Techno-economic feasibility of photovoltaic solar electrodialysis with bipolar membranes

Abstract

Electrodialysis with bipolar membranes (EDBM) can transform concentrated brines into acids and bases through the application of an electric field. Nevertheless, the widespread use of EDBM is limited by its high energy consumption, typically based on fossil fuels. Yet, the integration of EDBM with renewable energy sources, like solar photovoltaic (PV), remains unexplored. This study presents a techno-economic analysis of PV-EDBM to produce NaOH and HCl from seawater reverse osmosis (SWRO) brines. An integrated PV-EDBM model was developed and applied to a hypothetical PV-EDBM plant located in the SWRO facility of Lampedusa (Italy). Results revealed that PV has no negative impact on the performance in terms of product concentration, specific energy consumption and current efficiency. Meanwhile, the levelized cost of NaOH for PV-EDBM was reduced by 20 % in comparison to the electrical grid mix, achieving 210 €·ton−1 NaOH on an annual average for PV-EDBM. Therefore, the investment associated with PV is offset by the benefits of reduced electricity costs from the grid. Consequently, EDBM emerges as a feasible solution to address resource scarcity, representing a significant step towards integrating renewable energies with advanced wastewater treatment technologies, thus paving the path to a greener future.