Green hydrogen's water bill

Saudi Arabia, Oman and Egypt have each backed large export-oriented hydrogen projects.^3 4 5 Electrolysis splits water, and the IEA puts the process requirement at about 9 kilogrammes of water for every kilogramme of hydrogen, excluding water treatment losses and cooling.¹ The practical figure is higher, and volume turns out not to be the real question.

What a kilogramme really draws

A detailed accounting comes from IRENA and Bluerisk. Proton exchange membrane electrolysis consumes about 17.5 litres per kilogramme on average, and alkaline electrolysis 22.3. Steam methane reforming with carbon capture consumes 32.2, and coal gasification 31, rising to 49.4 with capture.² On these figures, electrolysis is the least thirsty of the low-carbon routes.

The source changes the draw. The same schematic feeds 10 litres of deionised water into the electrolyser for each kilogramme. Taken from a river or aquifer, that needs 17.2 litres of source water. Taken from the sea it needs 28.6, because desalination rejects much of its intake as brine. Evaporative cooling adds 19.5 litres of make-up water, of which 14.6 evaporates.²

The volumes, honestly

NEOM Green Hydrogen Company is building for up to 600 tonnes of hydrogen a day, from more than 2.2 GW of electrolysis and around 4 GW of dedicated wind and solar.³ At IRENA’s electrolysis averages, 600 tonnes a day consumes roughly 10,500 to 13,400 cubic metres of water. That range is arithmetic on published intensities; the project publishes no water figure of its own.^2 6 Taweelah, one Abu Dhabi desalination plant, produces 909,218 cubic metres a day.⁷

The regional total confirms the scale. IRENA estimates that current hydrogen production across the GCC needs 136 million cubic metres of desalinated water a year, about 1.1% of the six countries’ desalination demand.² The larger volume sits elsewhere: about 6 billion cubic metres of seawater a year for cooling.²

Cost is not the constraint

The IEA (2021) puts seawater reverse osmosis at 3 to 4 kWh per cubic metre and a cost of about US$0.70 to 2.50 per cubic metre. That adds only US$0.01 to 0.02 to the cost of a kilogramme of hydrogen.¹ Water is a rounding error in the hydrogen price. What matters is specification, siting and who supplies it.

NEOM shows one arrangement. The project’s environmental assessment lists air and potable water as the ammonia plant’s feedstocks, with connections to existing utility networks for potable water and power.⁶ The hydrogen company buys water from the utility rather than drawing it from the sea itself: the assessment’s process schematic shows a utility area within the project scope receiving nanofiltration permeate and potable water and supplying water for electrolysis.⁶

On the utility side, NEOM’s own desalination procurement stalled. NEOM’s utility, ENOWA, signed a development agreement with ITOCHU and Veolia in December 2022 for a renewables-powered desalination plant at Oxagon. It was to start at 500,000 cubic metres a day with zero liquid discharge. The agreement expired in May 2024 and ENOWA discontinued the project.⁸

The signal for the sector

Hydrogen is best read as a new industrial customer class for water: modest volumes, strict specifications, coastal sites and schedules set by energy milestones. Cooling is the larger decision, because evaporative systems more than double a plant’s draw: IRENA puts cooling at 56% of a green hydrogen plant’s withdrawal. Air cooling is technically feasible, but IRENA says it has higher capital and operational costs and that no existing hydrogen facility had yet used it.² On our reading, the openings for water firms are the water treatment inside the plant, the long-term utility supply contract and the cooling design.

In the region

NEOM is the reference project. Its developer reported 90% overall construction completion in March 2026, with up to 4 GW of wind and solar due by mid-2026, electrolyser commissioning after that, and first ammonia in 2027. The company puts total investment at US$8.4 billion, backed by 23 banks.^9 3

Oman is next. ACME’s Duqm project reached financial close on phase 1 in July 2024 and expects first green ammonia in the first half of 2027, from about 20,000 tonnes of hydrogen a year.⁴ Its design includes a desalination plant of about 7,000 cubic metres a day.¹⁰ For the blocks Hydrom auctioned, the energy minister said in March 2025 that the first investment decision was expected in 2026 or 2027.^11 12

In Egypt, the Scatec-led 100 MW project in the Suez Canal Economic Zone shipped a first green ammonia cargo from pilot production in November 2023.⁵ In January 2026 its consortium still expected the full-scale investment decision within months.¹³ In December 2024 the zone counted 12 finalised framework agreements for green hydrogen, alongside 30 memorandums of understanding.¹⁴

Who is doing this

The buyers and operators behind the procurements this brief describes.

• ACWA PowerDeveloper / operator · Saudi Arabia
• VeoliaDeveloper / operator · Regional

Mandates, procurement routes and the rest of the region’s institutions are in the decision-maker directory.

What to watch

• H1 2027First green ammonia from ACME’s Duqm phase 1, whose design includes a desalination plant of about 7,000 m³ a day.^4 10
• 2027First product from NEOM Green Hydrogen Company, after its wind and solar are complete and the electrolysers commissioned.⁹ The first large plant to publish an operating water figure will set the benchmark for the projects behind it.

Further reading

• IRENA and Bluerisk (2023), Water for hydrogen production. A water accounting by production route, with a GCC deep dive. irena.org
• IEA (2021), Global Hydrogen Review 2021. Page 109 sets out water use and the cost of desalinated feedwater. iea.blob.core.windows.net
• NEOM Green Hydrogen Company, Hydrogen Complex ESIA executive summary (v1.1, June 2022). What the region’s largest project says about its water supply. nghc.com