For the last six months, I’ve used a solar powered lighting system for a reading light and mood lighting at home, storing sunlight for later usage. This is all about resilience rather than energy saving as such – with this and a wood-fired stove I won’t immediately want for heat and light in a power cut. In addition, LED lighting gives an even light field which is very good as a reading lamp, even if only about 2W.
This has managed to keep powered purely from the sun even through the shortest day around the Christmas period, where the lighting demand was highest and the solar energy lowest. Constructional details are here for anybody who may be interested.
I have described the principles and options so that this could be adapted to things like allotment sheds and the like. There are some trade-offs to be made in terms of running time and what time of year the main usage would be
The solar panel used is one that Maplin in town occasionally has on offer for about £40, though the article describes some of the trade-offs with sizing the solar cell, some applications could use something smaller.