The vast majority of green hydrogen projects in the global pipeline are in regions likely to be short of fresh water in the future, according to recent analysis by Oslo-based consultancy Rystad Energy. As a result, they will need desalination plants to produce water for their electrolysers.

“Using water to produce clean hydrogen will be a key factor for the energy transition, but most of the world’s planned green hydrogen projects are to be located in water-stressed regions,” says Minh Khoi Le, a renewable energy analyst at Rystad. “This creates a need for growth in the desalination market, and for more renewable energy to power it, adding more costs for developers.”

More than 70pc of hydrogen electrolysers proposed up to 2040, and nearly 85pc of green hydrogen capacity—are located in potentially water-stressed regions, according to Rystad. These projects will require up to 526mn m³/yr of desalination capacity. There are 14 green electrolyser projects planned in countries with extremely high water-stress levels, 53 in high water-stress countries, and 162 in regions with medium-to-high water stress.

620mn m³ – Potential desalination demand by 2040

The number of proposed green hydrogen projects is growing fast, Rystad analysis shows, with 206GW of installed electrolyser capacity aiming to produce about 30mn t/yr of hydrogen by 2040. These electrolysers will require 620mn m³/yr of purified water.

Hydrogen electrolyser projects in countries rated as high to extremely high on the water stress scale, all of which will likely require desalination for their water supplies, imply a potential demand of 126mn m³/yr from desalination plants by 2040—accounting for a fifth of total electrolyser water consumption. These include high-profile projects such as Alwusta in Oman and Neom in Saudi Arabia, as well as numerous projects in Chile and Spain.

At the same time, four of the five top regions by planned green hydrogen capacity—Australia, Central Asia, West Africa and the Middle East but not Western Europe—have water-stress levels rated as medium-to-high, excluding parts of each suffering extremely high water stress.

At medium water-stress levels, demand for fresh water is starting to converge with the level of available supply, according to think tank the World Resources Institute. But stress levels will rise over time with increasing consumption and climate change, it says.

Starting small

Despite adding to project costs, the need for desalination should not significantly slow the scale-up of green hydrogen capacity, Le says. This is because those projects slated to move ahead in the first wave of development tend to be smaller and located in area of less water stress.

“From our analysis, water-related challenges will be a real obstacle only for multi-gigawatt facilities,” says Le. “We expect these will only start development from very late 2020s or early 2030s. So there will be time for technologies to develop and desalination capabilities, for that matter, to catch up.”

 “If there are already renewable-powered seawater desalination facilities in the water-stressed areas, there are no real challenges to slow down the deployment of green hydrogen production,” Le adds. 

There are only a handful of commercial-scale desalination plants using renewable energy. Two of the largest are in Australia: the Kwinana development powered, by the 80MW Emu Downs windfarm, and the Kurnell project, supplied by the 140MW Bungendore windfarm, as well as a few smaller-scale desalination projects powered by solar PV in the Middle East.

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Author: Vincent Lauerman