Molten Salt Solar Thermal Storage Patents 2026
Molten Salt Solar Thermal Storage Patents 2026
Molten salt thermal energy storage is shifting from CSP integration toward grid flexibility, industrial heat, and thermal power retrofits. This landscape covers patent and literature signals spanning 2008 through 2026.
How Molten Salt TES Works and Where It Stands
Molten salt thermal energy storage uses inorganic salt mixtures — most commonly binary nitrate Solar Salt (60% NaNO₃ / 40% KNO₃) — circulated between cold tanks (~270–300°C) and hot tanks (550–650°C). The heated salt drives a steam generation cycle, decoupling electricity production from solar irradiance and enabling on-demand dispatch.
The field spans five core sub-domains: two-tank direct storage systems as the commercial baseline; single-tank thermocline designs for cost reduction; novel ternary and nano-enhanced salt formulations; high-temperature fluoride salt systems targeting Brayton-cycle power blocks above 816°C; and hybrid multi-source integration coupling molten salt with PV, wind, and compressed air storage.
Global CSP-coupled molten salt storage capacity reached approximately 21 GWh-electric at end-2019, and the broader thermal energy storage market is projected toward USD 10–12 billion by 2025–2027. The field is pivoting from pure CSP toward broader industrial, grid-flexibility, and multi-energy applications, as evidenced by the most recent Chinese filings from 2024 to 2026.
Innovation is not concentrated in a single dominant entity. Chinese state enterprises and research institutes constitute the largest national cluster with an estimated 25+ CN-jurisdiction records in this dataset, while Western leadership is divided among specialized players including The Babcock & Wilcox Company, SolarReserve Technology, Stamicarbon B.V., and GE Vernova Infrastructure Technology LLC, each holding distinct technical niches.
Filing Activity by Technology Cluster and Jurisdiction
Patent filings in this dataset cluster into two major periods: a 2013–2018 wave of foundational system architecture patents from Western and Korean assignees, and a 2022–2026 surge dominated by Chinese institutional filers targeting hybrid storage, retrofit, and intelligent dispatch applications.
Patent Records by Technology Cluster — Molten Salt TES Dataset
Two-tank direct systems and hybrid/multi-source integration together account for the majority of retrieved records, with hybrid integration representing the fastest-growing cluster in 2022–2026 filings.
↗ Click bars to explorePatent Filing Activity by Period — Molten Salt TES Dataset
The 2022–2026 period shows the strongest filing activity in this dataset, driven by Chinese institutional assignees targeting hybrid integration, retrofit, and intelligent control applications.
↗ Click bars to exploreKey Deployment Domains for Molten Salt Thermal Storage
Molten salt TES is deployed across concentrated solar power generation, industrial process heat, grid flexibility retrofits, district heating, and geothermal hybridization — each domain represented by named patent filings and literature studies in this dataset.
Eastern Morocco CSP Reference Site
A comparative study of a 50 MWe tower plant in eastern Morocco found the molten salt configuration produced 86.3 GWh annual output versus 83.3 GWh for direct steam generation, with 12.5% lower levelized electricity cost. A 100 MW Linear Fresnel design study for Riyadh, Saudi Arabia also utilized molten salt TES, confirming cross-architecture applicability across high-DNI regions.
CSP Electricity GenerationBabcock & Wilcox Modular Tower Systems
The Babcock & Wilcox Company’s modular tower patents (filed 2016–2018 across US, WO, AU, IN, CN) explicitly target process heat applications at salt temperatures ≤850°F (~454°C), noting suitability for thermal desalination and lower-grade industrial steam. A 2021 literature review confirmed multi-energy hybrid configurations serving heating, cooling, and electricity for building and campus-scale applications.
Industrial Process HeatXi’an Thermal Power Retrofit Patents
Xi’an Thermal Power Research Institute Co., Ltd. obtained US patents in 2024 and 2025 for combined high-parameter and low-parameter molten salt systems integrated into coal and gas-fired power units, enabling peak-shaving, frequency regulation, and renewable energy absorption. This brownfield retrofit approach absorbs surplus electricity during off-peak periods and dispatches stored heat during peak demand, targeting existing generation infrastructure.
Grid Flexibility RetrofitBaijirui Tianjin District Heating Systems
Baijirui (Tianjin) New Energy Co., Ltd. filed two CN patents in 2019 covering a molten salt and solid combined energy storage heating system and a large-temperature-difference heat pump molten salt storage heating system. These designs exploit off-peak valley power arbitrage to charge molten salt, then discharge to building hot water circuits, demonstrating district heating integration at building and community scale.
District HeatingLeading Assignees in Molten Salt TES Patent Filings
The assignee landscape in this dataset is distributed across national clusters and technical niches. The Babcock & Wilcox Company leads by retrieved record count with 5 filings, while Stamicarbon B.V. (MT Innovation Center) holds the broadest multi-jurisdiction thermocline portfolio with 4 records across WO, US, and EP.
Top Assignees by Retrieved Record Count — Molten Salt TES
↗ Click bars to exploreThe Babcock & Wilcox Company
Babcock & Wilcox holds 5 retrieved records filed between 2016 and 2018 across US, WO, AU, IN, and CN jurisdictions, making it the top assignee by count in this dataset. Its patents cover modular molten salt solar towers with thermal storage for process or power generation or cogeneration, targeting salt temperatures ≤850°F (~454°C) with reduced-corrosion, lower-cost alloy designs. The multi-jurisdiction filing strategy indicates active international IP protection through at least 2018.
United StatesStamicarbon B.V. — MT Innovation Center
Stamicarbon B.V. (operating as MT Innovation Center, Netherlands) holds 4 records spanning a 2014 WO application and subsequent US grants (2016, 2018) and an EP filing (2016) for a thermocline-based single-tank system using natural density stratification to eliminate one storage vessel. The active US grants covering this single-tank thermocline architecture represent one of the broadest Western patent positions in cost-reduction TES design. Patent activity spans 2014–2018.
Netherlands — WO/US/EPFive Frontier Signals in Molten Salt TES (2023–2026)
The most recent filings in this dataset — concentrated in 2023–2026 — reveal five directional signals pointing away from standalone CSP toward retrofit, hybridization, seasonal storage, and intelligent dispatch.
Thermal Power Unit Retrofits as a Primary Market
Xi’an Thermal Power Research Institute Co., Ltd. secured US patents in 2024 and 2025 for combined high-parameter and low-parameter molten salt systems integrated into existing coal and gas power units. This represents a pivot from greenfield CSP plants to brownfield retrofit of existing generation infrastructure for grid flexibility. The retrofit addressable market is potentially much larger than new CSP build.
Cross-Seasonal PV-Driven Molten Salt Charging
A 2024 CN pending application from North University of China describes a solar photovoltaic-powered electromagnetic induction heating system that charges molten salt in summer for district heating in winter. This cross-seasonal storage concept addresses the seasonal mismatch challenge that conventional CSP cannot solve, using PV electricity rather than direct solar-thermal conversion as the charging mechanism.
Two-Tank Direct vs. Single-Tank Thermocline: Key Dimensions
Click any row to explore further.
| Dimension | Two-Tank Direct Storage | Single-Tank Thermocline |
|---|---|---|
| Commercial Maturity | Commercial baseline; deployed in multiple utility-scale CSP plants | Demonstrated at pilot scale; unresolved commercial scale-up challenges |
| Temperature Range | Cold ~290–300°C, Hot ~550–565°C (binary nitrate salt) | Same salt temperature range; gradient maintained within single vessel |
| Capital Cost | Higher — requires two full storage vessels and associated piping | 10–30% cost savings versus two-tank systems identified in literature |
| Key Challenge | Anti-freeze management; salt inventory cost; heat exchanger leak risk | Thermal ratcheting, filler degradation, imperfect stratification |
| Lead Assignees | Dongfang Electric Group Dongfang Boiler Co., Ltd.; China Gezhouba Group; East China Electric Power Design Institute | Stamicarbon B.V. (MT Innovation Center); Korea Institute of Energy Research |
| Jurisdiction Concentration | China (CN) dominant; also US and IN filings | WO, US, EP (Stamicarbon); US (Korea Institute of Energy Research) |
| Filler / Media | Salt only; no solid filler required | Quartzite or porous block filler materials enhance stratification stability |
| New Entrant Opportunity | Crowded IP space; incremental improvement focus | Limited assignee base suggests potential for new entrants with improved filler or baffle designs |
Frequently Asked Questions: Molten Salt Solar Thermal Storage
The most common commercial formulation is binary nitrate Solar Salt — a mixture of 60% NaNO₃ and 40% KNO₃. It operates between approximately 270–300°C in the cold tank and 550–650°C in the hot tank. This is the mainstream choice across two-tank direct storage systems described in the patent and literature records in this dataset.
Two-tank direct storage uses dedicated hot and cold vessels with pumps circulating salt between them and is the commercial baseline. Single-tank thermocline systems use density-driven thermal stratification within one tank — sometimes with quartzite or porous block fillers — to eliminate one vessel. Literature records in this dataset identify 10–30% cost savings for thermocline systems, but challenges including thermal ratcheting, filler degradation, and imperfect stratification have limited commercial scale-up.
The Babcock & Wilcox Company leads with 5 retrieved records filed between 2016 and 2018 across US, WO, AU, IN, and CN jurisdictions. Its patents cover modular molten salt solar towers targeting process or power generation at salt temperatures ≤850°F (~454°C). Stamicarbon B.V. and McBay, David Alan each have 4 records as the next-most-represented assignees.
The most recent filings in this dataset (2024–2026) point to five directions: thermal power unit retrofits for grid flexibility (Xi’an Thermal Power Research Institute, US patents 2024–2025); cross-seasonal PV-driven charging for district heating (North University of China, 2024 CN); molten salt coupled with compressed air storage (China Huadian, 2024 CN); solid + molten salt hybrid storage to exceed the 565°C nitrate salt ceiling (National Energy Investment Group, 2026 CN); and AI/IoT adaptive dispatch with anti-freeze control (North Wei Jiamao Coal Power, 2025 CN).
SolarReserve Technology, LLC patented fluoride salt systems (FLiNaK, FLiBe) capable of reaching 816–982°C, enabling Brayton-cycle (gas turbine) power blocks and advanced hydrogen or desalination co-production. This is distinct from the binary nitrate mainstream, which is typically limited to ~565°C, and targets next-generation efficiency levels. SolarReserve’s foundational EP patent dates to 2008, making it the earliest substantive record in this dataset.
China accounts for at least 25 of the patent records in this dataset, covering the full innovation stack: system architecture, heat exchange design, temperature control, modular storage units, and cross-seasonal storage. The content notes that Western entrants should audit freedom-to-operate carefully for China market entry, given the breadth of claims by Chinese state enterprises and research institutes across modular configurations, multi-source integration, and retrofit designs.
Data and insights on this page are based on a limited patent and literature dataset and are for reference only. Figures may not represent the complete technology landscape.