In the Spanish countryside, a strange sight rises from the landscape: a massive concrete tower surrounded by glowing beams of light. That tower may hold the key to a clean-energy future. The 40-story concrete tower is surrounded by four massive arrays of 600 mirrors each, all designed to track the sun on its path across the sky and beam the light back at the tower. Right now only one of the arrays is completed and functional, but construction is continuing on the other three. The Solar Tower, designed and built by Spanish energy company Solucar, generates 11 megawatts of energy--enough to power over 6,000 homes--without emitting any greenhouse gases or pollutants.

The station glows, even at night, as the concrete tower absorbs and radiates light and heat directed by the mirrors. The mirrors are focused in one location in order to turn water into steam, which then turns a set of turbines that generates the power. Currently, the Solar Tower collects enough energy to continue producing steam even after the sun goes down, albeit only for an hour. Engineers at Solucar hope to increase that time by getting the other arrays working and optimizing the efficiency of the generator.

Once the Spanish station is fully operational, they hope to deploy additional solar power stations in other parts of the world that get a lot of sunlight, like the Sahara desert. Power stations can cable power to markets in Europe, or possibly arctic and Antarctic regions where entire halves of the year are bathed in sunlight. [ via BBC News ]