Will Hydrogen Clear the Air? Maybe Not, Say Some
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November 12, 2003 By MATTHEW L. WALD

WASHINGTON, Nov. 11 - Widespread hydrogen use has been enthusiastically embraced by major corporations and environmentalists alike as a panacea for global warming and the depletion of fossil fuels, and is a particular favorite of the Bush administration. But skeptics, and even some hydrogen advocates, say that use of hydrogen could instead make the air dirtier and the globe warmer.

Next week, the Bush administration is convening a meeting of the energy ministers of 15 countries to Washington for a four-day meeting with the theme of an "International Partnership for the Hydrogen Economy." President Bush himself pledged in the State of the Union address in January that "the first car driven by a child born today could be powered by hydrogen, and pollution-free."

Use of hydrogen fuel cells could certainly help eliminate tailpipe pollution and dependence on foreign oil. But hydrogen is only a way to store energy. Where the energy comes from in the first place is where the problems start.

The most ambitious use of hydrogen is in a car powered by a fuel cell - a batterylike device that turns hydrogen into electricity while emitting only heat and water vapor.

Hydrogen can also be burned directly in engines much like those that run on gasoline, but the Energy Department goal is fuel cells because they get twice as much work out of a pound of hydrogen.

Intense research is now going on at major companies and universities in North America on the development of a practical fuel cell. Success could have a profound effect on the 200 million motor vehicles in use in the United States, making the streets cleaner and quieter, with hydrogen-powered electric motors. The transition to hydrogen could also wean the country away from gasoline and diesel fuel.

The main source for hydrogen today is natural gas, which is in short supply, is cumbersome to convert, and may have better uses. Waiting in the wings is coal, burned in old power plants around the country that are already the focus of a national dispute over their emissions. Coal is cheap and abundant, and produced by major companies that are eager to continue mining and using it. But it is a leading source of carbon dioxide, an important global warming gas, and pollutants that cause more immediate problems, like smog and acid rain.

"Even though fuel cells are great devices, you can still do unwise things with them," Patrick B. Davis, a team leader in the Energy Department's fuel cell program, told a recent meeting of experts at the University of South Carolina examining the engineering challenges.

The long-term hope is to make hydrogen from emission-free "renewable" technologies, like windmills or solar cells. In fact, hydrogen may be an essential step to translate the energy of wind or sunlight into power to turn a car's wheels, experts say. But electricity from renewable technologies is so costly that even companies based on these technologies see problems.

At Sharp Solar, which says it is the world's largest manufacturer of solar cells, Ronald Kenedi, the general manager, said that it was entirely possible that the energy source to produce hydrogen for vehicles would initially turn out to be coal, rather than the sun or wind. "That is the danger," he said in a telephone interview. "It seems like hydrogen is the buzz word right now, with the president talking about it, and maybe putting some money towards it," he said. "But the first stop on the hydrogen trail will be coal."

For now the government is mostly glossing over the problem. A strategy document published by the Energy Department in November, 2002, the "National Hydrogen Energy Roadmap," suggests marketing the idea of hydrogen to the public as the "freedom fuel." Another suggested theme was "Hydrogen is everywhere - it's right in our backyard."

"Hydrogen," the department said, "is the 'man on the moon' equivalent for this generation." In fact, the latter analogy might prove apt, with hydrogen fuel cells resembling the Apollo rockets, as an impressive technology that was made workable and repeatedly demonstrated, but not capable of making major inroads into general use.

For now, fuel cells are about 100 times as expensive, per unit of power, as internal combustion engines.

A likely source of hydrogen is from a machine called an electrolyzer, which is like a fuel cell in reverse. The difference is that a fuel cell combines oxygen from the air with hydrogen to produce an electric current, and water as a byproduct; an electrolyzer runs an electric current through water, to split the water molecule into its constituent hydrogen and oxygen atoms.

The problem is that if the electricity came off the power grid to run an electrolyzer for the production of hydrogen, about half of it, on average, would be generated by burning coal.

From an entrepreneur's point of view, coal has a tremendous advantage. At Proton Energy, a Connecticut company that builds the electrolyzing machines that use current to produce hydrogen, Walter Schroeder, president and chief executive, laid out the problem in terms of dollars per million B.T.U.'s, a standard quantity of heat in the fuel business.

At $20 a ton, he pointed out, a million B.T.U.'s of heat from coal costs roughly 82 cents. At $1.75 a gallon for unleaded regular gasoline, the price per million B.T.U.'s is $15.40. To use coal to run cars, the coal has to be converted into electricity, then into hydrogen, then back into electricity in the car, all of which costs money. But Mr. Schroeder is betting that his system can do that for a lot less than the difference between $15.40 and 82 cents.

The president's proposal contained an implicit recognition that a big part of the fuel cell question is the fuel, not the conversion device. He called for spending $1.7 billion over five years, with $1.2 billion of that on hydrogen, including production, delivery and storage.

Another problem is carbon dioxide, a greenhouse gas. According to the Energy Department, an ordinary gasoline-powered car emits 374 grams of carbon dioxide per mile it is driven, counting the energy used to make the gasoline and deliver it to the service station, and the emissions of the vehicle itself. The same car powered by a fuel cell would emit nothing, but if the energy required to make the hydrogen came from the electric grid, the emissions would be 436 grams per mile, 17 percent worse than the figure for gasoline.

The car would emit no nitrogen oxides, a precursor of smog, but the power plant would; exactly how much is now the subject of a national debate.

Hydrogen is commonly manufactured today at refineries and chemical plants, by mixing natural gas and steam. Natural gas is made of hydrogen and carbon atoms; steam is made of hydrogen and oxygen atoms. The reaction, called steam reforming, produces hydrogen and carbon dioxide.

According to the energy department, if fuel cells in cars used hydrogen from steam reforming of natural gas, cars would emit 145 grams of global warming gases per mile. That is a drastic improvement over the 436 grams emitted by the production of hydrogen using grid electricity, and a major improvement over gasoline's 374 grams, but experts say it may not be a particularly good use of natural gas.

One reason is that if the engineers had simply replaced the gasoline with the natural gas, skipping the hydrogen fuel cell step in between, the total carbon dioxide emissions per mile would fall to 310 grams, according to the Energy Department. No new technology is required for that step; buses burning natural gas in internal combustion engines are common today.

And there is a second option that involves hardly any new technology, hybridization. In a hybrid, a fossil-fueled internal combustion engine can turn the wheels or a generator that is used to charge batteries, and the batteries run an electric motor to drive the wheels. The Toyota Prius and the Honda Insight use that system. Hybridization improves the fuel economy of the Honda Civic by 43 percent, according to the company. So replacing a gasoline car with a hybrid electric fueled by natural gas would cut the grams of global warming gases to about 177 a mile.

That still leaves the fuel cell that runs on hydrogen from natural gas with an advantage over the typical hybrid of about a fifth, or a further reduction of about 32 grams of global warming gases per mile. But the fuel cell bus is many times more expensive than an ordinary or hybrid bus, and the fuel costs several times as much as diesel. And the natural gas hybrid solution is available almost immediately; it would be many years before fuel cell buses made a substantial debut.

Reuel Shinnar, a professor of chemical engineering at City College of New York, reviewing the options for power production and fuel production, concluded in a recent paper, "A hydrogen economy is at least twice as expensive as any other solution."

Supporters of fuel cell cars say that hydrogen can be made from almost anything, including hydropower, new nuclear reactors, and technologies barely dreamed of, like microbes that will produce hydrogen from waste materials, and that this justifies the research even if early batches of hydrogen come from coal.

"The mantra is, we don't choose now," said William Craven, manager, regulatory and technical affairs at the DaimlerChrysler Corporation. When it comes to hydrogen production he said, the trick at this stage is to "keep the portfolio open."

But some parts of the portfolio are more environmentally beneficial than others. Dan W. Reicher, a former assistant secretary of energy for conservation and renewables, who now manages a fund that invests in companies that produce energy from renewable sources, put it this way: "Not all hydrogen is created equal."

http://www.nytimes.com/2003/11/12/business/12hydrogen.html?ex=1070199087&ei=1&en=5b032edeee1016c7
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