If you live in the UK, you may have a difficult time with solar; for effective usage, a significant amount of sun is needed or you'll find your battaries are perpetually low. My inlaws are of what we call "Southern Wealth" and own a considerable amount of property in the Carolinas. I'm currently trying to convert one of their plantations/farm houses to be completely off grid. However, because it's down in the hollar of the Blue Ridge Mountains (very similar weather to many parts of the UK), it's not ideal area of solar--so I need to either have a lot of cells or figure something else out. Of course, if you're not going completely off grid and just powering some servers, solar cells may do the trick; if your cells are low, simply switch on to city power. Good luck with that project! I know I would love to see a mod guide on that!