The Dutch government aims for a green hydrogen economy with a production capacity of 8 GW in 2032. This asks for a substantial need on pure water as feedstock for the required electrolyzers. Currently, the solution seems to be a linear approach with Reverse Osmosis (RO): either desalination of seawater or using drinking water as a source. However, this linear approach has many disadvantages. Firstly, in both cases there is a lot of waste heat that needs to be dealt with. Secondly, desalination of seawater requires a high consumption of electricity. This waste heat and electricity issue leads an elevated carbon footprint. Thirdly, drinking water is more and more becoming a precious source.
As a preferable route, water technology experts of Wageningen University & Research advise establishing an integrated system. With this Nexus-approach, most of the disadvantages of RO are tackled, while adding various valuable utilities for society. We call this the SeaHydrogen concept. Our approach utilizes the waste heat of the electrolyzers to produce pure water and valuable minerals from seawater, as well as electricity. The pure water is not only used as feedstock for hydrogen production but is more than sufficient to create an alternative source of freshwater as well. This helps to reduce the expected freshwater shortages in the near future. Calculations and preliminary pilot studies confirm that more pure water can be produced than is needed for hydrogen production. As an additional advantage of exploiting the waste heat, less cooling of the electrolyzer is needed. This minimizes the use of cooling water and also saves energy.
