Bipolar membrane electrodialyzers as flexible demand response resources: Co-optimization of cost savings and product formation

Bipolar membrane electrodialyzers (BPMED) are widely used for chemical production and processing, including in the emerging ocean alkalinity enhancement (OAE) industry. In this paper, we explore the potential of BPMED devices as flexible electrochemical loads within power system operations. Their ability to modulate power consumption in response to grid conditions enables the provisioning of load balancing and other ancillary services. Using a multi-objective optimization framework, we evaluate BPMED operation across 24-hour and monthly horizons to examine how dispatch strategies respond to electricity prices and grid conditions. Simulation results show that altering the relative weights of the choices in the objective function strongly shapes the operating patterns, with cost-focused strategies suppressing operation during periods with peak prices. Furthermore, we propose alternative formulations that optimize operations to achieve both cost savings and alignment with periods of lower grid-side carbon intensity (CI), as low grid-side CI is key to maximizing OAE efficiency. Specifically, for the representative operating conditions in this study, the optimized control strategies reduce electricity costs by up to ∼70–95% relative to baseline operation, while achieving net CO2 removal on the order of 2–3 ton/day, depending on the relative weighting of economic and environmental objectives. Additionally, a detailed sensitivity analysis highlights the importance of device properties, where low area-specific resistance (ASR) of the membrane and high current efficiency (CE) are observed to jointly unlock cost-effective operation. However, even modest shunt efficiency losses are observed to erode performance and decrease system value. Importantly, the analysis demonstrates that BPMED can serve as a controllable and flexible demand response resource, shifting load to support multiple grid-side objectives, including (but not limited to) renewable integration, alleviating peak demand, and providing co-benefits for system reliability. These findings underscore BPMED’s dual role as a process technology and a grid-supporting asset, pointing to promising pathways for operational optimization of multiple objectives.