When most Americans think of sustainable technology, they think of Jimmy Carter's solar panels or the windmills that are beginning to pop up across the country. But so-called "sustainable" or "green" energy has a history that can be traced back to the 19th century. In this episode of The Road to Now, Alexis Madrigal explains sustainable energy's deep roots in American history, and discusses the viability of green energy as an alternative to coal, oil, and solar energy production in the 21st century.