Encyclopedia article
Solar panel
Device that converts sunlight into electricity using photovoltaic cells
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- 2,035 words
- 9 min read
- 19 sources
Truth Ledger
45 claims checked
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- Disputed
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Checked by GPT-6.1 Sol and Grok 4.7, each without seeing the other’s answers.
Neutrality: 4 of 4 framing flags fixed.
A claim is stated as fact only when both checkers confirm it from the cited sources; a split verdict is published with attribution, and a claim neither can confirm is cut.
See every claimA solar panel is a device that converts sunlight into electricity using solar modules made of photovoltaic (PV) cells, which produce direct current when exposed to light 113. Most modules are made from crystalline silicon, which accounted for 95% of worldwide PV production in 2021 1. Global cumulative installed PV capacity reached 2,261 GW at the end of 2024, according to the IEA Photovoltaic Power Systems Programme 15. Recent sources report falling costs and record cell efficiencies 1919. They also report installation declines in some markets, forecasts of slower global deployment, trade disputes and strain on electricity markets 2467.
History
#In 1839 the French physicist Edmond Becquerel first observed that some materials create an electrical charge when exposed to light 118. In 1873 Willoughby Smith found that light could produce this effect in selenium 118. William Grylls Adams and Richard Evans Day described their replication of Smith's results in 1876 118.
The American inventor Charles Fritts built an early selenium solar cell 118. Sources differ on the date: Wikipedia gives 1881 and calls it the first commercial solar cell 1, while a historical review gives 1883 and describes it as the first fully functioning selenium-based cell 18. These early cells remained too inefficient for practical power production 1.
Russell Ohl created a solar cell design in 1939 that is used in many modern panels, and he patented it in 1941 1. Bell Labs used this design in 1954 to create the first commercially viable silicon solar cell 1. The historical review states that the technology served military uses before reaching ordinary users 18.
Wikipedia reports that the cost of solar PV electricity has fallen 85% since 2010 1. It gives cumulative global capacity of about 1,185 GW at the end of 2022, supplying over 6% of global electricity demand 1.
Technology and construction
#A module consists of many solar cells, usually connected in series to raise voltage and then in parallel to raise current 1. Cells must be protected from mechanical damage and moisture 1. Most panels are rigid, though semi-flexible thin-film panels are also available 1. A junction box on the back of the panel serves as its output interface, and most outdoor modules use MC4 connectors 1.
Cell materials include silicon, copper indium gallium diselenide (CIGS), cadmium telluride (CdTe), perovskites and organic compounds 17. Thin-film technologies made up the roughly 5% of 2021 production that was not crystalline silicon 1. High-cost multi-junction cells made of gallium arsenide and other compound semiconductors are usually used on spacecraft because they give the most power per kilogram launched 1.
Manufacturers have adopted successive cell connection designs, including aluminium back surface field (Al-BSF), PERC, TOPCon and interdigitated back contact (IBC), to increase the area exposed to light 1. Bifacial cells generate power from both sides, and Wikipedia reports that as of 2024 bifacial panels were the leading choice for utility-scale installations 1. Concentrator modules focus light onto small, high-efficiency cells and can raise efficiency to around 45% 1.
A photovoltaic system typically combines panels with an inverter that converts direct current to alternating current, along with wiring, protective devices and sometimes batteries, charge controllers or solar trackers 113. In series strings the weakest panel limits the current, and bypass diodes are used to route current around shaded or broken panels 1.
Performance, efficiency and degradation
#Module ratings are measured under standard test conditions: irradiance of 1,000 W/m², an AM 1.5 spectrum and a module temperature of 25 °C 1. Actual output varies with location, time, tilt, cloud cover, shading, soiling and temperature 1. Typical modules of about 1 by 2 metres are rated from about 75 W to 600 W 1. Maximum power falls as cell temperature rises 1.
Sources describe efficiency in different ways. Wikipedia describes panel conversion efficiency as typically in the 20% range and silicon cells as 10–20% efficient, with newer models exceeding 22% 1. The U.S. Energy Information Administration (EIA) states that module efficiency averaged under 10% in the mid-1980s, rose to around 15% by 2015, and is approaching 20% for state-of-the-art modules 13. It also states that experimental and space-satellite cells are nearly 50% efficient 13.
In September 2026 Longi announced a 28.29% efficiency for a hybrid interdigitated-back-contact silicon cell, verified by Germany's Institute for Solar Energy Research Hamelin (ISFH) 9. The figure is a record for single-junction crystalline silicon cells 9. Longi said silicon cell efficiency had reached 96.2% of the theoretical limit, but it gave no further detail about the cell technology 9. The claim rests on that single report.
Output declines over time 1. Wikipedia cites a study finding linear degradation of 0.8% to 1.0% per year for crystalline silicon panels 1. It reports that a 2021 kWh Analytics study found median system-level degradation of 1.09% per year for residential and 0.8% for non-residential installations 1. That study's figures are higher than the common industry assumption of 0.5% per year 1.
Some thin-film panels lose 3% to 4% a year in their first years before stabilising, while CIGS panels show lower degradation than crystalline silicon 1. Potential-induced degradation can cause power losses of up to 30% 1. Modules are expected to last between 20 and 40 years 1.
Maintenance and safety
#Dust, pollen and other particulates, collectively called soiling, reduce output 1. Average global soiling losses in 2018 were estimated at 3% to 4% at least 1. Wikipedia reports that cleaning was cost-effective in many regions as of 2019, but that in California as of 2013 soiling losses rarely justified the cost of washing 1. Proposed alternatives include robotic and hydraulic systems, as well as a waterless electrostatic method announced by MIT researchers in 2022 1.
A UK study covering 2015–2018 examined 80 PV-related fire incidents 1. Over 20 of these were serious fires caused directly by PV installations 1. Where a cause was identified, most fires were attributed to poor installation, faulty products or design issues, and direct-current isolators were the most frequent single cause 1. Panels on the U.S. market are mostly UL listed 1. Standards applied to modules include IEC 61215, IEC 61730 and UL 1703 1.
Deployment and markets
#The IEA Photovoltaic Power Systems Programme estimated global cumulative capacity at 2,261 GW at the end of 2024 15. It gave 553.3 GW as the minimum and 601.1 GW as the most probable capacity installed during 2024 15. Its most probable figure is a 29% increase on 2023 15.
The China Photovoltaic Industry Association (CPIA) expects global additions to fall 8% to 612 GW in 2026 and to recover from 2027, reaching 864 GW a year by 2030 6. China installed 72.07 GW in the first half of 2026, about 66% below the first half of 2025 6. pv magazine notes that the comparison is distorted by a rush to connect projects before market-based pricing for new renewables began in June 2025 6. It also reports that most Chinese manufacturers continued to face losses 6.
According to the Solar Energy Industries Association (SEIA), the United States installed 43.2 GWdc in 2025, 14% less than in 2024 2. Solar made up 54% of new U.S. generating capacity that year, and solar plus storage made up 79% 2. SEIA attributes the decline partly to revised tax credit timelines and safe-harbour rules 2. It projects cumulative U.S. capacity rising from 279 GWdc at the end of 2025 to 769 GWdc by 2036 2.
Ars Technica reported that through September 2026 U.S. solar generation was 48 TWh higher than a year earlier, a 22% growth rate 10. It characterised this as a slowdown and suggested that changes to federal renewable-energy incentives and policy may have contributed 10. EIA data show that U.S. solar electricity generation rose from about 5 million kWh in 1984 to about 204 billion kWh in 2022 13. Utility-scale PV accounted for 70% of the 2022 total 13.
U.S. module manufacturing capacity grew from 42.5 GW at the end of 2024 to 65.5 GW in 2025, though actual production remained well below domestic demand 2. Preliminary U.S. trade determinations in 2026 set combined duty rates above 100% on cells and modules from India, Indonesia and Laos 4.
Costs and prices
#Wikipedia reports a module cost of about US$0.60 per watt in 2012, compared with US$150 in 1970 1. It also states that solar electricity became cheaper than grid electricity from fossil fuels in many countries from 2012 onward 1. A report on U.S. PV cost benchmarks documents reductions in capital cost and levelised cost of electricity from 2010 to 2024 19.
Forecasts of solar's future share differ. A 2015 study cited by Wikipedia predicted that solar could supply 20% of electricity consumption by 2030, while the International Energy Agency predicted 16% by 2050 1.
Harvard Business School, citing the installer Sunrun, reports an average U.S. rooftop installation cost of about $25,000, down from $40,000 in 2010 5. It adds that Americans often pay tens of thousands of dollars more than families in England, Australia, Japan and Germany 5. SEIA estimates that permitting costs can add up to $7,000 per system 5. It also estimates that a one-week permitting delay leads 5% to 10% of homeowners to cancel 5. Balance-of-system components make up about half of installation costs, according to RMI as cited by Wikipedia 1.
Grid integration and limitations
#Panel output depends on the availability and intensity of sunlight, and panels have high upfront costs 1. Rooftop PV creates two-way power flows that networks were not traditionally designed for, which can cause over-voltage 1. Wikipedia cites Queensland, Australia, where more than 30% of households had rooftop PV by the end of 2017 1. Rooftop systems usually need a battery to provide backup power during outages 1.
Reuters commentary reports that Europe's growing solar output is lowering prices during peak production hours 7. It also reports that solar's capture rate relative to average wholesale prices is falling and that curtailment is increasing 7. The commentary attributes the root problem to too little flexibility, such as storage and demand response, rather than to too much solar 7. CPIA also cites grid congestion, curtailment and negative prices as factors slowing projects in several markets 6.
Yale Environment 360 reports that regulators in developing countries are struggling to keep pace with solar growth 8. It notes that rate and grid-connection rules there were written for systems built around large power plants 8. Wikipedia states that falling panel costs are driving adoption in the Global South, where many countries rely on expensive fossil fuel imports 1.
Materials, waste and recycling
#PV manufacturing uses toxic and reactive chemicals, including cadmium telluride, lead and hexafluoroethane, and produces byproducts such as silicon tetrachloride 1. For materials such as tellurium, gallium and indium, Investopedia states that the ability to expand production may be a greater constraint than known reserves 11.
There were 30,000 tonnes of PV waste in 2021 1. BloombergNEF estimated that annual PV waste would exceed 1 million tons by 2035 and 10 million by 2050 1. Wikipedia notes that coal power produced 750 million tons of fly ash in 2022 1. That figure refers to a different year and waste type and is not expressed per unit of electricity generated, so it does not allow a direct comparison with PV waste. Around 90% of decommissioned U.S. panels went to landfill as of 2023 1.
More than 80% of a silicon module's weight can be recovered by crushing it and separating the glass, plastics and metals 1. Cadmium telluride recycling is designed to recover up to 90% of the glass and 95% of the semiconductor material 1. EU law requires manufacturers to ensure panels are recycled properly 1.
Policy debates
#Solar PV is a renewable electricity source, and Wikipedia states that solar panels reduce greenhouse gas emissions compared with hydrocarbon-sourced energy 1. The same source lists dependence on sunlight, cleaning requirements and high initial costs as drawbacks 1.
Observers disagree about the causes of the recent slowdown. SEIA attributes changes in U.S. installation timing to tax credit deadlines and safe-harbour rules 2. Ars Technica suggests that changes to federal renewable-energy incentives and policy may have contributed 10. pv magazine reports that CPIA expects China's policy transition to account for much of the 2026 global contraction 6. pv magazine USA, reporting the views of the consultancy Intertek CEA, says that oversupply, expanding tariffs and technology shifts are reshaping the U.S. outlook 4.
Scripture
Passages quoted from the King James Version. The text is fetched, never written by a model.
And God said, Let there be lights in the firmament of the heaven to divide the day from the night; and let them be for signs, and for seasons, and for days, and years: And let them be for lights in the firmament of the heaven to give light upon the earth: and it was so. And God made two great lights; the greater light to rule the day, and the lesser light to rule the night: he made the stars also. And God set them in the firmament of the heaven to give light upon the earth, And to rule over the day and over the night, and to divide the light from the darkness: and God saw that it was good.
Their line is gone out through all the earth, and their words to the end of the world. In them hath he set a tabernacle for the sun, Which is as a bridegroom coming out of his chamber, and rejoiceth as a strong man to run a race. His going forth is from the end of the heaven, and his circuit unto the ends of it: and there is nothing hid from the heat thereof.
And God blessed them, and God said unto them, Be fruitful, and multiply, and replenish the earth, and subdue it: and have dominion over the fish of the sea, and over the fowl of the air, and over every living thing that moveth upon the earth. And God said, Behold, I have given you every herb bearing seed, which is upon the face of all the earth, and every tree, in the which is the fruit of a tree yielding seed; to you it shall be for meat.
Through wisdom is an house builded; and by understanding it is established: And by knowledge shall the chambers be filled with all precious and pleasant riches.
Sources
- 1.Solar panel — Wikipedia (opens in a new tab)
en.wikipedia.orgWikipedia (CC BY-SA 4.0)
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- 3.The dark side of solar (opens in a new tab)
brookings.edu
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Truth Ledger
Every checkable claim in the draft, checked by GPT-6.1 Sol and Grok 4.7. A claim is stated as fact only when both checkers confirm it from the cited sources; a split verdict is published with attribution, and a claim neither can confirm is cut.
Showing 45 claims.
- Verified
Wikipedia dates Charles Fritts's selenium solar cell to 1881, while a historical review dates it to 1883.
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Source [1] dates Fritts’s first commercial cell to 1881; [18] dates his functioning selenium cell to 1883. / Wikipedia gives 1881; the review gives 1883 for Fritts’s selenium cell.
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Russell Ohl created a solar cell design in 1939 and patented it in 1941.
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Source [1] explicitly gives 1939 for Ohl’s design and 1941 for its patent. / Wikipedia says Ohl created the design in 1939 and patented it in 1941.
Cites1
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Bell Labs created the first commercially viable silicon solar cell in 1954.
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Source [1] identifies Bell Labs’ 1954 cell as the first commercially viable silicon solar cell. / Wikipedia says Bell Labs made the first commercially viable silicon cell in 1954.
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Crystalline silicon accounted for 95% of worldwide PV production in 2021.
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Source [1] states crystalline silicon represented 95% of worldwide PV production in 2021. / Wikipedia states crystalline silicon was 95% of worldwide PV production in 2021.
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PV cell materials include silicon, CIGS, CdTe, perovskites and organic compounds.
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Source [17] lists all five materials or material classes. / The factsheet lists silicon, CIGS, CdTe, perovskites, and organic compounds.
Cites17
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As of 2024, bifacial panels were the leading choice for utility-scale PV installations.
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Source [1] states bifacial panels were the leading utility-scale choice as of 2024. / Wikipedia says bifacial panels led utility-scale installations as of 2024.
Cites1
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Concentrating sunlight can raise PV efficiency to around 45%.
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Source [1] says concentrating sunlight can raise efficiency to around 45%. / Wikipedia says concentrating sunlight can raise efficiency to around 45%.
Cites1
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Standard test conditions are 1,000 W/m² irradiance, an AM 1.5 spectrum and a 25 °C module temperature.
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Source [1] specifies all three stated standard test conditions. / Wikipedia specifies 1,000 W/m², AM 1.5, and 25 °C.
Cites1
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Typical modules of about 1 by 2 metres are rated from 75 W to 600 W.
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Source [1] gives approximate dimensions of 1 by 2 metres and ratings from 75 W to 600 W. / Wikipedia rates roughly 1-by-2-metre modules from 75 W to 600 W.
Cites1
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EIA states that module efficiency averaged under 10% in the mid-1980s, about 15% by 2015, and is approaching 20% for state-of-the-art modules.
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Source [13] provides the stated efficiency figures and time periods. / EIA gives under 10% mid-1980s, around 15% by 2015, approaching 20% now.
Cites13
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Experimental and space-satellite PV cells are nearly 50% efficient, according to EIA.
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Source [13] explicitly describes experimental and space-satellite PV cells as nearly 50% efficient. / EIA says experimental and satellite PV cells are nearly 50% efficient.
Cites13
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Longi reported a 28.29% efficiency for a hybrid interdigitated-back-contact cell, verified by ISFH, which is a world record for single-junction crystalline silicon cells.
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Source [9] confirms the 28.29% HIBC result, ISFH verification, and single-junction crystalline silicon world record. / Source reports Longi’s ISFH-verified 28.29% HIBC single-junction silicon record.
Cites9
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Longi said crystalline silicon cell efficiency had reached 96.2% of the theoretical limit.
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Source [9] quotes Longi’s statement that efficiency reached 96.2% of the theoretical limit. / Longi said efficiency reached 96.2% of the theoretical limit.
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A study cited by Wikipedia found crystalline silicon panels degrade linearly by 0.8% to 1.0% per year.
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Source [1] cites a study finding linear annual degradation of 0.8%–1.0% for crystalline silicon panels. / Wikipedia cites linear crystalline-silicon degradation of 0.8%–1.0% yearly.
Cites1
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A 2021 kWh Analytics study found median system-level degradation of 1.09% per year for residential and 0.8% for non-residential installations, above the common industry assumption of 0.5%.
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Source [1] provides the study year, system-level medians, and comparison with the 0.5% industry assumption. / Wikipedia reports those 2021 medians and the 0.5% industry assumption.
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Potential-induced degradation can cause power losses of up to 30%.
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Source [1] states potential-induced degradation may cause power losses up to 30%. / Wikipedia says PID may cause power losses of up to 30%.
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Solar modules are expected to have a service life of 20 to 40 years.
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Source [1] gives an expected solar module service life of 20–40 years. / Wikipedia says modules are expected to last 20 to 40 years.
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Average global soiling losses in 2018 were estimated at at least 3% to 4%.
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Source [1] estimates average worldwide soiling losses in 2018 at at least 3%–4%. / Wikipedia estimates 2018 average global soiling losses at least 3%–4%.
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A 2015–2018 UK study examined 80 PV-related fire incidents, more than 20 of them serious fires caused directly by PV installations.
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Source [1] reports 80 incidents investigated during 2015–2018, including over 20 serious fires directly caused by PV installation. / Wikipedia describes 80 incidents and over 20 serious PV-caused fires.
Cites1
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Global cumulative installed PV capacity reached 2,261 GW at the end of 2024.
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Source [15] gives cumulative global installed capacity of 2,261 GW at year-end 2024. / IEA-PVPS says cumulative capacity reached 2,261 GW at end-2024.
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The most probable estimate of PV capacity installed in 2024 was 601.1 GW, a 29% increase on 2023, with 553.3 GW as the documented minimum.
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Source [15] supplies both capacity estimates and the 29% increase compared with 2023. / Source gives 601.1 GW as most probable, 29% above 2023, and 553.3 GW minimum.
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Global cumulative PV capacity was about 1,185 GW at the end of 2022, supplying over 6% of global electricity demand.
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Source [1] states approximately 1,185 GW at year-end 2022, supplying over 6% of global electricity demand. / Wikipedia gives about 1,185 GW by end-2022, over 6% of demand.
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CPIA expects global PV additions to fall 8% to 612 GW in 2026 and to reach 864 GW a year by 2030.
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Source [6] reports CPIA’s forecast of an 8% decline to 612 GW in 2026 and 864 GW annually by 2030. / CPIA expects an 8% decline to 612 GW in 2026 and 864 GW by 2030.
Cites6
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China installed 72.07 GW of solar in the first half of 2026, about 66% below 212.21 GW in the first half of 2025.
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Source [6] gives 72.07 GW, 212.21 GW, and an approximately 66% year-over-year decline. / Source reports 72.07 GW, about 66% below 212.21 GW a year earlier.
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The United States installed 43.2 GWdc of solar in 2025, a 14% decrease from 2024.
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Source [2] reports 43.2 GWdc installed in 2025, down 14% from 2024. / SEIA reports 43.2 GWdc installed in 2025, down 14% from 2024.
Cites2
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Solar accounted for 54% of new U.S. generating capacity in 2025, and solar plus storage accounted for 79%.
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Source [2] states solar’s 54% share and solar plus storage’s combined 79% share. / SEIA says solar was 54% and solar plus storage 79% of new capacity.
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SEIA projects U.S. cumulative solar capacity to grow from 279 GWdc at the end of 2025 to 769 GWdc by 2036.
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Source [2] projects cumulative capacity rising from 279 GWdc at year-end 2025 to 769 GWdc by 2036. / The SEIA report expects growth from 279 GWdc in 2025 to 769 GWdc by 2036.
Cites2
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U.S. module manufacturing capacity rose from 42.5 GW to 65.5 GW in 2025, but production remained below domestic demand.
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Source [2] gives both manufacturing capacity figures and says actual production remained considerably below domestic demand. / SEIA says capacity rose from 42.5 GW to 65.5 GW, with production below demand.
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Through September 2026, U.S. solar generation was 48 TWh higher than a year earlier, which Ars Technica described as 22% growth and a slowdown.
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Source [10] reports the 48 TWh increase, 22% growth rate, and slowdown through September 2026. / Ars reports a 48 TWh increase, 22% growth, and a considerable slowdown.
Cites10
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U.S. solar electricity generation rose from about 5 million kWh in 1984 to about 204 billion kWh in 2022.
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Source [13] gives approximately 5 million kWh in 1984 and 204 billion kWh in 2022. / EIA states the rise from about 5 million to 204 billion kWh.
Cites13
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Preliminary Solar 4 determinations set combined duty rates above 100% on cells and modules from India, Indonesia and Laos.
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Source [4] states preliminary combined duty rates exceeded 100% for cells and modules from all three named countries. / Source says preliminary combined duties exceeded 100% for those three countries.
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The cost of solar PV electricity has fallen 85% since 2010, according to Wikipedia.
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Source [1] explicitly states solar photovoltaic electricity costs have fallen 85% since 2010. / Wikipedia says solar PV electricity costs fell 85% since 2010.
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Module cost was estimated at about US$0.60 per watt in 2012, compared with US$150 in 1970.
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Source [1] gives approximately US$0.60 per watt in 2012 versus US$150 in 1970. / Wikipedia estimates quantity cost at about $0.60/W in 2012 versus $150 in 1970.
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A 2015 study predicted solar could supply 20% of electricity consumption by 2030, while the IEA predicted 16% by 2050.
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Source [1] reports both forecasts with the stated percentages and target years. / Wikipedia cites the 2015 study’s 20%-by-2030 prediction and IEA’s 16%-by-2050 forecast.
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According to Sunrun as cited by Harvard Business School, the average U.S. rooftop solar installation costs about $25,000, down from $40,000 in 2010.
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Source [5] attributes the approximately $25,000 current average and $40,000 2010 average to Sunrun. / The HBS page cites Sunrun’s about $25,000 figure, down from $40,000 in 2010.
Cites5
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SEIA estimates that permitting costs can add up to $7,000 to a rooftop system and that a one-week delay leads to a 5% to 10% cancellation rate.
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Source [5] attributes both the $7,000 permitting cost estimate and 5%–10% cancellation rate after a one-week delay to SEIA. / The page attributes both the $7,000 cost and 5%–10% cancellation estimate to SEIA.
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Reuters commentary reports that solar's capture rate is falling across Europe and attributes the problem to insufficient flexibility rather than too much solar.
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Source [7] reports falling European solar capture rates and explicitly identifies insufficient flexibility as the root problem. / Reuters says capture rates are falling and blames too little flexibility.
Cites7
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More than 30% of Queensland households used rooftop PV by the end of 2017.
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Source [1] states more than 30% of Queensland households used rooftop PV by the end of 2017. / Wikipedia says more than 30% of Queensland households used rooftop PV by end-2017.
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Regulators in developing countries are struggling to keep up with solar growth under rules written for large power plants.
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Source [8] explicitly describes regulators struggling with solar growth under rules designed around large power plants. / Yale E360 says regulators lag under rules designed for large power plants.
Cites8
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For tellurium, gallium and indium, the ability to expand production may be a greater constraint than known reserves.
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Source [11] states production expansion may constrain these three materials more than known reserves. / Investopedia says production expansion may constrain these materials more than reserves.
Cites11
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There were 30,000 tonnes of PV waste in 2021, and BloombergNEF estimated annual waste would exceed 1 million tons by 2035.
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Source [1] reports 30,000 tonnes in 2021 and BloombergNEF’s estimate exceeding 1 million tons annually by 2035. / Wikipedia reports 30,000 tonnes in 2021 and BloombergNEF’s over-1-million-ton 2035 estimate.
Cites1
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Around 90% of decommissioned U.S. solar panels ended up in landfills as of 2023.
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Source [1] states around 90% of decommissioned U.S. panels went to landfills as of 2023. / Wikipedia says around 90% of decommissioned U.S. panels went to landfills as of 2023.
Cites1
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Removed claim: An article published by Brookings argues that solar advocacy coalitions have backed policies, including nuclear closures and trade barriers, that could make deep decarbonisation more expensive.
Not published: neither checker could confirm it.
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Source [3] supports the decarbonization concern and nuclear closures, but its truncated excerpt does not identify the mentioned barriers as trade barriers. / Excerpt supports the cost argument and nuclear pressure, but says only unspecified “barriers,” not trade barriers.
Cites3
Text is available under the Creative Commons Attribution-ShareAlike 4.0 licence. Written by Claude Opus 5.5 from the sources listed and checked claim by claim by GPT-6.1 Sol and Grok 4.7.