Salinity-Gradient Power Patents: Top Companies & Filing Trends 2026
- 31.1% sits with five filers. The top 5 assignees combine for 225 of 723 records in scope, with a long tail of single- and few-filing entrants behind them.
- Filing peaked in 2021 at 70, then fell 51% by 2024. The 2021→2024 drop from 70 to 34 records is the clearest signal in the trend data — treat 2025-2026 counts as still filling in, not as continued decline.
- Separation and mechanical-power classes dominate; batteries and electrolysis trail. B01D (53.3%) and F03G (34.2%) anchor most filings, while C25B and H02N sit under 8% each — a gap between membrane engineering and electrochemical conversion claims.
Filing growth compares 2021 (70 records) with 2024 (34) — a three-year span. 2024 is the most recent year we treat as complete: publication lags filing by roughly 18 months, so 2025 onwards are still filling in and any growth rate that ends there would understate the field. Top-5 share is the combined record count of the five largest assignees divided by all 723 records in scope (CR5), not by the ranked leaders only.
What salinity-gradient power patenting actually covers
Salinity-gradient power covers technologies that extract energy from the mixing of waters with different salt concentrations — chiefly pressure retarded osmosis (PRO) and reverse electrodialysis (RED), alongside osmotic membrane systems sometimes bundled with desalination. The filing base in this dataset spans 2015 through the 2026 cut-off, with publication lagging filing by roughly 18 months, so the most recent one to two years understate real filing activity.
The 723 records in scope split across membrane separation, mechanical power conversion and water treatment classifications more heavily than into battery or electrolysis-adjacent classes, suggesting most patenting effort has gone into extracting and staging the salinity gradient itself rather than into downstream electrochemical conversion.
Filing trend and technology composition
Two views of the same 723-record dataset: how filing volume has moved year over year, and how records distribute across IPC subclasses.
Filing rose to a 2021 peak, then declined
Annual filings climbed from 56 in 2017 to a peak of 70 in 2021, then fell to 34 by 2024 — a 51% drop over that three-year span. Counts for 2025 and 2026 are still incomplete due to publication lag and should not be read as a continued slide.
Separation and mechanical classes lead by a wide margin
B01D (separation processes) appears in 53.3% of records and F03G (spring/weight and misc. motors) in 34.2%, with C02F (water treatment) close behind at 32.8%. Battery and electrochemical classes — H01M, C25B, H02N — each sit well under 20%, and since records can carry multiple classes these shares are not mutually exclusive.
Shares are the percentage of the 723 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Salinity-Gradient Power Patent Landscape with Eureka
This page is one run against one query. Ask Eureka your own question about salinity-gradient power patent landscape and every answer comes back with the patent numbers behind it.
Try EurekaA representative filing and the most-cited prior art
Apparatus for osmotic power generation and desalination using salinity difference
The filing describes a dual forward-osmotic-membrane reactor arrangement paired with a high-pressure pump, positioning osmotic power generation alongside seawater desalination in a single apparatus rather than as separate processes.Filed by Korea Institute of Machinery & Materials, published 2012-01-19.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20100183903A1 | Utility scale osmotic grid storage | 85 |
| 2 | US8795525B2 | Utility scale osmotic grid storage | 76 |
| 3 | US20110100218A1 | Method for combining desalination and osmotic power with carbon dioxide capture | 70 |
| 4 | US20160040648A1 | System for Harvesting Water Wave Energy | 67 |
| 5 | US20110044824A1 | Induced symbiotic osmosis [iso] for salinity power generation | 66 |
| 6 | US20120292187A1 | Reverse electrodialysis supported microbial fuel cells and microbial electrolysis cells | 64 |
| 7 | US20120012511A1 | Apparatus for osmotic power generation and desalination using salinity difference | 64 |
| 8 | US9738398B1 | Ejectable flight data recorder systems, methods, and devices | 55 |
| 9 | US20120006685A1 | Process for Preparing Composite Membranes | 53 |
| 10 | US20110073540A1 | Forward osmosis membranes | 52 |
Citation counts favour older records simply because they have had more time to accumulate citations within the searched corpus — read this as a signal of influence on later filers, not of current commercial relevance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Three findings that shape where to file next and who to watch.
A moderately concentrated field, not a monopoly
The top 5 assignees hold 31.1% of all 723 records and the top 10 hold 49.8%. That leaves roughly half the dataset spread across a long tail of smaller filers, universities and individual inventors — room to compete on technical merit rather than clearing a single dominant portfolio.
Volume has pulled back from its 2021 peak
Filing rose steadily through the late 2010s, peaked at 70 records in 2021, and had fallen to 34 by 2024 — a decline that predates the incomplete 2025-2026 counts, so it reflects a real pullback rather than a reporting artefact.
Membrane separation claims dominate the class mix
B01D and F03G together anchor most of the corpus, while electrochemical-conversion classes such as C25B (7.6%) and H02N (5.1%) remain comparatively thin — a gap between how the gradient is captured and how it is converted to usable electricity.
US and PCT routes lead filing strategy
The United States (185) and WIPO/PCT (102) are the leading receiving offices, ahead of Europe (91), Israel (52), Australia (49) and India (44) — a filing pattern consistent with early-stage commercial testing in a small number of jurisdictions before wider expansion.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to salinity-gradient power patent landscape, with the prior art for and against each one.
Leaders, collaborators and where the claim space is thin
The ranked leader holds 60 records; by fifth place that has fallen to 36, and by tenth to 22 — a steep early drop-off followed by a long, shallow tail typical of an applied energy field still short of a dominant standard.
One filer well ahead of the rest
The leading assignee's count of 60 is well clear of fifth place at 36, indicating a single organisation has built a materially larger portfolio than any single competitor, though not one large enough to foreclose the field.
Competitive middle tier
Between fifth and tenth place, counts fall from 36 to 22 — a group of established filers close enough in volume to be realistic licensing or partnership targets rather than a single blocking entity.
Research-institute pairings drive some of the densest claims
The strongest co-filing relationships pair individual inventors and academic-institute partnerships, including a French national research centre working with both an energy company and a university partner — a pattern suggesting some of the most cited claim clusters originated in applied research collaborations rather than single-company R&D.
| Assignee | Recent year | YoY |
|---|---|---|
| IDE Water Technologies Ltd | 3 | +50% |
| Applied Biomimetic AS | 0 | — |
| Oasys Water Inc | 0 | — |
| SALTPOWER HLDG APS | 0 | — |
| Fujifilm Manufacturing Europe BV | 0 | — |
| Korea Institute of Energy Research | 0 | — |
| NANA RAHUL S | 0 | -100% |
| FERIA RAFAEL A | 0 | -100% |
Where to take this analysis
The dataset points to a field with a clear leader, a thinning tail, and technology classes that have grown unevenly. Turning that into a filing or licensing decision means going deeper on specific claims and specific competitors.
Map claim boundaries around the most-cited records
The most-cited filings concentrate on osmotic grid storage and combined desalination-power systems — worth a freedom-to-operate check before drafting adjacent claims.
Explore claims in EurekaTrack the leader's recent filing behaviour
A portfolio leader with 60 records and a long tail behind it is worth watching for continuation filings or licensing moves rather than treated as static.
Monitor assignees in EurekaTest white-space claims against prior art
Under-claimed branches like electrochemical conversion of osmotic gradients look open on volume alone; a prior-art search confirms whether that is real or just a labelling gap.
Run a white-space search in EurekaCommon questions about salinity-gradient power patents
The dataset's ranked leader holds 60 of the 723 records in scope, well ahead of the fifth-place assignee at 36. The top five assignees combined account for 31.1% of all records, and the top ten for 49.8%, which means roughly half the field is spread across a long tail of smaller filers, universities and individual inventors. No single company controls the space outright, so competitive positioning depends on which specific claim clusters a given filer holds rather than raw count alone.
Filing rose through the late 2010s and peaked at 70 records in 2021, then fell to 34 by 2024 — a 51% decline over that three-year window. That is a genuine pullback rather than a data artefact, since it is based on 2024, the most recent year that can be treated as complete. Counts for 2025 and 2026 are still incomplete because publication typically lags filing by around 18 months, so they should not be read as evidence of a further slowdown.
Membrane separation processes (IPC class B01D) appear in 53.3% of the 723 records, and mechanical power classes (F03G) in 34.2%, with water treatment (C02F) close behind at 32.8%. Electrochemical and battery-adjacent classes — C25B, H02N, H01M — are all under 20%, indicating most patenting effort so far has focused on capturing and staging the salinity gradient rather than converting it electrochemically. Because a single record can carry multiple IPC classes, these shares overlap and do not sum to 100%.
The thinnest classes relative to the core membrane and mechanical-power categories are electrochemical conversion (C25B, 7.6% of records), non-membrane electric machine designs (H02N, 5.1%), and hydraulic-osmotic turbine coupling (F03B, 4.1%). These are not necessarily unpatented — they simply carry far fewer filings than B01D or F03G — so a prior-art check on the specific sub-claim is still essential before assuming open space. Polymer-based draw solution chemistry (C08J, 4.6%) is another comparatively thin branch worth checking directly.
The United States leads with 185 filings recorded at that receiving office, followed by WIPO's PCT route at 102 and the European Patent Office at 91. Israel, Australia and India follow at 52, 49 and 44 respectively. This pattern suggests filers are securing early protection in a small number of major markets before deciding on wider international expansion, which is typical for a technology still working toward commercial scale.
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Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing on this page constitutes an exhaustive prior-art, novelty, freedom-to-operate, or validity search, nor does it constitute legal, financial, investment, or professional advice, and it should not be relied upon as such. Any patent, commercial, or strategic decision should be verified independently and reviewed with qualified patent, legal, and domain professionals. Patsnap makes no warranties, express or implied, as to the accuracy, completeness, or fitness for any particular purpose of the information presented.
Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company’s registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.