While the water required for a large-scale hydrogen production industry will be significant, it is not unusual compared with other industrial uses.
Page 47 of Australia’s National Hydrogen Strategy shows the theoretical amount of water needed to produce a kilogram of hydrogen for each production pathway.
In practice water requirements for hydrogen production will vary depending on factors including production method and technology, the water content of the input fuel and the need for additional water for indirect production requirements such as cooling and input water purification. Different electrolysis technologies have differing water consumption requirements.
To produce enough hydrogen to satisfy Japan’s projected annual imports in 2030 would require less than one per cent of the water now used by Australia’s mining industry each year. To be a major supplier of a large-scale global hydrogen industry in 2050, however, would require more water. Under strong hydrogen growth settings, water consumption in 2050 in Australia may be the equivalent of about one-third of the water used now by the Australian mining industry.
Australia will therefore need to consider how to balance hydrogen’s demands with other water priorities. In many areas there will be limited capacity given existing demand from agriculture, industry, mining and households. Other uses for water may have higher economic, social or cultural value. Social acceptance of hydrogen production will depend on it not unduly affecting these existing uses.
There are also options to increase supply, including recycling and desalination. The cost of the electricity to desalinate seawater to produce hydrogen is minor – likely less than five cents per kilogram of hydrogen.
(Source: Australia’s National Hydrogen Strategy)