Demand growth in the US is typically projected @ ~1% growth per year in the 'business as usual' scenarios. So all that needs to be done is to get 2% per year energy efficiency & conservation gain over BAU, and it's a net 1% decline/year. So 20% less than today's use by 2030. Maybe a bit less, since the take back principle negates some of it. But less than today's energy use. It won't happen without aggressive policy though. And of course American popular culture isn't helping (a generalization, but one that is too often true).