# Concentrated solar power: Techniques

Troughs, towers, Fresnel rows and Stirling dishes compared

Source page: https://www.materialinsights.org/energy/e_csp/techniques/

What this tab covers The methods used to capture this energy: how each works, and how they compare on efficiency, cost, life-cycle emissions, maturity and scale.

Troughs built the first wave of plants; towers with molten-salt storage dominate new construction, mostly in China. CSP costs about two and a half times as much as PV per MWh but can deliver power after sunset.

#### Comparison

| Method | Efficiency | Cost | Life-cycle emissions | Maturity | Scale |
|---|---|---|---|---|---|
| **Parabolic troughs**^[1](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2013/IRENA-ETSAP-Tech-Brief-E10-Concentrating-Solar-Power.pdf)^[2](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2026/Jul/IRENA_TEC_RPGC_in_2025_2026.pdf)^[3](https://ideas.repec.org/a/bla/inecol/v16y2012is1ps93-s109.html)^[4](https://www.ren21.net/gsr/2025/csp) | 14-16% annual; capacity factor up to about 40% with 7.5 hours of storage | All-CSP average USD 115/MWh and USD 2,418/kW (2025) | Published median 26 g CO2e/kWh | mature | Part of 7.2 GW of CSP worldwide (end-2024) |
| **Power towers with heliostats**^[1](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2013/IRENA-ETSAP-Tech-Brief-E10-Concentrating-Solar-Power.pdf)^[4](https://www.ren21.net/gsr/2025/csp)^[3](https://ideas.repec.org/a/bla/inecol/v16y2012is1ps93-s109.html) | About 16% annual; capacity factor 68-79% with 12-15 hours of storage | Recent Chinese towers CNY 16,000-16,200/kW (about USD 2,222-2,251/kW); Redstone, South Africa, about USD 7,360/kW | Published median 38 g CO2e/kWh | mature | Most of about 3.3 GW under construction in China; the 386 MW Ivanpah plant (no storage) is slated to close in 2026 |
| **Linear Fresnel reflectors**^[1](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2013/IRENA-ETSAP-Tech-Brief-E10-Concentrating-Solar-Power.pdf)^[4](https://www.ren21.net/gsr/2025/csp) | 11-13% annual | No separate figure in the sources used | No harmonised figure | early commercial | Largest is 100 MW at Yumen, Gansu (operating since 2024) |
| **Stirling dishes**^[1](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2013/IRENA-ETSAP-Tech-Brief-E10-Concentrating-Solar-Power.pdf) | 25-30% | No commercial price | No harmonised figure | pilot | No significant fleet |
| **Solar updraft towers (experimental)**^[9](https://www.sbp.de/en/project/solar-chimney-pilot-plant-manzanares) | Very low; no figure in the sources used | No commercial cost | No figure | research | A 50 kW prototype at Manzanares, Spain, ran for seven years |

CSP's 2025 LCOE of USD 115/MWh is about 2.6 times PV's USD 44/MWh, and its cost per kW about 3.6 times higher (both calculated), because mirrors, towers and turbines are heavy engineering in a small market. Buyers pay for storage: a tower with 10-15 hours of salt serves the evening peak. Life-cycle emissions (26-38 g CO2e/kWh) are similar to or below silicon PV.

#### How each method works
**Parabolic troughs**

Curved mirrors track the sun on one axis and focus it on an oil-filled tube heated to about 390 C, which raises steam for a turbine; some heat can be stored in molten salt.^[1](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2013/IRENA-ETSAP-Tech-Brief-E10-Concentrating-Solar-Power.pdf)^[2](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2026/Jul/IRENA_TEC_RPGC_in_2025_2026.pdf)^[3](https://ideas.repec.org/a/bla/inecol/v16y2012is1ps93-s109.html)^[4](https://www.ren21.net/gsr/2025/csp)
**Power towers with heliostats**

Thousands of two-axis mirrors reflect sunlight onto a receiver atop a tower; molten salt at about 565 C is stored in a hot tank and drawn off to raise steam when needed.^[1](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2013/IRENA-ETSAP-Tech-Brief-E10-Concentrating-Solar-Power.pdf)^[4](https://www.ren21.net/gsr/2025/csp)^[3](https://ideas.repec.org/a/bla/inecol/v16y2012is1ps93-s109.html)
**Linear Fresnel reflectors**

Rows of nearly flat mirrors focus sunlight on a fixed pipe above them, boiling water directly into steam.^[1](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2013/IRENA-ETSAP-Tech-Brief-E10-Concentrating-Solar-Power.pdf)^[4](https://www.ren21.net/gsr/2025/csp)
**Stirling dishes**

A dish mirror focuses sunlight on a Stirling engine at its focal point, which drives a generator directly.^[1](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2013/IRENA-ETSAP-Tech-Brief-E10-Concentrating-Solar-Power.pdf)
**Solar updraft towers (experimental)**

A large glass roof warms air, which rises up a tall chimney through wind turbines; no concentration, so diffuse light also counts.^[9](https://www.sbp.de/en/project/solar-chimney-pilot-plant-manzanares)

#### Sources

1. [Concentrating Solar Power: Technology Brief E10](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2013/IRENA-ETSAP-Tech-Brief-E10-Concentrating-Solar-Power.pdf) IRENA and IEA-ETSAP, 2013
2. [Renewable Power Generation Costs in 2025 (Executive summary, Figure S1)](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2026/Jul/IRENA_TEC_RPGC_in_2025_2026.pdf) IRENA, 2026
3. [Life Cycle Greenhouse Gas Emissions of Trough and Tower Concentrating Solar Power Electricity Generation: Systematic Review and Harmonization (Burkhardt et al., Journal of Industrial Ecology 16 S1, S93-S109)](https://ideas.repec.org/a/bla/inecol/v16y2012is1ps93-s109.html) NREL LCA Harmonization Project / RePEc, 2012
4. [Renewables 2025 Global Status Report: Concentrating solar thermal power](https://www.ren21.net/gsr/2025/csp) REN21, 2025
5. [Solar chimney pilot plant Manzanares](https://www.sbp.de/en/project/solar-chimney-pilot-plant-manzanares) schlaich bergermann partner (designers of the prototype), 2024

## Other sections

- [Summary](https://www.materialinsights.org/energy/e_csp/index.md)
- [Overview](https://www.materialinsights.org/energy/e_csp/overview/index.md)
- [Correlation](https://www.materialinsights.org/energy/e_csp/correlation/index.md)
- [Efficiency](https://www.materialinsights.org/energy/e_csp/efficiency/index.md)
- [Resources and labour](https://www.materialinsights.org/energy/e_csp/resources/index.md)
- [Impact on the biosphere](https://www.materialinsights.org/energy/e_csp/biosphere/index.md)
- [Relationships](https://www.materialinsights.org/energy/e_csp/links/index.md)