Perceptions of solar

We're running a few online surveys on the merits of solar PV. Here are the questions:

1. What are your thoughts on solar generated electricity as opposed to wind (on shore / off-shore) and tidal.
2. What sort of payback period would you consider reasonable? Is that period different for home and work?
3. What would you think about a renewable energy installation that sells back to the grid as a part of your pension package?
4. Would you commit to an installation that could be upgraded over the next 30 years if efficiency improved?
5. What do you think about the the appearance of rooftop solar installations?