As I see it, the downside in moving to renewable energy (as we inevitably must and will do) is less to the environment and more to people's expectations. Our expectations about technology and the kind of society we can have were formed in a historically brief period of energy abundance, in the form of hundreds of millions of years of stored sunlight that comes down to us as an enormous, but finite, pool of highly energy-dense fossil fuel. In effect, we've been living off (in fact, spending profligately) our inheritance. When we switch to renewable sources, we will have to go back to living on an energy *income* instead. Cornucopians, or anyone who expects technology to make up the difference, are not reckoning with the fact that most of the benefits of technology are actually the benefits of energy. Technology is simply how we put the energy to use to achieve results that we like. There will be no technological singularity in a low-energy environment. A more realistic view of our future comes from the permaculture movement, who are a lot closer to dealing with reality in this respect. Get ready for less energy, lowered expectations, economic contraction, and a return to self-reliance for most.