[znpy]

Regarding 1, if you can accept some pollution at the beginning, hydro-electrical can be a solution, albeit probably not for a global scale.

We have a small hydro-electrical plant una River near my house and really it's no big deal, it fits very nicely in the surrounding environment and it produces clean energy.

It's also educational because since the river is near the city small children classes can visit it and learn about it.

[ajot]

Regarding hydro, you can go micro to power a house or some small comunity. There are lot's of books on microhydropower, but get a look at this fantastic post at ludens.cl

http://ludens.cl/paradise/turbine/turbine.html

[minhmeoke]

Rather than generating electricity directly, it might be more practical to reduce electricity consumption using other approaches:

Geothermal can be a solution for generating electricity directly, but if you'd like to minimize electronic waste perhaps it would be easier to use it to replace alternative energy sources for HVAC purposes.

Biofuels (eg: plant bamboo, grow it, then burn it) can also technically be closed cycle energy sources.

Solar water heaters can also reduce electrical or fossil-fuel-based energy consumed for generating hot water.

[adammunich]

I love hydroelectric power and I want the circuits I design for solar to be capable of utilizing the raw power from a small turbine as well without any hardware modifications.