<font face="Verdana, Arial, Helvetica" size="2"> Petrol. We can't live with it, we can't live without it. Burning it in the engines of our cars causes pollution and global warming. It shackles us to unstable Middle Eastern countries. And one day it'll run out. But we're hooked. As recent protests in Europe over the price of fuel have shown, shut off the supply and countries grind to a halt. We need a cleaner, greener fuel, and lots of it. Here it is...
THEY'RE calling it the "Bahrain of the North". These are exciting times in Iceland, the birthplace of the hydrogen economy. Thorsteinn Sigfusson, professor of physics at the University of Iceland in Reykjavik and chairman of Iceland New Energy, says that within 20 years his country can become the first in the world to run on hydrogen without recourse to fossil fuels. To start with, hydrogen will run its fleets of buses, trucks, cars and trawlers, and later it will provide electricity and heat its buildings through the long winters. Iceland could be the first of the 21st-century successors to the OPEC sheikhdoms. Call them HYPEC--the organisation of Hydrogen Producing Countries.
It's early days yet, Sigfusson admits. The first three hydrogen-fuelled buses won't hit the streets of Reykjavik until 2002. That's several years after Vancouver and Chicago introduced theirs. But Iceland's buses are the start of something much bigger. Unlike most hydrogen-powered buses, which fill up with hydrogen derived from old fuels such as oil, Reykjavik's buses will run on hydrogen made by splitting water, using hydroelectricity generated from Iceland's raging rivers. The umbilical cord to fossil fuels will be cut.
Since Iceland has a population of only 276,000, and you can't drive there from anywhere else, it is an ideal place to test out a future world where cars are no longer environmental pariahs, where urban smogs and greenhouse gases are banished. A world, in short, that has kicked the carbon habit.
Ask anyone with a stake in the energy economy if the revolution is really necessary and they will say yes. There are compelling reasons for change. Emissions of carbon dioxide from internal combustion engines are stoking the greenhouse effect. (See our Special Report on Global Warming,
www.newscientist.com/global)Burning oil fills our cities with smogs that kill hundreds of thousands every year. Technological improvements to cut emissions from conventional cars cannot keep pace with the rising tide of vehicles. There will probably be a billion on the world's roads by 2020--one for every seven people.
Meanwhile, the oil economy is starting to give us a bumpy ride. Nations the world over remain shackled to OPEC--a risky position to be in, as the price hikes of the past six months have shown. It doesn't take much to rock a government and threaten global recession. And one day the oil will run out. Oil geologist Colin Campbell was quoted in New Scientist last year as saying that "the world's oil companies are now finding only one barrel of oil for every four that we consume"
Even big oil companies now concede that we cannot carry on burning oil as we have in the past. "If the motor car is to stay with us, we need to explore radical new ways to fuel it," says Paul Histon, fuels technology manager at BP Amoco's oil technology centre in Sunbury-on-Thames near London. "If we are truly to get big CO2 reductions, hydrogen is the best long-term choice."
Why hydrogen? Well, it's ubiquitous, inexhaustible and clean. You can drive across the US on hydrogen without adding to the atmosphere anything more noxious than a bathtub-full of water. Back in 1874, Jules Verne argued in The Mysterious Island that when fossil fuels run out, hydrogen "will furnish an inexhaustible source of heat and light". Hydrogen's time seems to have come.
But is it safe? Some industrialists argue that storing hydrogen on filling station forecourts or in vehicle tanks is too dangerous. The image of the 1937 Hindenburg airship disaster still looms large. This is curious. The hydrogen filling the airship did not explode, and the 35 dead were either killed by burning diesel or jumped to their deaths. In 1997, a retired NASA scientist found that the real culprit was the flammable fabric of the airship's outer skin, not the hydrogen (!).
And let's not forget that cars are already carrying round tanks of dangerously explosive liquid, so it's really a question of comparative risk. Hydrogen is easy to ignite, but it's buoyant and dissipates rapidly. And if it is caught in a confined space, it requires more oxygen to burn than oil does. "Hydrogen is less hazardous than gasoline," says Amory Lovins of the non-profit Rocky Mountain Institute in Colorado, which specialises in the future design of cars.
The key questions today are not so much "Do we want a hydrogen economy?", as "What sort of hydrogen economy do we want, and how do we get there?" Do we make the new wonder-fuel from petrol, natural gas, methanol, biomass or water? Do we make it in centralised hydrogen factories, on the forecourts of service stations or under the bonnet? How do we store it? And do we put it in conventional internal combustion engines or fuel cells?
The world's biggest car makers are busy drafting a road map to the hydrogen-fuelled future. But nobody yet seems sure of the way. BMW is betting on an internal combustion engine that burns hydrogen, claiming it's the only way to deliver the acceleration and responsiveness drivers are used to. But most believe that the internal combustion engine, with its Heath-Robinson assembly of transmission and drive shafts, is too inefficient. It converts barely 20 per cent of its fuel's energy into traction. Electric engines can have an efficiency of up to 80 per cent. But batteries don't deliver enough power for their weight and need frequent recharging. So attention is increasingly focusing on electric engines without batteries.
Plan A, the so-called hybrid engine, has already been on Japanese roads for three years, under the bonnet of Toyota's Prius model. It's a petrol-burning engine hooked up to an electric motor. The engine doesn't drive the car directly, but generates electricity, which is stored in a battery and released as necessary to drive the car. So the petrol engine can always operate at its most efficient speed, rather than surging or slowing to the demands of road and driver. Result: fuel savings of 10 to 20 per cent and similarly reduced pollution. It's a start.
Further improvements could be made if the engine burnt a cleaner fuel. But the smart money is on something more radical. That something was invented way back in 1839 by Welsh physicist Sir William Grove: a fuel cell that runs on hydrogen.
Many types of fuel cell have been developed over the years (see "Fuelling the future", p 38). But until recently they were too large, cumbersome and low on power to run a car--even after NASA tinkered with them to provide pollution-free electricity inside the Apollo spacecraft.
The breakthrough came in the mid-1990s when a small company, Ballard Power Systems of Vancouver in Canada, dramatically improved their power-to-volume ratio. Up to that point, fuel cells delivered around 167 watts per litre. A car engine built with these would commandeer the entire boot and back seat. Around five years ago Ballard achieved 1000 watts per litre. For the first time, fuel cells could fit under the bonnet. The company's latest cell, the "Mark 900", delivers 1310 watts per litre, powerful enough to make a 75 kilowatt (100 brake horsepower) engine that fits comfortably inside a car.
Soon fuel cells will be on the highways. Ballard vice-president Paul Lancaster promises that by 2004 a quarter of a million fuel cells will be rolling out of its $400 million production plant every year. And he has development deals to put them in cars made by Ford, General Motors, Toyota, DaimlerChrysler, Nissan and Honda.
Ferdinand Panik, director of DaimlerChrysler's fuel-cell project in Germany, reckons hydrogen fuel cells will power a quarter of new cars worldwide by 2020. It could be a lot sooner, especially now oil companies are lining up too. Shell gave its blessing last March when Don Huberts, chief executive of Shell Hydrogen in Amsterdam, predicted hydrogen would be the world's number one fuel in the 21st century.
Ballard's proton exchange membrane fuel cell converts fuel into power twice as efficiently as an internal combustion engine while producing no noise or noxious emissions. No wonder hydrogen fuel cells have a green halo. British transport minister Gus MacDonald declared in December last year that fuel cells would allow more than half of new British cars to be "pollution-free" within a decade. But hang on a moment. Fuel cells are a major advance because they are a more efficient way of powering a vehicle. But "pollution-free" they are not.
This is what we might call the "electric kettle problem". Fuel cells, like electric kettles, emit only steam. But kettles are powered by electricity generated in power stations that burn coal or oil. And fuel cells are powered by hydrogen made by . . . well, by what? You cannot mine hydrogen or pluck it from the air. It has to be manufactured. And the method of manufacture determines the pollution. "If we make hydrogen from the wrong fuel source, such as gasoline, the green halo could vanish," says Rob Macintosh of the Pembina Institute for Appropriate Development in Alberta.
There are two main ways of producing hydrogen. The first is electrolysis, passing an electric current through water to split it into hydrogen and oxygen. This requires large amounts of electricity, most of which is generated by burning fossil fuels such as coal or oil. Use this to run a car and there's little, if any, gain. To make environmental sense, the electricity has to be generated from renewable resources (see "Make hydrogen while the Sun shines").
The second route to hydrogen is to refine it--either from a conventional hydrocarbon or a novel source such as plant matter. This refining, or "steam reforming", can be done in a number of ways: centrally at a refinery for delivery by pipeline to service stations; at the filling station itself, using hydrocarbons trucked or piped in; or on-board the car in a small "reformer" that directly supplies the fuel cell. In each case, reforming combines a hydrocarbon and water at high temperatures to produce carbon dioxide and hydrogen. The trick, in environmental terms, is to choose a hydrocarbon that produces maximum hydrogen for minimum carbon dioxide. Natural gas, which is mostly methane (CH4), is the best because it has the highest possible hydrogen-to-carbon ratio.
There are other potential methods of hydrogen manufacture, such as mimicking photosynthesis, using heat or high-energy particles to split water, or even harnessing bacterial enzymes. But all are still largely confined to the lab. Reforming natural gas, however, is already widely used in the production of chemicals.
But which of the options would be best for the environment? Macintosh accepts that "to be truly pollution-free, the hydrogen must come from a renewable source, such as solar or wind power". The green dream of electrolysis using a renewable energy source is technically feasible, but not yet economically viable. So Macintosh has analysed available technologies, using the test of how much greenhouse gas would result from making and using the fuel needed to drive a standard vehicle--a Mercedes A-class hatchback--on a 1000-kilometre drive across Canada.
Worst, not unexpectedly, was the regular gasoline-burning car. It emitted 248 kilograms of CO2, most of it in the exhaust gases. Next worst was a fuel-cell car with an on-board reformer that turned gasoline into hydrogen. This so-called "pollution-free" vehicle chalked up 193 kilograms, mostly from the reformer. After that came on-board reforming of methanol, the chemical many fuel-cell pioneers see as the most likely route to mass-produced fuel-cell cars. In Macintosh's study, methanol outperformed gasoline, producing 170 kilograms of CO2. But it lagged way behind the vehicles carrying hydrogen made from natural gas reformed either on forecourts or at a central facility. These emitted between 70 and 80 kilograms of CO2-- 70 per cent less than gasoline. Macintosh only looked at greenhouse gas emissions, but he reported that smog-creating emissions would show a similar profile.
Even if the problem of hydrogen generation is cracked, there are still roadblocks between here and a hydrogen economy. One is storage (see "Where to keep it"). Another is the need to create a new infrastructure for producing and distributing bulk hydrogen, costing perhaps trillions of dollars. This looks especially problematic, but there are potential solutions.
One is kick-starting the hydrogen economy in smog hot spots, such as southern California, or in areas of abundant "green" energy for hydrogen production, such as Iceland. Another is to make the transition in stages, perhaps by concentrating first on fuel-cell vehicles with on-board hydrocarbon reformers.
But which hydrocarbon would make the best stepping stone? Much of the car industry favours methanol. The argument is that methanol is a liquid, so is easier to manufacture and handle in bulk than hydrogen while still offering significant environmental advantages over oil.
Last year, Ballard signed a deal with Methanex of Vancouver, the world's largest methanol producer, to set up a prototype distribution system in Canada. Ballard is backing a similar project in the US along with the California Air Resources Board, Ford and DaimlerChrysler.
Macintosh, though, says this is misguided. "Unfortunately, on-board processing of methanol fuel does not offer anything near to the life-cycle greenhouse gas advantage of natural gas reforming," he says. It also requires a whole extra stage of manufacture, a reformer in every car, and its own distribution and storage systems. Methanol is corrosive so would have to be held in reinforced tanks. It's also water soluble, which means leaks into groundwater would be hard to contain. Paul Histon of BP Amoco fears setting up a system for shipping methanol round the country, only to have to move again to a hydrogen distribution system a few years later. "We only want one big change," he says. "If it's going to be hydrogen, let's get on and do it."
The logical solution, argues Macintosh, is for cars to fill up with hydrogen produced on garage forecourts from natural gas. This is cheap, because the natural- gas distribution network is already in place. It is the most environmentally friendly technology currently available. And it is very easy. Indeed, you might not even need filling stations. Your office or neighbourhood could do it (see "Fill 'er up"). A reformer the size of a water heater "can produce enough hydrogen to serve the fuel cells in dozens of cars", says Amory Lovins. The scenario is also flexible. As demand grows, bulk suppliers of hydrogen might get interested, developing pipeline networks if they felt they could undercut local production.
Natural gas, says Lovins, offers "a long bridge to a fully renewable energy system". And there could be unexpected bonuses along the way. Robert H. Williams of Princeton University's Center for Energy & Environmental Studies, sees potential for the owners of gas fields turning their product into hydrogen at the wellhead. That way, the resulting CO2 emissions could be injected right back into the emptying well.
But journey's end will be a true hydrogen economy, in which the link to fossil fuels has been cut for good. Greens and industrialists alike are beginning to glimpse the day when renewable energy--whether solar or wind, geothermal or hydroelectric--is ready to take over electrolytic production of hydrogen from water. Indeed, manufacturing hydrogen may turn out to be the most effective use of renewable energy. For it gets round the inconveniently intermittent nature of many sources--available only when the wind is blowing or the Sun is out. Hydrogen will, in effect, be able to store that energy.
Lovins sees hydroelectric dams, in particular, becoming "hydro-gen" plants. They have the unique advantage of bringing together abundant water and electricity supplies and could "earn far higher profits by selling not electricity but hydrogen--in effect shipping each electron with a proton attached".
This strategy even gets round one of the major problems of hydroelectricity--the need to flood large areas of land to store water. Reservoirs are only needed so that electricity can be generated on demand. But the need disappears if that electricity can be generated "at nature's convenience"--varying according to rainfall--and its energy stored as hydrogen. Large reservoirs could be replaced in many places by "run-of-river" hydroelectric plants that take power from passing water without damming it.
The hydrogen age could be closer than we think. Certainly, the route map is slowly emerging. But who will get on the road first? Right now, revving up at the front of the grid is the country with one of the largest hydroelectric reserves in the world. Plucky Iceland.</font>