Solar Aided Coal-Fired Power Generation 2026
Solar Aided Coal-Fired Power Generation 2026
Solar aided power generation (SAPG) integrates concentrated solar thermal energy into coal plant Rankine cycles, displacing steam extractions to boost output without proportional coal combustion. Patent and literature records from 2009–2026 map five identifiable sub-domains across this hybrid technology field.
Integrating Solar Thermal into Coal Plant Thermodynamic Cycles
Solar aided coal-fired power generation describes the physical and thermodynamic integration of solar thermal collectors — parabolic trough collectors, central tower heliostat fields, or linear Fresnel reflectors — into the Rankine cycle of an existing or newly built coal-fired power plant. The solar subsystem supplements the thermal energy budget at strategically chosen injection points within the steam-water circuit rather than replacing the coal boiler.
The core technical principle rests on solar thermal energy delivered at moderate temperatures (200–400°C) displacing steam extractions from high-pressure or intermediate-pressure turbines otherwise used to preheat feedwater. When those extractions are freed, steam continues to expand through the turbine, generating incremental electrical output without a proportional increase in coal combustion — a concept documented in the literature as early as 2012.
Among retrieved records, publication dates span 2009 to 2026, revealing a clear maturation arc. A 330 MW coal-solar hybrid demonstration was proposed for Xinjiang, China in 2014. By 2017, techno-economic validation for a 1,000 MWe system showed an internal rate of return of 8.7%. The 2022 Xi’an Jiaotong University US patent on a flexible SAPG system marked a milestone in cross-jurisdictional IP protection by a Chinese university.
Among the 11 patent records with assignee information in this dataset, the United States jurisdiction accounts for 6 patents — the most represented. Chinese academic and state-enterprise entities are increasingly active in international filing in retrieved records, while earlier Western engineering firm patents (GE, Bechtel) are mostly inactive. India’s NTPC Ltd. represents the clearest example of a national utility directly protecting solar-coal integration IP.
Technology Clusters and Innovation Timeline in SAPG
Among retrieved records, SAPG innovation spans five sub-domains with distinct maturity levels. Feedwater preheating via parabolic trough collectors is the dominant integration mode, while solar-aided CO₂ capture and load-flexible architectures represent more recent, less-populated clusters.
SAPG Sub-Domain Patent & Literature Record Counts (Dataset Snapshot)
Feedwater preheating via PTC is the most represented sub-domain in this dataset, with flexible multi-mode SAPG with thermal storage and solar tower augmentation also substantively represented across retrieved records.
↗ Click bars to exploreSAPG Innovation Timeline — Key Records by Phase (2009–2026)
Retrieved records show accelerating publication activity from the 2014–2018 development phase onward, with optimization and decarbonization coupling records concentrated in 2019–2023 in this dataset.
↗ Click bars to exploreKey Application Zones for SAPG: China, India, Kuwait, and Iraq
SAPG applications span large-scale utility power in China’s high-DNI northwestern provinces, retrofit projects in India led by NTPC Ltd., and case-study deployments in Kuwait and Iraq exploiting high direct normal irradiance alongside existing thermal infrastructure.
Xinjiang, Northwest China
A 330 MW subcritical coal-solar hybrid plant was proposed for Xinjiang, with solar heat at approximately 300°C replacing HP turbine extraction — documented in a 2014 study. Annual net solar-to-electric efficiency was reported at 21%. DNI data from Dunhuang was also used in a 2017 TRNSYS-based dynamic simulation optimizing heliostat field area.
Utility Power GenerationIndia — NTPC Ltd. Plants
India’s national thermal power utility NTPC Ltd. holds two active Indian patents (2015 and 2021) on solar integration into fossil-fired power plant feedwater circuits. The patented system installs a solar heat exchanger parallel to the last regenerative feedwater heater, diverting, heating, and returning tapped feedwater to the main circuit. These filings signal utility-scale deployment intent across NTPC’s coal fleet.
In-situ RetrofitKuwait — 300 MW Hybrid Plant
A 2020 study examined a 300 MW plant in Kuwait where removing LP turbine extractions and compensating with parabolic trough solar collectors increased net output by 9.8 MW. The levelized cost of electricity was reported 44% lower than an equivalent standalone PV system. Kuwait’s high DNI resource was identified as a key enabler for this integration approach.
Remote SensingChina — 1,000 MW CCS Integration
A 2018 thermo-economic study compared two solar-CCS integration architectures on a 1,000 MW coal plant: solar heating feedwater versus solar heating the MEA stripper reboiler for post-combustion CO₂ capture. Thermo-economic structural theory was applied to evaluate coal savings and capture energy penalty reduction. A 2015 study also documented CSP providing thermal energy for amine solvent regeneration in a coal plant CCS system.
GHG Flux MonitoringKey Patent Assignees in Solar Aided Coal Power — Retrieved Records
Among the 11 patent records with assignee information in this dataset, NTPC Ltd. (India) and Xi’an Jiaotong University (China) are the most prominent active filers, with Chinese academic and state-enterprise entities showing increasing cross-jurisdictional IP activity in retrieved records. Western engineering firms such as QGEN Ltd. and Bechtel hold earlier but mostly inactive patents.
Top Assignees by Patent Count — SAPG Dataset Snapshot (Retrieved Records)
↗ Click bars to exploreNTPC Ltd.
NTPC Ltd., India’s national thermal power utility, holds two active Indian patents on solar integration into fossil-fired power plants — filed in 2015 and 2021. The patented technology installs a solar heat exchanger parallel to the last regenerative feedwater heater, diverting tapped feedwater through solar heating and returning it to the main circuit. Both patents are active, representing the clearest example in this dataset of a national utility directly protecting solar-coal integration IP.
India — INXi’an Jiaotong University
Xi’an Jiaotong University holds one active US patent (2022) on a solar-aided coal-fired flexible power generation system and operation method. The patent introduces a high-temperature heat storage medium heater in the boiler flue integrated with the solar collection circuit, with a regulating valve and pump system that eliminates irradiation fluctuation and enables rapid load cycling. This cross-jurisdictional filing marks a milestone in international IP protection of SAPG technology by a Chinese academic institution.
China — CN (filed US)Forward-Looking Innovation Signals in SAPG (2020–2026)
The most recent filings and publications in this dataset (2020–2026) signal four forward-looking directions: load-flexible SAPG for grid ancillary services, multi-pollutant co-benefit optimization, solar-aided CCS for near-zero-emission coal, and point-focus/line-focus hybrid collector architectures.
Load-Flexible SAPG for Grid Ancillary Services
Xi’an Jiaotong University’s 2022 active US patent on a solar-aided coal-fired flexible power generation system introduces a high-temperature heat storage medium loop integrated directly into the boiler flue and solar collection circuit. A regulating valve and pump system eliminates irradiation fluctuation, enabling rapid load cycling and peak shaving. This signals a shift from steady-state solar supplementation toward dynamic grid-responsive SAPG architectures.
Point-Focus and Line-Focus Hybrid Collector Architectures
China Huaneng Group’s 2019 CN patent on point-focus and line-focus solar complementary coal power systems introduces cascaded energy grade utilization by combining high-temperature tower receivers with lower-temperature trough arrays. This enables wider temperature-range integration into the coal plant thermodynamic cycle. A 2022 literature study comparing three integration schemes found that a tower field connected in series between intermediate- and low-pressure cylinders achieves the lowest standard coal consumption rate of 275.11 g/kWh.
Parabolic Trough vs. Central Tower Integration in SAPG
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| Dimension | Parabolic Trough (PTC) | Central Tower / Heliostat |
|---|---|---|
| Integration Temperature | 200–300°C (moderate; LP/HP feedwater heating) | Higher temperatures; boiler-level or intermediate steam injection |
| Primary Integration Mode | Feedwater preheating; displaces regenerative heater steam extraction | Boiler augmentation or intermediate steam cycle injection |
| Representative Plant Scale | 300–330 MW subcritical (Xinjiang, Kuwait case studies) | 1,000 MWe supercritical (China techno-economic study, 2017) |
| Reported Output Gain | +9.8 MW from LP extraction bypass (300 MW Kuwait plant, 2020) | Lowest coal consumption rate 275.11 g/kWh (tower series integration, 2022) |
| Annual Solar-to-Electric Efficiency | 21% net (330 MW Xinjiang case, 2014) | Optimized via TRNSYS simulation using Dunhuang DNI data (2017) |
| Techno-Economic Performance | LCOE 44% lower than standalone PV (Kuwait, 2020) | IRR 8.7%; solar tower field cost identified as dominant sensitivity variable (2017) |
| Dominant Patent Filers (in dataset) | NTPC Ltd. (IN, 2015 & 2021 active); Xi’an Jiaotong University (US, 2022 active) | China Huaneng Group Research Institute (CN, 2019 active) |
| NOₓ Co-Benefit | Not explicitly documented in retrieved PTC records | Variable injection point improves SCR de-NOₓ efficiency by 3.1–7.9% at partial load (2017) |
Frequently Asked Questions: Solar Aided Coal-Fired Power Generation
SAPG integrates concentrated solar thermal collectors — parabolic trough collectors, central tower heliostat fields, or linear Fresnel reflectors — into the Rankine cycle of a coal-fired power plant. Solar thermal energy supplements the plant’s thermal budget at specific injection points, displacing steam extractions from turbines used to preheat feedwater, generating incremental electrical output without a proportional increase in coal combustion.
The five identifiable sub-domains among retrieved records are: (1) feedwater preheating via solar collectors — the dominant mode; (2) solar tower-aided steam generation and boiler augmentation; (3) solar-aided CO₂ capture energy supply; (4) photovoltaic integration for auxiliary power displacement; and (5) thermal energy storage coupled with SAPG for dispatchability.
Active patent holders in this dataset include NTPC Ltd. (two active Indian patents, 2015 and 2021), Xi’an Jiaotong University (one active US patent, 2022), Institute of Engineering Thermophysics of the Chinese Academy of Sciences (two active US patents, 2014 and 2016), China Huaneng Group Clean Energy Technology Research Institute (one active CN patent, 2019), Yeda Research and Development Co. Ltd. (one active EP patent), Applied Hybrid Energy Pty Ltd (one active AU patent), and General Electric Infrastructure Technology (one active US patent).
A 2017 techno-economic analysis of a 1,000 MWe solar tower aided system reported an internal rate of return of 8.7%, with solar tower field cost identified as the dominant sensitivity variable. A 2020 study on a 300 MW PTC-integrated plant in Kuwait found net output increased by 9.8 MW and LCOE 44% lower than equivalent standalone PV. The literature in this dataset establishes coal savings of 8–28% depending on solar resource and integration depth.
SAPG reduces CO₂ by displacing coal combustion with solar thermal energy input. A 2020 study specifically addresses CO₂ abatement cost of solar integration in Chinese SAPG systems. For NOₓ, a 2017 study showed that dynamically routing the solar injection point improves SCR de-NOₓ efficiency by 3.1–7.9% at partial plant loads in a 1,000 MW case study. SAPG can also be coupled with MEA-based post-combustion carbon capture to reduce the energy penalty of solvent regeneration.
The most recent filing in this dataset is a 2026 pending Indian patent by Vellore Institute of Technology, Chennai, on a hybrid energy-recovery system incorporating solar heat concentrators around industrial flare stacks. Prior to this, Xi’an Jiaotong University’s active US patent on a solar-aided coal-fired flexible power generation system was filed in 2022, and NTPC Ltd. filed an active Indian patent on solar integration into fossil-fired power plants in 2021.
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.