Economics of Solar in the UK
I am in the process of converting a place in the UK into residential and have been looking hard at the costs of going off grid. In this case the cost of connection to the grid is about GBP5,000. With a well insulated place and efficient equipment the worst case power consumption is around 4KWH/day. Solar panels currently cost about GBP450/kw plus cables, inverters, batteries and charge controllers. The economics of solar have changed hugely in the last 5 years and there will be sufficient power to keep all my geek obsessions happy.
My payback period works out as being about 5 years then all I need to do is change the batteries every 7 years or so along with the odd panel and charge controller. I'll probably use LIPO batteries in about 5 years from now once the safety issues have been addressed, even then I'll probably put them in the garden shed!
The real issue is December when solar daily outputs are at a minimum. The rest of the year I'll have more power than I know what to do with, in some months over 20kwh/day excess. I'll probably get PHEV or EV in a couple of years and run it for free from the excess power. Installation isn't such an issue either as in December vertical panels work surprisingly well and are easy to mount on walls etc.
The one thing which isn't practical to go off grid for is water. Utility cost is about GBP 1.50/cubic m and the cost to run a borehole for a single property ends up being higher than that. By the way, don't try to drink captured rainwater off the roof as a filtering issue can make you very ill. The building regs prohibit this for good reason.
So, yes, solar can economically power a place in the UK provided you are in a reasonable location. A microturbine can also be useful if you are limited in space for panels. The turbine won't do much for you most of the year but November-February a 1.8m turbine will provide something over 2kwh a day which makes up for the poor output of solar. You should probably dismount the turbine in summer to extend its lifetime.