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The Tallaght District-Heating Scheme

Eddie Conroy
3/6/2024

Present Tense

At just 6%, Ireland currently has the lowest share of renewable heat generation across the EU and is almost totally reliant on imported fossil fuels to meet its heat demand. This article discusses the benefits of South Dublin County Council’s recently commissioned district-heating scheme, its complex structure and procurement of same, and the role of the architect in such decarbonisation projects.

Photo of Heat Works Energy Centre Exterior (Image Credit: Joe Laverty & TODD Architects)

70% of the Dublin region is suitable for adaptation to DH (increasing to 86% in the city centre). There are sufficient waste heat sources in Dublin to service the equivalent of 1.6 million homes.

Space-heating accounts for 35% of total energy-related emissions in Ireland today. As one key component of its response to the National Climate Action Plan, South Dublin County Council (SDCC) committed to the decarbonisation of its county-town, Tallaght. Nationally, decarbonisation will rely on increasing renewable generation assets – wind and solar – on the grid to a target of 85% by 2030. This will enable significant carbon-savings through the widespread electrification of the heat and transport sectors.

The Tallaght District-Heating (DH) Scheme was identified as a pilot project to promote this switch to low-carbon, renewable heating. 70% of the Dublin region is suitable for adaptation to DH (increasing to 86% in the city centre). There are sufficient waste heat sources in Dublin to service the equivalent of 1.6 million homes; DH can recycle and harness this waste heat as a low-carbon resource for space-heating.

In 2016, as part of a five-city EU Inter-Reg programme to foster DH technology in northern Europe, €950,000 was made available (including €347,000 from SDCC resources) to underwrite initial work on the Tallaght DH network. This seed-funding allowed the formation of South Dublin District-Heating Company – Ireland’s first not-for-profit, publicly-owned heat utility, now trading as ‘Heat Works’.

The DH network was envisioned, championed, and project managed by the SDCC Architects Department, building on experience installing CHP, solar arrays, heat pumps, and bio-mass boilers in public buildings over a twenty-year period. The DH scheme was a collaboration between SDCC, Amazon, Fortum (the contractor), and the Dublin energy agency Codema, which has provided a low-carbon solution, optimising the potential of recyclable heat combined with innovative heat-pump technology. Heat Works is set up to act as an exemplar heat-network business in Ireland, delivering economic, environmental, and social benefits for residents and businesses while supporting the local and national climate action plans by reducing our carbon footprint.

Heat Source

At this time, Amazon Web Services (AWS) were planning a large data centre in Tallaght. As part of pre-planning discussions with SDCC, AWS agreed to collect and make available waste-heat from the data-centre’s cooling-system to the DH network. As part of this agreement, waste-heat collection equipment and ongoing heat delivery to Heat Works will be at the expense of AWS in line with their company commitment to global carbon-reduction. The Tallaght DH network is the first scheme in Ireland to capture and efficiently re-use waste heat from a large-scale data centre using bespoke 4G district-heating technology. 10MW of waste-heat is available for use in the Tallaght network on this basis.

Photo of Heat Works Energy Centre Exterior (Image Credit: Joe Laverty & TODD Architects)

It is currently estimated that by 2028 data centres may be using up to 29% of the national grid, and by 2030 will have added 13% to carbon-emissions on the grid. While not eliminating all primary energy use, DH can seriously offset the generation of both heat and carbon for space-heating required by DH customers and greatly reduce carbon emissions discharging energy-intensive waste-heat from cooling systems in data centres.

The Energy Centre and Pipe-Network

To utilise the waste-heat generated by AWS, a distinctive zinc-clad Energy Centre was constructed adjoining the data centre to collect, consolidate, and distribute hot-water to the DH network. The hot air from AWS is collected and run through a heat-pump to raise the temperature of water to 25-27°C. This water is then transferred to the Heat Works Energy Centre building where the temperature is raised again through bespoke centralised large-scale heat pumps to 85°C and sent through the pipe network. In turn, the servers in the data centre are provided with cool air as a by-product from the Energy Centre. The Energy Centre also includes full peak load back-up via a 3MW electric boiler to ensure heat supply to the network can be met at all times. The scheme is fully electric with no on-site combustion resulting in the elimination of particle emissions. In addition, the carbon content of the heat will continue to reduce over time in line with the decarbonisation of the national grid through increased deployment of renewable sources, e.g. onshore / offshore windfarms, solar power, etc [1].

This Tallaght DH scheme is currently providing both space-heating to buildings on the DH network and cooling to the data centre [2]. The scheme currently has planning permission for 400m³ of thermal water-storage. In time, this will enable greater flexibility and utilisation of off-peak electricity, which will increasingly enable the DH network to support the grid by providing greater demand-side response services to regulate large fluctuations associated with wind-power generation. The initial pipe network measures 1.6km in length, utilising different sizes of pre-insulated pipes to ensure minimal thermal losses. Hot water is distributed to customer buildings through the pipe network from the Energy Centre. Heat exchanger substations are located within the customer buildings with an indirect system (the network water crosses and heats the customers’ water, but they do not mix). Energy meters measure the amount of thermal energy used by the customer for heating spaces, HVAC systems, and sanitary hot water.

Network Map (Image Credit: Eddie Conroy)

Overall, the Tallaght DH Scheme produces CO₂ savings of 1500 tonnes per annum in the first phase of the scheme along with a reduction of 528kg in nitrogen oxide emissions. This will increase as the scheme expands and the input of renewably-generated electricity increases. In effect, fossil-fuel usage will be reduced by 100% as the grid is made fully renewable. The lack of combustion onsite eliminates particulates and provides cleaner air for Tallaght town centre.

In addition to road testing DH generation and control technologies in Ireland, the Tallaght scheme was set up to trial the legal, financial, procurement, and governance structures required for a heating network in Ireland. A series of innovative contract types had to be developed for the project carried out under the skilful direction and experience of Philip Lee and Associates Solicitors. The fledgling company required an experienced energy-supply company (ESCO) to design, construct, and operate the DH network. This role was tendered across the whole of the EU using the OJEU process. The tender was arranged as a ‘Competitive Dialogue’ in three stages culminating in the submission of a final design and financial bid. This included the design of the Energy Centre and the distribution pipe network. The preferred bidder was Fortum, a multi-national ESCO based in Finland with extensive experience in DH across the Nordic countries and Eastern Europe.

Procurement Models

A Local Energy-Supply Contract (Design, Build, Operate, & Maintain – DBOM) between the ESCO and Heat Works was agreed. This contract is divided in two phases – Construction Phase (Design & Build), and Operation Phase (Operate & Maintain). Heat Works buys the heat produced from the ESCO based on a fixed operational carbon-efficiency figure. The manner in which this heat is produced, and the risks associated with its production is the responsibility and risk of the ESCO, and the cost of electrical supply is at the risk of Heat Works. A separate new contract had to be developed and agreed to address the transfer of waste heat from AWS to Heat Works, and the return of lower-temperature water from the DH network to AWS to assist in cooling within the data centre.

Organisational Chart (Image Credit: Eddie Conroy)

A customer-contract was also required addressing the sale of heat from Heat Works to each customer. Heat Works are responsible for customer relations and calculation of customer bills. Monthly customer bills include fixed components (two standing charges for administration and network maintenance), and a variable charge for quantity of heat supplied. The initial customers are SDCC (County Hall and Library, the Innovation Centre, and two-hundred affordable apartments) and TUD Tallaght (main campus building, SSRH sports building, and the North Block Catering College). To date, 70,000m² of space are connected to the Tallaght network, and total investment stands at €8 million [3].

The contract for Design, Build, Operate, and Maintenance was signed in October 2020 and works commenced in 2021. Works were directly affected by COVID-19 government-imposed site closures. Testing began on the plant and network during October, November, and December 2022. Heat was delivered to first customers from 19 January 2023 with Substantial Completion achieved in July 2023. Since then, the district-heating scheme has been in its Operation and Maintenance phase.

Overall, the Tallaght DH Scheme produces CO₂ savings of 1500 tonnes per annum in the first phase of the scheme along with a reduction of 528kg in nitrogen oxide emissions.

Present Tense is an article series aimed at uncovering perspectives and opinions from experts in their respective fields on the key issues/opportunities facing Ireland's built environment. For all enquiries and potential contributors, please contact ciaran.brady@type.ie.

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Present Tense is supported by the Arts Council through the Arts Grant Funding Award 2024.

References

1. In March 2024 for instance, 43% of electricity from the grid was generated from fully renewable resources, with a target of 70% set for 2030.

2. The energy production system consists of primary production units, secondary auxiliary systems, automation and control systems, and electrical power systems based on 3MW of waste heat capacity and 5MW of district heat capacity. The system operates at 320% efficiency, i.e. every kW of electrical supply generates 3.20kW of heat to the network. The Energy Centre and network is controlled remotely from Finland via the SCADA system for optimal efficiency.

3. The project was funded through a blend of EU grant, Irish government grant, SDCC finance, and initial investment by Fortum, including:

•  €4.9 million grant funding through the Irish Government’s Climate Action Fund (Dept. of the Environment, Climate and Communications).

•  €670,000 via EU Inter-Reg project.

•  €770,000 through SDCC as matching funding to Inter-Reg grant and seed funding.

•  The remaining project upfront capital was provided by Fortum, to be repaid to them in monthly instalments over the ten-year duration of the DBOM Contract.

•  Capital funding for the Energy Centre equipment and network pipework was linked to connection charges payable by heat customers.

Contributors

Eddie Conroy

Eddie Conroy was County Architect in South Dublin County Council for 17 years in until his retirement in March 2023. He has worked as a public-sector architect in the areas of housing / renewal, masterplanning / urban space, and civic buildings. He has had a long-term commitment to renewable energy systems, and sustainable planning and transport.

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Drafting Identity: In Practice

Julia Przado
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Julia Przado
Ciarán Brady

Architecture is widely considered to be an incredibly innovative profession. For centuries, it has played a crucial role in shaping our urban landscapes and societies. This innovation and creativity which characterise the profession is first nurtured in the early stages of education. The excitement sparked by entering the first year of university develops into a growing sense of possibility as the years progress. However, for an industry so forward-thinking, the issue of how women fit into its identity structure has very much “remained unresolved” [1].

When I began my own career almost 7 years ago, it appeared to me that the field was largely male dominated, particularly in the way architects were celebrated and publicised. Many of the names, faces, and projects I encountered were male, which subconsciously shaped my understanding of who typically occupied positions of recognition and authority within the field. While my academic experience in architectural education has been shaped by a diverse student cohort, my professional experience beyond academia has highlighted an underrepresentation of women among firm partners, associates, and managers.

The statistics, supported by RIAI-sponsored research, show how gender balance in architectural education unfortunately doesn’t directly translate into female representation at the top level in the country. In Ireland, only 30% of registered architects are women, with as little as 16% occupying principal or leadership roles in RIAI-registered practices [2]. The issue, however, is not the lack of ambition, ability, or women’s desire to enter the field. Recent decades have seen a growing number of women choosing architecture as a career path with Irish architecture schools achieving gender balance since the 1990s. Since “as many women as men qualify with degrees in architecture”, it's important to question where the deeper rooted imbalance, often referred to as the “leaky pipeline", comes from [2]. This metaphor is often used to describe the disappearance of women from career pipelines as seniority increases.

Historically, architecture has been shaped by a culture of extreme working hours and a lack of flexibility, where wearing tiredness as a badge of honour is often expected. From under-recognition to pay gaps, the challenges women face within the profession remain largely unchanged. A survey discussed by Dervla MacManus and Katherine O’Donnell in the ‘I am an architect’, gender and professional identity in architecture research article reveals a clear contrast in how gender is perceived in architectural careers. While 45% of men reported that gender has no influence on their career thinking, only 2% considered it important. In contrast, 41% of women described it as extremely influential [1].

Since “architectural practice relies on long working hours, homosocial behaviour and creative control”, many women, particularly those with caregiving responsibilities, can find the profession difficult to sustain long term [3]. Those who do reach senior roles however, often receive less recognition in comparison to their male colleagues. From precedent case study lists handed out in universities, to the industry’s most prestigious awards; female architects contributions have not always received equal acknowledgement. The case of Denise Scott Brown is a well-known example of female achievements being overlooked, as she was excluded from the Pritzker Architecture Prize, which was awarded solely to Robert Venturi despite their collaborative work [4].

During my university exchange abroad one of the elective modules offered was titled ‘Women in Architecture’. It was a 5 credit course dedicated specifically to exploring women’s contributions to the field. I was excited to partake, however I equally found myself wondering why this topic needed to be defined seperately. Did the module come to life due to women’s work being significantly overlooked within the mainstream architectural curriculum? What stood out to me the most however, was how fast the class reached full capacity with a waitlist forming as a result. Its popularity suggested a genuine interest among students for a more expansive and inclusive learning environment, regardless of gender.

For students like myself who seek female role models on a daily basis, representation is incredibly valuable. Recognising and celebrating women is not only symbolic, but it actively shapes the aspirations of young women entering architectural education. How we record the history and achievements of all architects, despite gender or background, not only influences our understanding of the profession today, but also advocates for a more inclusive architecture culture. Conversations like these create a future that is not abstract or unattainable, but something women can see themselves embodying.

Experiencing representation first hand has deepened my understanding of what it truly means for women in practice. When I began my first role in the professional world of architecture, it came with the stress and imposter syndrome that often accompanies any new position, particularly your first. This pressure however, felt significantly eased after being assigned a female mentor; someone who reflected my background and experiences in a professional setting. This experience made a meaningful difference for me from the very first day. Her guidance played a key role in helping me settle in and grow in confidence. It also helped me understand the potential of my career development and the direction I wanted it to take. It allowed me to set goals that felt both tangible and exciting.

Recognition, representation and mentorship at the top tiers of the profession carry immense value. Having experienced it first hand, I understand how powerful it can be, not only for confidence building, but also for shaping drive and ambition. An industry with a ‘leaky pipeline’ misses out on a wider range of perspectives and approaches where design can suffer as a result. I hope the topic of a more inclusive architecture culture becomes an everyday norm – particularly for those starting out as young professionals, trying to navigate the uncertainties of their early careers in the pure chaos of the world of architecture.

18/5/2026
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Drafting Identity: The Crit as Performance

Kate Crowley
Present Tense
Kate Crowley
Ciarán Brady

The architecture crit as an assessment format has remained largely unchanged since its inception. Conceived in the 1850s by the Beaux-Art School curriculum, it marked a shift from apprenticeships at ateliers toward academic degrees at University [1]. Despite the profession itself undergoing numerous transformations, this aspect feels stuck in time. When asked to write a piece about my experience in architectural education, ‘crit culture’ immediately came to mind.

Ahead of presenting in front of a review panel, there is a feeling of discomfort. A mental note to speak loudly, stand tall and stay concise, all while getting your concept across. The week before a review becomes a drawing marathon, racing to complete and pin-up the ‘finished’ product. The dread of the crit is experienced by all students, but there is an unstated imbalance between male and female students.

It is undeniable that students learn important life skills through preparing for a review, such as public speaking and presenting under time constraints. However, the crit environment emphasises a particular kind of thinking where students are encouraged to present as the ‘masters’ of their project [1]. It is formal and declarative. By contrast, design work is rarely this way. It is a slow process that emerges from continuous iterations and thoughtful decision making. It is often difficult to portray the experiential intentions of the project during a review. It is much easier to defend a rigid master plan than it is to discuss the way a space feels and the material process behind it. These are gendered qualities of architectural presentation. Masculine ideas perform well in crit environments; they are more structured and easier to make coherent in a drawing. Whereas the feminine attributes fall to easier scrutiny; they are attributes rooted in process, feeling, and care.

During a crit, your work is performing and you become part of the performance to the audience of jurors. In this becoming, there is an inequality between male and female students. As the body plays a part in this performance, it is worth analysing the historical role of the female body in visual culture and performance. There has been a gendered dynamic present throughout visual culture in western society. Laura Mulvey diligently outlines this in her work ‘Visual Pleasure and Narrative Cinema’ [2]. She describes how men are accustomed to seeing themselves portrayed as the protagonist and driver of the narrative, whereas women are accustomed to seeing themselves as the spectacle. These dynamics are internalised and can affect the way in which each gender approaches a review.

Trevi Fountain in Rome - highlighting the idea of male represented as protagonist, driver of action, and females represented as spectacle. Image Credit: Kate Crowley

The lack of female role models in architectural discourse feeds this narrative. For decades, we have idolised the ‘starchitects’, who are predominantly male. It is no wonder women have trouble self-identifying with the protagonist in this profession. Typically, architecture schools place female students standing before a predominantly male, seated jury. This has a significant impact on female presenters, as it reinforces a spatial hierarchy where emphasis is placed on performance and presentation, rather than broadening conversation and engaging with people on a horizontal level. This structure is another aspect of the crit that is culturally coded in gendered norms of masculinity.

Established in an all-male environment, the review feels outdated and disconnected from the realities of working practice, where design is collaborative and dynamic, and involves multiple actors working together. The crit forces women to bend our femininity to fit a system that has historically excluded it. It perpetually legitimises gender norms within the realm of architectural education. With this, we lose an opportunity for critics to establish a self-identity with us and our work, and this generates a bias. I experience an immediate wave of calmness on review day when a female reviewer is present. It marks an opportunity for self-determination.

Elisa Iturbe said, within her paper ‘Women & The Architectural Review: the Gendered Presentation of Architectural Work’, that “Our femininity is rejected when we must speak loudly and boldly to an audience of predominantly men” [3]. In feminist pedagogy, relationships between teachers and students exist on a less vertical plane. Power and knowledge become shared [4]. Last semester, instead of the standard presentation format for our Architectural Technology module, a group of 4 female students, Julia, Róisín, Ciara, and I, came together to create a podcast to share our work with each other and our peers. This conversational and collaborative discussion was deeply beneficial to all of our learning. It removed the hierarchy associated with a presentation, and felt rooted in feminist pedagogy.

A crit established in an all-male environment is adversarial and performative, favouring bold ideas, structured drawings, and encouraging a ‘master’ mindset. A crit reimagined by an all-female group of 4 becomes a collaborative dialogue for sharing ideas. Hierarchies are removed and time is given to explain process and materiality. Architecture itself creates the physical and cultural framework in which we as a society exist and progress. Architectural education should be no exception. No aspect of it should perpetuate gender biases.

20/4/2026
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In this article, Kate Crowley continues our mini-series ‘Drafting Identity’ which focuses on the experience of women in Architectural Education from both personal and professional perspectives, supporting the FIAE movement. Kate discusses ‘crit culture’ in architectural education and the impact that dynamic has on women, in particular.

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Drafting Identity: The Loom vs the Machine

Róisín Hayes
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Róisín Hayes
Ciarán Brady

In the new year I took up knitting. I had previously crocheted, but I find knitting easier, more rhythmic, and I am more drawn to the textures it produces. Recently, however, I learned that while knitting is often regarded as the more refined craft, crochet might in fact be more ‘valuable’. Knit stitches are predictable and therefore more easily mechanised. Crochet, by contrast, relies on complex, irregular knots that demand the tension and judgement of a human hand. What appears somewhat more sophisticated and polished is also more reproducible.

When asked to reflect on my experience as a female architecture student, this question of value - particularly of historically feminised crafts - felt unexpectedly relevant. Textile work has long been associated with women and domestic labour and therefore devalued and positioned outside the realm of serious production or art. Analogously, women architects were historically steered towards domestic architecture and interior design. Stratigakos notes, it was considered that the female designer’s ‘essential womanliness’ made them naturally suited to the home, a space which was private, emotional and minor [1]. Civic or infrastructural projects were considered prestigious and carried heftier financial rewards, and as such were reserved for male architects. Qualities associated with women such as emotion, interiority, and care - domesticity, were treated as secondary and women were excluded from typologies that defined architectural ambition.

Crochet. Image Credit: Róisín Hayes

Le Corbusier described the house as ‘a machine for living in’, prioritising standardisation, efficiency and rational function over decoration or atmosphere. The aesthetics of stark functionalism has continued to shape contemporary architectural culture. Optimised plans, clean sections, seamless renders are easily produced, easily legible, and easy to defend. Contemporary techniques of modular or panelised construction used in large office or housing blocks can feel nearly human-less, designed and assembled by ‘the machine’ - although of course manual labour has indeed occurred [2]. The new age of AI further intensifies this condition; the machine in architecture. It can generate compelling plans, sections, and images in seconds. What it excels at are the same qualities architecture has long rewarded. Yet, just as a machine cannot feel the precise tension required for a double or treble crochet stitch, it does not possess haptic perception or a true sense of scale. Juhani Pallasmaa argues in The Eyes of the Skin that contemporary architecture’s dominance of image and form often comes at the expense of touch and care [3].

I recognise these tensions in my own education and practise. Formal strength, productivity, and technological fluency are often what succeed in crits. A rational plan can be convincingly argued, a clear section is reassuring. I have learned to provide a clear drawing to explain every essential argument or design choice. What I find harder to justify are decisions rooted in emotion; how I want a space to feel, how I imagine a body moving through it, why a corner should sharpen or curve, if a space should feel bright or dark. The more intuitive or impulsive my reasoning, the more difficult it is to articulate graphically or otherwise within a culture that prioritises efficiency and reproducibility.

Knit. Image Credit: Róisín Hayes

As a result, those qualities which resist such reproduction - those historically coded as feminine such as care - atmosphere and emotional intelligence have come to feel more important to me. Anyone can now optimise a plan; fewer can design for the subtle choreography of inhabitation or the quiet negotiations of domestic life. Eileen Gray argued, “A house is not a machine to live in. It is the shell of man, his extension, his release, his spiritual emanation” [4]. These sentiments can be read in her design of E1027. For example, the spacing of Gray’s pilotis are derived from internal spatial properties rather than mathematical calculations, and, as such, are wider in public spaces and narrower in those that are private [5]. Her layered window system retains a Corbusian panoramic view while simultaneously addressing the body’s vertically [6]. Her resistance to mechanisation was not superfluous or emotional, but human.

Architecture cannot be entirely abstracted from lived experience; it cannot be wholly mechanised. It demands a sense of human scale and feeling. This begs the question; why were care and emotional intelligence ever confined to the domestic setting? Are these not also essential skills required for the design of hospitals, schools, offices, or train stations? Those skills, historically feminised and therefore dismissed, may prove central to the profession which is being redefined in the age of AI. This renewed importance does not signal a retreat to domesticity. Instead, the craft of architecture and its attentiveness to atmosphere, material, and embodied experience gains value. What was once dismissed as soft may prove resistant.

16/3/2026
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