"Not wasting energy. It is the least sexy, but the single most important and always the least expensive. You would be very interested in a report by the McKinsey consulting firm that concluded that 40 percent of everything that we have to do to mitigate our emissions are net economic winners. They are cost effective and the most cost effective is not wasting energy. That's actually going to be the largest part of this whole journey, I believe - using less energy with the same beneficial results."