Old ideas die hard.

The country has been debating renewable energy for decades—how much we should support it, what place it should have in our energy policy, how big an impact it actually has.

Yet many of the things we think we know about renewable energy go back to the earliest arguments. Many of the debating points we hear today are based on outdated facts and assumptions that don't hold up anymore.

So, we set out to look at a few persistent myths or beliefs held by both supporters and critics of renewable energy. We've focused largely on wind and solar power, in part because they've shown explosive growth in recent years but also because they are at the center of political debates over energy.

MYTH NO. 1: Renewables Are an Insignificant Source of Power

One of the most persistent criticisms of renewables is that they account for a fraction of the U.S. electricity system—despite years of federal subsidies and breakneck growth.