It’s the least widespread CSP technology. As in the parabolic trough CSP technology, a long “linear” absorber is used in it. However, instead of a parabolic trough made of a single piece of appropriately profiled reflecting sheet, it uses an array of long flat light-reflecting “stripes”. Each stripe is inclined at a different angle, such that the beam of solar light reflected reflected by it is incident on the absorber.
A photograph of a large solar field in a CSP plant using linear Fresnel mirrors is shown in this Web page.
When the Sun moves across the sky, each reflecting “stripe” should be rotated at a different angle. So, controlling the rotation is more complicated than in the case of a parabolic trough, but perhaps still much simpler than controlling the alignment of many thousands of heliostats in tower-type CSP plants. Anyway, the Fresnel mirror technology is not very popular – in the list of the largest CSP plants one can find only one such 125 MW plant operating in India, and one under construction in South Africa.