This is my last full day in Wales. Hopefully, we will have seen a bit of sunshine so far. One of the best things about climbing mountains is the view from the top. Speaking on illumination…
Intuitively, I have long had the sense that solar power makes a great deal of sense as an alternative power source. There are no greenhouse gas emissions, there is no need to operate any massive industrial processes, other than manufacturing panels, and the technology only needs to become incrementally better to be cost-effective against fossil fuels. This map of solar energy, which was used in C.G. Rapley’s presentation, shows the size of solar collectors of the present efficiency that would be needed to satisfy our present electrical needs.
Cost is the first big problem with solar, though it may be a temporary one. According to The Economist:
Decades of research have improved the efficiency of silicon-based solar cells from 6% to an average of 15% today, whereas improvements in manufacturing have reduced the price of modules from about $200 per watt in the 1950s to $2.70 in 2004. Within three to eight years, many in the industry expect the price of solar power to be cost-competitive with electricity from the grid.
Full article (subscription required)
The other big one is load balancing. Because solar output isn’t constant, there is a need to either store power or redistribute it across long distances. Storage across the daily light-dark cycle is of inescapable importance, and the means for doing so are not terribly clear. Batteries are costly and bulky, as well as of a limited lifetime. Solar energy could be used to electrolyze water into hydrogen and oxygen, which could then be fed to fuel cells, but I expect that would increase costs a lot, while reducing efficiency. As with transportation, I think energy storage is a bigger long term problem than energy generation.
Of course, one technology is unlikely to be the solution, in and of itself. There are lots of places where hydro, wind, and geothermal power make sense. There may even be situations where biodiesel is an appropriate choice, despite the inefficiencies of production.