Concentrating solar power uses mirrors to concentrate and reflect solar rays to produce heat that is then used to make electricity usually through steam driven turbines. It is still considerably more expensive than fossil fuels. The advantage of concentrating solar power is that the heat can be stored, usually in tanks with molten salt. It is then is available for use during nighttime hours.
From "Solar Power and the Electric Grid," National Renewable Energy Laboratory
See the three minute YouTube from the U.S. Department of Energy that explains concentrating solar power.
Concentrating Solar Power has the disadvantage of using large amounts of water, often not available in sunny desert locations and not good for the environment. The water use chart from Energy Self Reliant States compares forms of solar energy to nuclear and fossil fuels.