It looks like a giant funhouse mirror. But the big new dish atop South Table Mountain could be a renewable energy breakthrough that helps make concentrated solar power more affordable and appealing to utilities and their customers. For the next several months, NREL engineers will be testing the performance of SkyTrough, an innovative parabolic trough that is coated with a gleaming reflective skin instead of mirrored glass. Parabolic-trough systems concentrate the sun's energy through long U-shaped mirrors. The mirrors are tilted toward the sun, focusing sunlight on a vacuum pipe that runs down the center of the trough.