Renewables could supply 80 percent of electricity demand in 2050 by using technologies commercially available today - in combination with a more flexible electric system, says a new report published by the National Renewable Energy Laboratory (NREL).

At such high levels of renewable electricity generation, the unique characteristics of some renewable resources, specifically geographical distribution and variability and uncertainty in output, pose challenges to the operability of the nation's electric system.

Increased electric system flexibility, needed to enable electricity supply-demand balance with high levels of renewable generation, can come from a portfolio of supply- and demand-side options, including flexible conventional generation, grid storage, new transmission, more responsive loads, and changes in power system operations, the RE Futures report says.

The abundance and diversity of U.S. renewable energy resources can support multiple combinations of renewable technologies that result in deep reductions in electric sector greenhouse gas emissions and water use.

The direct incremental cost associated with high renewable generation is comparable to published cost estimates of other clean energy scenarios. Improvement in the cost and performance of renewable technologies is the most impactful lever for reducing this incremental cost.

Playing more significant role than thought

The report is an initial investigation of the extent to which renewable energy supply can meet the electricity demands of the continental United States over the next several decades.

The study explores electricity grid integration using models with unprecedented geographic and time resolution for the contiguous United States to assess whether the U.S. power system can supply electricity to meet customer demand on an hourly basis with high levels of renewable electricity, including variable wind and solar generation.

As the most comprehensive analysis of high-penetration renewable electricity of the continental United States to date, the study can inform broader discussion of the evolution of the electric system and electricity markets towards clean systems.

RE Futures, funded by the U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy, is a collaboration with more than 110 contributors from 35 organizations including national laboratories, industry, universities, and non-governmental organizations.

Its results indicate that renewable generation could play a more significant role in the U.S. electricity system than previously thought and that further work is warranted to investigate this clean generation pathway.