The world's largest solar power tower recently began operating outside Seville, Spain, and it marks a historic moment in the saga of renewable energy. The solar tower PS20, next to its smaller sister PS10, produced even more power than expected over the course of its trial testing. It's been confirmed that the groundbreaking solar tower generates 20 megawatts of electricity: and it's now powering 10,000 homes with renewable energy. Here's how it works: PS20 consists of a solar field made up of 1255 mirrored heliostats, each with an area of 1291 square feet. They reflect the solar radiation they receive onto the top of a 531 feet-high tower, producing steam which is converted to electricity generation by a turbine. The image was acquired August 29, 2009, covers an area of 15 x 18 km, and is located at 37.5 degrees north latitude, 6.2 degrees west longitude.