Keep proper journalism alive. It's time to Back the Cable
The Bristol Cable

Councillors sign off 20-year deal aimed at decarbonising Bristol’s energy networks

Councillors this week approved the two-decade City Leap partnership, paving the way for hundreds of millions of pounds to be invested into heat networks, retrofit and other renewable technologies in Bristol.

A map of heat networks that will be created under Bristol's City Leap programme

A map of heat networks that will be created under Bristol’s City Leap programme.


A major deal has this week been approved that paves the way for hundreds of millions of pounds to be invested into renewable energy in Bristol.

Cabinet members signed off on the City Leap deal between Bristol City Council and Ameresco, marking a “very important step” in the route to net zero emissions.

The two-decade deal involves projects that will transform how Bristol generates, distributes, stores and uses energy. Projects include new district heat networks, installing wind turbines and solar panels, retrofitting homes with insulation, and rolling out heat pumps.

The City Leap deal was approved by the council’s cabinet on Tuesday 6 December, and was welcomed – with caveats – by opposition Green councillors.

At least £424 million will be invested into energy projects in the first five years of the deal, which will see a new joint venture firm created.

Kye Dudd, the council’s cabinet member for climate, claimed Bristol’s pace of change over the past five years towards its goal of being net-zero by 2030 had been “pretty good, probably the best in the country”. But he acknowledged it was not enough.

“We’ve invested about £100 million in decarbonisation and energy efficiency of our energy system in the city,” Dudd said. “But we need a change in scale to match the problem we face.

“We don’t have the money as a council and the government isn’t stepping up to the scale of the challenge, so we thought four years ago, why don’t we get some alternative investment from the private sector,” added Dudd, who is one of the Labour councillors for Southmead. “This is a groundbreaking approach to scale up investment into energy decarbonisation [and] possibly a blueprint for other cities in the UK and Europe.”

‘An important step but not the whole story’

The idea for City Leap began four years ago when the council declared a climate emergency, pledging to cut Bristol’s carbon emissions in a bid to tackle climate change. The problem is the council does not have the necessary funding to get the city to net zero emissions, and the current government is not providing the cash to local councils either.

Council bosses sent out a prospectus in 2018 searching for potential companies to stump up the money needed to decarbonise Bristol’s energy network. More than 100 firms showed interest, and in April this year the council announced the winning bidders – American firm Ameresco will lead the majority of the work, and Swedish firm Vattenfall will build heat networks.

Ameresco has previously been sued in the US over allegations it misled Illinois schools in a similar deal, and in June Bristol’s mayor Marvin Rees acknowledged the partnership carried “risk”. But he said that this was worth taking, given that without private-sector cash the decarbonisation work would not take place.

Carla Denyer, Green councillor for Clifton East and co-leader of the party, described the City Leap deal as “a very important step in Bristol’s decarbonisation journey”, adding that she was “really pleased to see it happen”.

“This will lead to hundreds of millions of pounds investment, with a potential to that increasing to £1 billion in the longer term,” Denyer said. But she warned that “10 times” as much would be needed to meet carbon neutrality.

“I have a healthy scepticism about public-private partnerships – I think history has shown that putting essential public infrastructure into private or semi-private hands can often have undesirable outcomes,” Denyer said. “So in an ideal world I would have liked to have seen more local and national government investment directly.

“However, I recognise the extremely difficult situation the Conservative government has created for us here,” she added. “So I welcome this. It’s not the whole story. It’s necessary, but not sufficient — but it’s a great step.”

Over the next five years, Ameresco has promised to save 140,000 tonnes of carbon dioxide, install 180 megawatts of renewable energy generation, and invest £22 million in energy efficiency. The company is also promising to subcontract some projects to local firms and create 410 new jobs in Bristol.

Burning waste for heat energy

Under the City Leap deal, thousands of homes in Bristol connected to new district heat networks could have their homes warmed by burning rubbish in an incinerator in Avonmouth. A 20-kilometre pipe is planned to run through the city from an energy-from-waste plant, costing up to £100 million.

Ahead of Tuesday’s cabinet decision, scrutiny councillors put questions to Vattenfall bosses as to whether relying on burning rubbish for heat is environmentally sustainable, given the unknown amount of carbon dioxide emitted from incinerating non-recyclable waste.

An image of the planned strategic heat main running from Avonmouth

Stuart Allison, strategy director at Vattenfall, said: “Heat networks are recognised by the government as one of the most cost effective ways to decarbonise cities.

“The council has done some great work establishing some existing heat networks, which present the seed from which we can scale up and grow,” Allison said. “Bristol is really at the forefront of thinking with the scale and ambition needed to actually make a dent in the climate ambitions.”

Heat makes up half of UK energy demands, with most currently coming from burning natural gas, a fossil fuel that emits carbon dioxide. A huge focus across the country on cutting carbon emissions and tackling climate change involves changing how buildings are heated, to more climate-friendly technologies including heat pumps and heat networks.

One major City Leap project could see Vattenfall laying a 20-kilometre strategic heat main running from Avonmouth, past Cribbs Causeway and Southmead Hospital, then down through St Jude’s to Old Market. Heat would partly come from an energy-from-waste plant in Avonmouth, where rubbish that can’t be recycled is incinerated to generate electricity – something David Wilcox, Green councillor for Lockleaze, warned was “obviously not climate sustainable”.

Environmental campaigners warn that incinerating rubbish can harm the climate, particularly as much household waste is plastic, which is made from petrochemicals. According to Zero Waste Europe, incinerating a tonne of household waste produces between 0.7 and 1.7 tonnes of carbon dioxide. These emissions come from burning plastics, wood, paper and food.

Role for disused coal mines

As well as the energy-from-waste plant, the strategic heat main could be powered from other sources, such as old coal mines. Geological processes mean many abandoned mines are filled with warm water, which can be used to provide heat for district networks.

“It’s clearly a major infrastructure project for the city,” said Vattenfall director Allison. “It would run through South Gloucestershire into the city to supply fossil-free heat to the networks being built out in the city centre. Along the route we would be looking to connect up to other buildings along the way.”

Get our latest stories & essential Bristol news
sent to your inbox every Saturday morning

Allison told councillors that Vattenfall was approaching the project based on the principle of “not [becoming] reliant on one single source of heat, but looking to capture it from multiple sources”.

“So today while we would be looking to connect to the existing industrial processes in Avonmouth, we would be designing that pipe to accept at low temperatures from other sources along that route,” he said. “South Gloucestershire Council has done a lot of work looking at capturing heat from depleted coal mines. There are other sources of clean heat along the route.”

Allison added that heat currently generated at the Avonmouth energy-from-waste plant is “is ejected to the atmosphere”, so capturing it for the heat network would be more efficient. He added that Vattenfall would also explore using carbon-capture technologies.

There are two existing heat networks in Redcliffe and Old Market with a third being built in Bedminster. Vattenfall plans to install a further five, in the city centre, St Phillip’s Marsh, Spike Island, Ashton Gate, and the Frome Gateway, eventually connecting all the networks in the city.

Join 2,500 Cable members redefining local media

Your support will help the Cable grow, deepening our connections in the city and investigating the issues that matter most in our communities.

Join now

What makes us different?


Report a comment. Comments are moderated according to our Comment Policy.

  • This Council is out of its depth, on this project and this is very likely to be a much bigger money pit than Bristol Energy. Only time will tell but watch out for the increase in costs. Many of the London heating networks are costing their users way over the cap on domestic tariffs as costs are not regulated?


Post a comment

Mark if this comment is from the author of the article

By posting a comment you agree to our Comment Policy.

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Related content

How St Paul’s residents fought to make the Malcolm X Centre a space for the community

The Malcolm X Centre on Ashley Road is one of Bristol’s most well-known and treasured community venues. What’s less well remembered is the struggle local people went through to lay the foundations for that status.

Listen: The Debrief – why does transparency matter, and is the council getting any better at it?

It’s almost six months since the Cable asked why Bristol’s performance on FOI requests was so poor. As the city’s political system prepares for change, Alex Turner talks to Priyanka Raval about why this is important, and whether we can look forward to more open local government.

Explained: WTF are Bristol’s local elections all about?

Bristol goes to the polls in May to decide which party will run the city as we enter the post-mayoral era. Here’s your in-depth guide to the local elections.

Listen: The Debrief – Bristol is ditching its mayor, but what can it learn from Sheffield?

On 2 May 2024, Bristol will wave goodbye to its mayor and return to a committee system. Isaac Kneebone Hopkins chats with Priyanka Raval about what we can learn from Sheffield's experience of local government reform.

Bristol is about to ditch its mayor. What can it learn from Sheffield?

The clock is ticking down on Marvin Rees’ time in charge, with a new less centralised power structure based around committees replacing the mayoral model. With a similar transition having taken place in South Yorkshire, are there lessons for our city?

What matters most to you about Bristol’s local elections?

We want to hear from readers what questions they'd like us to answer ahead of our comprehensive guide to May's local elections.

Join our newsletter

Get the essential stories you won’t find anywhere else

Subscribe to the Cable newsletter to get our weekly round-up direct to your inbox every Saturday

Join our newsletter

Subscribe to the Cable newsletter

Get our latest stories & essential Bristol news
sent to your inbox every Saturday morning