Hi Joel and Lion, thanks for answering to my comments! My intention was of course not to counterdict anything that was carefully planned and layed out in Lion's proposal, but to trigger discussion, new thoughts, looking at things from another angle, etc., and that apparently is beginning to happen. Regarding the supercapacitors, I only wanted to say that by the time we will be able to build an ecocity, things might have changed. And regarding the hydrogen problem, leaks can be fixed, valves and connectors can be designed more gas-tight, etc., but of course we should be aware of possible new problems we didn't even dream of. Those enemies of progress that are always lurking might use details like these to "shoot us down". What is interesting for me is that old technologies all the sudden have a "come back". That refers to the flywheel! Last time I saw one was when I was a kid, on a combine... And the Living Machine is no machine at all, but a clever use of micro- and macro-organisms. If I recall correctly, only about 2 square meters are required per household (average) to treat all sewer water. That sounds to me like an interesting option, especially combined with solar distillation, to eliminate all pathogens, foul odors, etc. Therefore I wanted to introduce it to the list. For those who are interested, a web search returns quite a few results. Last of all, long messages are a problem for me, so I want to give a good example with a short one. Uwe __________________________________ Do you Yahoo!? SBC Yahoo! DSL - Now only $29.95 per month! http://sbc.yahoo.com