One secret of our cities is that they generate heat almost everywhere you look. From the local data centre powering your Wi-Fi to the fridges in your local supermarket, usable heat is all around us – yet too often this heat is wasted. In London alone, there is enough heat wasted every year to meet 38 per cent of the city’s heating demand. Capturing and recycling even part of that energy through heat networks could keep homes, businesses and public buildings warm without having to generate as much new energy in the first place. If you’re reading this in the City of London – where E.ON’s Citigen is helping to heat, cool and power buildings – there is an active heat network literally underneath your feet!
Done properly, a large-scale roll-out of heat zones could become one of the UK’s most powerful tools for lowering energy bills and decarbonising cities. By moving away from volatile global fossil fuel markets towards locally produced, low-carbon heat, the UK can build a more stable, resilient and more affordable system. Simultaneously, investment in heat infrastructure can create tens of thousands of skilled jobs while supporting greener, more liveable. Heat zones are likely to be the biggest single change to our energy infrastructure for a generation and will demand close partnership between central government, local authorities, businesses and communities.
Our extensive experience of building and operating heat zones at scale across Europe holds some vital lessons for the UK:
Lesson 1: Heat Zones need scale
Europe shows that heat zones work best when they are planned at scale rather than building by building. In cities such as Malmö in Sweden, large, connected networks serve the vast majority of residents, allowing new neighbourhoods to plug in without constantly re-digging roads. Scale unlocks efficiencies, builds investor confidence and makes it easier to phase out fossil fuels and phase in cleaner sources of heat over time.
Lesson 2: Heat Zones require access to low carbon heat sources
The most successful European zones are anchored in the low-carbon resources on their doorstep – from rivers and lakes to sewage, industrial processes and energy-from-waste. Our Citigen heat network in the heart of the Square Mile taps a variety of heat sources – including the geothermal energy of the London Aquifer – to provide heating, cooling and electricity through a 12km network of pipes to homes, offices and iconic heritage buildings such as The Barbican and Guildhall.
Lesson 3: The UK needs a more supportive regulatory environment
Replacing gas with heat networks will require billions of pounds of investment – and a framework that keeps costs fair for consumers. European experience suggests that clear long-term regulation, supportive planning rules and stable revenue models are critical to attracting low-cost institutional finance. Capital support to get projects built, combined with mechanisms that narrow the price gap between electricity-powered heat pumps and gas, can help crowd in private investment while ensuring households and businesses are protected.
Lesson 4: Coordinate the delivery of infrastructure to maximise benefit
Digging up streets for new pipework can be disruptive – but it is also a once-in-a-generation opportunity to rethink how our cities work. Across Europe, heat zone construction is often coordinated with upgrades to other utilities, new cycle routes, greener walkways and sustainable drainage systems. By aligning heat networks with wider regeneration plans, cities can cut overall costs, reduce disruption and leave neighbourhoods more resilient, attractive and ready for a low-carbon future.
Lesson 5: Support and incentivise customers to join the Heat Zone
A heat zone is only as effective as the number and diversity of buildings connected to it. European cities combine clear expectations to connect with strong, tailored support: energy audits, building-level efficiency upgrades and integrated offers that bundle network connection with technologies such as solar, batteries or smart controls. Customers see lower consumption as well as lower-carbon heat, strengthening the commercial case and accelerating growth of the network.
Lesson 6: Harness Heat Zone investment to train and upskill
Heat zones are also an opportunity to create long-term, high-quality jobs. European schemes show how major infrastructure programmes can be tied to apprenticeships, local supply chains and targeted skills initiatives. In the UK, that means working with colleges, training providers and city authorities to build the technicians, engineers and digital specialists needed for the transition. Linking capital investment to green skills and local employment ensures the benefits are felt far beyond carbon and cost.
As the UK prepares to designate and deliver new heat zones – including the City of London – it has a chance to turn wasted heat into a strategic asset. By learning from European experience and working with partners who have already delivered city-scale schemes, we can move quickly from pilots to full-scale zones that cut bills, reduce emissions, boost resilience and create a new green backbone for urban life and ultimately futureproof our cites.