• Apr 20th 2012 at 10:00AM
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Techsplanations: Fuel Cell

To scientists, running vehicles on hydrogen makes all the sense in the world. Hydrogen can be derived from so many different things, including water, and constitutes roughly 75 percent of the universe's chemical elemental mass.

Consumers, however, often shy up when presented with the option of a hydrogen-powered vehicle. They think of "H-bombs," or the explosion of the Hindenburg. But that's pretty silly when you consider we handle 15 to 25 gallons of highly volatile gasoline in our vehicles now.

As the U.S. struggles politically and culturally to map out a logical energy future, hydrogen doesn't get a lot of attention. Most of the talk is about battery-powered electric vehicles and gas-electric hybrids that can run on either gasoline, electricity, or a combination of both simultaneously. But to mark Earth Day 2012, we want to shed some light on perhaps the most abundant energy solution of all for our vehicles – hydrogen.

What is it?

A fuel-cell vehicle is a type of electric vehicle. Like the Nissan Leaf and other EVs, it uses an electric motor to drive the wheels. But rather than draw electricity from heavy batteries that take time to recharge, a fuel cell generates electricity as needed by creating a chemical reaction using hydrogen and oxygen. The hydrogen is stored onboard the car in tanks as a compressed gas and the oxygen comes from the air. A fuel-cell vehicle can be refueled by pumping hydrogen into its tank at a hydrogen refueling station, similar to a regular gas station.

While fuel cell vehicles are still considered advanced technology, the science is not new. Fuel cells were developed in the NASA space program in the 1960's and the first fuel-cell vehicle, the Chevrolet Electrovan, was built by General Motors in 1966. At the time, the fuel cells were too big and costly to even dream of deploying in a production version. But much has changed in the past five decades, as sophisticated computer control systems have allowed the size of fuel cells to shrink along with the costs. Modern demonstration vehicles have been logging miles since the 1990s, though automakers' interest in the technology has waxed and waned over the ensuing years.

Techsplanation recently drove a Mercedes-Benz F-Cell fuel-cell vehicle (See video). The system is built into the Mercedes B-Class. This F-Cell has an electric engine rated at 100 kW (134 horsepower), and a range of about 250 miles. This improvement in range over an earlier version is due in part to the B-Class's greater space for holding the compressed hydrogen tanks and higher storage pressure.

We so enjoyed driving the F-Cell around Los Angeles, with such ease of refilling the tank when we needed, that we keep asking ourselves: Why can't we have this now in larger numbers?
How does it work?

A fuel cell works by catalyzing hydrogen, a fancy way of saying a chemical reaction breaks down hydrogen atoms into their atomic components: electrons and protons. The electrons create an electric current – that's where the electric power comes from – before they're recombined with the protons and oxygen from the air to create water, the fuel cell's only emission.

A fuel cell is comprised of several hundreds of these cells, wired together to create the full system large enough to power the vehicle's electric motor, just like a battery.

Fuel cell cars have an actual battery in them as well, usually a lithium-ion one like in your laptop computer. The vehicle uses this battery to store energy from regenerative braking, just as in a battery electric vehicle or a hybrid like the Toyota Prius. Because the fuel cell vehicle is powered by an electric motor, that motor can regenerate electricity any time the vehicle is decelerating. It does this by allowing the wheels to spin the electric motor, rather than the other way around. The motor then acts like a generator, returning electric current to the battery. Of course, a computer controls this entire process, as well as deciding when the motor should draw its power from the fuel cell, the battery, or both.

Why would I want it?

The big reason to want fuel cell vehicles is it doesn't produce any harmful emissions. That's right, no carbon monoxide, no carbon dioxide, no nitrogen oxides, none of the traditional tailpipe emissions associated with internal combustion engines. Zip. Nada.

Fuel-cell vehicles improve upon battery electrics because they are theoretically just as convenient to operate as a gasoline- or diesel-powered vehicle. When a battery EV runs low on charge, it can take quite some time – often hours – to recharge. But a hydrogen fuel cell vehicle can have its tanks refilled in a matter of minutes, just like a gasoline engine.

Is there any downside?

The biggest issue facing fuel-cell adoption is there's virtually no hydrogen refueling infrastructure anywhere in the world. We filled up our tank at a station in Los Angeles as part of a pilot program. While we have more than 100,000 gas stations in the United States, you can count the number of hydrogen refueling stations on your fingers.

There's also the question of where the hydrogen would come from. Hydrogen needs to be manufactured by extracting it from other substances, like water, natural gas or coal. Heck, you can even crack hydrogen from gasoline, but we don't want to go down that road. These processes have their own energy cost and associated emissions that can blur the picture of just how "green" fuel-cell vehicles are. However, given that the U.S. has abundant stores of natural gas, it is the most logical fuel stock for hydrogen in the near term.

Then there's cost. Estimates have pegged the cost to build each 2008 Honda FCX Clarity fuel cell vehicle in the six figures. While the FCX Clarity is a first-generation purpose-built fuel cell vehicle, Mercedes has recently stated its expectation that costs of so-called second-generation hydrogen fuel cell vehicles will come down. Mercedes forecasts that by 2014 they might be comparable to the cost of diesel hybrids, which while still expensive, would be feasible for carmakers to build and sell at a profit.

What vehicles offer it?

The thing about cars powered by fuel cells is that there aren't many of them. Honda launched the first purpose-built, publicly available fuel cell car in 2007, the FCX Clarity. But only a handful of cars have been sold – just 30 to date – and their availability has been restricted to leases in Southern California. Honda did this because the cars cost far more to build than the $600/month lease price will cover, and the limited number of hydrogen refueling stations means the cars can't be sold just anywhere.

The Mercedes-Benz F-Cell was launched in late 2010, and used a similar leasing program to put its cars in the hands of the public. These cars, based on a European model called the B-Class, were also restricted to California customers, for similar reasons. Mercedes has said it plans to lease a total of 200 F-Cell cars globally, although through 2011, 20 cars had been delivered here in the U.S.

These two car programs are only a small step beyond experimental, but that's not deterring car-makers from moving forward with plans to put more fuel cell vehicles on the road. General Motors, Toyota, and Hyundai have all announced plans to start producing fuel-cell vehicles within the next two to three years. The technology is just too smart for them not to keep pushing the costs down. And there is widespread agreement – outside the oil industry – the U.S. must, for the sake of its environment and national security, diversify our transportation fuel stock beyond oil.

Bottom line

Hydrogen fuel cell vehicles have been perpetually a decade away from the mainstream for 20 years. That could change, as automakers have gotten serious about developing alternatives to the internal combustion engine in recent years.

If you get a chance to drive a fuel-cell vehicle, take it. You will be driving the future, and you may just be part of a wave that brings the future a bit closer to the present.

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    • 1 Second Ago
      • 3 Years Ago
      It is misleading to say that because of hydrogen's abundance, energy available in the form of hydrogen is abundant. Hydrogen in compressed, stored and isolated form is only as abundant as whatever OTHER energy sources are used to obtain it in such state. Separating hydrogen from water takes no less energy than the energy recovered during hydrogen fuel cell use. Fuel cells make outstanding batteries. they are not sources of energy.
      • 1 Year Ago
      Some time ago a company perfected the technology to convert almost any gas fueled vehichle over to Hydrogen including a way to store large amounts of hydrogen in a non-explosive state. BUT the difficulties of creating a Hydrogen delivery infrastructure at that time was so overwhelming that the project was shelved.
        • 1 Year Ago
        Tell us who which company this is. No one but you is aware of this ground breaking technology.
      • 1 Year Ago
      They glossed over the hydrogen production method and cost which are two major factors when considering how green and feasible it is. The energy storage does seem promising though.
      • 1 Year Ago
      The hydrogen economy is simply a shell game. Fuel cells convert the hydrogen into electricity. Where did you get the hydrogen? Hydrocarbons, or perhaps electrical generation (coal, dams, solar, etc.)? The myth is that hydrogen cars are 'clean' and 'efficient'. They are not. Take the simple example of using coal to generate electricity that's used to produce hydrogen and then converted back to electricity in the car. That's hugely wasteful. Why not cut out the middle-man and just go electric and charge at home? There's also the detail that fuel cells use rare expensive metals, hydrogen is difficult to store and transport in quantity safely and there's no existing distribution infrastructure.
        • 1 Year Ago
        I would love to see you go across country in that electric vehicle. How many weeks do you anticipate you would need? The idea behind Hydrogen cars is that they can be refueled in seconds (faster than gasoline). It is even anticipated that soon you will be able you fuel up at a home station (to work and back type of stuff) with stations for longer runs, and later they say it can be developed so that it is converted ONBOARD so that you never have to stop. ANOTHER advantage to hydrogen is NO batteries. Where do you think all those dead batteries will go - millions and millions of them each filled with a HIGHLY toxic chemical known as hydrochloric acid? Even recycling them takes immense amounts of energy and leaves toxic byproucts. I suppose you think that electricity in your current electric car is free and clean when in actuality it is neither. It is very expensive and for reference check the prices of operation for a gas furnace/water heater vs electric and eletric only seems to get more so. As far as clean, that electricity comes from a power plant like the coal burning plants that greenies are continually trying to shut down. Electric cars were a waste because it was the fast easy fix and never thought out. Just like Ethanol which they are now finally starting to admit causes more emmissions than gas when you include the creation (HUGE amounts of fuel burning to distill it), transportation to blend it from the north corn belt area to the refineries in the south, and the blending process. Short term thinking...
        • 1 Year Ago
        Hey Fill...You are only partially correct. Yes, a hydrogen fuel cell powered vehicle is inefficient and expensive. A conventional gasoline engine that has been converted to burn pure hydrogen gas is cheap and efficient. And hydrogen is neither difficult to store or transport. Chemical and gases supply houses such as Air Products and Linde have been doing it for decades.
      • 1 Year Ago
      the article mentions using natural gas as a hydrogen feedstock-----why not just burn the gas, as in CNG, which is currently available, far cleaner than gasoline, requires similar tankage as hydrogen and is extremely abundant here in the USA? it is also currently piped virtually all over the country. LPG would be another alternative and both these fuels are well understood.
      • 1 Year Ago
      • 1 Year Ago
      People, its so sad to see that we are victims of our own ignorance. Would think tts time for a Renaissance. The internal combustion engine is over 100 years old. Its time for an upgrade. In 1963 GM displayed at the New York Worlds Fairs a car and truck, both powered by a turbine engine. They said it would run on anything that would burn. Since then only batman has a turbine powered car..? Really, we are told every time the subject is brought up that we don't have the technology to put it in a car. Yet we do have then in our helicopters and o yes the M1 Main Battle tank. Most big airliners have one to generate electricity. So what is the truth?? As for hydrogen, its kind of nice for the petrochemical industry to say we need to get Hydrogen from Hydrocarbons. Hydrogen, good, Oxygen, good, then what do we do with the Carbon??? like oil or gas...? WHY?? $$$$$$ in some peoples pockets. What happen to water? H2O. Two good no bads...? Lets use that 100-year reserve of gas we have here in the good old USA to generate electricity and power cars. Or wind powered generators or use all the excess power we have in the electric power grids at night when industry is not running. Then we can make Hydrogen. We can get hydrogen from all the water that surrounds the planet. Once burned it goes back to being water. As for complicated.......? If you remember the science class in which your teacher made hydrogen and oxygen in the class with nothing but two electrodes and electricity. Not rocket science. Hydrogen offers many option, there's the HHO gasoline hybrids that can increase mileage and reduce gasoline consumption and help gasoline burn cleaner by adding hydrogen with pure oxygen to the engine intake. The gases can be generated onboard the car from water, and little programming of the car computer. The auto industry has the know how to make it happen from the get go. More oxygen is what a turbo gives the engine. We used turbos for our aircraft engines in WW2 so we could fly at 25,000 feet, old technology. Then there is the fuel cell. NASA has been using them since the beginning of the space program in the 1960's. I would think by now we should know all we need to know about the technology. Then there is the straight Hydrogen powered car. Gas station would not need to work with the petroleum industry. They could generate and compress it on site using electrolysis and electric pumps. Think of all the savings. Hydrogen for the car and oxygen for us people. Nice. This country has a chance of being a technology leader and owning all the patent for the process, why are so few controlling the future of so many?
      • 1 Year Ago
      the fuel cell is the most expensive way to burn hydrogen
      • 3 Years Ago
      I agree with Mr Ramos. Extracting H2 from any source is energy negative in the final outcome. You cannot get hydrogen directly, it must be manufactured and that costs much more energy than the energy you get back. Hydrogen, as a fuel source, is at least a distraction, at worst a conspiracy to keep everyone confused about fuel. Same is true for ethanol, even in Brazil, where offshore deepwater drilling is going on despite the abundance of ethanol. Hydrogen is interesting, but not economical.Ethanol should be made for internal consumption, not internal combustion.
      • 1 Year Ago
      Everybody thinks that burning natural gas (aka methane) is a solution to all our problems. First, it produces Carbon Dioxide, which some think is causing (anthropogenic) global warming. NUTS. Sure, it contributes, but water is the prime, atmospheric, global warming gas. The main advantage of methane is that it is a clean burning fuel and does not pollute like other petroleum based fuels, but it produces more greenhouse gases, proportionately, per molecule, than any other petroleum based fuel. But explain that to the treehuggers. Hydrogen is the clear winner when it comes to fuel, but technical obstacles (see my previous post), are holding us back.
      David Anderson
      • 1 Year Ago
      Has anyone stopped to consider what the real price of gasoline is
      • 1 Year Ago
      Point me to one! Or I would drive a car with a solar panel on top.
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