Concentrated Solar Thermal Storage 2026 — PatSnap Eureka
Concentrated Solar Thermal Storage: Patent & Innovation Landscape 2026
CST-TES enables dispatchable renewable electricity by storing solar heat for use when the sun isn’t shining. This report maps the technology regimes, assignee landscape, geographic signals, and frontier IP directions across 80+ patent and literature records spanning 2010–2026.
Three Storage Regimes Across Four Collector Architectures
Concentrated solar thermal storage (CST-TES) divides into three core storage physics regimes: sensible heat storage (SHS), latent heat storage via phase change materials (PCM-LHS), and thermochemical energy storage (TCES). These regimes are implemented across four major CSP collector architectures — parabolic trough (PTC), solar power tower (SPT), linear Fresnel reflector (LFR), and parabolic dish — each imposing different temperature requirements on the storage subsystem.
Among retrieved records, sensible heat storage using molten salt two-tank configurations is described as “the most widespread TES medium” across commercially operational facilities. The canonical binary Solar Salt (60% NaNO₃ + 40% KNO₃) appears across multiple records, including designs for a 100 kW CSPonD prototype at Masdar Institute/MIT and a 100 MW Linear Fresnel plant in Riyadh, Saudi Arabia. Packed-bed thermocline systems using solid media such as silica rock and concrete are presented as lower-cost alternatives to the two-tank architecture. At the frontier, thermochemical storage offers volumetric energy densities 5–10× those of sensible systems.
A critical enabling function of TES in CSP is dispatchability: the ability to schedule electricity delivery independently of real-time solar flux. This property distinguishes CSP-TES from photovoltaic-battery combinations, particularly for storage durations exceeding 4–10 hours. PatSnap’s analytics platform enables R&D teams to track this evolving IP landscape in real time.
Four Patent Clusters Defining the CST-TES Landscape
Retrieved records group into four distinct technology clusters, each representing a different storage physics approach and commercial maturity level.
Two-Tank Molten Salt Sensible Heat Storage
The dominant commercial architecture stores thermal energy in two tanks of molten salt — one hot, one cold — with Solar Salt (60% NaNO₃ + 40% KNO₃) operating at 290–565°C. Key assignees include Bechtel Power Corporation and Bindingnavale Ranga Krishna Kumar. Constrains power cycle efficiency to Rankine cycle parameters. Documented in plants from 10 MW to 111.7 MW across Spain, USA, Saudi Arabia, and China.
290–565°C operating rangePacked-Bed Thermocline & Solid-Medium Sensible Storage
A cost-reduction strategy using a single stratified tank filled with solid packing (silica rock, concrete, steel) through which HTF circulates. Air and gaseous HTFs are frequently paired with this architecture, enabling atmospheric operation without freeze-risk fluids. The dataset also documents direct-irradiation solid storage, where reflected sunlight strikes the solid medium directly through a gated aperture. Skibo Systems LLC and HyperLight Energy are key assignees.
Single-tank thermoclineLatent Heat Storage via Phase Change Materials (PCM)
PCM-based storage exploits the latent heat of fusion at a near-isothermal phase transition temperature, delivering higher energy density than sensible systems and isothermal heat release beneficial for power cycle integration. A 2023 review identifies PCM as a significant growth area for CSP over the past decade, with nano-enhanced PCMs emerging as a performance frontier. Key challenges include low thermal conductivity and encapsulation integrity under thermal cycling. P S R Engineering College’s 2026 IN filing targets non-corrosive ceramic PCM buffers at 300–600°C.
300–600°C ceramic PCM (2026 frontier)Thermochemical Energy Storage (TCES)
TCES systems store energy as chemical bond enthalpy via reversible endothermic/exothermic reactions, achieving volumetric energy densities approximately 5–10× those of sensible heat systems with near-zero thermal standby losses — enabling theoretically seasonal storage. Key reaction systems include calcium looping (CaO/CaCO₃), metal oxide redox cycles (CaAl₀.₂Mn₀.₈O₂.₉₋δ), and destabilized lithium hydrides (LiSi, LiAl, LiSn). Described as “the less studied and the most attractive” TES option. Abengoa Solar’s WO/US/ES filings (2013–2015) represent the foundational IP cluster.
5–10× energy density vs sensibleInnovation Timeline & Energy Density Comparison
Key quantitative signals from the retrieved patent and literature corpus, illustrating the multi-phase evolution of CST-TES and the relative performance of storage regimes.
CST-TES Innovation Phase Timeline (2011–2026)
Four distinct development phases identified from publication dates across 80+ retrieved records, from foundational hybrid concepts to 2024–2026 frontier filings.
TES Volumetric Energy Density by Storage Regime
Thermochemical storage achieves 5–10× the volumetric energy density of sensible heat systems, with PCM-LHS occupying an intermediate position, based on retrieved literature records.
From Utility-Scale Power to Desalination and Grid Services
CST-TES applications span five distinct domains, each with different scale, temperature, and economic requirements documented across the retrieved corpus.
Fragmented IP with India Emerging as Dual-Role Jurisdiction
| Assignee | Jurisdiction(s) | Filing Years | Status | Technology Focus |
|---|---|---|---|---|
| Abengoa Solar Inc./LLC | WO, US, ES | 2013–2015 | Inactive (3 filings) | Grid-tied high-temp TES with electric heating element hybridization |
| PhotonStor Corp. | US, IN | 2024, 2026 | Active / Pending | Near-blackbody receiver-integrated TES, direct irradiation storage |
| Bechtel Power Corporation | US | 2015 | Inactive | Hybrid collector field CSP plant |
| Skibo Systems LLC | WO | 2011 | Single filing | Multistage cascade TES with geothermal integration |
Five Frontier Signals from the 2023–2026 Filing Cluster
The most recent filings and literature records in this dataset identify five convergent innovation directions that define the current frontier of CST-TES IP development.
High-Temperature Storage for sCO₂ Power Cycles
The most consistent frontier signal: coupling next-generation supercritical CO₂ Brayton cycles (700–1000°C turbine inlet temperatures) with compatible TES media. Records document redox-active metal oxide particles (CAM28, achieving 1,200°C air delivery) and destabilized lithium hydrides (LiSi, LiSn at 700–750°C for sCO₂). A 2023 dual receiver-storage design using cast steel at 850–1000 K targets sCO₂ integration via beam-down optics.
Near-Blackbody Receiver-Integrated Storage
PhotonStor Corp. (US 2024, IN 2026) and Andric Milos (WO 2021) describe architectures where concentrated sunlight strikes the storage medium directly — eliminating HTF thermal resistance losses and pumping infrastructure. Consistent with the CSPonD concept at Masdar/MIT (2015), this represents a conceptual convergence toward receiver-storage unification that challenges conventional plant topology.
Non-Corrosive PCM Alternatives to Molten Salt
The 2026 IN filing from P S R Engineering College explicitly targets replacement of corrosive molten salts with ceramic-based or specialized solid PCM buffers at 300–600°C. This addresses one of the most persistent operational barriers — high-temperature corrosion of metallic containment components — and is consistent with the broader PCM research surge documented in the 2023 review literature.
Five IP and R&D Strategy Signals for CST-TES Decision-Makers
Key strategic takeaways for IP professionals, R&D teams, and technology strategists, derived from the patent and literature corpus.
Molten Salt Two-Tank Systems Face Headwinds
The dominant commercial TES architecture has well-documented operational challenges including freeze risk, high-temperature corrosion, and elevated capital cost. IP and R&D teams should assess whether portfolio strategies weighted toward next-generation materials — PCMs, redox oxides, destabilized hydrides — offer defensible differentiation, particularly as ceramic and solid-medium alternatives accumulate patent filings in IN and WO jurisdictions. See the PatSnap analytics platform for portfolio gap analysis.
Freeze risk · High-temp corrosion · Capital costThe sCO₂-TES Interface is an Underprotected IP Frontier
Multiple literature records identify supercritical CO₂ Brayton cycle integration as the primary pathway to sub-6 cent/kWh LCOE, yet the patent dataset shows minimal issued IP specifically covering TES-sCO₂ integration architectures. This represents a white-space opportunity for R&D organizations pursuing high-temperature solid particle or metal oxide storage systems. Access global patent databases through PatSnap’s open API for freedom-to-operate analysis.
Sub-6¢/kWh LCOE target · White-space IPIndia is an Emerging Dual-Role Jurisdiction
India appears as both a growing demand market (techno-economic studies in Rajasthan, Udaipur) and an active IP filing jurisdiction, with three recent IN filings (2016, 2026×2) in this dataset. IP strategists entering Asian markets should prioritize IN prosecution alongside CN, where CSP policy support and installed capacity ambitions are documented at the national level. China’s CSP industry review (2018) and subsequent policy analysis (2021) indicate government-backed ambitions.
IN filings: 2016, 2026×2 · CN policy ambitionDirect Irradiation TES Challenges Conventional Plant Topology
Patents from Andric Milos (WO 2021) and PhotonStor Corp. (US 2024, IN 2026) converge on eliminating the HTF loop between receiver and storage — a structural disruption to conventional CSP plant architecture. Incumbents with IP covering HTF-based systems should monitor this cluster as a potential design-around threat to established two-tank and thermocline portfolios. Track emerging filers with PatSnap competitive intelligence tools.
HTF loop elimination · Design-around riskConcentrated Solar Thermal Storage — key questions answered
Concentrated solar thermal storage encompasses systems in which solar radiation is optically concentrated and converted to heat, which is then stored in a thermal medium for later extraction to drive power generation or industrial processes. It enables dispatchable renewable electricity generation by capturing and storing solar heat for use during periods without sunshine.
The field divides into three core storage physics regimes: sensible heat storage (SHS), latent heat storage via phase change materials (PCM-LHS), and thermochemical energy storage (TCES). These regimes are implemented across four major CSP collector architectures—parabolic trough, solar power tower, linear Fresnel reflector, and parabolic dish.
Thermochemical storage offers volumetric energy densities 5–10× those of sensible systems, with near-zero thermal standby losses enabling theoretically seasonal storage. Key reaction systems include calcium looping (CaO/CaCO₃), metal oxide redox cycles, and destabilized lithium hydrides. It is described as “the less studied and the most attractive” TES option, consistent with its pre-commercial status.
The economic benchmark target of 6 cents/kWh LCOE for 10-hour storage tower plants is referenced across multiple records. However, Crescent Dunes’ operational failure documented in this dataset recorded an effective cost of $2.38/kWh from a 110 MW plant, highlighting that this target remained unachieved at commercial scale as of 2020.
Among patent records retrieved, the US has 5 filings, WO (PCT) has 4 filings, IN has 3 filings, and ES has 1 filing. The emergence of Indian jurisdiction filings in 2025–2026, including both a global company (PhotonStor) and a domestic institution (P S R Engineering College), signals India’s growing role as both an innovation source and target market.
A 2022 macro-scale energy modeling study concludes that CSP-TES holds economic advantages over PV-battery combinations for storage durations of 4–10+ hours. The dispatchability property—the ability to schedule electricity delivery independently of real-time solar flux—distinguishes CSP-TES from photovoltaic-battery combinations, particularly for storage durations exceeding 4–10 hours.
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