Pipework solves wind farm battery heat challenge
A pioneering pipework cooling system tackles overheating in wind farm battery storage, enabling efficient energy management in confined spaces and offering a scalable solution and grid stability challenges
From the opening of the first commercial wind farm to contribute to the National Grid in 1991, wind now accounts for around a third of the country’s annual electricity supply. While significant progress has been made, new obstacles have arisen, particularly around electricity storage. This was the situation facing one of Scotland’s leading wind farms, where batteries used to store turbine-generated power were vulnerable to overheating, leading to the innovative use of REHAU pipework to create a cooling system.
Wind power is now the UK’s leading renewable energy source and represents a major success story. However, intermittency has long been a concern, with questions about how energy can be stored during periods of lower generation. The answer lies in battery energy storage system (BESS) technologies, which stabilise wind power output and support the National Grid.
Consequently, lithium-ion batteries are increasingly installed on-site at wind farms in dedicated facilities. With pressure to maximise building footprint, these systems are often densely packed into tight spaces, leading to overheating risks and associated health and safety concerns.
Precision cooling
This was the issue facing one of Scotland’s largest wind farms. With precise cooling and heating required to maintain optimum operational conditions, a pipework system was needed to deliver chilled and low-temperature hot water (LTHW) to the adjacent BESS facility. Given the restricted space, the pipework also needed to be easy to handle and install.
A.Alexander & Son (Electrical) Ltd, a Glasgow-based Mechanical and Electrical contractor, was engaged to meet the brief. The specification called for two air-cooled chillers with free-cooling capability to supply water at 15°C to two buffer vessels. These would maintain a mean water temperature of 18°C, with a design delta of 6°C (21°C return).
From these buffers, five header circuits would distribute chilled water to the battery racks. Each rack required a constant flow of 0.75 litres per second at 18°C (±3°C), with inlets, outlets and isolating valves. The system also required reversible heat pumps forming a closed heating system to provide LTHW up to 40°C to two additional buffer vessels with a design delta of 5°C.
All of this had to be achieved within a building where every millimetre mattered. As Bernard Diamond, Director at A. Alexander & Son, explains: “The density of the battery racks presented a major challenge. Structural constraints meant there was almost no spare space, which led to redesign support to ensure installation was possible and would deliver the required performance.”
The design team had already selected REHAU as the pipework supplier. This was positive for A. Alexander & Son, who had previously worked with the polymer solutions provider. However, earlier projects involved buried pipework for conventional applications. This project required above-ground installation in uniquely constrained conditions.
“This project was not just about supplying pipework,” Bernard continues. “It was about engineering a system to meet specific hydraulic requirements while fitting complicated routes. We had to consider all angles when determining how everything would connect.”
This involved component redesigns, sizing adjustments, and adapting to non-standard bends and tees to accommodate tight spaces and pinch points. Installation also needed to avoid welding and hot works, which were not possible in confined areas. The solution was to pre-fabricate in an onsite workshop compound using two teams, one for fabrication and one for installation.
Making it fit
Customised versions of REHAU’s PP-R pipework were fabricated for the chilled and LTHW circuits. Pipes of 5.8m length ranged between SDR 11 and 17.6 in diameters from 40mm to 250mm. These were supported by elbows, tees, reducers, header connectors, flanges and adaptors, sized to meet site requirements.
REHAU calculations confirmed that even under a worst-case 20°C differential, expansion would not exceed 15mm, allowing it to be absorbed by elbows and bending arms without additional expansion loops.
The lightweight, flexible construction proved invaluable. With weights ranging from 0.438kg to 10.965kg per metre, the team could manoeuvre and install lengths more easily within the battery hall.
REHAU also advised on flow rates and delivered training to give the installation team confidence in delivering the required cooling and LTHW systems.
“From the outset, we knew this project would test our offering,” says Kenny Boyle, sales manager for REHAU Building Solutions. “Ongoing collaboration between technical, planning and site teams was key to mitigating potential issues during construction and operation.”
Setting the standard
Despite the complexity, the system was successfully commissioned. Chilled water flowed to every rack, with operators able to adjust flow and temperature, while reversible heat pumps provided additional LTHW control. The installation was completed as a functional prototype, offering valuable insight for future windfarm deployments.
“Once training was complete and routing agreed, progress was steady,” Bernard says. “The PP-R pipework delivered as promised — light to lift, and modularity suited confined spaces compared to traditional systems. Reliability is crucial on a project of this complexity. REHAU delivered on product performance and support, and the partnership was invaluable.
“Projects like this show the value of collaboration. Despite spatial challenges, the result is a system that keeps batteries cool and could support future energy storage projects at wind farms, data centres and beyond.”
