Concentrating solar power thermal system generates electricity and heat for various industries like water desalination, oil recovery, and more. The U.S Department of Energy Solar Technologies Office (SETO) supports CSP research to enhance performance, cut costs and boost reliability. Over the past decade, CSP electricity costs have dropped by over 5%, thanks to better systems and increased use of thermal energy storage, enabling continuous solar power. SETO seeks to additionally decrease CSP expenditures to $0.05 per kilowatt hour for baseload facilities with a minimum of 12 hours of thermal energy storage.
Concentrating solar thermal power setups are typically employed in large-scale projects, known as utility-scale CSP plants, and offer various configurations. Power tower systems position mirrors in a circular arrangement surrounding a central tower, which functions as the receiver.
Concentrating Solar Thermal Power System Configuration
Concentrating solar thermal power (CSP) methods can harness solar energy to produce electricity by converting sunlight into turbine power. These underlying technologies can also be utilized to provide heat for various industrial uses like mineral processing, water desalination, food processing, increased oil recovery, and chemical production.
Also See: What is a Solar Thermal Collector?
Working of CSP
The functionality of concentrating solar thermal power involves mirror configurations to concentrate the sun’s energy onto a receiver, transforming it into heat. This heat is converted into steam to propel a turbine and generate electrical power. The storage capability of CSP makes it adaptable to renewable energy use, storing power for periods with limited sunlight.
CSP systems can be combined with other energy sources, forming hybrid plants. They can combine with thermal-fired power plants using fuels like coal, natural gas, or biofuels.
There are four CSP technologies:
- Parabolic Dish Systems: Parabolic dishes concentrate sunlight onto a receiver with a tracking system, generating high temperatures suitable for solar reactors.
- Parabolic Trough Systems: Curved reflectors concentrate solar energy onto a receiver pipe containing thermal oil, heating it for electricity generation.
- Power Tower Systems: Mirrors or heliostats, track and focus sunlight onto a receiver atop a tower, heating fluid which is often molten salts, to generate steam for a turbine
- Linear Fresnel Systems: Rows of flat mirrors on the ground reflect sunlight to a receiver pipe, similar to trough and tower systems, with potential for storage integration.
PV Vs CSP
The primary distinction between solar PV and CSP lies in their methods of generating electric power.
Concentrating solar thermal power system employs various mirror configurations to harness the sun’s energy, driving a heat engine to produce electric power. In contrast, photovoltaic solar panels utilize the sun’s light directly, converting it into electricity.
Unlike CSP, PV cells absorb light, stimulating electrons to generate a current. This direct current (DC) is then captured and converted into an alternating current (AC) using inverters for distribution on the power network.
CSP systems excel in energy storage through Thermal Energy Storage technologies (TES), allowing power usage in the absence of sunlight. On the other hand, PV systems cannot store thermal energy since they rely on direct sunlight rather than heat. Consequently, CSP systems are more effective for energy storage and overall efficiency.
Also Read: What is Concentrated Photovoltaics?
Pros and Cons of CSP
The benefits of CSP are:
- It’s a renewable, sustainable energy source that curbs its carbon footprint. Unlike fossil fuels, CSP taps into the earth’s natural resources, benefitting the environment and addressing climate change.
- CSP ensures a more consistent power supply compared to solar PV and wind thanks to energy storage in molten salts, ensuring reliability.
- Easy integration into existing power plants, even those using fossil fuels, results in lower operation costs than nuclear and hydrocarbon-based alternatives.
- CSP, combined with other energy sources, enhances grid security and meets future electricity needs. Additionally, it aids oil recovery by producing steam to concentrate heavy oil for easier pumping.
- There’s potential for CSP to serve as a portable energy form, as seen in studies exploring its use in generating cost-effective hydrogen for transportation.
While Concentrating solar thermal power offers various advantages it faces challenges.
- Location dependence, requiring large land areas like solar PV and wind, limits its feasibility in populated regions.
- Water-intensive operations for driving turbines and cooling reactors raise environmental concerns, with seawater posing potential solar radiation issues.
- CSP plants may attract animals due to light, posing risks to some species.
- The technology is costly to run, with thermal storage materials being expensive and challenging to obtain Molten salt, a common choice, has operational limitations
- Competition from solar PV and nuclear power hinders CSP development, posing a risk of obsolescence amid breakthroughs in other energy sources.
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