Utility Week

36 | JUNE 2023 | UTILITY WEEK Water Analysis Hydrogen: A thorn in thewater sector's side? The most talked about obstacle to producing hydrogen is the massive amounts of renewable energy required, but what has been ignored is that the process also demands lots of water. D elivering the UK's hydrogen strat- egy could increase water demand by the equivalent of an extra 3.3 million people per annum. Depending on carbon capture and storage, the • nal total could be far•higher. For water companies already managing rising demand and increasingly scarce sup- ply, this equates to needing to • nd an extra 5% volume of drinking water annually. The vast quantities of renewable energy that will need to be sourced for hydrogen production has received ample air time but the critical role that water will play is only now emerging as a key issue to address by industry and policymakers alike. A joined-up approach has the potential to ensure hydrogen production is aligned with water availability, while co-siting with waste- water facilities could improve the business case for early hydrogen production and help the water sector meet its net-zero emissions targets. A hydrogen future While hydrogen plays a minimal role in the UK currently, it is expected to be centre stage in meeting the UK's net-zero ambitions. The government has been clear about its desire for the UK to be a major hydrogen producer. It's Hydrogen Strategy states that the UK's geology, infrastructure and techni- cal know-how makes the UK "ideally posi- tioned" to be a global leader in hydrogen. The strategy, published in 2021, set the target of 5GW of electricity to be produced from hydrogen by 2030, but this has since been upped to 10GW. The exact volume that the UK will ulti- mately require is unknown, but demand is likely to outstrip supply given its potential use within industry and transport, as a form of long duration storage, as a replacement for methane in balancing power plant, and potentially even replacing natural gas in domestic heating systems. According to National Grid's Future Energy Scenarios, one of the best indicators of likely demand, the UK could need as much as 330,000 tonnes of hydrogen by 2030, or as little as 60,000 tonnes. Work is now under way to try to better understand the extent of likely demand and its location – two key fac- tors that will a• ect water use. The production technology used will also have a big impact on the amount of water needed, with the UK looking to make both green and blue hydrogen. Hydrogen is cre- ated by splitting water into its elemental components. What di• ers between the dif- ferent methods is how this split is performed. The preferred option – green hydrogen – uses renewable electricity and between 9-14kg of water per kg of hydrogen produced. Blue hydrogen is produced from high- temperature steam from a methane source, such as natural gas. Blue hydrogen requires carbon capture and storage (CCS) to be con- sidered low-carbon but uses less water at 6-13kg per kg of hydrogen produced. As well as drinking water, desalinated water can also be used, but this comes at an increased cost and raises environmental questions around brine disposal when car- ried out away from coastal areas. Other options being looked at include try- ing to harness wastewater supplies, such as by Wales & West Utilities in its trial looking at using electrolysis on harvested rainwater. If successful, wastewater could lower operational barriers and reduce costs for green hydrogen production. In its hydrogen strategy, the govern- ment acknowledges the critical role water will play, saying it will require "signi• - cant amounts" and will continue engaging with parties in the water industry to ensure "appropriate plans are in place for sustain- able water resources." However, so far there is little public dis- cussion of water's relationship with hydro- gen production, either with regard to water requirement, or as an opportunity for the water industry. The water sector's perspective Water UK's Net Zero 2030 Roadmap puts the likely increase in water demand much higher than 5% – it sets it at between 15 and 20%. This • gure takes into account that supply is likely to drop in the future. Many areas in the east and south of England were classi- • ed as "water stressed" by the Environment Agency in 2021. The Climate Change Com- mittee foresees those water-stressed areas expanding in future unless there are sub- stantial changes in water use. Michael Taylor, innovation integration manager at Anglian Water Services, says the hydrogen economy must be sustainable. "[Hydrogen] can bring economic prosperity for a region, but it has to be sustainable and responsible," he says. Taylor maintains that meeting Water UK's estimate on a national level is "very achiev- able", but di¥ culty arises at the local level because it is not easy to transport water from one area to another. "We may struggle to identify su¥ cient water resources, especially in areas where there are other water users, like agriculture," he says. Where hydrogen production is located will therefore be key, but as most hydrogen will initially be needed by industry this will continued overleaf

• Cover