Industrial scale feasibility of emerging membraneless flow electrolyzer technology: an ex-ante technoeconomic assessment

Traditional PEM and alkaline electrolyzers rely on membranes or diaphragms for gas separation. These membranes are expensive and failure prone. Therefore, the membraneless electrolyzer concept promises an intrinsically robust low cost electrolyzer technology as an alternative. The literature on membraneless electrolyzers so far, showing only cell-level designs of several cm² electrodes, does not capture the economic feasibility at scale. This technoeconomic assessment based on a 200 kW membraneless electrolyzer system closes this gap. It is found that the estimated membraneless stack cost can be higher than alkaline stack cost, as omitting the separator necessitates stringent electrolyte flow management. At an early adoption scenario, the price of membraneless stacks is ∼572 € kW⁻¹ in comparison to ∼544 € kW⁻¹ for alkaline stacks. Exploiting the stack cost reduction opportunities, the cost can be projected to be reduced to ∼367 € kW⁻¹. Regardless of the stack cost reduction, the levelized cost of hydrogen (LCOH) at ∼15 € kgH₂^-1 remains 30% higher than that for alkaline electrolyzers at ∼11.6 € kgH₂^-1, as the balance-of-plant capital and operating cost also scale up with the higher electrolyte flow required in membraneless electrolyzers. Hence, to unlock the full potential of the membraneless concept, innovative design of the stack as well as the balance-of-plant is crucial.