Water underpins every economic and consumer activity, but much like the warnings with fossil fuel consumption, we need to change our ways.  The world faces a 40% global water deficit by 2030 under a business-as-usual scenario, warns the UN.

Hydrogen is unusual in that the industry is in its infancy, but with all the steep growth projections, is there enough water to support a hydrogen economy, in an era when pressures on water have never been greater?

Water is involved throughout the production process, whether as a feedstock, cooling agent for thermoelectric methods of producing hydrogen, such as steam methane reforming, and electrolysis. While most water can be recovered, it is not generally returned to the original body of water and treated as ‘consumed’.

The only sector in which the use of hydrogen does not regenerate the entirety of the water feedstock by fuel cell or combustion is chemical synthesis, which will account for 540 Mt of hydrogen, using at most 4.8bcm or 0.3 ppm of global freshwater annually, according to ACS research.

It estimates 2.3Gt of hydrogen requires 20.5Gt, or 20.5bcm per year, of freshwater, which accounts for 1.5 ppm of earth’s available freshwater, and green hydrogen production will consume 1.5 ppm of Earth’s freshwater or 30 ppb of saltwater each year, an amount smaller than what is currently consumed by fossil fuel-based energy production and power generation.

It concludes water supply will not be the limitation for electrolysers, and we should instead “continue to focus on technological improvements for the energy efficiency of electrolysers, which is currently the limiting factor and has the potential for significant advancements”.

Many have still questioned whether using hydrogen for energy storage and transportation fuel will force industries, such as the energy sector and agriculture, to compete for water resources – although it is unlikely that countries will switch entirely to a hydrogen-based energy supply.

Only nine of the 135 countries analysed by the World Economic Forum (WEF) would require an increase in their current freshwater withdrawal of over 10% to completely transition to hydrogen-based energy, whereas 62 countries would need to increase their freshwater withdrawal by less than 1%.

Singapore, which relies highly on neighbouring Malaysia for freshwater resources – and recently unveiled its National Hydrogen Strategy – tops the list. It would have to increase the water it uses to convert to hydrogen-based energy by about 46.4%. On the other hand, Tajikistan, being at the very bottom, would require an increase of only 0.056%. The average value for all 135 countries is 3.3%.

“The hydrogen economy also opens up interesting prospects for countries that are already experiencing water shortages, including Singapore and Qatar,” according to a WEF paper.

“It is unlikely that these two states will produce their own hydrogen, they will rely on imported hydrogen. This allows them to capture water produced from the reconversion of hydrogen back into energy, either via combustion or fuel-cell technology, and then reuse this high-purity water locally.”

It is clear that the shift to a hydrogen-based economy for most will not negatively impact water security or other water-heavy industries, it concludes.

“While hydrogen can gain a significant share of the transportation market, other energy-related sectors will most likely experience a mix of different technologies, which lowers the percentage of water used for hydrogen. In addition, when hydrogen is burned or converted with atmospheric oxygen in the fuel cell, water is formed, which can be captured and reused to produce more hydrogen.”

Professor David Hannah, Chair in Hydrology at the University of Birmingham and UNESCO Chair in Water Sciences, said we need to consider the value of water and our collective ability to value this precious resource remains inadequate, but the effects of climate change – including on human health, prosperity and security – are interlinked with safe and sufficient access to water.

“Sustainable water management is therefore an essential part of the solution to climate change,” he said.

“Water is the ‘climate connector’ that offers opportunities for collaboration across the Sustainable Development Goals, Paris Agreement targets on climate change and Sendai Framework on disaster risk reduction.

“Yet despite this, water resources, which are already under severe pressure in many regions of the world, remain under increased threat from climate change (as well as other human impacts causing pollution and restricting safe access), which amplifies water-related extremes including floods and droughts.”