Concentrated solar power (CSP) systems employ a mirror arrangement to focus solar radiation onto a receiver, converting it into thermal energy. The heat can subsequently be utilized to generate steam that drives a turbine for electrical power generation or employed as industrial process heat for many applications, including increased oil recovery, water desalination, chemical production, food processing and mineral processing. Compact CSP systems can be situated precisely at the point of power demand. Single dish/engine systems can generate 5 kW to 25 kW of power per dish and can provide power in distributed applications.

Integration with current technologies

CSP systems can be integrated with combined cycle power plants, yielding hybrid power plants that deliver high-value, dispatchable energy. They can also be incorporated into existing thermal-fired power plants via a power block similar to CSP, including geothermal, natural gas or biofuel facilities. CSP plants may utilize fossil fuels to augment solar production during intervals of diminished solar radiation. A natural gas-fired heater or gas steam boiler/reheater is utilized in that scenario.

CSP operating principles

CSP technologies can work in four different ways as follows:

1. Parabolic trough systems:

Curved, trough-shaped reflectors concentrate solar energy and direct it onto a receiver pipe in this arrangement. In a steam generator, the thermal power block is responsible for producing electricity by heating the thermal oil, which is typically contained in the pipe.

2. Power tower systems:

Heliostats, which are mirrors, follow the sun's movement and direct its rays toward a receiver atop a tower in such systems. In order to power a turbine generator, steam is produced by heating a fluid — typically molten salts — within the receiver.

3. Linear Fresnel systems:

There are a lot of collectors lined up. Flat on the ground, the mirrors reflect the sun's rays onto the receiver pipe situated above. Fresnel systems, like trough and tower systems, can directly produce steam or incorporate storage into a power block.

4. Parabolic dish systems:

A tracking system follows the sun's movement across the sky, directing the reflected solar energy onto a receiver attached to a parabolic-shaped dish that serves as a concentrator. A heat engine is used to create the collected heat. The system may be suitable for use in solar reactors because of the dish's ability to reach extremely high temperatures.

Most efficient type for large-scale energy generation

There are a number of variables that affect how efficient a CSP system is. The operating efficiency is dependent on the system type, engine and receiver. But most CSP systems only work 7% to 25% of the time. In order to put things in perspective, wind turbines may reach efficiencies of 59% and hydroelectric systems can reach 70%. However, most photovoltaic (PV) panels achieve an efficiency of 14% to 23%, which is comparable to CSPs.

Solar power tower CSP with molten salt storage is the most efficient and scalable for large power plants, as it can reach high temperatures, improving thermal efficiency and enabling longer energy storage. Parabolic trough systems are the most commercially established but operate at lower temperatures and efficiencies. Linear Fresnel reflectors are a cost-effective alternative but have lower performance, while dish Stirling engines, though highly efficient, are limited to small-scale applications.

Benefits of CSP

The fact that CSP is renewable is probably its biggest selling point. Since its supply can be used indefinitely, it is a sustainable energy source. A smaller carbon footprint is another benefit. It is more eco-friendly than burning fossil fuels since it makes use of the Earth's natural resources. In addition to slowing global warming, it can enhance air quality.

In contrast to PV and wind power, which offer intermittent supply, CSP also offers a rather constant source of power. The consistent and trustworthy power output is a result of CSP plants' ability to store solar energy in molten salts.

Existing steam-based power facilities can simply incorporate CSP. One can utilize them for CSP systems even if they run on fossil fuels. Because CSP facilities are easier to operate and maintain, their operational costs are lower than those of nuclear and hydrocarbon-based plants.

By combining it with other energy sources, CSP can make the energy system more reliable. The usage of CSP in the energy mix can contribute to the fulfillment of future electricity demand. Additionally, the steam it generates can be utilized to concentrate heavy oil, making it easier to pump, which aids in oil recovery. Potentially, it might also be utilized as a portable energy source.

Conclusion

CSP is a promising technology for large-scale energy generation, particularly in regions with high direct sunlight. Unlike PV systems, CSP uses mirrors or lenses to focus sunlight onto a receiver, generating heat that can drive a steam turbine to produce thermal power. One major advantage of CSP is its ability to integrate thermal energy storage, typically using molten salts, allowing electricity generation even after sunset.