Utility Week

38 | JUNE 2023 | UTILITY WEEK Water Analysis be di cult to determine, says Paul Aldous, technical director, Water Environment at AECOM. Aldous says domestic water changes are largely predictable but "the industrial sector doesn't have to plan in the same way. Their planning horizons are driven by economics, which makes them much shorter". He adds that a balance must be struck between meeting industry's needs and pro- tecting the environment. Although the 2030 production target is well within the 2025 to 2050 focus of the Water Resource Management Plans water companies are currently consulting on, the need to provide the hydrogen industry with water gets little more than a passing mention. Instead, according to Chris Fawcett, direc- tor, water management for , that issue is being addressed in ‰ ve regional plans that look more broadly at water needs. "We need to consider beyond the water industry," heŠsays. Power is a key aspect of these plans, says Fawcett, with National Grid's Future Energy Scenarios providing a basis for potential use. However, he adds that there is great uncertainty over the exact mix of power production and its likely location due to the competitive nature of the power industry. AECOM's Aldous says more feasibility studies are needed and these might need to be multi-sector. "Engage the water compa- nies, engage the regulators, and have that open debate. Not about economics of any particular scheme, but about the principles. "How do we manage water in a way that there is enough for the environment, enough for public supply, enough for all the other users, particularly agriculture, and enough for the environment so we don't damage it?" He says now is a good time for the hydro- gen industry to engage, with Water Resource Framework Plans and regional water plans out for consultation. He warns that unless the industry does engage it might ‰ nd its production plans come to nothing because its feedstock isn't there. Quantifying the potential impacts of larger-scale hydrogen production on water resources is one of the main aims of a new project working group at UK Water Industry Research (UKWIR). It aims to identify what is realistic in terms of hydrogen production compared to government targets. A larger role for water companies As well as bringing a myriad of challenges for the water sector, a hydrogen economy could also bring opportunities for water companies to harness the supply chain to lower emissions from their water processing activities. As well as looking at water demand, the UKWIP group will also consider how the water industry will both use and potentially produce hydrogen. It aims to provide guid- ance on business models for water company engagement in the hydrogen value chain, of which there are several options. One is to utilise the by-product of hydro- gen production – oxygen. Taylor explains: "There is little demand for oxygen from electrolysis, but the water sector may be positioned to use it. "Co-locating hydrogen electrolysis with wastewater treatment means you could use the oxygen in the process. It enhances the treatment and nutrient removal, so it could have a positive impact." Roughly 55% of the energy consumed by a typical sewage works is used to process wastewater, according to Thames Water sta- tistics, with reducing carbon emissions from treatment works also a key focus for the industry. Taylor says that sites could be chosen for early hydrogen production based on the location of water treatment works rather than solely on existing energy sector assets. This could help cut costs in Australia, which is put forward as an exemplar in the Water UK's Net Zero 2030 Roadmap. In Australia the drought-prone climate and reliance on fossil fuels makes hydrogen production pro- hibitively expensive. A thought leadership paper by Jacobs, published in 2020, considered the potential role of wastewater treatment plants in accel- erating the development of Australia's hydro- gen industry. Co-siting hydrogen production with wastewater treatment works would cut capi- tal and operating costs for the water sup- plier. At the same time the sale of oxygen would allow hydrogen production to be com- mercially viable while remaining in the nec- essary competitive price range. Another route water companies are exploring is to become hydrogen producers themselves. Again, there are several tech- nologies in trial at various stages of the water supply cycle which could produce hydrogen for use by the companies themselves and potentially others. Although it requires more processing, water companies are also exploring if waste- water can be used instead of drinking water. In 2020 NI Water became the ‰ rst com- pany in the UK to produce hydrogen through electrolysis at a wastewater treatment site when it installed a 1MW electrolyser to prove it could increase processing capacity, reduce carbon emissions and o¢ er grid £ exibility. Another option is to use microbial elec- trolysis cells, such as those trialled by Severn Trent at its sewage processing plant at Min- worth to treat wastewater while also produc- ing hydrogen. These cells consist of electromagnetic organisms which grow on recycled carbon ‰ bre mats and break down organic pollut- ants in wastewater to produce hydrogen. Severn Trent is also working on another trial which aims to convert ammonia from sewage into hydrogen, rather than just destroy the ammonia, as is current practice. If successful, the study will develop a more e cient method of processing the waste product while also producing a clean fuel which could be used in the transport industry. Severn Trent alone has the potential to recover up to 10,000 tonnes of green ammo- nia per year from its wastewater treatment plants, which could be converted into 450 tonnes of hydrogen. An extensive study into the commer- cial viability of water companies producing hydrogen has been carried out by Welsh Water. It plans to convert sewage-derived biogas to renewable bio-hydrogen at a plant near Cardi¢ . The plant would utilise 35GWh of biogas to help generate 2000kg per day of hydrogen, enough to ‰ ll up the equivalent of 100 buses. Welsh Water says that using the biogas to produce renewable fuels could have up to 10 times larger decarbonisation impact than using it to produce renewable electricity. However, a key step in the process is establishing that there is su cient local demand for the hydrogen to ensure commer- cial viability. Working with Cardi¢ Council, its study concludes that there is signi‰ cant appetite within the region from buses, refuse collection vehicles and critical response vehicles – particularly blue light vehicles for the police. In fact, the potential hydrogen fuel cell vehicle user demand in South East Wales could satisfy all daily production from the proposed facility within two years of opera- tions, commencing in the mid-2020s. The UK water industry estimates that approximately 2TWh of biogas could be diverted to produce biomethane. If half of this biogas is used to produce low-carbon hydrogen, the industry has the potential to produce 20 million kg of hydrogen. Lucinda Dann, features editor continued from previous page

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