A comparative economic assessment of freshwater versus chloralkali electrolysis for eMethanol production

In recent years, renewable-powered eFuels syntheses have gained significant attention due to their potential to reduce the reliance on fossil fuels and consequently greenhouse gas (GHG) emissions. However, the cost of eFuels production is still a major concern and is mostly driven by two major components: the cost of non-fossil based carbon dioxide (CO 2 ) that is expected to be sourced from direct air capture (DAC) technology, and the cost of H 2 production from conventional freshwater electrolysis. This paper explores the substitution of freshwater electrolysis with saltwater electrolysis, which yields a product-basket of eMethanol (eMeOH), caustic soda, chlorine and desalinated water, which are feedstocks vital to modern industry. This improves the total revenue generated from the equipment and energy consumed by the system as compared to the Benchmark freshwater based eMeOH production. For the normalized production of ⁓1.0 tonne/hour (t/h) of eMeOH, this novel process route consumes ∼18 % more electricity than the Benchmark but also produces ∼6.8 t/h of chlorine gas and ∼7.7 t/h of caustic soda. Using the same price index to compare the processes, the gross revenue of the considered process route is estimated at ∼5290 USD/t-eMeOH product basket, exceeding by far the gross revenue calculated for the Benchmark freshwater based counterpart at ∼800 USD/t-eMeOH. Consequently, for every unit of energy consumed, the eMeOH-containing product basket produced through the chloralkali electrolysis route exhibits the capacity to generate 6.6 times more revenue than the Benchmark, and thus produces eMeOH at significantly lower net cost. • Saltwater electrolysis transforms eFuels economics through multi-product synergy. • Integrated chlorine and caustic soda production boosts eMethanol profitability. • Renewable energy driven saltwater route sharply reduces net eMethanol production costs. • Chloralkali-based eFuel synthesis generates higher revenue despite energy increase.