Produced by John Daley

Colorado and other western states require that more and more electricity be generated from renewable sources. And they’ve set deadlines for reaching a certain percentage. Here’s, for instance, the big utilities must reach 30 percent by 2020. In Arizona, it’s 15 percent by 2025. In the scheme of things, that’s not too far away. And, increasingly, energy officials are asking “what comes next?” and “what are the obstacles to developing wind and solar even further?” That’s what we’re going to talk about with the author of a new report from the National Renewable Energy Lab in Golden. David Hurlbut is an economist there.