Giant Fresnel lenses power a Stirling heat engine

These huge flat plastic lenses produce a large amount of heat in a small space for just a few hundred dollars, which can run a heat engine, or cook a meal. These Greenpowerscience guys have an awesome series of solar power video clips! I really want to play with some Fresnel lenses, I'll have to make sure I have some safety goggles to protect my eyes from the concentrated glare as well.