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Concentrated Solar Thermal with molten-salt storage

High-temperature solar heat captured by a heliostat field, stored in molten salt, and released on demand as firm power or process heat, day and night.

How it works
Concept render · illustrative

How it works

From sunlight to dispatchable power

Sunlight is concentrated, stored as heat in molten salt, and released on demand, so the plant keeps delivering firm power and process heat long after the sun goes down.

Sunlight Heliostat field Receiver · 565 °C Hot salt · 565 °C 8–14 h storage Dispatching from storage Steam generator Steam turbine Synchronous inertia Firm power · 24 h day & night Process heat · ≤565 °C Cold salt · ~290 °C

Daytime: the field charges storage while the turbine dispatches.

Concentrated sunlight → hot salt charge → cold salt return. 8–14 h storage, dispatch day or night.

  1. Heliostat field

    Thousands of individually tracked mirrors concentrate sunlight onto a central receiver at the top of a tower, raising the working fluid to temperatures approaching 565°C.

  2. Molten-salt storage

    Hot molten salt flows from the receiver into insulated tanks. Storage duration scales by adding more salt and steel: the cheapest part of the plant. 8–14 hours is standard.

  3. Steam turbine dispatch

    When power or heat is needed, day or night, hot salt generates steam to drive a turbine. The synchronous generator provides grid inertia at no extra cost.

Configurations

Tower and trough: two proven forms of CST

Concentrated solar thermal comes in two mature configurations. We are neutral between them: the host's duty profile decides the mix.

Concept render of a central-receiver tower above rings of heliostat mirrors Concept render · illustrative

Point focus

Molten-salt tower

Thousands of tracked heliostats concentrate sunlight onto a central receiver, heating molten salt to 565°C. The highest operating temperatures and the cheapest deep storage: the configuration for firm power, synchronous grid strength and high-temperature process heat.

Concept render, close view of curved parabolic trough mirrors focusing sunlight onto a receiver tube Concept render · illustrative

Line focus

Parabolic trough

Rows of curved mirrors track the sun and focus it onto receiver tubes running the length of each row. The most widely deployed form of CSP worldwide, with decades of commercial operating history: well suited to process steam and heat duties, and to running alongside a tower in a hybrid solar park.

The duration wall

Why CST, not batteries

A battery's cost rises almost in a straight line with the hours it must run. Molten-salt storage adds hours simply by adding salt to a larger tank: the cheapest part of the plant. Batteries win the sprint of one to four hours; thermal storage wins the marathon of eight to fourteen hours and beyond.

Output · illustrative 6 am noon 6 pm midnight 6 am Solar PV PV collapses at sunset Molten-salt dispatch · 8–14 h Battery · 1–4 h Firming gap · unserved 24/7 industrial load 8 pm · the duration wall

With 8–14 hours of thermal storage, the evening and overnight load stays served through to sunrise.

Illustrative dispatch shapes only; no load or output values are implied. Screening-grade and indicative.

  • Advantage

    8–14 h storage

    Thermal storage scales cheaply with duration: salt and steel, not chemistry. A mining load runs all night, and that overnight block is where this technology delivers.

  • Advantage

    Synchronous inertia

    The steam turbine delivers grid strength that PV and batteries cannot: frequency response and fault current included at no extra cost.

  • Advantage

    Process heat

    Stored solar heat can be delivered directly as high-temperature process steam: cheaper than electrify-then-reheat for many mineral processing applications.

  • Advantage

    Diesel displacement

    Lowest total cost as storage duration and heat demand grow, plus synchronous grid strength and diesel and gas displacement at remote sites.

Concept render, wide panorama of a hybrid solar park at night: the tower receiver still lit while trough rows and PV sit dark under the stars Concept render · illustrative
After sunset: the park keeps dispatching from stored heat

Track record

A proven, operating fleet

China's tower-CSP fleet represents approximately 1.7 GW across 27 plants as of end-2025 (SolarPACES / CSTA China Blue Book). These are not demonstration units. They are commercial plants delivering power to the grid, with years of operating data.

~1.7 GW
Installed capacity
27
Operating plants
8+ years
Commercial operation

All figures are screening-grade and indicative.

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