The assignee ranking for this dataset covers 45 companies across 130 records, with a single leading assignee holding 41 records — far ahead of the fifth-ranked holder at 7. The top five assignees combined hold 66.9% of all 130 records, and the top ten hold 87.7%, so the field has a short, dominant leadership tier rather than a broad spread of comparable competitors. Anyone assessing competitive position should focus first on that top tier rather than the long tail below it.

Filing activity rose from a single record in 2017 to a peak of 23 records in 2021, then declined toward a midpoint of 9 records in 2022. Recent-year momentum among the leading assignees is at or near zero, which together with the post-2021 decline suggests the field has moved past its build-out phase. Because publication lags filing by roughly eighteen months, the very latest year in any such dataset will always look thinner than it eventually turns out to be, but the multi-year decline predates that lag effect.

The two largest IPC classes are F01K (steam and thermal power plants) and F25J (gas liquefaction and separation), each covering 40.8% of the 130 records in scope. F02C (gas-turbine plants) follows at 28.5%, with F01D and F17C both at 16.2% and smaller shares in H02J, B01D and F03D. Because a single record can carry multiple IPC classes, these shares add up to more than 100%, and they show that most claims concentrate on the thermodynamic cycle and the liquefaction process rather than on storage vessels or grid-side integration.

The classes with the lowest coverage relative to the core cycle and liquefaction classes are H02J (power supply and grid systems) at 10.8%, B01D (separation processes) at 8.5%, and F03D (wind motors) at 5.4% of the 130 records. That pattern suggests grid-side integration, membrane-based separation pre-treatment, and wind-hybrid liquefaction scheduling are comparatively under-claimed relative to the dense cycle and liquefaction art. A first claim in one of these branches would face less prior art density than a claim filed directly against F01K or F25J.

EP4679658A1, filed by Cnooc Gas & Power Group and published 2026-01-14, describes a liquid air energy storage system that routes LNG cold energy through a first main heat exchanger into a compressor group, and links a second main heat exchanger, hydraulic turbine, air separator and liquid air storage tank in sequence on the storage side. It is a recent filing rather than a long-established one, so its practical blocking effect will depend on prosecution outcome and jurisdiction. Anyone designing a system that integrates LNG cold energy with liquid air storage should review its specific claim scope directly rather than relying on the abstract alone.