Utility Week

Utility of the Future: Business models and skills Yorkshire Water looks to anaerobic digestion The next generation of super-efficient anaerobic digestion technology is expected to result from a research partnership between Yorkshire Water and the University of York. The water company aims to treat 100 per cent of its sewage sludge using anaero- bic digestion from this year and make existing digesters work harder to process sew- age into biogas for electricity generation (Knostrop treatment works, pictured above). The York project is backed by funding from the Royal Society and involved con- struction of 60 five-litre automatically fed, temperature controlled anaerobic digest- ers in the Department of Biology at the University of York (known as System-60), as well as a pilot-scale digestion facility at Yorkshire Water's wastewater treatment works at nearby Naburn. The laboratory environments will be used to investigate the microbial communi- ties that drive digester performance and screen conditions (photograph of launch event below), the pilot rig will demonstrate the benefits at a larger scale to build a case for operational changes across the water company's digester fleet. Improvements to anaerobic digestion would mean more sewage sludge is processed in the same facilities, reducing the need to build new infrastructure, while boosting levels of renewable energy production and generating a higher-quality fertiliser by-product for farming. Professor James Chong at the Department of Biology commented: "The new facilities we've built allow us to mimic large-scale installations and use state-of-the- art techniques to understand how the microbial communities that drive anaerobic digestion change in response to the material that enters the digesters." Yorkshire Water treats around 150,000 tonnes of sewage sludge using anaerobic digestion each year. 10 | 17TH - 23RD JANUARY 2020 | UTILITY WEEK The bottom line "Who pays?" is a tough question to answer in the context of rapid decarbonisation, and the necessary investments in new technolo- gies, vehicle fleets, upgrades to treatment processes, etc, threaten to damage water company profits and put pressure on bills. Ofwat's decision in December in its final determinations for PR19 to order water companies to spend £51 billion on improv- ing services and infrastructure, as well as to cut customer water bills by an average of £50 over the next five years, may dampen some stakeholders' appetite for net zero. However, some low-carbon improve- ments involve minimal outlay or provide longer term cost savings by enabling more efficient operations. The cost of renew- able generation technologies like solar photovoltaics and wind turbines have sig- nificantly dropped and using a waste prod- uct like sewage sludge to generate biogas as an energy source is both economic and sustainable. Companies can work with suppliers to develop more efficient solutions and tech- nologies that avoid the need to build new infrastructure and plant, and investigate more eco- nomic procurement and commer- cial models. Yorkshire Water's Barber points to the success of a sustainable finance framework, adopted by the company last year, which requires that any pro- ject demonstrates clear environ- mental and social benefits before financial spend is approved. In addition, the sector-wide approach to net zero should provide opportunities to identify lowest economic cost options. For example, Company A could offer to invest in a project to mitigate emissions costing £1 million, but a project proposed by Company B could cut the same amount of carbon but cost half as much. Atkins' Cox comments: "[The sector needs to] identify cost-optimised solutions for each emissions reduction pathway, including time scales, milestones, key deci- sion points and required changes. This can then be used to create a simple strategic risk framework, underpinned by solid technical considerations and working with stake- holders to measure performance. However, the costs at present remain uncertain." This type of decision-making will be critical to ensure the sector delivers on net zero and lowers its high emissions profile, without adversely hitting the wallets of businesses and consumers. Decarbonising water "Some low-carbon improvements involve minimal outlay" The Utility of the Future is also the theme of Utility Week Live taking place at the NEC in Birmingham on 19-20 May. Visit www.utilityweeklive.co.uk for more information. continued from previous page

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