Battolyser Systems, a Delft University of Technology spin-out, is building a device that does two jobs in one cell. Run it as a battery when grid prices are low, store the electrons in iron-nickel electrodes, then keep charging past full and the same cell starts producing hydrogen by splitting water. The company calls the device the battolyser, and the bet is that one integrated unit can solve grid imbalancing and electrolyzer underutilization at the same time, two of the harder economics problems in a decarbonized power system.
The technical premise comes from work by Fokko Mulder, a professor in TU Delft's Materials for Energy Conversion and Storage group, describing how an Edison-style iron-nickel battery transitions naturally into alkaline electrolysis at full charge. The Edison cell, dormant in industry for decades, has two properties that suddenly matter: it is robust to overcharge, and it runs on iron and nickel rather than lithium or platinum group metals. The battolyser exploits both. The cell stores energy with battery efficiency when prices are low and produces hydrogen with electrolyzer efficiency once full, capturing more revenue per asset than either function alone would justify.
Mattijs Slee runs the company as CEO. The leadership team has wrapped a commercial spin-out around Mulder's chemistry with manufacturing-scale ambitions. Battolyser has demonstrated the technology at pilot scale, including a deployment at the Magnum power plant in Eemshaven that RWE operates in the north of the Netherlands, where engineers ran an integrated battery-electrolyzer cell under grid-scale conditions.
The European Union's Innovation Fund, the bloc's largest funding program for low-carbon technology, has selected Battolyser as a recipient under its large-scale projects awards. The grant supports the company's plans to build a gigawatt-class manufacturing facility for battolyser cells in Rotterdam, anchoring a domestic supply chain for both grid storage and electrolyzer capacity inside the Netherlands. The Dutch government has been an early supporter through the national climate envelope, but the move from pilot to production runs through Brussels: Innovation Fund grants, IPCEI Hy2Tech and Hy2Use hydrogen designations, and the broader REPowerEU pipeline that is meant to absorb the supply gap the bloc faces in indigenous green hydrogen.
Three things to watch over the next twelve months. First, whether the Rotterdam facility breaks ground on the announced timeline and whether Innovation Fund disbursements arrive on the milestones the grant contemplates. Second, whether utility offtakers in Germany and the Netherlands sign multi-year contracts for the dual-function service, the customer profile most likely to underwrite the unit economics. Third, whether cell-level cost tracks the bidding curve from competing alkaline-electrolyzer manufacturers in China, since the European battolyser premium has to be defended on grid-arbitrage revenue, not on hydrogen cost alone.