We have a geothermal heat pump that heats all our hot water and underfloor heating. Solar panels heat the water in the thermal store so the heat pump is not starting from cold.
In the pipeline(!) I have a garden cottage planned and could end up putting pv panels on the roof, but I doubt I will go for the 'free' installations on offer. Nothing is ever free and I would rather find a way of paying for them and then reaping all the rewards myself.
I am also interested in a micro micro hydro scheme in a ditch in the garden. It will only produce electricity when it is flowing strongly in the winter, but I use most electricity in the winter.
I took the opportuntiy when building a new house to do what I could to embrace renewable technology. Even in 2007 we were still a bit ahead of the game, for example there seemd to be no easy way to actually measure the energy produced by our solar thermal roof panels. We hear the pump running and know the water is hot, so that helps. But how much energy do they produce?
Even as far north as Highland Perthshire they have been worth the invetment...we think.