Concentrate the Light
More than 90% of all electricity comes from heat. Unlike solar panels, in concentrated solar power (CSP) the sun is simply used as a heat source to drive a heat engine, just like a traditional power plant. In the first step, sunlight is reflected from mirrors (not solar panels) to the top of a tower. This increases the concentration of the light rays, similar to using a magnifying glass in the sun, and enables operation at high temperatures.
Store the Heat
The primary advantage of CSP over solar panels is the fact that the sun’s energy can be stored more inexpensively as heat than as electricity in batteries. In step 2 the now concentrated light rays are absorbed onto what is termed the “receiver”. A fluid is pumped through the receiver to absorb the heat from the sun, which can then be stored efficiently in large tanks.
Discharge the Heat
The thermal storage tanks act as a thermal battery. In a CSP plant, the thermal battery charges during the day when the sun is out, as cold fluid is heated by the sun and stored in the hot tank. Whenever electricity is needed, during the day or at night, the fluid from the hot tank is pumped through a heat exchanger, which transfers the energy from the storage fluid to water producing high temperature and high pressure steam.
Convert to Electricity
The now high temperature and high pressure steam then enters a conventional turbine where its thermal energy is converted to mechanical motion/torque as it expands and pushes through the turbine blades. The rotating turbine shaft then drives an electrical generator, which then supplies electricity to the utility grid.