What else can we expect? Gas prices go up, people need to fill their tanks, a legitimate need arises, and so in come the people to try and fill that need. We see bicycle stores and public transport benefit from a world with higher gas prices. Of course, in such times it is sadly predictable that others would try to make a fast buck off of people's ignorance. This is where a website called Water4Petrol comes in.
Now hydrogen can be used as a fuel and, since it combines with oxygen to form water vapor under normal conditions, an exceptionally clean fuel at that. It's not the idea that hydrogen can be used as a fuel that I find appalling. Right now considerable investment is going into research to find easy and cheap ways to produce hydrogen, and while I'm not optimistic about the prospects so far, I wish them luck.
Now any chemist, scientist, engineer, or well-informed layperson should be able to look at the site and quickly understand why it's a not a plausible method of saving money on gas. So for the benefit of the completely uninitiated, I'll try to keep this on a very basic level. To summarize what the website purports:
1. Water is electrolyzed in what can best be described as a jar, but let's give these people the benefit of a doubt and call it a magic jar. To electrolyze something means to break it up using electricity. In the case of water, this means breaking it up into hydrogen and oxygen. When hydrogen bonds to oxygen to make water, a certain amount of energy is released in forming the bond. When the bond is broken, therefore, it stands to reason that the same amount of energy must be used to separate the elements. Keep that in mind for later. The electricity in this case comes from the car's own battery or alternator. If you're quick, you'll see where this is going.
2. The mixed gas, remember that it's hydrogen and oxygen together, is then shunted into the engine airflow where it presumably ignites in the cylinders. This part is a little beyond my expertise, I only know very vaguely how an automobile engine works. So I will assume that a car can run on hydrogen in the first place, just for the sake of argument.
3. The combustion of hydrogen in the engine will reduce the amount of gasoline/diesel needed to run the engine, thus saving you money at the pump. To that end, I call bullshit.
You see, there are these things called the laws of thermodynamics. I'm not going to list and explain them. Instead I'm going to call on that rare thing called common sense, and get Socratic on your asses: Based on what you have observed of the world around you, does energy, whether it's mechanical (dropping a ball, using a gear, etc.) or chemical (burning something), come out of the nether? Basically, is it free? Can you call upon you chakras, Qi, God(s), or Barry Manilow to move your car in the morning?
"No! Of course not! Energy has to come from somewhere!" You exclaim, taking me aback (I had no idea you were so passionate). So where does the energy to break water down into hydrogen and oxygen comes from? According to the website, run by the dubiously named Ozzie Freedom, it comes from your battery. Where does the energy from your battery come from? If your battery goes dead because you left the headlights shining into your neighbor's bedroom to teach him a lesson about returning that lawnmower, you know you don't recharge it. You "jump" the battery, and leave your car running a little while. This is so the battery can use your gasoline to charge itself up using the alternator. So when you use battery power to make hydrogen, you're just using gasoline all over again.
If you hook the apparatus (read:magic jar) up to your alternator, the same reasoning applies. The alternator is a moving part that generates electricity, and what makes it move is (tah-dah!) gasoline.
So how do we know that the hydrogen isn't somehow miraculously better than gasoline? The answer lies in something I said earlier, when you break a bond, it generates the same amount of energy to reform that same bond. So you can only get the same amount of energy you used to separate water in the first place. It is impossible to benefit from this system. In fact, it would seem from the prices Ozzie charges for a magic jar (240 South African Rand=31.34 US Dollars), the only person that stands to benefit financially is one Ozzie Freedom.