The catch, unfortunately, is that they need the government to inflate the price of coal through a cap and trade scheme or some other carbon tax to make the new power plant a viable alternative.
According to the researchers' recently published Journal of Energy Sources article, the system would use solid-oxide fuel cells, which produce power from fuel without burning it. The system would not require any new technology, but would rather combine existing components, or ones that are already well under development, in a novel configuration.
The proposed power plant system would also have the advantage of running on relatively plentiful natural gas, which is considered more environmentally friendly than coal or oil. (Present natural-gas power plants produce an average of 1,135 pounds of carbon dioxide for every megawatt-hour of electricity produced — half to one-third the emissions from coal plants, depending on the type of coal.)
Absent any price for carbon emissions, however, the new electricity source is not viable. As co-author Thomas A. Adams explains, "the cheapest fuel will always be pulverized coal." But as soon as there is some form of carbon pricing — which attempts to take into account the true price exacted on the environment by greenhouse gas emissions — "ours is the lowest price option," they say, as long as the pricing is more than about $15 per metric ton of emitted carbon dioxide.
Such a pricing mechanism would be put in place, for example, by the Waxman-Markey "American Clean Energy and Security Act" that was passed by the U.S. House of Representatives in July, through its "cap and trade" provisions. If the program becomes law, the actual price per ton of carbon would vary, being determined through the free market. Although, the researchers never explained how a government mandated carbon scheme resembles anything close to a free market.
Natural gas already accounts for 22 percent of all U.S. electricity production, and that percentage is likely to rise in coming years if carbon prices are put into effect. For these and other reasons, a system that can produce electricity from natural gas at a competitive price with zero greenhouse gas emissions could prove to be an attractive alternative to conventional power plants that use fossil fuels.
The system proposed by Adams and Barton would not emit any carbon dioxide or other gases believed responsible for global warming, but would instead produce a stream of mostly pure carbon dioxide. This stream could be harnessed and stored underground relatively easily, a process known as carbon capture and sequestration (CCS).
One additional advantage of the proposed system is that, unlike a conventional natural gas plant with CCS that would consume significant amounts of water, the fuel-cell based system actually produces clean water that could easily be treated to provide potable water as a side benefit.
Although no full-scale plants using such systems have yet been built, the basic principles have been demonstrated in a number of smaller units including a 250-kilowatt plant, and prototype megawatt-scale plants are planned for completion around 2012. Actual utility-scale power plants would likely be on the order of 500 megawatts.
And because fuel cells, unlike conventional turbine-based generators, are inherently modular, once the system has been proved at small size it can easily be scaled up. "You don't need one large unit," Adams explains. "You can do hundreds or thousands of small ones, run in parallel." Adams says practical application of such systems is "not very far away at all," and could probably be ready for commercialization within a few years. "This is near-horizon technology," he says.
Citation: Thomas A. Adams II, Paul I. Barton, 'High-efficiency power production from natural gas with carbon capture ', Journal of Power Sources, 2009, doi: 10.1016/j.jpowsour.2009.10.046