compressed carbon dioxide greater than the total annual world flow of oil.

But Smil has also asserted that it’s unrealistic to think that the world can leave behind coal-fired generation any time soon.

Tri-State, which supplies power to La Plata County and other rural areas of Colorado, plans continued burning of coal, because it is abundant and cheap – even with a price on carbon emissions.

“We feel we will be using it in the future,” says Jim Van Someren, manager of communications at Tri-State. “We just need to find ways to use it more wisely.”

A part of this calculus, he acknowledges, is the expectation that “at some point we will be operating under a carbon-constrained scenario.”

The first federal constraint could come late this year. The Waxman-Markey bill passed by the U.S. House of Representatives caps carbon emissions. Some climate-change activists charge that the legislation grants utilities too many allowances to effectively drive innovation. Others see it as a tepid step in the right direction.

Opponents see Waxman-Markey as too costly and a step in the wrong direction. After all, if greenhouse warming theory is half-baked, then burning fossil fuels isn’t a problem.

Matthews sees a continued role for coal in our future – and he doesn’t see natural gas filling the void.

“We’re not going to be off coal for a long time,” he says “We can’t possibly get off coal for a long time.”

Texas energy magnet T. Boone Pickens has famously argued that natural gas will be the bridge fuel to an economy built upon renewable resources. Lately, as new techniques have inflated estimates of natural reserves in the United States, some in the environmental community have agreed that it will be the bridge fuel.

Matthews isn’t persuaded.

“I agree with a lot of what Pickens wants to do,” he says. “But my concern is that everybody wants natural gas to be their answer. Pickens wants it to displace imported oil. Proponents of renewable energy want it as a backup to fill the intermittency of wind and solar. Anti-nuclear people want it instead of nuclear. And anti-coal people want it to displace coal. Everybody wants to put all their eggs in the basket of natural gas.”

But Matthews isn’t persuaded that enough natural gas exists to be the answer for all needs. Unlike the earlier deposits of natural gas, the so-called shale plays stop producing very rapidly, requiring far more drilling. To get the same volume of gas in 2008 as was produced in 1995, he says, required more than three times as many wells, 31,000 and 9,000 respectively.

“You have to drill more and more just to stay even,” says Matthews, for many years a leading geologist for Amoco.

It’s not about reserves, he goes on to explain. It’s all about production.

“It’s just like oil shale. What difference does it make that the U.S. Geological Survey has increased the estimated reserves of oil shale from 1 trillion to 1.5 trillion barrels. We haven’t gotten one drop from it yet.”

Despite all the fanfare about the so-called shale plays, says Matthews, U.S. production of natural gas last year dropped to 2001 levels. Nor, he points out, has U.S. production of gas regained 1973 levels. The gap is filled by imports.

Jim Rogers, the chief executive of Duke Energy, one of the nation’s largest utilities, made the same point during a talk last week in Boulder. He called natural gas the “crack cocaine of our industry.” Rogers, whose company recently announced a major wind farm in eastern Colorado, said he believes all options need to stay on the table, including nuclear and coal. But sequestering coal remains a daunting challenge, he said.

Matthews readily admits to challenges but doesn’t view earthquakes as a show-stopper. However, because of the experience at the Rocky Mountain Arsenal near Denver, the issue must be dealt with. “I tell people, when that issue comes up, don’t blow it off.”

But carbon sequestration will be expensive. “It will be expensive to capture, expensive to compress for injection, and it will be expensive to inject.”

By some estimates 30 to 40 percent of the energy harnessed from a coal-fired power plant could be required to capture and store the carbon.

A study by Harvard researchers Mohammed Al-Juaied and Adam Whitmore released in July estimated that carbon capture and storage will add an average 10 cents per kilowatt hour to the price of electricity, or about double the going rate in Colorado.

Other states in the Rocky Mountains have also been planning for carbon sequestration. Wyoming, with its still large stores of coal in the Powder River Basin, has begun to assemble the regulatory and legal framework for governing risk. Two years ago legislators adopted laws governing administration of pore spaces, the spaces between rock in underground formations where the carbon would be injected. As well, universities in Wyoming and Utah have geared up with special divisions devoted to sequestration efforts.