The leading assignee in this dataset holds 154 of the 2,588 records in scope, with the top 5 assignees combined accounting for 22.8% of all records. That leaves the majority of filings spread across a long tail of organisations with fewer filings each, so no single company controls the field outright. Anyone assessing competitive risk should look past the single leader and review the broader ranked list, since a meaningful share of relevant art sits outside the top handful of filers.

Filing volume grew from 97 records in 2017 to a peak of 336 in 2025, passing through 169 at the 2022 midpoint, which is clear multi-year growth. The 2026 figure of 55 looks like a sharp drop, but publication typically lags filing by around 18 months, so the most recent year is always understated in any patent trend. The more reliable read is that the field grew steadily through 2025 and the true 2026 trajectory will only be clear once later filings from that year publish.

The heaviest claim density sits in F01K (steam and thermal power plants) at 30.1% of the 2,588 records, F04B (positive-displacement pumps) at 29.6%, and F02C (gas-turbine plants) at 27.2%. Because a single record can carry multiple IPC classes, these figures overlap rather than sum to a whole, showing that most filings combine compression, expansion and thermal-storage claims in one application. Grid integration (H02J) and pressure-vessel storage (F17C) are present but at noticeably lower shares, at 15.6% and 6.0% respectively.

China is the dominant receiving office with 1,584 of the 2,588 records, well ahead of the United States at 355, the European Patent Office at 153, WIPO/PCT filings at 143, Canada at 58 and the United Kingdom at 54. This distribution means a competitive or freedom-to-operate review limited to US and European filings would miss the majority of the documented patent activity in this field. Chinese-language search and translation are effectively required for a complete view of this landscape.

US20110100010A1, assigned to General Electric Company and published in 2011, claims an adiabatic CAES system built around a liquid thermal energy storage medium held in a container, circulated by pumps through heat exchangers, with a thermal separation system inside the container to maintain distinct temperature zones. It is one of the more cited records in this dataset, reflecting its influence on how later filings describe liquid-medium TES integration. Anyone designing a liquid-TES-based ACAES system should review its specific claim language on the separation mechanism and conduit coupling before finalising a design, though citation volume alone does not establish current enforceability or scope.