Ma Yanjun, a Chinese farmer in Shaanxi province, invented a rooftop solar hot water heater by connecting a bunch of beer bottles with some tubing. He says it heats enough water for his whole family to get a daily hot shower. It must work because ten other families in the village have already copied his design.
It’s a great example of small scale sustainable technology. And China needs a lot more of that these days. The country’s energy needs have sky-rocketed as it rapidly industrializes. Almost overnight, the world has gained a billion new consumers. The Worldwatch Institute’s China Watch program has great info about China’s environmental crisis.