exotic and alternative energies sources have been available since the 1930s. Water is funny stuff and if you hit it with the correct resonance using electricity and electrodes it will simply break apart. The hydrogen and oxygen can then be recombined giving you more energy than you put in to seperate it. There are US patents registered for equipment that servers this purpose and you can build a test setup in your garage for under $500 USD.
There are other alternatives such as aquafuel, that is documented, patented and has been produced and tested, search google for it.
Cold fusion is another concrete reality with COP observed inexcess of 5.0 a petrol engine having a pathetic COP of around 0.2 Again you can get details of how this works and how you can build your own rig and test it out for yourself.
There are simply dozens of ways of making energy. Read about Tesla and some of his inventions. Sure there is a lot of rumor and crazy stuff out there, but the guy has some genuis ideas that were basically burried.
The problem with free energy is one of security. Imagine Hitler or Stalin with solar or cold fusion powered armies. Even terrorists hiding out in the mountains with unlimited energy supplies would be a threat.
It's nice to think that these technologies would bring peace on earth, but most likely they would give madmen unlimited powers.
For that reason and a varitey of others, including greed, dogma and pride many amazing inventions have been surpessed.
Here is a good example of a very simple one, tested and confirmed by BMW.
http://anon99.tripod.com/water_engine/
This stuff is out there but it is not happeing.
Many Japanese companies have developed overunity engines (produce more electricity than they consume) and have made public statements that they cannot release them at the moment.
http://www.cheniere.org/misc/kawai.htm
There is no need for urgent development, if these things were allowed, they could be on the market within weeks. You could retrofit your own car to produce and run on hydrogen if you did some investigations and spent a couple of grand.
The technology is simple 1930s electrical stuff, that has just been swept aside.
And please no, dogma, and slandering against this posting. I am not interested in bigoted opinions. If you think this is a bunch of rubbish then prove it by building and testing a unit for yourself, not by shooting off your toungue. Certainly there are a lot of hoaxes and conspiracies out there but there is also a lot of genuine science.
cold fusion was burried because a buch of respected scientists had been busy spending billions a year on hot fusion (the suns processes) with zero results. Cold fusion can be up and running with a few hundred dollars of components. Their careers would have been ruined if they had admited the realities of cold fusion. Many of these other ideas also have problems against the established physics of the day. Scientists have been wrong in the past and it has also been notoriously difficult to get them to admit it.
There is much we need to learn about physics and the universe.