Solar and wind energy are now among the cheapest new power sources in many countries, yet they contribute only 4% of global electricity. Scaling them up 25-fold poses a major challenge, but they offer a carbon-free alternative. In this episode, Robert Bryce, best-selling author, and Leia Guccione, Managing Director of Carbon Free Electricity at RMI, discuss the potential for wind and solar to power the world and the obstacles ahead.