Shawfair is one of the UK’s largest heat networks to adopt chemical-free water treatment, with more than 500,000 litres of system water protected. The project was named Water Treatment Project of the Year at the CSA Awards 2025.
eleXion supplied the water treatment solution for the £30 million low-carbon heat network near Edinburgh, developed as a joint venture between Vattenfall and Midlothian Energy Limited.
The network uses waste heat from the Millerhill Recycling and Energy Recovery Centre, with residual steam transferred through a new energy centre to Shawfair Town. The system helps provide low-carbon heat to homes, education facilities and retail properties.
The Challenge
Large heat networks require careful water quality management to protect long-term system performance.
At Shawfair, the network includes extensive underground pipework, multiple substations, plate heat exchangers and major energy centre plant. The project required a water treatment approach that could support reliability, efficiency and long-term asset protection.
The Solution
eleXion supplied a chemical-free water treatment package designed to protect system performance without ongoing chemical dosing.
The solution included:
- eleXion chemical-free water treatment technology
- ioniX mini FS filling systems
- Magnesium anodes for ongoing oxygen removal and corrosion protection
FES fabricated much of the project off site under controlled conditions before installation on site. PPSL District Heating Ltd installed the underground pipework network, while SWEP brazed plate heat exchangers were used within the substations.
The energy centre has also been designed with fallback plant, including electric boilers from PARAT and biomass boilers from HOVAL.
The Outcome
Shawfair is now one of the UK’s largest heat networks operating with chemical-free water treatment.
The initial phase supplies around 3,000 homes, alongside education and retail properties. A £120 million business plan has also been approved for further expansion, with the heat network expected to increase capacity to around 10,000 homes.
The wider heat network is expected to save over 2,500 tonnes of CO₂ per year in phase 1.
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