It's a gas!

I have long believed that hydrogen and oxygen - two of the most common elements in the universe - would one day be the fuel and oxidizer that replaced all other major energy sources. Together they can be burned for heat; by itself hydrogen can be fused for even more heat. The biggest problem is getting the hydrogen, which on Earth is mostly locked up in various compounds.

One technique is using electrical current to break it out of water (hydrolysis) which can be carbon free if you generate your electricity from non-carbon sources. This is done on an industrial scale, and the raw feedstock is abundant, but it takes so much electricity that - so far - it's too expensive to compete with other fuels. Additionally, hydrogen is relatively difficult to work with and can leak out of what would otherwise be considered air-tight containers.

Of course if you could only generate the hydrogen as you needed it where it was needed, then you wouldn't need to store and transport large quantities. You'd only need to store water, which is relatively well behaved and easy to control. Of course, that only makes sense if you want to use the actual gas (say, as fuel for a torch), since there's no point using electricity to split water to recombine to run a machine (say) when you could use the electricity directly.

Yet there are those who claim it does make sense. They claim that something called "Brown's Gas" or "HHO", which is produced by hydrolysis, can be used to boost automobile and truck gas milage. The claim is that the output of a portably hydrolysis unit run by the vehicle's alternator can be run into the fuel stream and will dramatically improve gas milage.

Now, from a strict thermodynamic sense this is ludicrous. It takes more energy to create electricity to split water than you can get in useful work from burning the resulting gas. Yet the internal combustion engine is not a simple heat engine, but a complicated machine. Look at hybrid cars - they manage to get better fuel economy using large batteries that get charged by the gasoline engine and the brakes. Is it possible that these systems are somehow using energy that's otherwise wasted and using it for useful work?

Or consider: only 21% of air supports combustion. Is it possible these portable hydrolysis units - producing an entirely combustible output - is increasing the amount of fuel burned and, thus, increasing the engine's efficiency?

Google produced a lot of qualitative analyses - really opinion pieces no more rigorous than this one - on both sides of the discussion. There are some reports of great results; there are a discussions on why those results are bogus. There are a surprising number of really dopey claims about "Brown's Gas" which, some claim, is in some way different from a mixture of molecular hydrogen and molecular oxygen and is imbued with strange powers - but I digress.

Couldn't someone, I wondered, do a real, rigorous test to settle this once and for all? If it actually worked such a study would be a boon for humanity.

Fortunately someone did. Popular Mechanics ran an article describing the results of what appears to be a very rigorous and repeatable test and the results were:

These devices do no good whatsoever.

This is indeed a blow to those who want to be able to improve their gasoline use by spending a couple thousand bucks, and to those who want to meet that desire by selling a device to do it. But then, isn't it better to know?