The receiver, heat engine, and generator are integrated into one assembly that is mounted at the focus of the mirrored dish. An alternative approach, called the open Brayton cycle, passes air through a porous medium in the receiver, causing the air to heat and expand rapidly. The hot air is then fed into a separate gas turbine that drives a generator to produce electricity. Issues Mirror Technologies Concentrators use reflective surfaces of aluminum or silver on the front or back surface of thin glass or plastic. Researchers are developing new reflective materials, such as advanced polymer films , that are less expensive to produce than glass.
Stretched membranes are thin reflective membranes stretched across a rim or hoop.
Another membrane stretched on the back creates a partial vacuum. This forces the membranes into a spherical shape, which is the ideal concentrator shape. Hybrid Systems Researchers are working with utilities on experimental hybrid power towers that run on solar energy and natural gas. The advantage of hybrid systems is that they could run continuously. Concentrating solar power is the least expensive solar electricity for large-scale power generation, and has the potential to make solar power available at a very competitive rate.