PR24 will be ‘key moment for process emissions’

The 2024 price review will be critical for water companies to reduce process emissions from sewage works to meet future UK carbon budget targets, Wessex Water has insisted.

The company’s head of sustainability and innovation, Dan Green, told Utility Week that firms must be able to invest in the necessary monitoring equipment for wastewater treatment processes and solutions to lower emissions of nitrous oxide, even if those solutions are not yet fully formed.

“PR24 is a key moment for process emissions, particularly for nitrous oxide emissions from sewage,” Green said. “We won’t necessarily know which solution we are going to go with – there could be a family of solutions that need to be worked into the business plan.”

At present there are no formal regulatory drivers for such investment, with limits on nitrous emissions self-imposed by the industry.

“We could be facing targets down the line as the UK looks to meet its sixth and seventh carbon budgets,” he explained.

He added that monitoring could be done via probes and sensors within a treatment process to provide data on the nitrous oxide forming within the liquid. This could be used to explore how the aeration regime could be changed to limit the nitrous oxide being gassed off into the atmosphere.

“We can start to work out roughly how many rigs are needed at a treatment works to gain that data and the software that would go with it and then ways to change the aeration regime within a sewage treatment tank to reduce the risk of nitrous oxide being expelled.”

A rollout at scale of such technology would be necessary at pace if the sector is to adequately quantify and manage and modify processes to lower such emissions. “We don’t want to be in the situation where we know how much we emit without doing something about it.”

While Green said a set regulatory target may not be the answer, he believes it does require Ofwat to agree it is necessary to invest in this kind of technology.

“In the absence of a firm permitted volume of emissions that each site is allowed, we know the sector wants to get its carbon footprint to zero,” Green said. “It depends on what steer we get from Ofwat to include in the business plan. Not including it would mean that it wouldn’t get funded until after 2029, which means another five years will have gone by without any concerted action.”

In its net-zero route map published last month, Wessex said achieving the targets would require challenging traditional attitudes to investment and infrastructure.