I'm not convinced that electric or hydrogen power are the future - other than in cities perhaps - as they are not environmentally clean, it's just that the pollution happens somewhere else. Power generation will normally entail the burning of fossil fuels or nuclear reaction, neither of which can be described as clean; hydrogen would be generated, I imagine by reforming hydrocarbons, carbon dioxide being an inevitable by product to be released to the atmosphere, so let's not kid ourselves that these technologies result in zero emissions!