The launch earlier this year of Tallaght District Heating Network means that, after years of hot air, district heating is finally becoming a reality. Trading as Heat Works, this is Ireland’s first publicly owned, not-for-profit energy company, providing low-carbon heat to public buildings in this part of southwest Dublin.
The project is the brainchild of South Dublin County Council and its energy agency Codema, and will initially provide heat for council buildings and for the Tallaght campus of Technological University Dublin. By 2025 133 affordable apartments in the area will also be connected.
The network uses excess heat from the Amazon Web Services’ (AWS) data centre to provide low-carbon heat to the network’s customers. The Tallaght data centre’s heat-collection systems provide this recycled heat for free, though it will not be free to users. However, it will be cheaper than fossil fuels and, more importantly, carbon free.
It is estimated that in the first phase of delivery of the Tallaght District Heating Network alone, carbon emissions in the area will fall by more than 1,500 tonnes per year.
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District heating currently accounts for less than 1 per cent of the Irish heating sector but its potential is significant. The Sustainable Energy Authority of Ireland’s (SEAI) National Heat Study, published last year, found that up to 54 per cent of heat demand in Ireland could be provided by district heating. To deliver on that, a District Heating Steering Group was set up to co-ordinate its development. The Government’s Climate Action Plan 2023 commits to implementing the recommendations of its report and to delivering up to 2.7TWhr of district heating by 2030.
Decarbonising Ireland’s existing stock of residential and commercial buildings, primarily those built before 2006, is one of the biggest challenges facing the country. As things stand, Ireland has the lowest share of renewable heat and cooling in Europe. To increase that, to increase security of supply from indigenous renewable heat sources, and to improve price certainty and affordability, district heating is seen as vital.
If you are unfamiliar with the concept of district heating, UCD associate professor Paula Carroll, a member of UCD’s Energy Institute and its Centre for Business Analytics, as well as a self-described “lapsed electronic engineer”, explains it simply. “In terms of analogy, it’s the equivalent of a gas network,” she says. “Thirty years ago we didn’t have one. Then they dug up the roads, and now we do.” And similarly to gas, if you’re near a district heating network, you can choose to connect to it.
“A district heating system is a network of hot water pipes. We have a little one here in UCD which, if it were a town, would be the eighth biggest in Ireland,” she says.
However, district heating only makes sense where there is a certain density of housing, as in Dublin; it is not a solution for rural areas and unfortunately, as Carroll points out, rural areas account for a significant amount of fossil fuel use.
It also requires additional kit, such as a heat pump at each home; and for heat pumps to be effective, homes must be fully insulated.
“A heat pump is like a fridge in reverse,” says Carroll. “Just as you’d never leave your fridge door open, if you haven’t got your house insulated, you are losing efficiency.”
Progress on our environmental goals is being made, step by step.
“We’ve had the weirdest weather all summer,” says Carroll. “I think [the climate crisis] is getting real to a lot of people, and certainly the Government is very serious about implementing its climate action plan.”
District heating may also help to allay concerns about the size, number and energy usage of data centres in Ireland.
“Many of these data centres have a public image issue,” says Carroll, who suggests that providing recycled heat “could be one way in which these multinationals can contribute and redeem themselves, so there are wins in this for everybody”.
Cloud Infrastructure Ireland (CII), part of Ibec, cites district heating is an example of where members of the business representative body are championing sustainability.
CII director Michael McCarthy describes the Tallaght District Heating scheme as an “innovative project”. It will, he adds, “help Ireland meets its 2030 emissions targets and inform good environmental practice by democratising the energy sector and contributing positively to the energy transition”.
“Cloud Infrastructure Ireland is committed to working with Government, national and local, and other stakeholders to drive the decarbonisation agenda at every level,” says McCarthy. “As an industry, we believe cloud service providers have led the way in this instance – district heating – and will inevitably encourage others to follow.”
Minister for the Environment, Climate and Communications Eamon Ryan chose to launch the District Heating Steering Group’s first report at the site of the next most likely district heating scheme to come on stream, the Dublin Waste to Energy facility at Poolbeg.
The plant has been operational since 2017 and, since day one, has had the pipes and pumping equipment required to send waste heat from its incineration facility into what will become the largest district heating network in Ireland.
Once the external pipe network is installed to meet it – which is currently out to tender by Dublin City Council – Dublin Waste to Heat will be able to provide heating for up to 50,000 homes in the locality, cutting carbon emissions by around 24,000 tonnes annually by reducing the use of fossil fuels. It is set to do this as soon as 2025.
“We have the plant all set up for it, ready to rock’n’roll,” says project director Kieran Mullins.
