26.06.2024
Source: Energie & Management Powernews
An important aspect in the selection of electrolyser locations is the local water conditions. The industry association DVGW has now compiled information on this.
It is important to know the total water requirements when locating larger electrolysis capacities. In addition to the process water for splitting into hydrogen and oxygen, large quantities are usually required for cooling the systems. The German Technical and Scientific Association for Gas and Water (DVGW), together with its research center at the Engler-Bunte-Institute of the KIT (DVGW-EBI), has investigated how large the consumption can be and which factors play a role.
The detailed results have been compiled in a factsheet. This "enables planners and operators of electrolysers to select adequate processes and procedures that minimize the water footprint and at the same time ensure the economic feasibility of the project by taking sufficient account of the local conditions", according to the industry association.
The splitting of water into oxygen and hydrogen releases energy in the form of heat, which must be dissipated in order to keep the operating temperature stable in the optimum range between 50 and 90 degrees. The waste heat can be used to generate energy. However, if this is not possible on site, a cooling system must be used. In electrolysis, cooling processes with water are mainly used: once-through cooling and closed-circuit cooling. However, there are also systems that use air.
The National Hydrogen Strategy sets an expansion target of at least 10,000 MW of electrolysis capacity for 2030. Assuming 4,000 operating hours per year and an electrolysis efficiency of 70 percent, this corresponds to the production of 28 billion kWh of hydrogen per year. For the year 2045, the Federal Ministry of Economics assumes that the capacity could increase to around 80,000 to 100,000 MW. This corresponds to 220 to 280 billion kWh. The DVGW expects the electrolysis sites and therefore also the water demand to be unevenly distributed regionally and concentrated in the north of Germany.
The factsheet "Total water demand for water electrolysis - How big is the water footprint including cooling systems?" can be downloaded from the DVGW website.
Author: Günter Drewnitzky
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