While U.S. demand for electricity has risen in all but four years since 1949, the rate of increase has been steadily going down. The Energy Information Administration predicts an annual growth rate around +1% to 2030 (which RMI extrapolates to 2050).
Rocky Mountain Institute’s four scenarios for the future U.S. electricity system ( detailed here ) all deliver the same energy services but with varied end-use efficiencies. In the fourth scenario (Transform), projected efficiency gains cut nationwide demand by 1% each year, even with the added demand from 150 million electric vehicles.
U.S. Energy Information Administration. 2010a. Annual Energy Outlook 2010: WIth Projections to 2035. Washington, D.C.: U.S. Department of Energy, April. link
U.S. Energy Information Administration. 2010b. Electric Power Annual 2009. Washington, D.C.: U.S. Department of Energy, November 23. link