Despite the fact that it has been around for more than half a century, there is still something about solar energy that seems space-age and futuristic. The idea that we can generate electricity from ‘nothing’ seems like something from a science fiction novel. Of course, as we shall see the idea of free energy is still a very long way off, but the sheer elegance of using sunlight to power our lives has a certain utopian appeal. Perhaps this is one of the reasons it has taken so long for it to be regarded seriously by the general population – it simply seems too good to be true. There are other reasons also. Despite rapidly falling costs, the technology is still relatively expensive. While the solar fuel may be free, the equipment to harness it and the grid lines to carry it are most certainly not. Nonetheless, when I finally got my own solar panels installed at the beginning of 2010, it felt like a revolution (Figure 1.1). It wasn’t cheap, and even with the UK’s new feed-in tariff it will take ten years to pay itself back, but as I sit here in my flat in London’s Camden Town, with my laptop being powered by the late spring sunshine, the concept makes a great deal of sense.