World energy demand is projected to rise more than 25 percent over fifteen years and could nearly double by 2050, and this film asks how that power gets generated and at what cost to the climate. Geologist Richard Alley argues the physical answers already exist in sunlight, wind, and heat, pointing to the sheer scale of the resource: sunlight striking the Earth's crust delivers roughly 120,000 terawatts, far beyond anything humanity currently burns. The film traces solar power back to Frank Shuman, who around 1910 built a system of mirrors focusing sunlight onto metal tubes to heat liquid, drive a steam turbine, and pump irrigation water with a 75-horsepower engine. It also looks at wind projects already running whole communities and at conservation measures that researchers say could cut projected 2030 energy demand by 30 percent. Alley and other scientists frame the real obstacle as political, economic, and cultural rather than technical, since nineteenth-century fuel sources still dominate the world's largest economies. The second installment in a mini-series on energy and climate.