I pity Chris and Mark, up on our roof in the rain today. They are fixing the Genersys panels, which should enable us to meet 70% of our hot water needs from sunlight. Even on a day like today, the dial would show some return, we are assured. I asked about maintenance, and there is none - further, the life expectancy is 35 years (which should see us out).
I suppose it's worth it, not just financially, but because it's a small step towards a new, low-carbon future. John Beddington, the chief government scientist, was talking this morning about the impending global food crisis, in the light of the latest Foresight project Global Food and Farming Futures report: half the world is even now being failed by the food system, he said. "We have to think very seriously about taking together climate change, food, water, energy: they are integrally linked."