Concentrating solar power (CSP, also known as concentrated solar power) systems generate solar power by using mirrors or lenses to concentrate a large area of sunlight onto a receiver. The energy from the concentrated sunlight heats a high temperature fluid in the receiver. This heat - also known as thermal energy - can be used to spin a turbine or power an engine to generate electricity.
Concentrating technologies exist in four optical types, namely parabolic trough, dish, concentrating linear Fresnel reflector, and solar power tower.
An optical collector for a parabolic trough consists of a linear parabolic reflector that concentrates light onto a receiver positioned along the reflector's focal line. The receiver is a tube positioned at the longitudinal focal line of the parabolic mirror and filled with a working fluid. The reflector follows the sun during the daylight hours by tracking along a single axis. A working fluid (e.g. molten salt) is heated to 150–350 °C as it flows through the receiver and is then used as a heat source for a power generation system.
A dish Stirling or dish engine system consists of a stand-alone parabolic reflector that concentrates light onto a receiver positioned at the reflector's focal point. The reflector tracks the Sun along two axes. The working fluid in the receiver is heated to 250–700 °C and then used by a Stirling engine to generate power.
Fresnel reflectors are made of many thin, flat mirror strips to concentrate sunlight onto tubes through which working fluid is pumped. Flat mirrors allow more reflective surface in the same amount of space than a parabolic reflector, thus capturing more of the available sunlight, and they are much cheaper than parabolic reflectors. Fresnel reflectors can be used in various size CSPs.
Solar power tower
A solar power tower consists of an array of dual-axis tracking reflectors (heliostats) that concentrate sunlight on a central receiver atop a tower; the receiver contains a heat-transfer fluid, which can consist of water-steam or molten salt. Optically a solar power tower is the same as a circular Fresnel reflector. The working fluid in the receiver is heated to 500–1000 °C and then used as a heat source for a power generation or energy storage system.
Global Concentrating Solar Power Market
The global concentrating solar power (CSP) market was worth USD 3.25 billion in 2020. It is further projected to reach USD 8.40 billion by 2027 at a CAGR of 14.6% during 2021-2027 (forecast period).
Countries are looking for ways to reduce carbon emissions while also being able to produce energy in large amounts. It is expected that every country will increase its budget and attempt to shift toward renewable energy sources, thereby propelling the demand for concentrating solar power, globally. CSPs are the best choice for doing this since they generate electricity at high efficiencies while having lower operating costs.