Ahascragh Distillery is first to produce carbon-neutral spirits in Ireland

Background

Ahascragh Distillery is a craft distillery producing premium Irish whiskey and gin. A husband-and-wife team, Gareth and Michelle McAllister, have lived and worked in countries across the world. They have turned their passion for Irish spirits into a family-run distillery business in Ahascragh, Co. Galway. In 2020, they took on the construction and redevelopment of an old mill, which dates to the early 1800s. They gave it a new lease of life as a visitor destination and the distillery and visitor centre officially opened its doors in July 2023.

Ahascragh Distillery is in the town of the same name in County Galway. The site produces Irish Whiskey in traditional copper stills and a gin product in a small gin still. It is unique in the industry in that it was designed with the intention of zero energy emissions in mind. The site does not burn gas or biomass to produce steam in boilers for heating its stills as all other similar facilities do. The careful design of the process utilises high temperature hot water generated from heat pumps and recycles all waste heat effectively to eliminate the need for burning fossil fuels. 

The distillery is committed to sustainable production and has positioned itself as one of Ireland’s leading examples of low-carbon distilling. As part of this commitment, the distillery engaged with SEAI EXEED to apply the Energy efficient Design (EED) methodology in accordance with IS. 399, during the development of its distillery operations.

The project

The McAllisters' goal was to distil the first zero-emissions spirits in Ireland. This would change producing Irish whiskey in an energy intensive process to a more sustainable and environmentally friendly way.

A huge part of achieving that goal was down to their distillery building itself. Instead of constructing a new building, they renovated an old mill using energy efficiency design (EED) principles. They worked with SEAI's Excellence in Energy Efficiency Design (EXEED) programme team to achieve this.

The retention of the existing heritage buildings and the reuse of existing materials, demonstrated the commitment to sustainability, further advancing environmental sustainability through circular economy principles.

The Challenge

Distilling is an energy intensive process requiring significant thermal energy for mashing, fermentation and distillation. Traditionally, distilleries rely heavily on fossil fuels to generate the heat required for these processes.

Key processes in distilling

• Mashing = Converting starch to sugar, agitation to prevent congealing 
• Distillation Heating = Heating of wash to evaporate most volatile components
• Distillation Cooling = Condensing vapours, ensuring effective separation of volatile compounds

From the outset, the team at Ahascragh Distillery, sought to design a facility that would minimise energy demand and reduce reliance on fossil fuels but would maintain the quality and authenticity expected in Irish spirits production.

Actions taken

During the design phase of this project, the original steam-based system was removed. It was replaced with a pressurised hot water storage system. This change reduced peak heating demand. It also improved overall efficiency. The heat exchanger systems across the distillery were redesigned. They were updated to use hot water instead of steam.

Normally, waste heat from distillation is released through cooling towers. It can also be used in a standard hot water loop. In this project, the waste heat is recovered instead. It is reused as a high-quality heat source for the heat pump system.

A high-temperature heat pump is used. This pump upgrades the recovered heat. The upgraded heat is reused to produce hot water. This hot water is used for both still heating and the mashing process. This approach greatly improves energy efficiency. It also reduces the need for fossil fuels.

Solar PV

A 67kWp Solar PV system with 164 solar panels was fitted to five south-facing roofs onsite. These contribute to the electrical demand for distillation.  

Renewable Energy

Both Gareth and Michelle wanted to power the distillery using renewable energy. This became possible using new technology that combines high temperature heat pumps with an innovative energy storage system. Heat is provided to the distillery through heat pumps which means that there are no flue related emissions or associated impacts on the local environment.

The heat pump design, heat recovery and thermal storage means that the energy inputs to the distillery are a third of what would be used by traditional technology.

Results

The verified energy and carbon savings for the project:

• Energy Intensity - With an energy performance indicator of 6.71 kwh/ LPA  (litre of pure alcohol), Ahascragh distillery is 40% less than a traditional fossil fuel system. 
• Carbon Emissions Savings – 1,691 tCO2e/yr savings (based on 3 shift operation 5 days a week and 50 weeks of the year)
• Energy Performance Indicator - ENPI #1 (kWh per litre of pure alcohol (LPA). The Ahascragh Distillery actual energy intensity data has improved from 8 kWh/LPA (2024) to 6.71 kWh/LPA (2025). This was benchmarked against the industry standard of ~ 11.0 kWh/LPA, as per confirmation from the Sustainability committee of the IWA and featured in the Project Execution Plan (PEP) documentation through to the Measurement & Verification (M&V) plan.The initial design parameters for heating (120 °C) and cooling (35 °C) were refined during design and commissioning to 115 °C and above 35 °C respectively, demonstrating continuous optimisation of energy variables under the supervision of the Energy Efficiency Expert. This reflects proactive control and improvement within the design and operational stages. 
• Energy Performance Indicator - ENPI #2 – (tCO₂e per litre of pure alcohol (LPA) Study results show 0.1082 tCO2e/LPA (pure litre of alcohol), in comparison to statistics in the wider industry this can be up to 3.9 tCO2e/LPA. In Ahascragh Distillery, the tCO2e saved annually on a normal production shift is 1,691 tCO2e.

Ahascragh Distillery is environmentally, and sustainability focused. Results have been validated by FDT / NIRAS in line with International Organization for Standardisation (ISO) 14040:2006, ISO 14044:2006 on life cycle assessment (GHG) studies (ISO, 2006) and Greenhouse gases ISO 14064-1:2018 (ISO, 2018) and measurement and verification to ISO. 50015.

The project achieved EXEED Verified certification, demonstrating that the energy efficient design process was successfully implemented and independently validated. Certification confirms that the project met the requirements of the EXEED programme. The energy performance improvements were independently verified in accordance with the international measurement and verification standard ISO 50015 by the NSAI.

Ahascragh Distillery's work to date has delivered excellent results:

• The peak heating and cooling demand has more than halved.
• Unlike other distilleries in Ireland, the heat delivered to the distillery does not require the combustion of any fossil fuels and uses green electricity.
• The heat source for the heat pump technology is the waste heat from the distillation process resulting in an innovative continuous closed efficient heat recycling method.
• The building itself has been protected with much of the original machinery and with wooden beams being restored and reused.

These activities combined deliver lower energy bills and lower carbon emissions. The result is a distillery designed to operate with significantly lower carbon emissions than conventional distillation facilities, supporting Ireland’s wider climate and energy objectives.

Next steps

Ahascragh Distillery plans to increase the renewable energy use on the site. 

• Generate hydro - electric power from the existing mill water wheel infrastructure and modern hydro turbines. 
• Additional on-ground Solar PV capacity to be added at the back of the distillery,
• Battery Energy Storage system (BESS) in progress to store the energy generated from the solar and hydro installation (due to arrive onsite in May 2026),

With the EXEED Verified certification achieved in accordance with ISO 50015, Ahascragh Distillery continues to demonstrate how innovative design, and engineering can deliver sustainable distilling while maintaining high product quality. The project provides a strong example for other energy intensive food and beverage producers seeking to decarbonise their operations.  

EXEED process

Through the EXEED IS. 399 process the project team applied the Energy Efficient Design methodology. They focused first on reducing energy demand through process optimisation and system integration before introducing renewable energy technologies.

The process examined the entire distillery energy system, including:

• Thermal energy requirements for distillation,
• Process heat recovery opportunities, 
• Integration of renewable heating technologies,
• Optimisation of supporting mechanical systems.

The EXEED process ensured that energy efficiency and renewable opportunities were identified and maximised at the earliest stage of the project. By systematically challenging design assumptions and analysing energy flows across the facility, the project team was able to identify opportunities to significantly reduce overall energy demand.

Ahascragh Distillery is an excellent demonstration of a project that has gone through the EXEED process. Its design has yielded a solution that recycles thermal energy that would normally be rejected. This makes the process significantly more efficient than a conventional design would have been. The distillery is compatible with a broad range of renewables and there is massive scope for replication of this approach throughout the food and drink industry.

Grant support

SEAI EXEED provides grant support for projects, which follow the EXEED Certified standard based on the IS 399 methodology. This includes capital investment projects, for new builds, major renovation and major energy upgrades of existing buildings and assets, as well as feasibility studies to identify the most suitable projects for a particular asset or process.

In 2022, SEAI provided the Ahascragh Distillery project with grant support of €500,000 through the EXEED Grant programme. The project was supported by NIRAS (previously known as FDT Consulting), throughout as the project energy efficient design facilitators for Ahascragh Distillery and the project design team. Overall, the project demonstrates a highly innovative approach to brewing and distilling, with Ahascragh Distillery achieving substantial energy efficient design improvements compared with traditional business-as-usual processes.

Organisations across Ireland can follow a similar pathway by adopting Energy Efficient Design through the SEAI EXEED programme.  

The programme supports companies to design out energy demand, reduce emissions, and deliver measurable performance improvements in new builds, and major retrofit projects.

Award winning

Ahascragh Distillery won the SEAI Energy Award 'Innovative Deployment of Renewable Energy' for 2023. Watch their finalist video to see the distillery.