SWANSEA: The £100m plan to heat the city centre with warmth from the sewage works

Heat from Swansea’s wastewater works could one day warm the city’s leisure centre, prison and biggest stores, under a network councillors were told could cost in the region of £100m.

Swansea Council has used a £218,300 UK Government grant to investigate a district heat network: a web of insulated pipes carrying hot water from a single source into large buildings.

Members of the economy and infrastructure service transformation committee heard the network could run from around Swansea University‘s Bay Campus on Fabian Way, through SA1 and into the city centre. Any further and too much heat is lost in the pipes.

Cardiff already has one, linked to the incinerator in Cardiff Bay.

Head of property services Geoff Bacon told the committee two heat sources had been examined: the data centre planned as part of the Blue Eden tidal lagoon scheme, and Dŵr Cymru’s wastewater treatment works.

The business case is being worked up on the treatment works, judged “a more certain option” than a data centre that depends on the lagoon being built first.

Potential customers, known as offtakers, could include the council itself, the leisure centre, the prison and Tesco, Mr Bacon said. They would buy heat at a guaranteed level for a period of years.

A data centre would hand investors a return of about 8%, the committee heard. The treatment works would still pay its way, but customers would pay more: a green tariff for renewable heat.

What the council will not do is pay for it. Mr Bacon said the authority was very unlikely to be the lead investor, owns none of the land involved and would simply be one customer among many.

“We haven’t got any great skin in the game,” he said.

An outline business case is now being finalised by consultants Granlund, with the feasibility work having begun in October 2024. Mr Bacon said taking the scheme to market within 12 to 18 months would be “extremely ambitious”, and a political decision was needed on what the council does with the idea.

Committee members for St Thomas pressed on what the ward would get from a scheme built on its doorstep. Mr Bacon said most of the work would sit south of Fabian Way, and any community benefit would rely on “the goodwill of a developer”.

Homes are largely out of the picture. Retrofitting existing streets was described as hugely disruptive, with the realistic residential option being new developments built onto the network from day one, and possibly some flats in SA1.

Cabinet member Cllr Andrea Harrington told the committee the council priced a Swansea heat network at about £14m when it last looked more than a decade ago. “It just goes to show how inflation works,” she said, calling the £100m figure “a staggering sum of money”.

She said the council’s role was as an enabler: “We can’t lead on everything. We can’t deliver everything.” Some schemes were best delivered by commercial partners, she said, “and this is one of them in my opinion”.

The council first announced a heating network was in the pipeline in 2024, when the idea was framed around cutting businesses’ energy bills and the city’s carbon footprint.

It was Mr Bacon’s last meeting with the committee before his retirement. Asked whether the scheme was on the ground floor, he told members the council had “come up in the basement”.