A wind turbine spins above corn fields near Carroll, Iowa on Monday, Aug. 26, 2013. | Bill Clark/Getty Images

Powering America on Renewable Energy Alone May Be Harder Than Anticipated

A new analysis critiques a 2015 blueprint for achieving 100 percent renewable energy production in the United States by midcentury.

This map shows wind resources across the contiguous United States at 80 meters above ground level. The team's research says that this resource is variable, so a broad portfolio of other technologies is needed to move to a zero-emissions energy future. | Christopher Clack and Vibrant Clean Energy LLC.