I don't know how to get an answer to this question. The only economic way of getting hydrogen now is to make it from natural gas. The article in Pop Science about the Coleman fuel cell unit said $100 for 10 hrs of operation at 1.2 kw. This is almost $10/kwhr. There is no possibility of replacing gasoline with anything but natural gas and increased consumption of this will bring disaster sooner. There is nothing that can possibly replace oil and gas. A partial replacement, enough for tractors, trains, and trucks would be Methanol made from wood or coal. Unfortunately no one has the brains to mass plant the trees. We can grow 10% to 20% of our present yrly consumption and probably could store 50 % if we did not cut. If we spend enough money, we can probably get 10% each of present consumption from solar and wind.
The only way to give the kids a chance is by making massive investments in energy including solar, wind, biomass, coal, and nuclear. Then we have to cut consumption per capita by more than 50%. This should stop a dieoff for 200 years and would give some time to find more answers and cut the population some. Conservation is the most important thing and that can only be achieved by the planned self sufficient community and the apartment house. Snuggle up to stay warm.