We've talked a lot about how different kinds of power generation create different amounts of carbon. We've also discussed how one of the major problems of climate change will be water shortages. Those two debates are more connected than I thought - most types of power plants (including thermal solar) use water as a coolant. There are different ways to do this of course, with different considerations. Some methods put warm water back into rivers and lakes, which can kill wildlife, and other types let it evaporate, which doesn't kill the wildlife but wastes the water. It's a really interesting debate - and yet another wrinkle to an already complex issue of trying to generate power. At the same time, however, California has successfully put regulations in place that are encouraging new power plants to put in less water-consuming cooling systems. It remains to be seen how this issue will finally play out, but I'm looking forward to seeing where people go from here.