Coal Power:
Enemy Number One?


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It's remarkable that a fuel that has powered industry since the beginning of the Steam Age has become, for some, Public Enemy Number One—the role being foisted on it by an assortment of activists.

To some, it's the mining of coal that's problematic, with entire mountains in Appalachia being turned upside down to get at the mineral. Others object to toxic residue such as mercury that rains downwind from some coal-fired power plants; indeed, the Obama administration is reportedly ready to negotiate an international treaty controlling mercury emissions. And the recent retaining wall collapse at a coal ash lagoon in Tennessee raised alarms about the solid by-products of coal burning.

It is, of course, the production of carbon dioxide during combustion that has created the biggest problem for coal. Aside from a disproportionately vocal remnant, scientists agree that emissions of certain gases due to human activity—not just coal burning, but also petroleum use, logging, and letting food rot in landfills—are contributing to climate change. And some of those scientists, along with sympathetic political leaders, have called for the elimination of carbon emissions from coal plants.

But coal's allies haven't done it many favors in recent years. The Bush administration killed the FutureGen project that would have built and tested a coal power plant designed to capture its emissions and sequester them underground. The prospect of carbon capture and sequestration has been held up as a sign that coal could be burned in a way that was environmentally benign.

Even if the project is eventually revived, experts have expressed concern that due to the cancellation, progress on the technology may be delayed by at least a decade. The longer it takes for that technology to become widely implemented, the greater the chances are that the way coal emissions are reduced is by eliminating coal power production.

Generating Capacity by First Year of Operation

Setting aside the issue of whether such a ban would be at all desirable, some people argue that eliminating coal power production is simply impossible. And an immediate cessation of coal power is unthinkable. Coal-fired power plants supply roughly two billion megawatt-hours of electricity a year. That's half the national net generation, and almost all of it in some regions. Forsaking coal today would mean sitting in the dark tonight.

In the longer term, however, the prospect is not as daunting as the naysayers suggest. One factor is the age of the coal power fleet. Relatively little capacity has been added in recent years. According to the Energy Information Administration, in 2007 the net of coal power additions and retirements was only 210 megawatts of nameplate capacity (versus 6.4 gigawatts for natural gas and 5.2 gigawatts for wind). And 2007 was a banner year for coal, with the most capacity added since 1996.

Generating capacity by first year of operation.

In fact, looking at the chart of operating capacity versus date of opening, one can see that the largest cohort of coal power plants are in their middle age. One could imagine a program of plant retirements that would systematically reduce coal emissions. While only 4 percent of the generating capacity is more than 55 years old now, that ramps up to 22 percent by 2020 and 54 percent by 2030.

The other half of the argument is whether it's even possible to replace that capacity. But it is much less heroic an undertaking than one might imagine. Simply doubling the number of wind and gas turbines put online each year would get us most of the way there. Or consider that in the five years, from 2000 to 2004, nameplate generating capacity for natural gas plants—which in a combined cycle produce electricity with as little as 40 percent the carbon emissions of a coal power plant—increased by a staggering 208 gigawatts. That's the equivalent capacity of every operating coal-fired plant built since 1970. Granted, those new natural gas power plants weren't designed as replacements for baseload coal generation, but it does show that the industrial capacity for such a changeover exists.

Coal has a central place in the energy economy at present, but it's not invulnerable, and replacing it over a couple of decades with natural gas, wind, solar, and nuclear power is not only feasible, but could be done without much disruption. Whether there will be the actual desire to do such a thing is a whole other question, one that can't be settled with charts and graphs.

[Adapted from "Up to the Challenge" by Jeffrey Winters, Associate Editor, Mechanical Engineering, May 2009.]

Coal has a central place in the energy economy at present, but it's not invulnerable.

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November 2010

Jeffery Winters

by Jeffrey Winters