Dramatically increased energy efficiency could flatten or even modestly decrease total electricity use. In both buildings and industry, smarter technologies and designs can cost-effectively deliver the same or better services with 70% less electricity per dollar of GDP than in 2010 (or 65% with electrified automobiles).
Next, most of America’s aging power plants can continue to be replaced by renewable energy sources, which since 2007 have captured half the world market for new generating capacity and now make up one-fourth its total and 18% of all power generation. Today’s commercially and practically viable renewable resources have the potential to generate over 20 times America’s total 2010 electricity use.
U.S. installed wind and solar power capacities and projections, 1990–2050
Together, wind and solar will account for 71% of total U.S. installed capacity in 2050 in Rocky Mountain Institute’s Transform case, up from 4.4% in 2010. Along with hydro, geothermal, and biomass, renewables will meet more than 80% of 2050 U.S. electricity demand.
2050 generation by case
Each of Rocky Mountain Institute’s four scenarios for the future U.S. electricity system (detailed here) will have a very different electricity generation mix.
Historic and projected U.S. electricity demand, 1950-2050
While U.S. demand for electricity has risen in all but four years since 1949, the rate of increase has been steadily trending down. The Energy Information Administration predicts an annual growth rate around +1% to 2030 (which RMI extrapolates to 2050). Successfully implementing the energy efficiency improvements in buildings and industry discussed in Reinventing Fire
could reduce this to a steady –1%.
2050 installed capacity by case
The required generating capacity and its breakdown are very different in each of Rocky Mountain Institute’s four scenarios for the future U.S. electricity system (detailed here
Hourly operability in a high-penetration renewables scenario
Production from wind and solar resources, in particular, is both variable and uncertain. However, with good resource and demand forecasting and high availability of flexible demand and supply side resources, it is possible to operate an electricity system reliably with a high percentage of variable renewable energy.
Variable renewable output (hourly)
The dynamic nature of variable renewable resources presents challenges to conventional electricity system operations. Production from wind and solar resources, in particular, is both variable (fluctuating throughout the day according to availability of the “fuel”) and uncertain (weather forecasting is required and by definition is not always accurate).
Hourly operability on a microgrid
The dynamic nature of variable resources presents challenges to conventional electricity systems operations, especially on a small grid. But if a microgrid has sufficient dispatchable supply- and demand-side resources and storage capacity, these can enable the integration of a large percentage of local variable renewable energy. Grid power can play a supporting role in balancing the microgrid, complementing the onsite resources, and allowing demand to be met throughout the year.
U.S. renewable energy potential
Considering budding technologies that could be commercially available in the future, the potential U.S. generation capacity from renewables is overwhelming. Wave and tidal generators, offshore deep-water wind farms, and enhanced geothermal power (which uses the Earth's heat but doesn’t require a natural steam source) are all in development and represent a huge potential energy resource.