Science .

Take an eye-opening look at some of the world’s most important case studies in energy policy. In Spain and Morocco, large-scale solar farms and individual photovoltaic panels atop tents in the Sahara are beginning to bring the vast potential of the sun down to Earth. In Brazil, abundant natural resources — sun, rain and sugar cane — are transformed into efficient, sustainable biofuel, making Brazil the only nation whose cars could run normally if gasoline were to vanish. In Samsø, Denmark, and in West Texas, citizens have taken sustainability — and economic realities — into their own hands by becoming stakeholders in wind turbines. In China, a full-throttle approach to multiple sustainable energy technologies is giving rise to a “new empire of clean tech.” What about America? One energy insider predicts an “energy abyss” if smart decisions aren’t made. Learn how great nations and small communities are finding sustainable solutions that provide for people and protect the planet.

Watch Earth: The Operator’s Manual Monday, April 23, 2012 at 9pm.

Watch Powering the Planet Preview on PBS. See more from EARTH: The Operators Manual.