This dataset identifies 89 patent families published between 2015 and mid-2026 that match claims and abstracts referencing high-temperature steam electrolysis, SOEC operation and efficient hydrogen generation, cross-classified against the core electrolytic-production IPC codes. That count is a family-level figure, which neutralises duplicate continuation filings and multiple national filings of the same invention, so it is a fairer measure of underlying invention activity than a raw document count. Because publication lags filing by roughly 18 months, the true 2025–2026 total will be higher once pending applications publish.

Filing rose from 13 families in 2017 to a peak of 19 in 2022, and has not exceeded that level since, which reads as a flat-to-declining trend once the peak year sits at the midpoint of the tracked range. The most recent one to two years will revise upward as pending filings publish, so treat the apparent drop-off at the very end of the chart with caution. The broader pattern — a rise through the late 2010s, a peak around 2022, and a plateau since — suggests the core claim space around reversible SOEC/SOFC designs is largely staked out.

The most-cited records in this set are dominated by heat-management and reversible-cell architecture claims, including a family on reversible high-temperature electrolysis with hydride-tank coupling that carries 85 citations and a Sunfire GmbH filing on SOEC/SOFC/RSOC heat management at 83 citations. These citation counts favour older filings that have had more time to accumulate references, so they signal foundational influence rather than which assignee is most active today. Several of the most historically active assignees show zero filings in the latest tracked year, which points to a maturing rather than an expanding competitive set.

The United States receives the largest share of filings in this dataset at 40 of 89 records, with the European Patent Office second at 16, followed by Japan, Canada, India and the WIPO/PCT route in smaller numbers. That concentration means US filing and litigation risk is the primary clearance concern for anyone commercialising SOEC systems for the North American market, with Europe as the secondary jurisdiction to check. A filer targeting Asia-Pacific markets should note that Japan's count, while smaller, still exceeds Canada and India individually.

The IPC composition shows heavy concentration in C25B (all 89 records) and H01M (57 of 89), meaning the reversible SOEC/SOFC core is densely claimed. Smaller counts in C10G, C07C, C01B, F22D and B01J — each in the single digits — mark downstream integration areas such as refinery coupling, synthetic hydrocarbon co-electrolysis, boiler feed-water heat recovery and catalytic offgas conditioning that carry far fewer families. These thinner branches are where a narrowly drawn claim is more likely to clear prior art, though a full freedom-to-operate search against the dense C25B/H01M core remains essential before filing there.