November 28, 1997

Coal Nightmares, Electrical Dreams

By MATTHEW L. WALD

ASHINGTON -- It's an environmentalist's nightmare: in the next century, India and China build a thousand new power plants, mine all their coal and dump its carbon into the air by burning it for electricity.

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But one of the paradoxes that climate-change issues pose for policymakers is that just such a scenario could actually be a good way for China and India to reduce their carbon dioxide emissions.

Of course, another paradox is that such an approach would rely heavily on -- and is being strongly promoted by -- the very people responsible for pumping perhaps the largest share of carbon into the atmosphere over the last century: the world's makers of electricity. In fact, some people in utilities say that a great way to reduce carbon dioxide emissions is to burn as much coal as possible.

The utilities may have a tough time making their case if the world gets serious about global warming. In this country, they burn 80 percent of the coal and in almost every country they are the easiest targets to identify, as controlling a few hundred power plants is far easier, politically and technically, than controlling tens of millions of tailpipes.

But electricity proponents say regulators have it backward. What counts, they say, is not how much fuel goes into the system to make kilowatts, but how much fuel the electricity displaces when it is used.

It sounds like an "annoying proposition," acknowledged Mark P. Mills, an energy consultant here, but "using more coal reduces carbon dioxide emissions in the real world."

When a woman in a third world village cooks a meal over an open fire, for example, only about 2 percent of the fire's energy goes into the food. String a wire to her house and give her an electric hot pot, and the same amount of fuel, when burned in a power plant, will supply enough energy to cook 10 or 15 dinners, the electric advocates say.

The phenomenon is not limited to the developing world. Anywhere on earth, running a car on electricity instead of gasoline can halve the amount of energy needed to travel a mile, which saves carbon. And in the developed world, everything from drying the paint on a Coors beer can to smoothing out the ice of a hockey rink with a Zamboni machine can be converted to electricity, with tremendous savings in total energy used, the advocates say.

If poor nations burn more coal, will the air get dirtier? (Andrew Sacks/The New York Times)

The idea is not universally popular and many environmentalists want to concentrate on more efficient electric motors and lights, better-insulated refrigerators and homes and other efficiency improvements. No doubt those measures will take hold, especially in countries where demand for power is soaring.

Cleanest of all would be electrification with power from no-fuel "renewable" technologies like wind. But with a stubbornly low price of oil, and declining prices for coal, their future popularity is hard to predict.

Globally, electricity use is growing; in this country, about 40 percent of all fuel is converted to electricity before the energy is consumed; that total is slowly rising. Another area for improvement, therefore, is the choice of fuel and the means by which it is converted to electricity.

Of the hydrocarbon fuels, coal has more carbon than hydrogen, and when it is burned -- or oxidized -- it produces relatively little H2 O and lots of CO2 . Oil is more evenly balanced, and natural gas is mostly hydrogen, and so the fuels line up in that order in greenhouse effect.

But in coal plants and conventional oil and gas plants, two-thirds of the heat potential of the fuel is lost by the generating process, which involves heating water into steam, using some of the steam's energy to turn a generator, and then cooling the steam back into water.

From a greenhouse standpoint, natural gas presents a better possibility, because it has less carbon and because a modern combined-cycle plant wastes only about half the heat value of the fuel. It burns gas in a jet engine and uses the waste heat to boil water and make more electricity, thus producing about a quarter of a pound of carbon per kilowatt-hour. (Enough power to light 10 100-watt bulbs for an hour; a typical American house uses about 20 kilowatt-hours a day.) In contrast, a coal plant that makes the same amount of electricity produces about six-tenths of a pound.

But in many places, coal, for now, is the cheapest or only option.

Carbon dioxide output from electricity production is already large, and could become staggering. According to Westinghouse, which wants to sell zero-carbon nuclear reactors, China was consuming 560 billion kilowatt-hours in 1990, when about 70 percent of its electric grid was powered by coal, but wants to triple output to 1,593 billion kilowatt-hours by 2010, which would vastly increase carbon emissions. (By contrast, in 1990 the United States was using 20 times as much electricity per person as China, about double China's projected level for 2010.)

The next step, to hold down carbon emissions, is to make the best use of the electricity.

Not if it is used to make electricity, say the people who make electricity. (Jack and Betty Cheetham/Magnum)

Take, for example, the way that Coors paints its beer cans. For years it used the traditional method: applying paint and then running the cans on a conveyor belt through a giant natural gas oven. The paints emitted pollutants, so Coors used yet more natural gas to burn the fumes.

Now, Coors sends the cans through a much smaller chamber filled with ultraviolet light, curing the paint almost instantly.

"There is a savings in natural gas, minus a slight increase in electrical use, obviously, to run the ultraviolet lamps," said Jon S. Goldman, a Coors spokesman.

The company calculates that if the electricity came from a coal plant, a pessimistic scenario, then curing one billion cans with electricity releases 1,900 tons of carbon into the atmosphere. The same job with natural gas, assuming extra gas to burn the pollutants, releases 5,700 tons.

Bigger than such carbon savings -- but a bigger change -- would be to electrify the transportation sector, the only major part of the economy where little electricity is used.

In recent tests, electric versions of a Geo Metro and a Toyota RAV4 got twice as many miles as the gasoline originals, because the efficiency of an automobile engine is only about 17 percent, while a combustion turbine, the kind of electricity generator now most commonly built, can be 50 percent, meaning it extracts three times as much energy per unit of fuel.

The same is true in other examples of electrification, according to Mr. Mills, the energy consultant, although it would be threatened if carbon taxes drove up the price of a kilowatt-hour, making electrification less attractive.

"De-carbonization has come through electrification, even though lots of coal plants are chugging away," he said.