Disadvantages of Hydrogen Fuel Cells

Hydrogen fuel cells are the wave of the future. At least that is what many would want you to believe. They have a point because a hydrogen fuel cell is a novel way to power a car. The car would require no gasoline, run on hydrogen and its only waste would be water, a natural and safe emission. However, it is not a perfect science by any means and too many times there is talk about all the great advantages without any discussion of the disadvantages of hydrogen fuel cells.

With anything, there is going to be drawbacks. If it were such a perfect technology, don't you think every car would have one by now? Besides being expensive, the hydrogen fuel cell creates certain problems that haven't been completely tackled yet.

Here are the three main disadvantages of hydrogen fuel cells:

1. It's big and cumbersome. Your gas tank already uses a nice portion of your car, but a hydrogen fuel cell will be three times bigger than a gas tank. But that is not that all. The fuel cell has to be insulated to keep it safe and protected.

2. Safety issues. Liquid hydrogen has the ability to freeze air. There have also been reports of accidents with the fuel cell itself. Sometimes a valve will get plugged up when there is too much pressure in the cell. The only place to go is out, and the cell explodes. There is no way of knowing, yet, if this problem can be fixed, but there are many working on it. In a car accident, the tank might rupture, but the good news is the hydrogen will evaporate quickly. However, it is a more serious condition in a closed area such as a garage.

3. The hydrogen evaporates. Strange, but true. The insulation is not a perfect process and the hydrogen evaporates out of the cell at roughly 1.7 percent a day. This means that eventually cars are going to need a fill up. What? You thought you never had to use a pump again? The other problem with this is gas stations don't sell hydrogen. You will have to find a customized fueling station or work something out with the manufacturer of the car. Cars that are blends with fuel cells and gasoline will never have to worry about being stranded.

General Motors Co., currently has the Chevy Equinox Fuel Cell, one of the first fuel cell vehicles of its kind. If you are thinking about purchasing a vehicle of this type, speak to the manufacturer of the disadvantages of hydrogen fuel cells. By having the technology, they are aware of the pitfalls of hydrogen fuel cells and have begun work on how to make it better.

The good news is that automobile companies are working at ways to make this a safer environment by creating less emissions and the more we learn about alternative methods, the better the Earth will be for it. Just don't go blindly in one direction without asking questions. Learn about the disadvantages of hydrogen fuel cells before you agree to use it.

Hydrogen Cars vs Electric Cars

With gas prices being so high, alternative fuel vehicles have become a popular topic. Two of the types of vehicles that tend to get a lot of press are the hydrogen fuel cell powered vehicles and electric powered vehicles. Both are lauded as the way of the future

But which of these two options are really has the better chance of being the car your children drive.

Let’s look at hydrogen fuel cells first. When burned in an engine, the only emissions giving off is water, so a hydrogen powered vehicle is a zero emission vehicle. Hydrogen is also a better fuel than gasoline, it actually has the highest energy content per unit of weight of any known fuel.

Hydrogen is also a very abundant element. While current methods for making hydrogen are done by using fossil fuels, such as natural gas, coal, and oil, American wouldn’t be dependent on foreign oil anymore. Also, hydrogen can be extracted from water, and we all know there’s a lot of water on this planet.

However, hydrogen is not without its share of drawbacks. Probably the biggest problem right now is that it would require an entire new infrastructure. While gas stations could be outfitted with hydrogen fueling stations that would take years. Also, the technology to store hydrogen efficiently is still not ready for prime time.

Then there’s the electric car. Electric cars can also be considered zero emission vehicles since they give off no emission when running. However, electric cars do require power from the electric grid, which does give off emissions. As the electric grid gets cleaner, though, so do electric cars, and electric powered cars are substantially less polluting than gasoline powered cars due to the fact that power plants are far cleaner and more efficient than an internal combustion engine in a vehicle.

The technology for mainstream electric cars is also not quite ready for all the major manufacturers to stop making gasoline powered cars, but it’s much closer than hydrogen currently is. The challenge with electric cars right now is the batteries. The batteries are both expensive and current models, like the Tesla Roadster, have a range of only 250 miles – great for commuting, but not so good for road trips. The other problem is the length of time these vehicles take to charge. It’s not simply a matter stopping at your local power station and plugging in for five minutes and leaving. A typical charging cycle for current prototypes is 4-5 hours – again, fine if you’re commuting, but impossible for a road trip. While technology is being developed to make charging your vehicle as quick as quick as filling up with gas, it has a ways to go before it’s ready, just like hydrogen fuel cells.

Fleets of electric cars will certainly be hitting the roads sooner hydrogen fuel cell cars, but which one ultimately ends up being the vehicle of choice for drivers remains to be seen as both have plenty of challenges to overcome before people will readily give up their cheap gas powered cars in favor of these alternatives.

Hydrocarbon Fuel Reformer for Fuel Cell Car

Fuel cell vehicles offer many advantages when compared to internal combustion or battery-powered electric vehicles. Advantages over the internal combustion engine (ICE) include the potential for higher fuel efficiency and lower emissions. The advantages over a battery- powered vehicle include an improved driving range and shorter refueling times.

The fuel efficiency of a fuel cell vehicle is expected to be about twice that for current internal combustion engines and the overall energy consumption (fuel chain and vehicle) is expected to be lower than that of battery-powered vehicles. Emission levels are expected to meet the Super Ultra Low Emission Vehicle Standard, much lower than those from current ICEs.

The ideal fuel for the low-temperature proton exchange membrane (PEM) fuel cells being considered for automotive applications is hydrogen. Currently, the infrastructure for hydrogen refueling is lacking, and hydrogen storage technologies available for onboard storage provide a decreased driving range compared to gasoline and ICE technology.

However, it is apparent that the commercial success of a fuel cell vehicle will be tied to the availability of a refueling infrastructure. In other words, it will be difficult to sell hydrogen-powered fuel cell vehicles without first investing in a hydrogen refueling infrastructure. However, it will be difficult to convince investors to build a hydrogen infrastructure if there are no commercial vehicles to use it.

A solution to this “chicken or the egg” dilemma is to provide an onboard reformer to convert a hydrocarbon fuel into a hydrogen-rich gas for utilization by the fuel cell. This strategy could help introduce fuel cell cars to the marketplace earlier and smooth the transition from internal combustion engine to fuel cell-powered vehicles. Hydrocarbon fuels can use the existing infrastructure for refueling and provide a higher hydrogen density than current hydrogen-storage technologies.

Currently, hydrogen is produced industrially from natural gas using a steam reforming process. A similar process can be used for onboard conversion of natural gas or higher hydrocarbons to hydrogen-rich product gases. However, onboard reforming presents several unique challenges, which include size and weight limitations and the need for rapid startup and the need to be responsive to demand. In addition, since the fuel to be used for onboard reforming is still to be determined, the reformer should be fuel-flexible.

There is some debate about which hydrocarbon fuel is optimal for fuel cell systems. Methanol and ethanol are available commodity chemicals and have numerous advantages as fuel (e.g., water soluble, renewable), and methanol is easy to reform. Gasoline and diesel have advantages over the alcohols, including existing refueling infrastructures and higher energy density. However, they are blends of different kinds of hydrocarbons and are more difficult to reform.

Fuel Cell vs Batteries

Until new batteries that can provide much higher energy densities without compromising safety are discovered, fuel cells will continue to outperform today’s heavy and large storage batteries. On the other hand, it is less expensive to build electric cars with batteries than with fuel cells.

Today’s batteries are less expensive than fuel cells, but their energy density is insufficient, and their weight and size are too high to provide the required driving range. The final outcome of the battery-versus-fuel cell race cannot be predicted. All that is obvious right now is that there are substantial developments in both fields.

In the area of fuel cells, reliability and availability have much improved. Recent U.S. military experience with phosphoric acid fuel cells found that the mean time between failure (MTBF) was almost 1,800 h and the availability was 67%. This is comparable with the MTBF service intervals for diesel generators. These fuel cells also favorably compare with the service interval needed for a typical gas turbine generation set. Still, much more development is required to obtain a commercially viable product. Today, the typical fuel cell system still requires servicing every 3–4 days to replace its scrubber packs.

The early electric cars used the old lead–acid batteries. Today’s hybrids are provided with more robust nickel–metal units. The EVs of the future are likely to be provided with lithium–iron batteries, found in today’s laptops and cell phones. Much work remains to be done in this area to increase safety and life span (to 100,000 mi of driving), while reducing their cost. Nissan and Mitsubishi are both making major investments in building lithium-ion battery mass production plants.

New battery developments include the ultracapacitor hybrid barium titanate powder design (EEStors). These devices can absorb and release charges much faster than electrochemical batteries. They weigh less, and some projections suggest that in electric cars they might provide 500 mi of travel at a cost of $9 in electricity. But these are only the projections of researchers.

Another direction of battery development involves high temperature and larger units. NGK Insulators, Ltd., in Japan uses sodium–sulfur batteries operating at 427°C (800°F) that are able to deliver 1 mW for 7 hours from a battery unit. The size of these units is about the size of a bus. Such units could be used at electric filling stations that are not connected to the grid.