Fuel Cells: Unleashing the Power of Hydrogen
As politicians conclude their 10-day environmental summit in Kyoto tomorrow, an unlikely band of scientists and entrepreneurs is reviving a long-forgotten technology that may represent our best hope for solving the problem of global warming: the fuel cell.
Across the globe, car companies including Daimler-Benz, Toyota, Chrysler and Honda are pouring hundreds of millions of dollars into research and development for replacing conventional internal combustion engines with electric motors powered by fuel cells.
"Of all of the technologies that are out there, this is the one the auto industry seems to look at as the best option for getting the kind of super efficiency the governments are looking for," said Henry Lee, director of the Environmental and Natural Resource Program at the John F. Kennedy School of Government.
Daimler has said that it will manufacture 100,000 fuel cell engines a year by 2005, at prices competitive with conventional engines.
What is often left out in the buzz is that fuel cells are hardly a new technology--though the techniques that are making them accessible to the masses are.
Fuel cells have been around since well before the Civil War, but until now, like many other "environmentally-friendly" energy sources, they have been too expensive to be worth using.
Unlike an internal combustion engine, which burns its fuel so inefficiently that only 20 percent of the energy in gasoline gets used, a fuel cell can pull off at least 30 percent efficiency by reacting its special fuels--hydrogen and oxygen gas--electrochemically.
Pure, Clean Air
But efficiency isn't the only reason fuel cell advocates take the gadgets so seriously. In theory, unlike internal combustion engine--which spew greenhouse gases such as carbon dioxide into the atmosphere--a fuel cell's only "pollution" is pure water and electrical current.
In practice, the equation isn't so spotless. Though oxygen is plentiful in the air, pure hydrogen is much harder to come by and must be obtained artificially.
The process of extracting hydrogen from more conventional fuels such as gasoline and methanol inevitably releases some carbon dioxide--but not as much as the internal combustion engine does, and therein lies the rub.
Though the issue is still controversial, many scientists believe that a documented rise in carbon dioxide levels worldwide has caused large-scale climate changes. If the trend continues, it could lead to environmental problems such as the melting of polar ice caps and a rise in ocean levels across the globe.
But despite their advantages, fuel cells still have yet to find their way under the hood of passenger cars. Industry experts attribute the delay to scarcity of fuel, price and size.
Yet there is room for optimism and profit, as Daimler's $350 million investment in Ballard Power Systems, a Canadian manufacturer of high-tech fuel cell, would suggest.
"In the next 10 years we might have some breakthroughs," Lee said.
"I think there are some real possibilities here--significantly improving the efficiency of the automobile and being able to price the car at something close to competitive," said Lee, who is also a lecturer in public policy at the Kennedy School.
But the low pollution levels of fuel cells, while seemingly their raison d'etre, is also their most damning flaw. A fuel cell is a highly efficient reactor, but is notoriously picky about what it consumes--only pure hydrogen and oxygen gas.
Oxygen is readily available in the atmosphere. But hydrogen only exists in trace amounts in the air, and must be produced artificially--usually from fossil fuels, and perhaps in the future from rotting biomass and solar panels.
But while a multi-trillion dollar global industry has evolved to refine and distribute gasoline, no such infrastructure is in place for producing hydrogen gas.
"In today's society, you can't run over to the corner gasoline station and fill up on hydrogen," said William L. Mitchell, senior program manager for the Hydrogen Technologies Unit of Arthur D. Little--a Cambridge based technology consulting firm.
"Gasoline is the only thing out there that people are comfortable buying for their cars," Mitchell said. "If you're asking one of the Big Three auto makers to bet a billion dollars on making a car that doesn't have a fuel, that's a hard thing for them to do."
While alternatives have been proposed, some companies have tried to find a middle ground by using methanol instead of hydrogen gas.
For example, Daimler plans to use methanol in its fuel cell cars and extract the hydrogen on-board. But experts have said that it will also be difficult to supply methanol to customers.
The Ideal Solution
Because of the distribution problems associated with any exotic fuel, companies have struggled for many years to figure out a way to extract hydrogen directly from gasoline.
Chemical refineries routinely break down fossil fuels into hydrogen gas and carbon dioxide. But, until recently, there was no way to carry out this reaction in a box small enough to fit under the hood.
For the past five years, a team of 48 engineers and market strategists at Arthur D. Little has been working with the Department of Energy and the Chrysler Corporation to develop a high-tech gadget called a "reformer" that would solve that problem.
This October, they succeeded.
"We were able to reduce the reformer to the size for an automobile, and we got it so that it can power a mid-sized vehicle," said Bob Derby, head of marketing for Arthur D. Little.
The reformer is distinct from the fuel cell--which generates the electricity for a fuel cell car--but is critical in allowing the cell to run indirectly on ordinary gasoline.
Mitchell estimated that a fuel-cell car with the Arthur D. Little reformer could offer between two to three times the gas mileage of a conventional, internal combustion engine car, which gets no more than 30 miles per gallon for city driving.
"I would expect that the first ones would be somewhere between 60 to 80 miles per gallon," he said.
Others, however, said they were skeptical of Arthur D. Little's announcement of its reformer technology.
"In my opinion, it's an old technology," said Dr. Hans Maru, executive vice president and chief operating officer of Energy Research Corporation, based in Danbury, Conn., adding that a fully functional reformer was "years away."
Several auto manufacturers have expressed interest in using the Arthur D. Little reformer in their cars, said Derby. "We're having discussions with Honda and Toyota, and also with Chrysler," he said.
Today's fuel cells can not compete on a price basis with mass-produced internal combustion engines. The usual indicator of measuring the cost-efficiency of an engine is the amount of money required to build one that puts out a kilowatt of power (about 1.3 horsepower).
On that scale, an internal combustion engine is about $50 per kilowatt. In comparison, a proton-exchange-membrane (PEM) fuel cell--the ideal fuel cell for vehicles--costs up to $10,000 per kilowatt, according to Maru.
In addition, scientists must still determine how to maximize the power output of a fuel cell engine.
"We have to ramp up the energy in terms of getting high enough output," Derby said. Arthur D. Little's test run in October produced a kilowatt of power--but the fuel cell will have to put out at least 50 kilowatts to power a car.
But fuel cell proponents see these figures as a challenge, not an obstacle, and argue that mass production will shave down the price of a fuel cell vehicle to competitive prices.
According to Arthur D. Little financial projections, "they shouldn't be more than a thousand or two thousand dollars more than your typical vehicles," Derby said.
Coming to a Dealership Near You
Experts disagree as to when the public might see cars run by fuel cell engines hit the market.
"You're going to see a lot of prototype vehicles coming out in the next couple years, but you wouldn't see any commercial vehicles coming out until 2002 to 2004," Mitchell said.
But Maru is less optimistic.
"Vehicles with fuel cells are still years away," he said. "Hopefully they will be utilized in buses five years from now, and in passenger vehicles, maybe, in 2010."
"Most people are talking in the vicinity of 2008 to 2010," Lee said. "We have a lot of technologies that work, they just cost too much."
Robert Walker, former chair of the House Science Committee and president of the Wexler Group--a Washington based lobbyist firm--said that fuel cells have a bright future, but are marred by high costs today.
"It's been some time coming, and I think there are some hopeful trends," he said. "The problem with fuel cells has always been that they're very expensive to build and expensive to maintain.
Lee agreed, noting that very few people will be willing to purchase a car based out of sympathy for the environment.
"Some people will do it just because they want to be trendy or environmentally greener, but more people won't," Lee said.
"In the end, you've got to be competitive," Lee said, noting the current low prices of gasoline. "It's going to be hard to compete with gasoline at these prices."
The Greatest Thing Since Unleaded Gas?
But the debate continues as to whether there will be tangible environmental results if millions buy into the fuel cell revolution.
"One of the promises of fuel cells is that you will cut global [carbon dioxide] emissions and global warming, but there's a two step process to getting to that," Mitchell said. "In order to get fuel cells out there, you need to let them run on fuels we use today."
"Once there is a critical mass of fuel cells out there, people will begin to address [those issues]," he added.
Mitchell said the new reformer would provide a comfortable transition to renewable fuels, but emphasized that a near-term solution would have to use fossil fuels.
"In North America, we've done some pretty extensive analysis that says, if you want to replace 10 percent of the fueling infrastructure with methanol, the cost for that will be $60 billion," Mitchell said. "That's the kind of level you're going to need from day one. If you ask somebody to sign up for that, there's a good possibility that nobody would."
Walker agreed, saying that a generation of cars with a fuel tank in the past and an engine in the future would encourage the acceptance of futuristic renewable fuels.
"That would be a very interesting transition, since it would allow the present infrastructure to be used, yet we would end up with hydrogen vehicles that would be better environmentally," he said.
Although environmentalists--both here at Harvard, and outside--have said that the Arthur D. Little reformer does little to reduce dependency on fossil fuels, Derby defended the firm's strategy.
"We're working with the system," he said. "It doesn't necessarily meet all the concerns of the environmentalists, but it does say that we can get something out there in the next five to 10 years that people can use."
1 Liquid fuel (Gasoline, Ethanol, etc.) is vaporized using waste energy from the fuel cell to insure high efficiency operation.
2 Vaporized fuel is burned with a small amount of air in a Partial Oxidation (POX) reactor producing carbon monoxide and carbon.
3 Sulfur compounds from the fuel are removed to eliminate emissions that form acid rain.
4 Using the heat from the POX zone, steam is reacted with most of the carbon monoxide to form additional hydrogen and carbon dioxide.
5 The remaining carbon monoxide is Preferentially Oxidized (burnt) over a catalyst to reduce its concentration to less than 10 ppm.
6 The hydrogen gas combines with air to form electricity, water and heat to propel the vehicle with virtually zero emissions. Fuel cell by-products are water and heat.