"Super Power Bank" for Concentrated Solar Power Plants-Molten Salt Energy Storage

In December 2025, the National Development and Reform Commission and the National Energy Administration jointly issued the "Several Opinions

on Promoting the Large-Scale Development of Concentrated Solar Power (CSP)." This document explicitly set the target of achieving a total installed

capacity of 150 gigawatts (GW) for CSP by 2030 and reducing the levelized cost of electricity (LCOE) to a level comparable with coal-fired power. This

policy not only injects strong momentum into the CSP industry but also paves a solid "policy runway" for the long-term development of molten salt

energy storage technology.

Molten salt, in simple terms, is salt in a molten liquid state. Common types include nitrates, carbonates, and chlorides. They possess characteristics

such as low cost, wide availability, high boiling point, high heat capacity, low viscosity, and good thermal stability, making them an ideal medium for

heat storage and transfer. Currently, they are widely used in tower-type CSP plants and industrial heat storage systems.

In tower-type CSP plants, the most commonly used formulation is the binary molten salt mixture of 40% potassium nitrate and 60% sodium nitrate. Its

operating temperature can be stably maintained between 290°C and 565°C, ensuring both system safety and heat transfer efficiency.

Molten salt plays a dual core role in CSP plants, combining energy storage and heat transfer functions, much like a "super power bank" for the grid.

Heat Transfer and Storage System

Power plants typically feature two molten salt storage tanks—low-temperature and high-temperature—forming a complete thermal energy cycle

system:

✔ Heat storage during the day: Molten salt from the low-temperature tank is pumped to the receiver, where it absorbs concentrated solar energy

 reflected by heliostats. Its temperature rises to approximately 565°C before being stored in the high-temperature tank.

✔ Power generation at night or during peak demand: High-temperature molten salt flows through a steam generator, heating water to produce high-

temperature, high-pressure steam, which drives a turbine to generate electricity. After cooling, the molten salt returns to the low-temperature tank, 

completing a closed-loop cycle.

Achieving "Solar Energy ≠ Immediate Power Generation"

Molten salt energy storage enables CSP plants to overcome the limitation of relying solely on real-time sunlight. It allows excess solar energy to be 

stored as thermal energy on a large scale and released as stable electricity when the grid requires it, significantly enhancing the dispatchability and 

stability of the power system.

Flexible Peak Load Regulation

Power plants can operate at full load during peak electricity price periods to maximize revenue, while storing thermal energy or reducing output

during off-peak hours. This operational flexibility significantly enhances the project's economic viability.

 Long-Duration Energy Storage

The system is capable of single-cycle heat storage lasting 6 to 15 hours or even longer. This extended discharge duration provides substantial support

for grid stability, effectively smoothing out fluctuations and mitigating the intermittency challenges associated with renewable energy sources like

solar and wind.

Safety and Environmental Sustainability

Molten salt is inherently safe—it is non-toxic, non-flammable, and operates at atmospheric pressure, eliminating explosion risks. The storage medium 

is also recyclable, making the system an environmentally friendly choice for large-scale energy storage.

1. Complementing Wind and Solar Power

Constructing multi-energy complementary bases integrating "concentrated solar power (CSP) + photovoltaic (PV) + wind power" to achieve 24-hour 

stable power supply and improve the overall utilization efficiency of renewable energy.

2. Industrial Heat Supply

Providing stable high-temperature heat sources for industrial processes in chemicals, textiles, food processing, etc., supporting energy conservation

and carbon reduction in the industrial sector.

3. Grid Frequency Regulation Services

Leveraging rapid response capabilities to participate in grid frequency regulation, enhancing the operational flexibility of the power system.

4. Integration with Hydrogen, Nuclear, and Other Energy Systems

In the future, it can serve as a high-temperature heat source for comprehensive energy systems such as nuclear-powered hydrogen production and

thermochemical energy storage, expanding the boundaries of energy services.

Molten salt systems must operate stably long-term under extreme conditions of 565°C high temperature and strong corrosiveness, posing severe challenges to every core component. Among these, molten salt valves, as the critical "switches" controlling molten salt flow, have their reliability directly impacting the safety and efficiency of the entire power plant.

The Wanlong molten salt valve is precisely the solution born for such extreme conditions. It effectively addresses two core challenges of molten salt 

systems through a trace heating system specifically designed to prevent molten salt crystallization in the bellows area and scientific material selection 

for high-temperature corrosive environments:

High-Temperature Corrosion Resistance: The valve body and internals utilize special materials resistant to molten salt corrosion, ensuring long-term 

operation at 565°C without erosion, significantly extending equipment lifespan.

Solidification Prevention Design: To counter the tendency of molten salt to solidify at low temperatures, the valve integrates an efficient trace 

heating 

system and insulation structure, preventing localized solidification during startup, shutdown, and operation, and ensuring the system is always ready 

for flexible dispatch.The application of such high-performance valves is a crucial guarantee for molten salt energy storage systems to achieve long 

lifespan, high availability, and low maintenance costs, laying a solid industrial foundation for the large-scale and commercial development of CSP 

plants.

Despite its significant advantages, molten salt energy storage still faces some challenges:

• Material Corrosiveness: Long-term high-temperature operation imposes higher requirements on pipeline and equipment materials.

• Low-Temperature Solidification Prevention: Insulation and heating measures are necessary in cold regions to prevent molten salt solidification.

• High Initial Investment: Costs associated with storage tanks, pipelines, and control systems still constrain its widespread adoption.

Looking ahead, with advancements in material technology, increased localization and cost reduction of key components (such as valves), the 

realization of scale effects, and continued policy support, the cost of molten salt energy storage is expected to decrease further. Its application 

scenarios will also expand from CSP plants to comprehensive energy services, district heating, industrial steam supply, and various other fields, 

making it a vital supporting technology for building a new-type power system.