This dataset tracks 910 patent families filed between 2015 and mid-2026 that combine green hydrogen production language with claims touching electrolyzer integration, levelized cost, intermittent operation, purification or compression. That is a bounded search scope, not a count of every hydrogen-related patent — broader searches without the IPC and claim-language restrictions would return a larger number. Because publication lags filing by roughly 18 months, the true count for 2025 and 2026 filings is understated in any snapshot taken now.

The assignee base is long-tailed rather than dominated by a single filer, with named organisations including Toshiba Corporation (Toshiba) and its energy-systems subsidiary showing among the more active filers and collaborators. Several assignees that were active in prior years show zero filings in the latest tracked year, which may reflect a real slowdown or simply filings still working through the publication pipeline. China accounts for the largest share of receiving-office activity at 500 of 910 records, so filer analysis that ignores Chinese assignees will miss a large part of the picture.

Electrolytic production (IPC class C25B) and non-metallic inorganic compound processing (C01B) together account for over a thousand of the classification hits across the corpus, far ahead of separation, catalysis, water treatment, fuel cells, hydrocarbon refining or gasification. This indicates that core electrolysis chemistry and the associated inorganic-compound handling are the most densely claimed areas, meaning new filings there face denser prior art than filings in adjacent branches like compression or intermittent-load control.

Not clearly. Filings rose from 16 in 2017 to a peak of 165 in 2023, but the 2022 midpoint already sat at 139, close to the eventual peak, and activity has been flat or declining since. Readers should treat the most recent one to two years with caution because of publication lag, but the overall shape of the curve — steep early growth followed by a plateau — is a real signal, not an artifact of missing recent data alone.

Relative to the dense electrolysis and inorganic-chemistry claim clusters, sub-areas such as intermittent-load electrolyzer stack control, integrated compression trains, catalyst regeneration loops and hybrid gasification-electrolysis routes carry noticeably fewer filings. That does not mean these areas are unpatented, but the filing density is thinner, which is generally where a well-drafted first claim has more room to stand without colliding with a large body of prior art.