ratryu asked the question: Can any of you explain how this process is efficient?and I thought I'd give my two cents. I think that hydrogen is being proposed, not as a new source of energy, but as a new (portable) storage system for energy. Petroleum products have a lot of readily accessible energy, but burning them on the run (e.g. in your car) is inefficient and burning them at all results in unwanted waste. Electric engines have been proposed as replacements for combustion engines. But batteries for electric cars are expensive, heavy, and use toxic materials. Producing hydrogen is an alternate method of storing energy attained from numerous sources, as shown in the video. ratryu says:If you use renewable energy, then you would be wasting energy. It would be far more efficient to just use the electricity in an electric car.But I would argue that the storage systems in electric cars are not 100% efficient either. There is certainly some loss in storing and retrieving the energy. Even if batteries are currently more efficient that fuel cells, this does not necessarily mean that we should stop developing fuel cells. Improvements in technology will improve the efficiency of hydrogen systems so that, perhaps one day, hydrogen systems will be more cost effective or require less toxic materials, than battery systems.