It's worth getting a sense of what other fora already cover sustainable living. One use would be to mine them for questions that aren't well-addressed in that format, but would be well-addressed in the StackExchange format.
http://permies.com/ - permaculture, defined very broadly. For example, solar power is on topic there.
- Earth Science SE, e.g. climate change, global warming, environmental protection, pollution
- Gardening SE topics include: composting, organic gardening, permaculture, vermicomposting
- Home Improvement SE sustainable construction materials, insulation, making your home more sustainable / energy efficiency
- Personal Finance & Money SE save money by reducing energy consumption or waste
- Physics SE relevant tags include renewable energy, building physics, climate science, photovoltaics
- Seasoned Advice SE ingredients from sustainable farming, organic food
- Skeptics SE e.g. climate change, climatology, energy-efficiency
- Electronics SE e.g. solar panel installation, solar cell, energy harvesting
- Chemistry SE e.g. green chemistry, environmental chemistry
- Politics SE e.g. sustainable development, ecology, global-warming
which may have interesting questions we could take here, and then point those groups to the answers here
Note that these are discussion forums and we are not. So most of the questions asked there, would not be appropriate questions for here. But some would.
The main competitor sites of Stack Exchange are Quora and Yahoo Answers!. Both have sections about sustainability-related topics:
Quora: (requires registration to read)
- Sustainable Technology
- Energy Efficiency
- Alternative Energy
- Solar Energy
- Waste Materials
- Climate Change