The UK’s cities are full of energy. The problem is that much of it is being thrown away, writes Philip Ord, UK CEO, Qvantum.
Across urban areas, buildings, data centres, supermarkets, commercial premises, transport infrastructure and cooling systems are constantly releasing heat into the atmosphere. Invariably, this heat is treated as a by-product to be removed, rather than a resource to be captured. At the same time, nearby homes and buildings are consuming energy to create heat from scratch.
For a country trying to decarbonise heating at scale – as outlined in the Future Homes Standard published in March – this is a fundamental inefficiency. It is also a major opportunity.
From generation to reuse
The challenge of low-carbon heat is often framed around generation: what technology should replace the gas boiler, and how quickly can it be deployed? That matters, but it is only part of the answer. In dense urban environments, the bigger question is how we design heating and cooling infrastructure so that energy can be shared, balanced and reused across buildings.
This is where the UK has much to learn from Scandinavian markets. In countries such as Sweden and Denmark, low-temperature, or fifth generation, heat networks have long been used to capture surplus heat and redistribute it to where it is needed. Heat from industrial processes, energy recovery facilities and commercial buildings is not seen as waste. It is part of the wider urban energy system.
Unlike traditional high-temperature district heating systems, which typically move centrally generated hot water through insulated pipework, these ambient temperature networks operate at much lower temperatures. This changes the economics and engineering of heat sharing.
At lower temperatures, network losses can be dramatically reduced and the same pipework can support both heating and cooling. A building or dwelling that needs cooling can reject heat into the loop, via an individual water-to-water heat pump, while another building, or a home connected to the same network, can use that heat as an input. The network becomes less like a one-way supply chain and more like an energy sharing platform.
This distinction is important for developers and specifiers, particularly following the strengthening of Part O regulations on overheating. In a conventional model, heating and cooling are often treated separately. Boilers, chillers, dry coolers and rooftop plants are specified to solve individual building requirements. The result can be duplication of equipment, avoidable grid demand, and energy being wasted on one side of a development while being purchased on the other.
A low-temperature thermal network allows those flows to be considered together so, rather than forcing every building on the network to accept the same high operating temperature, each connection can take what it needs.
An urban heating ecosystem
For mixed-use schemes, regeneration sites and high-density residential developments, this has significant implications. A city block may include homes, offices, retail space, and leisure facilities operating with very different demand profiles across the day and year. Some buildings may need cooling when others need heating. Some may reject heat continuously. Data centres are an obvious example, with large and consistent cooling loads, but they are far from the only source.
The opportunity is to stop viewing these loads in isolation. If a source of surplus heat sits across the road from a major residential scheme, the strategic question should be why the infrastructure does not already exist to use it.
This is not only an emissions issue. It is a question of urban efficiency. Reusing local heat can reduce primary energy demand, ease pressure on electrical infrastructure and improve the value of existing assets. It can also support better building design by reducing the need for extensive equipment on roof space, which in cities carries a premium that matters commercially as well as technically.
There is also a resilience benefit. A network that can draw on multiple sources of ambient and waste heat is not dependent on a single central plant strategy. It can evolve as a development grows, as new buildings connect and as new sources of recoverable heat become available.
A shift in thinking
For specifiers, this requires a shift in thinking. Waste heat should not be treated as an optional enhancement added late in design. It needs to be considered at master planning stage, alongside grid capacity, plant strategy, phasing, pipe routes and long-term operation. The earlier those decisions are made, the easier it becomes to design a system that captures value rather than leaving it on the table.
Waste heat is not a technical curiosity. It is one of the UK’s most underused urban energy assets. The countries and companies that move fastest will be those that stop asking how to dispose of it and start designing infrastructure to share it.
