Material Insights · Understanding the Material World

Hydrogen and Water

Electrolysis makes hydrogen by splitting water, using about 9 litres of purified water per kilogram before cooling needs. The volumes are small next to farming, but many of the sunniest and windiest sites planned for green hydrogen, including in western India, are short of fresh water, so siting and water sourcing matter.

Hydrogen (chemical) and Water (commodity): 4 relationships.

How they are linked

1. Feedstock for electrolysis

Physical flow · Strong · Water to hydrogen

An electrolyser splits water into hydrogen and oxygen, so every kilogram of green hydrogen carries a fixed minimum water need, plus extra for purification losses and cooling.

  • about 9 litres water per kg of hydrogen from electrolysis, IEA estimate
  • about 50 billion litres water a year for India's 5 Mt green hydrogen target, WRI India estimate (consistent with 5 Mt x 9 litres per kg)

The 9 litres is close to the chemical minimum; real plants need more because feed water must be demineralised and many designs use evaporative cooling. Estimates that include water used to make the solar or wind power run higher. Today most hydrogen is still made from natural gas or coal, which also use water as steam and for cooling.

Sources: Scroll.in (Mongabay-India)

2. Water use differs by route

Substitution · Medium · Electrolysis uses less water than fossil routes with capture

Hydrogen from gas or coal with carbon capture needs water for steam and for the capture plant's cooling, so the water footprint per kilogram varies by production route.

  • roughly a third less water per kg for green hydrogen than for blue hydrogen
  • more than twice water per kg for coal-based hydrogen with capture than for green hydrogen

IRENA and Bluerisk found green hydrogen to be the most water-efficient of the low-emission routes. That favours electrolysis on water grounds, but the comparison depends on cooling design and on whether water is drawn from fresh sources, recycled waste water or the sea.

Sources: IRENA and Bluerisk; Canal Solar

3. Water stress at good sites

Shared risk · Rising · Local water scarcity limits hydrogen siting

The cheapest green hydrogen needs strong sun or wind, and many such places are dry, so projects compete with farms and towns for scarce fresh water unless they desalinate or reuse waste water.

  • more than a third of planned or operating green and blue hydrogen projects in areas of high water stress
  • about 5% estimated extra cost of desalinating or treating water, relative to green hydrogen cost

In India, Rajasthan, Gujarat (including Kutch) and Tamil Nadu have strong renewable resources but frequent water shortages. Desalination removes most of the conflict at a modest cost, but adds brine disposal and coastal siting constraints.

Sources: Scroll.in (Mongabay-India); Canal Solar

4. Green hydrogen targets

Policy · High in India · Hydrogen targets create new water demand

National hydrogen targets turn a small industrial water use into a planning question, because plants cluster in hubs where water must be allocated alongside power and land.

  • 5 Mt a year India's green hydrogen production capacity target for 2030
  • Rs 19,744 crore outlay of India's National Green Hydrogen Mission, approved January 2023
  • almost 100 Mt world hydrogen demand in 2024, less than 1% of it low-emission

India's mission pairs the 5 Mt target with about 125 GW of new renewable capacity. Globally, low-emission hydrogen is still under 1% of demand, so most water use for hydrogen today is at gas- and coal-based plants in refineries and fertiliser complexes.

Sources: IEA; The Tribune

For investors

Key learnings

  1. Water is a small cost in green hydrogen, around 5% extra if it must be desalinated or treated, but lack of a secure water source can stall a project.
  2. Projects at coastal sites with desalination, or using treated waste water, carry less permitting and community risk than those drawing on stressed groundwater.
  3. On water grounds electrolysis compares well with fossil routes fitted with carbon capture, which supports its case in dry regions.

What to track

  • Water source named in project approvals (sea, waste water, fresh): Reliance on fresh water in stressed districts raises delay risk (As filed · state environment clearances, company disclosures)
  • Electrolyser capacity reaching final investment decision: Shows how much new water demand is becoming real (Annual · IEA Global Hydrogen Review)
  • Groundwater stress maps for hydrogen hub districts: Worsening stress raises the cost and risk of inland sites (Annual · Central Ground Water Board, WRI Aqueduct)

For policymakers

Key learnings

  1. India's 5 Mt target implies about 50 billion litres of water a year, small nationally but material in dry districts where hubs are planned.
  2. Steering hubs to coastal sites with desalination, or requiring treated waste water, avoids competition with farms and towns.
  3. Water allocation should be planned with land and power for green hydrogen hubs, not left to project-by-project approval.

What to track

  • Water allocated to green hydrogen projects by source: Shows whether fresh water is being diverted from other users (Annual · state water resources departments, MNRE)
  • Green hydrogen production capacity commissioned: Progress towards the 5 Mt target and the water it will need (Quarterly · MNRE)
  • Desalination capacity in hydrogen hubs: More desalination reduces pressure on fresh water (Annual · state industrial development bodies)

India

India targets 5 Mt a year of green hydrogen by 2030, which needs about 50 billion litres of water a year, and several of its best solar and wind regions, such as Rajasthan, Gujarat and Tamil Nadu, face frequent water shortages.

Sources

  1. In India, the future of water-intensive green hydrogen ironically lies in water-scarce regions, Scroll.in (Mongabay-India) (2023)
  2. Water for hydrogen production, IRENA and Bluerisk (2023)
  3. Green hydrogen uses less water than blue hydrogen, report says, Canal Solar (2023)
  4. Global Hydrogen Review 2025: Demand, IEA (2025)
  5. Government approves launch of National Green Hydrogen Mission worth Rs 19,744 crore, The Tribune (2023)