The Scottish Government New Build Heat Standard is now being enforced which means that any new builds are not allowed to use polluting heating systems, like oil and gas boilers, and must use clean heating systems instead, such as heat pumps and heat networks.

In an episode of the Scottish Housing News podcast, the hosts spoke to Eoghan Maguire of Heat Networks Scotland at Vattenfall Heat UK about the delivery of a heat network in the new town of Shawfair, just south of Edinburgh.

What is a heat network?

Heat networks, or district heating, are a form of clean heating that do not rely on fossil fuels. Instead, they supply heat to consumers from a central source via a network of underground pipes carrying hot water. This form of heating avoids the need for individual electric heaters or boilers in every home.

The central heat source of a heat network can be inputted from various places, including energy from waste facilities, power stations, and data centres.

‘…heat networks [are] more efficient with the resources we have… the heat’s already there, we’re just moving it…’

A ‘heat exchanger’, which, for a residential connection, is about the same size as a small gas boiler, brings the heat into each building. The user has access to all the same heating controls. The central heating and hot water system works in the same way as with a gas-fired central heating system – the main difference is that no combustion needs to take place inside the building to generate heat.

Heat networks are most commonly used for high-density urban areas and can vary in size. Overtime, they can be extended, and new heat sources and heat demands can be added to the network. For example, a heat network in Amsterdam has grown over the past 20 years, starting in one area, and now provides heat to around 145,000 homes.

What’s happening at Shawfair?

The 3,000 new homes being built in the new town of Shawfair will all be connected to a heat network. The project is a combined venture by Vattenfall UK, Midlothian Council, and the Scottish Government.

The heat for this network is currently generated from the Millerhill recycling and energy recovery centre. But this may be expanded to extract heat from nearby old mine workings.

In terms of reducing emissions, the carbon content of a gas boiler is around 220 grams of CO2 per kilowatt hour. This comes down to nearly zero when using a heat network because the heat is generated predominantly from waste heat.

For the new build estate at Shawfair, it’s clear that a heat network is a viable option: they can start from scratch and do not need to build around existing sewage, electric, gas, and water systems. But what about heat networks for tenements? Is it possible?

Would a heat network work in a city like Edinburgh or Glasgow?

Maguire is positive about the potential for heat networks to grow into older buildings and older cities, drawing on the example of Amsterdam. Like Shawfair, Amsterdam’s heat networks began in the new build large developments on the outskirts and are now starting to go into the city. Vattenfall are also working to develop a heat network in the city centre of Bristol, which Macguire recognises is ‘a large-scale utility undertaking’.

He acknowledges the challenges of getting people to work together as well as issues with obtaining the workforce but says that heat networks are also an opportunity for Scotland to expand into a new sector and industry. He notes that working with communities and local stakeholders will also be important.

Heat networks have formed part of the Local Heat and Energy Efficiency Strategies for Glasgow City Council and City of Edinburgh Council, as well as other local authorities. While relatively few tenements are currently connected to a heat network, Shawfair and other schemes like it are potentially paving the way for more to transition to this low carbon form of heating – an alternative to heat pumps that can be tricky to install in many tenement buildings.

Listen to the full podcast episode or read the transcript.

^{Note: The featured image has been taken directly from the Shawfair website.}