Those sound like very interesting projects. Are they written up anywhere? You want to write an update for me sometime ;)?
The greenness of technologies is always an issue. I've heard that despite the power savings we'll get with CF bulbs, the waste problem is large and with incandescents disappearing in the US soon, that's something to think about. I like LEDs, but the cost has to come down. And I need to see how well they work compared to other technologies.
Renting solar is a good idea. I wish I had more choices there, or even some rebates here to help things along. Alas my co-op is not very interested as of yet in trying to make things work better.
Most tidal power doesn't depend on wind. However I'm still concerned about the durability of the devices.
What do you do when there's no wind (or solar, etc)? That's a good question. If you have everyone in an area using wind and it dies, then the grid takes a hit. However if we still have a national grid, then hopefully some other area has less of a demand because they have wind or solar or geo or something. I still think that if we can reduce our dependence on big power plants, especially fossil fuels, then we're better off. Maybe we have more, smaller generators that kick on to handle the lack of wind. Maybe we use flywheels or compressed air to "store" energy.
Lots of choices, we just need these industries to grow with demand and bring costs down. And probably most importantly to me, we need builders to start building everything with lower energy requirements, more efficiency, or alternative technologies integrated.
Hey, no one likes my "build in fridge" idea?