Swedish startup pioneers on-site carbon removal through salt formation eliminating need for geological storage

Swedish start-up Cestore AB has begun preparing to test a novel approach to permanent carbon dioxide removal that converts captured CO2 into stable, water‑soluble salts for on‑site storage. The company, founded in 2023, says the electrochemical process eliminates the need for compression, long‑distance transport and geological injection by chemically binding emissions into a form it describes as analogous to natural oceanic carbon sequestration.

According to the announcement by Cestore, the method produces salts that can be stored in water and , the company claims , yields electrical energy in the conversion step. Johanna Hultén, Cestore’s CEO and the inventor of the concept, is quoted as saying: “In our process, CO2 gas is converted into natural, stable salts that are chemically stored in water, in the same way that the oceans naturally bind carbon over thousands of years.” She added that because the conversion produces a benign, easily handled product, conventional CCS infrastructure such as pipelines and deep geological storage become unnecessary.

Cestore reports that an intermediate prototype, roughly 30 times larger than initial laboratory rigs, was completed in spring 2025 and independently assessed by RISE at technology readiness level four (TRL4). The company has lodged two patent applications covering the core electrochemical concept and is now moving to scale‑up and industrial pilot testing.

The pilot, labelled “Maris”, has received SEK 3 million in funding from the Swedish Energy Agency and will be carried out with Nynas AB as industrial partner and co‑financier. Nynas operates a hydrogen production unit at Nynäshamn that emits about 60,000 tonnes of CO2 each year. Peter Eriksson, Technical Director at Nynas, is quoted as saying: “For a point source like ours, a solution like this could be crucial – not least in combination with future biogenic fuels such as biogas. The project gives us the opportunity to explore a technology that has the potential to create both emission reductions and negative emissions, which can play an important role in Nynas’s long-term climate work.” Cestore aims to have a TRL6 pilot plant operating by summer 2026 and to evaluate conditions for a full‑scale plant capable of storing roughly 50,000 tonnes of CO2 per year at the Nynas site.

For industrial decarbonisation professionals assessing the proposition, the claimed advantages are clear: a potentially lower‑cost route that sidesteps the logistics and regulatory complexities of transporting and injecting CO2 underground, and a route that could be colocated with existing emission sources. However, industry observers will note that the broader CCS landscape remains diverse and contested. Major projects continue to pursue the conventional capture–transport–geological storage chain: for example, the U.S. Department of Energy’s CarbonSTORE initiative is developing field laboratories to accelerate validation of geological storage in different formations and to reduce commercial risks. Energy utilities such as SSE emphasise capture combined with secure underground storage in depleted fields or saline aquifers as a core decarbonisation pathway.

Large‑scale initiatives elsewhere underline the differing technical routes under development. Stockholm Exergi is progressing a multi‑billion‑krona investment to build one of the world’s largest facilities for permanent removal of biogenic CO2, while Ørsted has been developing and constructing capture projects in Denmark targeting several hundred thousand tonnes of CO2 annually. At the same time, equipment suppliers continue to expand capture options with modular amine and other solvent technologies designed for industrial integration.

Key questions remain for Cestore’s approach that industry decision‑makers will expect answered during piloting: whether the salts can be proven safe and permanent under regulatory scrutiny for discharge or long‑term aquatic storage; the full lifecycle carbon balance and energy requirements under real industrial conditions; scalability to multi‑site deployment; and the capital and operating cost profile compared with both conventional CCS and other removal technologies. Independent verification beyond TRL4 and demonstration of sustained operation at TRL6 will be critical to establish credibility with customers, regulators and financiers.

Cestore and Nynas have framed the pilot as an exploration of technical, economic and regulatory feasibility ahead of potential commercial roll‑out. According to the Swedish Energy Agency’s funding notice, the support is intended to move the concept from laboratory validation towards industrial proof‑of‑concept. For industrial players focused on decarbonisation, the Maris pilot will be watched closely: if the chemistry and operational claims hold up under scrutiny, it could offer an alternative pathway for on‑site negative emissions; if not, it will nevertheless contribute data to the evolving set of options for hard‑to‑abate sectors.