BMW 745h at the Chutes Montmorency waterfalls, Canada. Click image to enlarge
by Kelly Taylor
Hydrogen. The smallest, lightest and first element on the periodic table. As one component of water, it is arguably the first building block of all life. It is the most abundant substance in the known universe. It is also the fuel of the future.
Whether it is burned or fused with oxygen in a fuel cell to create electricity, the only result is water. It has a renewable life cycle, which means the same hydrogen atom can be used again and again. As William Harney, director of product development for automotive parts conglomerate Magna International says, “You’re only borrowing its energy.”
It is clean. A 1998 report by renowned researcher and author James Cannon, for the U.S. non-profit environmental think-tank Inform, says a switch to hydrogen-based transportation could lead to a 65 to 95 per cent reduction in greenhouse gas emissions.
BMW is pushing hard to move the world to hydrogen. Their slogan, “The hydrogen age has begun,” is perhaps premature, but they present compelling arguments to suggest it is not unreasonably optimistic.
Fossil fuels do have a limited supply, but that’s not the overriding concern, Huss said. The goal is to move the world toward a carbon-free fuel.
“Carbon,” present in all fossil fuels and in agrifuels like ethanol and methanol, “is the enemy,” Harney says.
It is the carbon in gasoline and other petroleum-based fuels that is the leading suspect in global warming. Carbon-based fuels, when burned, emit carbon dioxide or carbon monoxide, which climatologists and environmentalists suspect is trapping heat from the sun in our atmosphere and leading to a rise in global temperatures. If true, the results could be catastrophic, including coastal flooding if the polar ice caps melt and unending droughts in the agricultural heartlands of Earth.
None of which even addresses the impact on smog and other forms of pollution. Yet, despite the best efforts of the environmental lobby, demand for energy is only going to increase. Millions of people in developing nations are beginning to thirst for energy. The number of people on Earth is, of course, rising, and each one will be demanding increasing amounts of energy, says Lauren Segal, general manager of hydrogen development for oil giant BP.
Set against the knowledge that fossil fuels will one day run out — though it’s unclear when — those two points indicate the need to explore alternative fuels now, Huss said. Huss said BMW’s goal is to move to a green fuel source without limiting individual mobility. And they want such a fuel source to still be the source of the driving excitement BMW is known for.
Hydrogen has already been tagged as the fuel of choice for fuel cells, which generate electricity by letting hydrogen and oxygen fuse into water. And BMW has created a fleet of 15 hydrogen-powered 7-series sedans, the 745h, to demonstrate the conversion of the internal combustion engine to hydrogen as its fuel. In conjunction with Magna Steyr, an Austrian subsidiary of Canada’s Magna International, and Linde AG, BMW has developed the ability to store hydrogen on board, deliver it to filling stations and transfer it to cars. BMW is now lobbying governments around the world to designate hydrogen as the fuel of the future and to support the creation of a “hydrogen economy,” where an infrastructure is developed to distribute hydrogen to end-users.
But even though BMW has chosen to burn hydrogen — and they have their reasons — they don’t care if the infrastructure is developed for fuel cells or for internal combustion engines. As long as one is developed.
Because hydrogen is so light, it does present numerous problems as a source of energy. It lacks density to the point that in its gaseous state, the amount of hydrogen needed to drive around the block would fill a gymnasium. Even in liquid form, three litres of hydrogen are needed to travel the distance covered by one litre of gasoline. Its atoms are so small that containing them is an arduous task. The slightest compromise to imperviousness means the hydrogen will leak out in short order.
To both problems there are two answers, neither of which is easy to pull off. The first is to store it in liquid form at low pressure. That’s easier said than done, since the boiling point of hydrogen is -253 Celsius. That’s only 20 degrees shy of 0 Kelvin. Storing liquid that cold requires a super-insulated tank and an equally well-insulated connection to the filling station.
The other alternative is to store it at high pressure, over 700 bars, which is more than 700 times normal atmospheric pressure or 10,000 psi. That presents enormous structural concerns. BMW, Linde and Magna Steyr have chosen the first method. To address the insulation problem, the answer is to build a two-layer tank, much like two-pane windows. The inner tank is surrounded by several layers of highly reflective, “space blanket”-like material, which itself is surrounded by a high vacuum.
Jorg Buchholz, Magna Steyr’s assistant executive vice-president for research and development, said the company’s cryogenic fuel tank can keep hydrogen in liquid form for 15 days, at which point an automated system will bleed off some hydrogen to reduce the pressure inside the tank and allow the remaining hydrogen to retain its liquid form.
BMW and the California Fuel Cell Partnership have each built a hydrogen filling station in Oxnard, California and in Munich. When a car pulls in, an automated arm opens the fuel-filler door while another arm automatically inserts the nozzle into the fuel-filler receptacle. A lock is achieved and then liquid hydrogen (LH2) is pumped into the tank.
BMW’s Huss said the system employed in each station is compatible with either a LH2 (liquid) fuel tank or a 700-bar (high-pressure) system, should another company choose the latter system.
Canada well-positioned to produce hydrogen
Producing hydrogen is relatively simple. Insert two electrodes into a vessel of water. Apply direct current. Hydrogen bubbles out of the water near the negative terminal, oxygen from near the positive terminal.
You can also crack hydrocarbons into hydrogen, but this misses the boat in two ways. You’re still using non-renewable fossil fuels and you still end up with carbon in the fuel. So you don’t eliminate CO2 from exhaust and you don’t reduce dependence on fossil fuels.
Also, what remains when the hydrogen is extracted is highly toxic. But even the water option isn’t free of problems. The laws of physics state that energy can be neither created nor destroyed. And they also state that no system can be 100 per cent efficient or it would be the theoretically impossible perpetual motion device.
All of which is one way to say that the energy involved in creating hydrogen MUST be more energy than will be expended propelling the vehicle. Burning coal or splitting atoms to heat water to produce electricity to produce hydrogen to produce motion just doesn’t make sense.
Hydrogen, then, must be produced cheaply using renewable resources, or its benefits are contradicted. So the hydrogen experts at BMW and BP are exploring different means to create electricity. Some involve the sun, which would be used to heat water to create electricity to crack water into hydrogen. Solar power can also be used to directly create electricity, but the low efficiency of so-called photo-voltaic cells currently rules this option out. Others involve wind power for the generation of electricity.
Canada, it seems, has another answer. Hydroelectric power is more abundant in Canada than anywhere. Our cheap hydro can be to Canadian hydrogen production what the sun will be to equatorial states and the wind to wind-blown areas. Hydrogen makes the most sense, Segal said, when it’s mass produced in areas with low electric costs like B.C., Quebec, and Manitoba and shipped, much like oil is today.
Areas able to generate electricity cheaply could be to the hydrogen economy what the Middle East represents to the petroleum age.
The beauty of a hydrogen economy is that it learns from nature instead of trying to superimpose its will on nature. If you consider the Earth a closed system, using hydrogen either in fuel cells or in internal combustion engines can be made environmentally neutral. This is where Magna International’s Harney gets his statement about borrowing hydrogen’s energy.
If you take water, use renewable energy to create hydrogen and then burn the hydrogen, you’re in essence returning it back to the Earth’s ecosphere as water. So in essence, the hydrogen remains in the system. Physical laws against perpetual motion remain unbroken: external energy is required to produce the hydrogen and is therefore the needed input into the system. In such a way, hydrogen can be used again and again.
First hydrogen vehicles will be dual-fuel
If hydrogen is to be the fuel of the future, it will first be seen in fleet use, either to fuel transit buses or inner-city delivery trucks, neither of which are likely to stray far enough that they would need any hydrogen filling station other than the one at home.
For hydrogen to be attractive to consumers, Lauren Segal, general manager of hydrogen development at BP, estimates 25 per cent of BP’s stations (and by extension, 25 per cent of all filling stations) would need to offer hydrogen.
That is an expensive proposition, since the stations currently in play cost $1 million US each for a station with just one pump. Segal says BP is estimating that economies of scale will reduce that cost to $400,000 per filling station, but even at that, it adds considerably to the cost of building a gas station, which often isn’t that expensive for the entire station, convenience store, washrooms and drive-through car wash included.
Hydrogen, however, presents the classic chicken-and-egg argument, Segal said. People won’t buy cars they can’t fill up and gas stations won’t invest in
fuels they can’t sell. Until then, it’s likely that any passenger cars would be powered by dual-fuel systems, able to switch automatically to gasoline when the hydrogen runs out. As the network of hydrogen stations grows, the need for dual-fuel systems will decrease.
Segal said the demand for a move to hydrogen is growing in different regions of the world, but for different reasons. In Europe, countering pollution is the main goal. In the United States, ending dependence on foreign petroleum is the goal.
Segal and BMW’s Huss estimate a mass market for hydrogen vehicles is at least eight years away. But BMW will begin production of 745h models some time between 2004 and 2006, Huss said. These will be, as is the current fleet of 745h models, bivalent, or dual-fuel, systems.
Hydrogen as safe as gasoline
The next step, says Magna’s Harney, is to “create market pull.” Governments, and other carmakers, Harney says, won’t jump on the hydrogen bandwagon until consumers begin to demand it. So in conjunction with the World Conference on Hydrogen, BMW landed in Montreal for one stop on the BMW CleanEnergy World Tour 2002. With displays in a park on Rene Levesque Boulevard downtown and at the Montreal Science Centre, BMW and Magna Steyr were hoping to generate some interest in hydrogen.
Part of that is alleviating fears of hydrogen’s safety. People who remember the Hindenburg disaster often wrongly fault hydrogen for the fireball that engulfed the airship, but because hydrogen dissipates so quickly in air, the real culprit was the magnesium-impregnated skin of the airship.
“There is a tendency to be tentative toward hydrogen,” Segal admits. But Huss said extensive crash testing by BMW has shown that hydrogen-powered cars present a similar degree of risk to gasoline-powered cars in a crash. Gasoline, he said, flows out of a fuel tank and spreads under the car. Ignited, it has the potential to immolate anyone inside. Hydrogen, on the other hand, dissipates rapidly into the air.
Hydrogen doesn’t explode but it does burn quite quickly. “Gas burns on the ground, hydrogen burns in the air.”