August 11, 2010


Ken Silverstein
EnergyBiz Insider
Editor-in-Chief

Carbon capture could become commercial within 10-15 years. And while it holds the potential to significantly cut heat-trapping emissions, it may be noticeably more expensive than current technologies and thereby cause consumers to pay more.

That's the primary findings of the Government Accountability Office, which concluded that current carbon capture and sequestration technologies would increase the cost of power by 30 percent to 80 percent, albeit it has greater potential to reduce carbon emissions than other ideas. The alternative to such progressive technologies is one that centers on improving efficiency gains, or reducing the amount of coal that is burned so as to limit emission levels.

But those "ultra-supercritical" generation technologies are expensive and may only be worth it if the nation attaches a price to carbon and therefore increases the costs of coal. Otherwise, utilities may find it cheaper to build natural gas plants and particularly if the price of such fuel remains relatively low.

"Commercial deployment of carbon capture and sequestration is possible within 10 to 15 years while many efficiency technologies have been used and are available for use now," says the government watchdog GAO. "Use of both technologies is, however, contingent on overcoming a variety of economic, technical, and legal challenges."

Among the key impediments, obviously, is the lack of legislation that would provide direction to those utilities that must create long-term business plans. Nevertheless, the U.S. Supreme Court has said that the Environmental Protection Agency can move forward with plans to regulate carbon dioxide under the Clean Air Act. As such, it plans to enact such rules in 2011 -- unless Congress stops or delays it.

Coal now generates about half of all electricity in this country. By 2035 -- and because of pressures to reduce the level of harmful emissions -- it is expected to provide about 44 percent of all such power, says the U.S. Department of Energy. Coal now accounts for about a third of all carbon dioxide emissions. To that end, the Energy Department will spend $600 million to help commercialize advanced coal generation technologies.

Carbon capture and sequestration is the gasification or combustion process by which the carbon dioxide is separated from flue gases before it would be captured. It is then compressed, transported and stored in underground geological formations such as saline aquifers that are comprised of porous rock filled with brine, says the GAO.

In 2007, the Energy Department estimated that the cost to install current carbon capture and sequestration technologies was 85 percent higher for plants that use post-combustion capture and 36 percent higher for those coal gasification facilities that use pre-combustion technologies. Efficiency levels for such advanced plants, though, would be about 60 percent, or notably greater competing facilities.

Setting Benchmarks

Carbon capture and sequestration and advanced coal technologies focused on efficiency are not mutually exclusive of one another. The two can be used in tandem; however, the current high prices would tend to prevent that possibility. Efficiency upgrades, meanwhile, could be made to existing coal-fired power plants.

Those older and pulverized coal-fired plants are the least efficient units with about 35 percent of the energy input converted to electricity. But as more power generators opt for supercritical units with higher water-side operating pressures the efficiencies associated with pulverized coal units can increase to at least 40 percent. Ultra-supercritical facilities are said to have efficiency rates of 50 percent or more.

While the existing coal-fired plants pale when compared to modern power facilities, the aging plants won't likely be retired anytime soon. Utilities with those plants say that they need the capacity. They also reason that it is cheaper to retrofit them with pollution controls than to replace them altogether -- improvements that can involve either the use of newer supercritical coal units or pending, but ultra-clean, coal-gasification plants.

"Gasification has been around for some time," John Mead, director of the Coal Extraction and Utilization Research Center at Southern Illinois University Carbondale, told this writer earlier. "But incremental improvements can make the technology more attractive to industries that use conventional processes. However, ultra-supercritical coal generation can rival coal gasification in power generation applications. We need to move on multiple fronts. From a planning standpoint, government and industry must collaborate."

The ultimate goal, though, for coal generators is to nearly eliminate their emissions while at the same time, burying the carbon dioxide. Several test projects are currently underway. But the most prominent of those is expected to be FutureGen, a 275-megawatt coal gasification facility that aims to trap 90 percent of all carbon emissions and one that would break ground next year, becoming operational in 2014.

American Electric Power, meantime, is testing a much smaller coal facility in West Virginia to see if carbon can be captured and buried on site. It is also building an ultra-supercritical coal facility in Arkansas that it says will use less coal.

The success of all those projects is still unknown. What is clear is that they will come with a high price tag -- but one that would purport to significantly reduce the level of harmful emissions. GAO is saying that energy regulators must set benchmarks by which to measure the results. Only then will the government know how to allocate its money.

Coal-fired generation will change. Government mandates along with the emergence of modern technologies will work in tandem to improve efficiencies. The evolution is not just necessary to meet the challenges of a carbon-constrained world. It is also essential to coal's future, if it wants to remain a significant part of the global energy mix.



 

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