Future cost and performance of water electrolysis: An expert elicitation study

TLDR

Renewable electricity storage via electrolysis is gaining interest, but high capital costs and uncertain future performance hinder investment, making expert elicitation a valuable tool for decision‑making. This study aims to elicit expert opinions on future capital cost, lifetime, and efficiency for alkaline, PEM, and solid‑oxide electrolysis technologies. Experts were surveyed to provide estimates of cost reductions, lifetime convergence, and efficiency changes for each technology, using a structured elicitation framework. Experts predict that R&D funding could cut capital costs by 0–24 % and scale‑up by 17–30 %, lifetimes may converge at 60,000–90,000 h with negligible efficiency gains, and innovations in cell‑level design and production methods—particularly in SOECs and zero‑gap AECs—could challenge PEM dominance, thereby lowering investment barriers and guiding policy.

Abstract

The need for energy storage to balance intermittent and inflexible electricity supply with demand is driving interest in conversion of renewable electricity via electrolysis into a storable gas. But, high capital cost and uncertainty regarding future cost and performance improvements are barriers to investment in water electrolysis. Expert elicitations can support decision-making when data are sparse and their future development uncertain. Therefore, this study presents expert views on future capital cost, lifetime and efficiency for three electrolysis technologies: alkaline (AEC), proton exchange membrane (PEMEC) and solid oxide electrolysis cell (SOEC). Experts estimate that increased R&D funding can reduce capital costs by 0–24%, while production scale-up alone has an impact of 17–30%. System lifetimes may converge at around 60,000–90,000 h and efficiency improvements will be negligible. In addition to innovations on the cell-level, experts highlight improved production methods to automate manufacturing and produce higher quality components. Research into SOECs with lower electrode polarisation resistance or zero-gap AECs could undermine the projected dominance of PEMEC systems. This study thereby reduces barriers to investment in water electrolysis and shows how expert elicitations can help guide near-term investment, policy and research efforts to support the development of electrolysis for low-carbon energy systems.