RE: Hydrogen generators
When we're talking about energy from hydrogen, what we're actually talking about is using H2 as an intermediate storage source. This is because the energy cost of splitting a water molecule are at least as high as the energy value of the split hydrogen. Any company that claims to make this process energy efficient is actually masking costs of other hidden energy sources such as electrochemical energy (during electrolysis), heat energy and solar energy. These energy costs may someday become cost-efficient in terms of financial benefits, but the process itself can never generate more energy than what is put in, because of the law of conservation of energy. So when people talk about splitting water and producing electricity, we must keep in mind that we are putting in at least as much energy as we are getting from the hydrogen.
Read this to get an idea about how the law of conservation of energy applies here: http://www-formal.stanford.edu/jmc/progr...stlaw.html
Read about this new H2 producing microbe to see how new technologies using solar energy (harnessed by bacteria) could someday be used to scale up production of hydrogen as a fuel source in compressed form that can find direct applications in industry: http://www.scientificamerican.com/articl...comes-natu
"Fossil rabbits in the Precambrian"
~ J.B.S.Haldane, on being asked to falsify evolution.