Concentrated Solar Power: The renewable energy technology that works after dark

Updated: Sep 23, 2025
7 min

Sergey FedorovAuthor

Welcome to concentrated solar power (CSP), the renewable energy technology that's rewriting the rules of solar generation. Unlike rooftop solar panels, CSP plants use massive mirror arrays to create temperatures hot enough to melt copper – and store that heat for later use.

Key takeaways

Concentrated solar power uses mirrors to focus sunlight, creating temperatures up to 1,000°C to generate steam and electricity
CSP plants can store thermal energy in molten salt, enabling electricity generation for 6-15 hours after sunset
Four main CSP technologies exist: power towers, parabolic troughs, linear Fresnel, and dish/engine systems
While CSP costs more upfront than photovoltaic solar, it provides dispatchable renewable electricity that works like traditional power plants

What is concentrated solar power?

Concentrated solar power represents a fundamentally different approach to harnessing solar energy. While photovoltaic panels convert sunlight directly into electricity, CSP systems use mirrors to concentrate sunlight onto a receiver, creating intense heat that drives conventional steam turbines.

These systems focus enough solar energy to heat fluids to extreme temperatures. This concentrated solar thermal energy then generates steam to spin turbines – the same process used in coal or nuclear plants, but powered entirely by sunlight.

The game-changing advantage? CSP plants can store this thermal energy in molten salt systems, allowing them to generate electricity long after the sun sets. This makes concentrated solar power the only renewable energy technology that can provide dispatchable baseload power without fossil fuel backup.

How concentrated solar power works

The magic of CSP lies in its ability to concentrate sunlight to create extreme temperatures. Here's the step-by-step process:

Solar collection Thousands of mirrors track the sun throughout the day, reflecting and focusing sunlight onto a central receiver or linear tube system.
Heat transfer The concentrated sunlight heats a fluid (usually molten salt or thermal oil) to temperatures between 300°C and 1,000°C, depending on the system type.
Steam generation This superheated fluid flows through a heat exchanger, creating steam that drives conventional turbines to generate electricity.
Thermal storage Excess heat gets stored in insulated tanks filled with molten salt, which can maintain temperatures for hours or even days.
After-dark generation When the sun goes down, stored thermal energy continues generating steam and electricity, making CSP plants dispatchable like traditional power plants.

Types of concentrated solar power systems

The CSP industry has developed four distinct technologies, each with unique advantages for different applications and locations.

Power tower systems

Power tower CSP represents the newest and fastest-growing technology in the concentrated solar field. These systems surround a central receiver tower with hundreds or thousands of computer-controlled mirrors called heliostats.

The heliostats track the sun and reflect concentrated sunlight onto a receiver at the tower's top, creating a brilliant focal point visible from miles away. Modern power towers can achieve temperatures up to 1,000°C, enabling higher efficiency electricity generation than other CSP technologies.

Parabolic trough systems

Parabolic trough technology dominated early CSP deployment and still represents the majority of global concentrated solar capacity. These systems use curved, mirror-lined troughs to focus sunlight onto receiver tubes running along the trough's focal line.

The receiver tubes contain heat transfer fluid that reaches temperatures around 400°C. While lower than power tower temperatures, trough systems offer proven reliability and lower technical risk for large-scale projects.

Linear Fresnel systems

Linear Fresnel represents a cost-optimized approach to concentrated solar power. Instead of expensive curved mirrors, Fresnel systems use flat mirrors arranged in rows to focus sunlight onto elevated receiver tubes.

This design reduces manufacturing costs and simplifies maintenance compared to parabolic troughs. However, Fresnel systems typically achieve lower concentration ratios and temperatures, resulting in reduced efficiency.

Dish/engine systems

Dish/engine systems represent the smallest scale CSP technology, using parabolic dish concentrators to focus sunlight onto Stirling engines mounted at the focal point. These systems can produce 5-25 kilowatts per dish, making them suitable for distributed applications.

Despite their smaller scale, dish-Stirling systems hold the record for highest thermal-to-electric conversion efficiency, with a 25-kW system achieving 31.25% peak solar-to-grid conversion efficiency—significantly higher than other CSP technologies.

Global CSP Market

As of 2023, global concentrated solar power capacity reached 8.1 GW, with NREL counting 6.6 GW of operational capacity and another 1.5 GW under construction. Parabolic trough technology still represents the majority of global concentrated solar capacity. By comparison, solar power reached 1 TW of global capacity in 2022, of which the overwhelming majority was photovoltaic.

CSP Technology Performance Comparison

Conversion Efficiency:

Dish-Stirling systems: Highest efficiency among CSP technologies
Power towers: High efficiency enabled by extreme operating temperatures

Operational Performance:

Parabolic troughs: 28-29% capacity factors without storage, 29-33% with storage
Linear Fresnel: Lower performance but reduced manufacturing costs

Pros & cons of concentrated solar power

Dispatchable renewable electricity: Unlike photovoltaic solar or wind power, CSP plants with thermal energy storage can generate electricity on demand, providing grid operators with flexible, controllable renewable capacity.
High-temperature industrial applications: CSP systems can supply process heat for industrial applications, including water desalination, enhanced oil recovery, food processing, and chemical production.
Grid stability services: CSP plants can provide ancillary services like frequency regulation and spinning reserves, helping maintain electrical grid stability as more intermittent renewables come online.

High capital costs: CSP plants reached a record low installation cost of $6,589 per kilowatt in 2023, with NREL projecting costs could drop to approximately $5,180/kWe by 2030 and $4,455/kWe by 2050 – still significantly more expensive than photovoltaic solar installations.
Geographic limitations: CSP requires high direct normal irradiance found primarily in desert regions. Cloudy or humid climates dramatically reduce system effectiveness.
Water requirements: Most CSP plants require substantial water for cooling, creating challenges in arid regions where the technology works best.
Competition from cheaper alternatives: Rapidly declining costs for photovoltaic solar plus battery storage systems increasingly challenge CSP economics.

Need a solar system installed?

Fill out form and compare offers from solar professionals

Get quotes

CSP vs photovoltaic solar: Which is better?

The choice between concentrated solar power and traditional photovoltaic systems depends on specific application requirements and local conditions.

Best use cases for CSP	Best use cases for photovoltaic
Utility-scale projects in high-DNI regions Applications requiring dispatchable renewable power Industrial facilities needing high-temperature process heat	Distributed residential and commercial installations Lower-cost utility projects with separate storage Regions with moderate solar resources

The future likely holds room for both technologies, with CSP filling specialized niches requiring thermal storage and high-temperature applications, while photovoltaic solar continues dominating cost-sensitive utility and distributed markets.

Concentrated solar power may not revolutionize residential energy like rooftop solar panels, but its unique ability to store solar energy thermally ensures this technology will play an important role in our clean energy future.

Sergey Fedorov

Co-founder & CTO

Sergey has been running A1 SolarStore since 2017 with the main idea in mind – making going solar easier for everyone. Based on a thorough market research and his personal experience, he shares his ideas on both solar industry and management related topics