The DOI matches its Crossref record; 121 of the 122 references it cites were found in a registry or an index.
Hydrogen-Based Energy Systems: Current Technology Development Status, Opportunities and Challenges
Open accessAbstract
The use of hydrogen as an energy carrier within the scope of the decarbonisation of the world’s energy production and utilisation is seen by many as an integral part of this endeavour. However, the discussion around hydrogen technologies often lacks some perspective on the currently available technologies, their Technology Readiness Level (TRL), scope of application, and important performance parameters, such as energy density or conversion efficiency. This makes it difficult for the policy makers and investors to evaluate the technologies that are most promising. The present study aims to provide help in this respect by assessing the available technologies in which hydrogen is used as an energy carrier, including its main challenges, needs and opportunities in a scenario in which fossil fuels still dominate global energy sources but in which renewables are expected to assume a progressively vital role in the future. The production of green hydrogen using water electrolysis technologies is described in detail. Various methods of hydrogen storage are referred, including underground storage, physical storage, and material-based storage. Hydrogen transportation technologies are examined, taking into account different storage methods, volume requirements, and transportation distances. Lastly, an assessment of well-known technologies for harnessing energy from hydrogen is undertaken, including gas turbines, reciprocating internal combustion engines, and fuel cells. It seems that the many of the technologies assessed have already achieved a satisfactory degree of development, such as several solutions for high-pressure hydrogen storage, while others still require some maturation, such as the still limited life and/or excessive cost of the various fuel cell technologies, or the suitable operation of gas turbines and reciprocating internal combustion engines operating with hydrogen. Costs below 200 USD/kWproduced, lives above 50 kh, and conversion efficiencies approaching 80% are being aimed at green hydrogen production or electricity production from hydrogen fuel cells. Nonetheless, notable advances have been achieved in these technologies in recent years. For instance, electrolysis with solid oxide cells may now sometimes reach up to 85% efficiency although with a life still in the range of 20 kh. Conversely, proton exchange membrane fuel cells (PEMFCs) working as electrolysers are able to sometimes achieve a life in the range of 80 kh with efficiencies up to 68%. Regarding electricity production from hydrogen, the maximum efficiencies are slightly lower (72% and 55%, respectively). The combination of the energy losses due to hydrogen production, compression, storage and electricity production yields overall efficiencies that could be as low as 25%, although smart applications, such as those that can use available process or waste heat, could substantially improve the overall energy efficiency figures. Despite the challenges, the foreseeable future seems to hold significant potential for hydrogen as a clean energy carrier, as the demand for hydrogen continues to grow, particularly in transportation, building heating, and power generation, new business prospects emerge. However, this should be done with careful regard to the fact that many of these technologies still need to increase their technological readiness level before they become viable options. For this, an emphasis needs to be put on research, innovation, and collaboration among industry, academia, and policymakers to unlock the full potential of hydrogen as an energy vector in the sustainable economy.
Overview
The claims and statistics of this paper haven’t been checked yet.
Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.
Integrity signals
Registry
Cites
Statistics
Verification
Claims the paper makes
The claims and statistics of this paper haven’t been checked yet.
Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
The source backs part of the claim, not all of it — or backs it for a different population, condition or comparison.
In the citing paper
“When comparing common energy carriers, liquid ecofuels exhibit substantially higher gravimetric and volumetric energy densities than current battery technologies, although typically lower than conventional fossil fuels like gasoline or diesel [36,37].”
From Biofuels, E-Fuels, and Waste-Derived Fuels: Advances, Challenges, and Future Directions (2025) · cites this paper as [37]
Experimental — accuracy not yet measuredThe source backs part of the claim, not all of it — or backs it for a different population, condition or comparison.
In the citing paper
“Current battery technology, while advancing, faces limitations in energy density, restricting its applicability in long-distance aviation and maritime transport, where gravimetric and volumetric energy densities are critical [36,37].”
From Biofuels, E-Fuels, and Waste-Derived Fuels: Advances, Challenges, and Future Directions (2025) · cites this paper as [37]
Experimental — accuracy not yet measuredThe source backs part of the claim, not all of it — or backs it for a different population, condition or comparison.
In the citing paper
“Hydrogen, due to its low volumetric energy density, requires specialized high-pressure or cryogenic storage and transport, and a completely new refueling network for widespread use in transport [37,55].”
From Biofuels, E-Fuels, and Waste-Derived Fuels: Advances, Challenges, and Future Directions (2025) · cites this paper as [37]
Experimental — accuracy not yet measured
Self-check
Percentages, sums and reported differences re-computed from the paper’s own numbers.
The self-check needs the paper’s full text.
Citations
Cites
The United Nations Framework Convention on Climate Change
Sands, P. (1992) · Review of European Community & International Environmental Law · doi:10.1111/j.1467-9388.1992.tb00046.x · Cited by 3,602
Hydrogen production for energy: An overview
Dawood, F., Anda, M., & Shafiullah, G. (2020) · International Journal of Hydrogen Energy · doi:10.1016/j.ijhydene.2019.12.059 · Cited by 3,148
Hydrogen energy systems: A critical review of technologies, applications, trends and challenges
Yue, M., Lambert, H., Pahon, E., Roche, R., Jemeï, S., & Hissel, D. (2021) · Renewable and Sustainable Energy Reviews · doi:10.1016/j.rser.2021.111180 · Cited by 2,345
A review on hydrogen production and utilization: Challenges and opportunities
Ishaq, H., Dinçer, İ., & Crawford, C. A. (2021) · International Journal of Hydrogen Energy · doi:10.1016/j.ijhydene.2021.11.149 · Cited by 1,532
An overview of water electrolysis technologies for green hydrogen production
Shiva Kumar, S., & Lim, H. (2022) · Energy Reports · doi:10.1016/j.egyr.2022.10.127 · Cited by 1,526
Hydrogen storage methods: Review and current status
Usman, M. R. (2022) · Renewable and Sustainable Energy Reviews · doi:10.1016/j.rser.2022.112743 · Cited by 1,292
Hydrogen Production Technologies: From Fossil Fuels toward Renewable Sources. A Mini Review
Megía, P. J., Vizcaíno, A. J., Calles, J. A., & Carrero, A. (2021) · Energy & Fuels · doi:10.1021/acs.energyfuels.1c02501 · Cited by 1,276
Underground hydrogen storage: Characteristics and prospects
Tarkowski, R. (2019) · Renewable and Sustainable Energy Reviews · doi:10.1016/j.rser.2019.01.051 · Cited by 1,235
Recent development of hydrogen and fuel cell technologies: A review
Fan, L., Tu, Z., & Chan, S. H. (2021) · Energy Reports · doi:10.1016/j.egyr.2021.08.003 · Cited by 1,041
Hydrogen Storage for Mobility: A Review
Rivard, E., Trudeau, M. L., & Zaghib, K. (2019) · Materials · doi:10.3390/ma12121973 · Cited by 1,008
Flagged first, then by citations
Research works printed but not linked: 4
- Mankins, J.C. (2023, July 10). Technology Readiness Levels: A White Paper. Available online: https://www.researchgate.net/publication/247705707_Technology_Readiness_Level_-_A_White_Paper.
- Grot, W.G. (1982). Electrochemistry in Industry: New Directions, Springer.
- Salvador Aceves, G.P. (2017, January 7). Performance and Durability Testing of Volumetrically Efficient Cryogenic Vessels and High Pressure Liquid Hydrogen Pump. Proceedings of the DOE Annual Merit Review and Peer Evaluation Meeting (AMR), Washington, DC, USA.
- IRENA (2023, July 10). Global Hydrogen Trade to Meet the 1.5 °C Climate Goal: Part II—Technology Review of Hydrogen Carriers. Available online: www.irena.org/publications.
Cited by
Sorted by citations
Items 201–269 of 269
Role of hydrogen powered fuel fells for a sustainable future
Mani, S. B., Kasimani, R., Rajamohan, S., & Sacratees, S. (2025) · Elsevier eBooks · doi:10.1016/b978-0-443-34090-1.00004-x
Faraz, J. A., Tariq, S., Bilal, M., & Hussain, T. (2025) · International Journal of Innovations in Science and Technology · doi:10.33411/ijist/20257313531364
Rajesh, M. (2025) · Research Square · doi:10.21203/rs.3.rs-7493667/v1
Hydrogen storage methods and emerging challenges for a sustainable energy future
Singh, R., & Behera, U. S. (2025) · Elsevier eBooks · doi:10.1016/b978-0-443-34088-8.00065-3
Liu, J., Li, C., Tian, Y., Ren, H., Yan, Y., & Li, J. H. (2025) · Journal of Energy Engineering · doi:10.1061/jleed9.eyeng-6263
GNR-supported CoNi/Fe3O4 nanocomposites empower hydrogen evolution and environmental remediation
Halvacı, E., Akkoyun, B., Seyrankaya, A., & Şen, F. (2025) · International Journal of Hydrogen Energy · doi:10.1016/j.ijhydene.2025.152580
Hydrogen fuel cell technologies
Gupta, A., Kumar, R., Iliev, I. K., Beloev, H. I., Blažek, V., Najser, J., Frantík, J., & Gupta, N. (2025) · Elsevier eBooks · doi:10.1016/b978-0-443-33771-0.00015-0
Agro-waste-based microbial biorefinery for biohydrogen production
Muthuvelu, K. S., Nagendran, P., Chandrashekar, G., Ravichandran, M., & Murugaiyan, A. (2025) · Elsevier eBooks · doi:10.1016/b978-0-443-34015-4.00014-8
Pt Single Atoms Outperforming Pd on Vo‐TiO 2 for Enhanced Photocatalytic Hydrogen Evolution
Shi, H., Wang, Q., Zhou, Y., Wang, C., Wang, Y., Li, J., Mele, G., & Wang, C. (2025) · Applied Organometallic Chemistry · doi:10.1002/aoc.70494
Covaci, R., Ungureanu, Ş., Dumitrașcu, D.-G., & Micu, D. D. (2025) · International Conference on Future Energy Solutions (FES) · doi:10.1109/fes65767.2025.11341834
Hydrogen Fuel Cells and Applications: Powering the Future
Ibitoye, O. T., Adewale, O. B., Kayode, J. F., Obamiyi Stephen, E., Nwankwo, S. O., & Afolalu, S. A. (2025) · NIPES Journal of Science and Technology Research · doi:10.37933/nipes/7.4.2025.si374
Khan, M. Z., Kostylev, M., Iyer, K. S., & Saunders, M. (2026) · International Journal of Hydrogen Energy · doi:10.1016/j.ijhydene.2026.153610
Introduction to Hydrogen in the Energy Transition
Hussain, M., Zhang, T., & Nazir, U. (2026) · Green energy and technology · doi:10.1007/978-981-95-5609-0_1
Douvi, E. C., Douvi, D. C., Tsahalis, J., & Tsahalis, H.-T. (2026) · Computation · doi:10.3390/computation14020038
Addressing Energy, Environment, and Housing Challenges Through Nanotechnology
Ahmad, S., Maqsood, Z., Hasan, A., Mahmood, S., & Hussain, A. (2026) · IGI Global eBooks · doi:10.4018/979-8-3373-3556-8.ch005
Kanwal, F., Asif, M., Tabassum, A., Hira, Rehman, S., Saddique, S., Saleem, N., Nasreen, H., Asghar, G., Zeb, H., et al. (2026) · International Journal of Energy and Water Resources · doi:10.1007/s42108-025-00473-6
Laboratory appraisal of measurement electrodes for a wet circuit in closed channels
Sionkowski, T., Halecki, W., & Chmielowski, K. (2026) · Archives of Civil Engineering · doi:10.24425/ace.2026.157462
Abbade, H., Intidam, A., Fadil, H. E., Lassioui, A., Hamed, A., Hasni, A., Ancary, M. E., & Mouyane, M. (2026) · Processes · doi:10.3390/pr14050844
Ahmed, B. A., Tahir, M. B., Parveen, A., Abbas, Z., Elsaeedy, H. I., & Said, N. M. (2026) · Journal of Molecular Graphics and Modelling · doi:10.1016/j.jmgm.2026.109364
Energy-economy analysis of 35 MPa/70 MPa liquid hydrogen refueling station schemes
Qu, S., Chen, G., Lv, H., Yin, H., De, B., Zhang, G., & Tan, Y. (2026) · International Journal of Hydrogen Energy · doi:10.1016/j.ijhydene.2026.154585
Mbengwa, M. C., Tetteh, E. K., & Rathilal, S. (2026) · Hydrogen · doi:10.3390/hydrogen7020048
Ghalgaoui, A., Amara, S., & Errachdi, A. (2026) · SSRN Electronic Journal · doi:10.2139/ssrn.6628552
Ghalgaoui, A., Amara, S., & Errachdi, A. (2026) · SSRN Electronic Journal · doi:10.2139/ssrn.6628551
Kumar, A., Kh, T. A., Azamovich, K. B., Nisar, K. S., Ahmad, A., & Malik, I. (2026) · International Journal of Hydrogen Energy · doi:10.1016/j.ijhydene.2026.155233
Ramirez-Gomez, S., Soon, A., & Ramirez, I. D. A. (2026) · Surfaces and Interfaces · doi:10.1016/j.surfin.2026.109428
Fan, G., Guo, M., & Wang, Y. (2026) · Energy Storage and Conversion · doi:10.59400/esc4190
Said, R. B. (2026) · Structural Chemistry · doi:10.1007/s11224-026-02805-6
Li-decorated T-graphene nanocapsule as a promised vector for H2 storage: A DFT study
Kumar, A., Khwaldeh, A., Raj, P. B., Kaur, J., Shhab, S. A., Samal, S. K., Sharma, R., & Singh, R. K. (2026) · Journal of Physics and Chemistry of Solids · doi:10.1016/j.jpcs.2026.113860
宋, 佳., Yang, Q., Ding, X., Li, H., & Li, Y. (2026) · International Journal of Minerals Metallurgy and Materials · doi:10.1007/s12613-026-3371-3
Gul, E. (2026) · Materials research proceedings · doi:10.21741/9781644904176-9
Hager-Roiser, S., Zimmerleiter, R., Gattinger, P., Zorin, I., Pedarnig, J. D., & Brandstetter, M. (2026) · Measurement Science and Technology · doi:10.1088/1361-6501/ae7d49
Hydrogen from biomass: Pathways, performance, and prospects
Sharma, N., Yadav, P., Kumar, S., Yadav, S., Warkar, S. G., & Kumar, A. (2026) · Next Materials · doi:10.1016/j.nxmate.2026.102549
Temperature-Optimized Control of PEMFC System Considering Efficiency
Hou, T., Song, K., Sun, C., Jiang, J., Fan, F., Xue, R., & Chan, S. H. (2026) · Lecture notes in electrical engineering · doi:10.1007/978-981-92-0549-3_11
Qi, Y., Zhao, X. L., Zhang, R., Cao, L., & Cai, F. (2026) · Research Square · doi:10.21203/rs.3.rs-10106643/v1
Lekoui, A., Saidi, K. M., Najri, B. A., Moussaoui, M., Laouar, R., Tlili, A., Khelili, S., Kivrak, A., & Kıvrak, H. (2026) · Geoenergy Science and Engineering · doi:10.1016/j.geoen.2026.214655
Wearable Technologies in Energy Harvesting for Sustainable Power Generation in Smart Textiles
Danso, E. K., Fobiri, G. K., Oppong, D., Seidu, R. K., & Tawiah, B. (2026) · Fashion and Textiles Review. · doi:10.35738/ftr.v7.2025.75
Olelewe, C. J., Makanjuola, O., Onyeachu, I. B., Enock, A., & Emekwisia, C. C. (2026) · International Journal of Advanced Engineering and Nano Technology · doi:10.35940/ijaent.g0489.13070726
Trovò, C., Introna, V., Santolamazza, A., & Mazzoni, S. (2026) · Energies · doi:10.3390/en19153544
The application of fuel cell vehicles in hydrogen-based renewable systems
Ahmadi, S., Nazar, M. S., & Nazari‐Heris, M. (2026) · Elsevier eBooks · doi:10.1016/b978-0-443-36684-0.00008-4
Zoghby, H. M. E., Elmesalawy, M. M., & Shindi, I. (2026) · Scientific Reports · doi:10.1038/s41598-026-64755-7
Jin, P., Ma, H., Cui, W., Zhao, Y., Yang, M., Kang, H., Cheng, X., Zeng, Y., & Wu, J. (2026) · Ocean Engineering · doi:10.1016/j.oceaneng.2026.127420
Advanced energy storage technologies for renewable power systems: a comprehensive review
Sutikno, T., Baswara, A. R. C., Arsadiando, W., Purnama, H. S., & Jopri, M. H. (2026) · Bulletin of Electrical Engineering and Informatics · doi:10.11591/eei.v15i4.4864
Shah, S. A., Mohammad, S. F., Gull, A., Arif, A., Riaz, M. S., Shaaban, I. A., Hayat, A., Nishan, U., Song, H., & Abbas, A. (2026) · Journal of Materials Science · doi:10.1007/s10853-026-13586-y
Haldar, B., Kilari, N., Manideep, B., Kumar, T. R. S., Karthik, K., Prabagaran, S., Mohan, M., Maranan, R., Rajendran, A., & Sathiyamurthy, S. (2026) · Environmental Progress & Sustainable Energy · doi:10.1002/ep.70640
Yu, W. B., Ng, Y. F., Li, H., & Zhao, H. (2026) · International Journal of Hydrogen Energy · doi:10.1016/j.ijhydene.2026.157170
Emezirinwune, M., Babatunde, O. M., & Olanrewaju, O. A. (2026) · Energies · doi:10.3390/en19174097
Fatima, K., Abro, S. A., Hussain, I., Noor, A., & Memon, S. A. (2026) · International Journal of Energy Research · doi:10.1155/er/4759362
Kota, S., & Muthu, J. (2026) · Hydrogen Economy & Engineering · doi:10.1016/j.hee.2026.100014
Eddahmani, O., Hadhoud, M., Farhan, N. M., Shakeel, A., Al-Buriahi, M. S., Hadda, T. B., Alzaidi, O., & Touti, R. (2026) · Chemical Physics · doi:10.1016/j.chemphys.2026.113504
Ali, W. (2026) · Process Integration and Optimization for Sustainability · doi:10.1007/s41660-026-00871-1
Agouri, M., Ouhenou, H., Fatihi, H., Abbassi, A., Sadiki, Y., Idrissi, M. E., Yaacoubi, A. E., Taj, S., & Manaut, B. (2026) · Chemical Physics · doi:10.1016/j.chemphys.2026.113500
Abd-elaal, A. M., Yousef, A., Abdelsalam, M. M., Rashed, I. G., & El-Halwany, M. M. (2026) · Catalysis Letters · doi:10.1007/s10562-026-05491-5
Shankaranarayanan, S., Murugan, D. K., & Said, Z. (2026) · Elsevier eBooks · doi:10.1016/b978-0-443-33767-3.00008-2
Hasan, M. M., Mahmud, M., & Rahman, M. (2026) · International Journal of Energy Research · doi:10.1155/er/3810306
Shcherbakova-Sandu, M. P., Meshcheryakov, E. P., Al-Shibah, A. M. M., & Gulevich, S. A. (2026) · International Journal of Hydrogen Energy · doi:10.1016/j.ijhydene.2026.157824
Feng, R., Chu, Q., Zhang, J., Liu, J., Lv, J.-T., & Tao, P. (2026) · Energies · doi:10.3390/en19194621
Safe regimes of hydrogen storage via a potassium formate/Pd-based catalyst systemPreprint
Franco, F. D., Russo, D., & Benedetto, A. D. (2026) · SSRN Electronic Journal · doi:10.2139/ssrn.7549354
Arshad, K., Sher, M., Fatima, A., Alanazi, S. J. F., Ashraf, S., Hayat, A., & Abbas, A. (2026) · Biomass and Bioenergy · doi:10.1016/j.biombioe.2026.110154
Peedikayil, J. J., Pandi, V. R., Suresh, M., & Merlo, M. (2026) · Energies · doi:10.3390/en19204804
Jannat, M., Khanom, M. S., Hossain, M. R. R., Banik, B., Hasan, M. M., & Ahmed, F. (2026) · SSRN Electronic Journal · doi:10.2139/ssrn.7601825
Waqar, M., Shah, S., Ullah, A., & Humayun, M. (2026) · Materials · doi:10.3390/ma19214441
Vedanarayanan, M., Pitchai, C., Chen, C., Kumar, U., & Heng-Jui, L. (2026) · Artificial Intelligence Chemistry · doi:10.1016/j.aichem.2026.100136
Anti, N. Y. D., Lotsu, J. S., Bimpong, G. Y., & Boakye, K. (2026) · Sustainability · doi:10.3390/su182110961
Hritani, Z. M., Aladwani, A. M., Bawazir, W. A., Akhtar, K., Bakhsh, E. M., & Khan, S. B. (2026) · International Journal of Biological Macromolecules · doi:10.1016/j.ijbiomac.2026.155054
Liu, S., Shi, Y., Huang, P., Qiao, X., Wang, J., & Zhang, N. (2026) · Energy Technology · doi:10.1002/ente.70693
Subbiah, G., Venkadeshwaran, K., Mohapatra, T. K., Molvi, I., Karthik, M. H., Dadhich, A., Pai, Y., Smerat, A., & Kamakshi Priya, K. (2026) · International Journal of Sustainable Energy · doi:10.1080/14786451.2026.2753312
Renewable energy exports logistics: Evaluating green hydrogen delivery and HVDC power transmission
Hajihosseini, M., Khajehsaeidi, Z., Yazdani, M., & Gorji, S. A. (2026) · Energy Reports · doi:10.1016/j.egyr.2026.109861
Al‐Saeedi, S. I., Hefnawy, M. A., Al‐Senani, G. M., Al‐Kadhi, N. S., Ahmed, H. A., & Medany, S. S. (2026) · RSC Advances · doi:10.1039/d6ra07425a
Kumar, S., Kharb, A. S., Bist, S., Yadav, H., Chawla, A. K., Awasthi, S., Singh, A., & Pandey, R. K. (2026) · Frontiers in Materials · doi:10.3389/fmats.2026.1942932
Metadata
- Authors
- Rolo, I., Costa, V. A. F., & Brito, F. P.
- Affiliations
- University of Aveiro (PT)
- University of Minho (PT)
- Corresponding author
- Brito, Francisco P.
- Venue
- Energies
- Publisher
- MDPI AG
- Published
- 2023-12-28
- Volume
- 17
- Issue
- 1
- Pages
- 180
- ISSN
- 1996-1073 (ISSN-L)
- OpenAlex
- W4390347341
- Cited by
- 258
- References
- 121
- Citations by year
- 2026: 117 · 2025: 105 · 2024: 36
- FWCI
- 11.88
- Type
- journal article
- Language
- en
- Open access
- gold
- doi.org
- Licence
- Locations
- Energies (publishedVersion, cc-by)
- RePEc: Research Papers in Economics (submittedVersion)
- DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
- Funders
- Fundação para a Ciência e a Tecnologia (SFRH/BD/145124/2019, UIDB/00481/2020, UIDB/04077/2020, UIDP/00481/2020-FCT, CENTRO-01-0145-FEDER-022083, Norte2020)
- Centro Portugal Regional Operational Programme (Centro2020) (SFRH/BD/145124/2019, UIDB/00481/2020, UIDB/04077/2020, UIDP/00481/2020-FCT, CENTRO-01-0145-FEDER-022083, Norte2020)
- PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (SFRH/BD/145124/2019, UIDB/00481/2020, UIDB/04077/2020, UIDP/00481/2020-FCT, CENTRO-01-0145-FEDER-022083, Norte2020)
- Topics
- Physical Sciences › Energy › Energy Engineering and Power Technology › Hybrid Renewable Energy Systems
- Physical Sciences › Materials Science › Materials Chemistry › Hydrogen Storage and Materials
- Physical Sciences › Energy › Energy Engineering and Power Technology › Advanced Power Generation Technologies
- Keywords
- hydrogen energy carriers, green hydrogen, water electrolysis, solid oxide electrolysis cells, proton exchange membrane fuel cells, hydrogen storage, high-pressure hydrogen storage, underground hydrogen storage, hydrogen transport, gas turbines, reciprocating internal combustion engines, energy efficiency, decarbonization, technology readiness level, hydrogen production cost, renewable energy integration, waste heat recovery
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
Statistics and arithmetic are recomputed, not judged.
Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.
What counts as a claim ›How we measure confidence ›How we check this ›
Are you an author, or do you see a problem with this page? Request a review
