Hydrogen fuel cells get a fair amount of coverage as an alternative to gasoline, but actually producing the hydrogen efficiently is a key point. According to Nikkei's Tech-On!, Japanese company Genepax has developed a fuel cell system that only takes in water, and it's used it to power a small car. The site describes the Water Energy System as follows:
The system can generate power just by supplying water and air to the fuel and air electrodes, respectively. . . . The basic power generation mechanism of the new system is similar to that of a normal fuel cell, which uses hydrogen as a fuel. According to Genepax, the main feature of the new system is that it uses the company's membrane electrode assembly (MEA), which contains a material capable of breaking down water into hydrogen and oxygen through a chemical reaction.
Though the company did not reveal the details, it "succeeded in adopting a well-known process to produce hydrogen from water to the MEA," said Hirasawa Kiyoshi, the company's president. This process is allegedly similar to the mechanism that produces hydrogen by a reaction of metal hydride and water. But compared with the existing method, the new process is expected to produce hydrogen from water for longer time, the company said.
The system doesn't emit any carbon dioxide, although existing prototypes cost around $18,000 to produce and can only generate up to 300W of power. That said, Tech-On! says Genepax plans to produce a 1-kW generation system for powering electric cars and homes, and it believes it can cut costs to around $4,000 or less if mass production works out. In electric cars, Genepax expects the system will be used "as a generator to charge the secondary battery."