Hydrogen: The Answer. What was the question?
bkkAutos.com is a car site, not a science site, so if you are looking for loads of detail for a science project, or you want to build your own fuel cell car, then you might find this article is a little light on technical details.
If you want to know what hydrogen will mean to us, then I hope you will find this article insightful and perhaps it will make you think more about the issue, something many in the auto and energy industries don't seem to be doing.
So, what is all the fuss about? Why is so much effort and money being spent on hydrogen "power"?
What is hydrogen?
I was not alive in 1937 but like everyone who has lived in the presence of a TV, radio or the Internet in the years since I have heard of the Hindenburg. Even if you don't know the name you might recall watching a horrific video clip of a giant airship bursting into flames and crashing to the ground.
But this is not why I don't like hydrogen, I'll get to that later. Actually the Hindenburg disaster was not caused by hydrogen. Sure the hydrogen burned in the disaster, but it was not the cause of the fire. If you are interested you can read about the cause here.
Apparently hydrogen makes up about 75% of the mass of the universe. It is 15 times lighter than air - hence its use in blimps, and it burns pretty well which is the reason it was unfairly banished from blimps in favor of the heaver - but virtually incombustible - helium.
But we are not interested in blimps. We want to power our cars, and we want to do it in a way that will allow our kids to respect us. Hydrogen is the much touted answer to our pollution problems.
How can hydrogen power a car
There are currently two ways in which hydrogen can be used to power a car. The first and easiest for me to explain is "combustion." Hydrogen is flammable, and igniting it in an internal combustion engine can power a car, just like regular gas.
Hydrogen powered cars based on the internal combustion engine can also be hybrid. This video shows a test drive of a Toyota Prius that has been converted to run on hydrogen. This video will also give away some of the issues that I have with hydrogen.
Okay, hope you enjoyed that. A 75 mile range is not particularly impressive, but these are early days.
The second way hydrogen can be used to power a car is by using it in a fuel cell. Again, I want to keep this simple: Think of a fuel cell as a battery that can be replenished by adding hydrogen and oxygen into it continually, whereas a battery is sealed and we need to charge it up to use it. This means that fuel cell vehicles must be refueled at a "hydrogen station" just like a car with an internal combustion engine. The hydrogen is stored in a tank in the car, and is fed into the fuel cell to create electricity.
Sounds good right? Well, maybe. Read on.
Hydrogen is NOT a source of energy
Hydrogen is currently being hyped as the solution to our dependence on fossil fuels. It is believed that in the next 5 to 10 years cars powered by hydrogen will be gliding down our streets and highways. Hydrogen powered cars will not pollute and the exhaust will be pure water.
This is a lovely picture isn't it. But here is the first major problem: Hydrogen is not an energy source.
Hydrogen has to be produced, and this production process uses more energy than the resulting hydrogen will contain. The pretty picture of hydrogen that is being painted for us all includes the notion that hydrogen will be produced from water via electrolysis. While this might eventually be the case, currently this is over three times more expensive than producing hydrogen from natural gas. Finding cheaper ways to produce hydrogen from water will not be easy.
Hydrogen is really being used as an energy carrier. The idea is that hydrogen can be produced using other forms of energy, such as by burning coal, oil and gas and then transported around the world to supply cars with the hydrogen they need to power their fuel cells. Since the production of hydrogen can be handled at large stations, the pollution caused during the process can be better managed.
It is also possible that solar, wind and other green forms of power could be used to produce the hydrogen, but to produce enough of it to drive our cars would require massive investments in solar and wind energy. Currently the vast majority of hydrogen is produced using the cheapest method of generating it from methane and this produces greenhouse gas.
Hydrogen powered cars might be nonpolluting, but indirectly the pollution is still going to be produced. Hydrogen is only clean if it is produced cleanly. Currently this is not the case.
The issue is not helped by the fact that hydrogen fuel cells are only around 22% efficient, while the energy required to produce the hydrogen is already more than the energy that is contained in the resulting hydrogen. A lazy calculation on my part would conclude that over 5 times more energy is used to power your car than would be needed in a 100% efficient system - should one exist. Electric motors are over 90% efficient!
Hydrogen is a poor energy carrier
So hydrogen is not actually a wonder alternative fuel source at all! Why then is there so much interest in it?
Well, hydrogen is a way of providing clean energy for use in cars. Let's ignore everything that I wrote in the last few paragraphs, and assume that hydrogen production is eventually going to be carried out using green power sources so that we can just take a look at the merits of using hydrogen to transfer energy around the world.
Actually it's not much good for transferring energy at all. First off, Hydrogen in storage leaks at a rate of at least 1.5-1.7% per day. It doesn't matter what the tank in your car is made out of, the hydrogen fuel will leak away. So while you are off on holiday your fuel is leaking out of your car, and when you get home it's empty and won't start.
This problem is also apparent when you try to transport hydrogen around. And this makes pipelines and other transportation systems expensive. Metal embrilttlement is also a problem that needs to be overcome.
So actually hydrogen is not easy to transport, and is difficult to store. But there is another big issue with hydrogen: It will require a completely new infrastructure to transport it and filling stations have to be specially designed.
Range of hydrogen vehicles
There seems to be a notion that hydrogen vehicles will have a longer range than oil burning vehicles. However this doesn't seem to hold up to the facts either. First, hydrogen has a very low energy density (per unit of volume), which means that in order to facilitate a useful range the hydrogen must be compressed.
Even so, the tank capacity still needs to be 4 times larger than a petrol tank to provide the same range! And that's before we take into account the leakage problem.
But we'd be willing to sacrifice some boot space to our hydrogen tank if it meant saving the planet, so let's not get too hung up on this point.
What will it cost
Since hydrogen vehicles are currently not in production it is hard to tell what sort of price they will be when they eventually reach production. Currently the Fuel Cell prototype and demo models are costing well over US$1 million. Internal combustion engine hydrogen vehicles will be cheaper, as is seen with the converted Toyota Prius from the video above costing around US$100,000.
Expect hydrogen itself to be very hard to find, and very expensive initially. Even after the infrastructure is built somebody is going to have to pay for it. Right now hydrogen is not competitive with other fuels.
Benefits and positive aspects of hydrogen cars
If hydrogen was the only option available to us then I would probably find it easier to fill up this section with enough positive points about hydrogen that it would cancel out any of the negatives.
Oil is finite; we know, the oil industry knows and the motor industry knows. We don't know when it is going to run out, but it will. Don't worry, I'll save the "end of oil" theme for another post. Hydrogen does represent a possible way for us to bring power to our cars in the absence of oil.
In this hydrogen future, power collected from solar and wind farms could be used to produce hydrogen from water, resulting in a very environmentally friendly power transfer.
It is entirely possible that I'm missing something very big. Maybe there is something I don't understand about the universe, the laws of thermodynamics or whatever, that is resulting in me underestimating the value of hydrogen. But given the facts at hand I don't understand why hydrogen is considered the best way forward.
When you consider the fact that it is expensive to produce, difficult to store, difficult to transport, will require a completely new transport infrastructure and leaks out of the car it is just too easy to believe that there must be better ways forward.
Her are just two alternatives to hydrogen:
Before you start laughing think about it a little. Okay, I'll wait until you've stopped laughing. While you trying to compose yourself maybe you'd like to take a look at this video. It goes some way to explaining why electric cars never really took off:
Think about it. The infrastructure is in place to transfer electricity all over Thailand (and pretty much everywhere else in the world where there are cars). I would go so far as to presume that nearly everyone who owns a car, also owns a house that has an electrical supply. So, no need for costly developments of new supply methods.
Electric motors do not have exhaust at all.
Electric motors are 90% efficient, and even if you take into account losses of efficiency due to friction in the transmission system an electric car will be at least 50% efficient. Compare this to hydrogen fuel cell which is around 22% efficient.
Remember, to produce hydrogen cleanly we need to first make electrical energy anyway. Why throw any of it away producing hydrogen, which is then going to be less efficient than if the electricity had been used directly in an electric car.
There are a few negative aspects to electricity, but only a few. Battery technology is improving, but this is still the major limiting factor for electric cars. The range and power available is determined by the batteries.
If you are still doubting that electric cars are viable, you should check out the Tesla Roadster. Tesla are also working on a more affordable electric sedan, but the Roadster at around US$95,000 is proof enough that battery technology has come a long way. If you are wondering why the Roadster looks a lot like a Lotus Elise it is because the car is based on the same chassis, and was actually designed by Lotus. With a 0-60 time of 4 seconds it's faster than the Lotus, it has a 250 mile range, and will recharge in under 4 hours.
And it does exist. Here is a video of it:
Although I am not suggesting ethanol as a perfect solution, and I would rather see electric cars make a comeback (the first cars were electric), ethanol is a realistic alternative fuel, and it has many advantages over hydrogen.
First, ethanol can be used as a fuel additive in existing petrol engines as a way of phasing it in. See our Gasohol 95 article for more on that. Modern cars with no modification can use up to E10 (10% ethanol blended with petrol). After market solutions are available to allow up to E85 to be used in most petrol cars. What this means is that we can start reducing our fossil fuel usage now, and buy a E100 car next upgrade.
Second, unlike hydrogen, ethanol is energy efficient to produce. In Brazil, where an extensive national ethanol strategy has been going since the 70s, there are ethanol production centers that get all their power from the waste of the ethanol production process.
Ethanol is renewable and carbon neutral. Hydrogen and electrical solutions can also be carbon neutral depending on how the power is produced in each case. As you have read above, hydrogen production is rarely carbon neutral.
Hydrogen is expensive to make and hard to transport. It offers no obvious advantages over simpler alternatives, while presenting many disadvantages.
Any of the promise of hydrogen fuel cell is counteracted by the seemingly pointlessness of the entire exercise. Why expend energy extracting hydrogen at all? Why not simply use that electricity directly in electrical cars?
Hydrogen has somehow shaken off the stigma it attracted after the Hindenburg disaster, and come through to be widely accepted as the solution to our energy problem. Nobody seems to worry that it doesn't actually produce any energy at all.
But given the amount of money, time and energy that is being spent marketing hydrogen fuel cars to the public, never mind the money being poured into research and development, there must be merit to the whole exercise. Either that or "the emperor's got no clothes."