Substations plays a vital role in transmitting renewable energy from offshore windfarms to the national grid. Protecting the substation’s buildings from water ingress is essential to maintaining a stable electricity supply for homes, businesses and communities.
Project summary
| Organisation | Electricity transmission company |
| Scope | Water and gastight sealing of cable entry points |
| Solution | NOFIRNO® Duct Seal System |
| Completion | June 2020 |
High-voltage transmission substations sit at the heart of the UK’s electricity system. They enable large volumes of power generated offshore to be stepped up, transmitted over long distances and delivered reliably to where it is needed. In 2024, renewable sources generated over 50% of the UK’s electricity for the first time, with offshore wind forming a significant and growing proportion of that mix. This places increasing importance on the resilience and reliability of transmission infrastructure that connects renewable generation to consumers.
Despite being a new-build facility, water ingress was occurring through cable entry points, creating concern around the long-term reliability of this critical infrastructure.
In high-voltage environments, even minor water ingress can pose a serious risk. Moisture entering buildings can accelerate asset degradation, compromise insulation performance and increase the likelihood of faults, outages or costly reactive maintenance. For infrastructure that underpins national energy security, these risks must be addressed decisively and permanently.
The challenge
Previously installed sealing materials were failing, increasing the risk of water damage to high-value electrical equipment and potential disruption to power transmission.
The challenge was not only to replace failed seals, but to do so with a solution capable of performing reliably over the long term in a demanding substation environment, where access is restricted and tolerance for failure is extremely low.
The solution
CSD Technical Services carefully removed all existing sealing materials, ensuring cables were protected throughout the process. Each cable and duct opening was then thoroughly cleaned before the NOFIRNO® Duct Seal System was installed across the site.
The solution was designed to deliver consistent, long-term performance in a demanding substation environment.
CSD’s experience working within critical energy and utilities infrastructure meant the team understood the importance of precision, durability, and compliance in high-voltage transmission settings. The NOFIRNO® system was selected for its proven water and gastight performance, pressure resistance, and long service life, providing confidence that the integrity of the building envelope would be maintained for decades to come.
The outcome
All buildings at our client’s substation are now fully water and gastight. By addressing a hidden but critical vulnerability, the project helps ensure that renewable electricity generated offshore can continue to flow reliably through the transmission network, supporting homes, businesses and the UK’s transition to a low-carbon energy system.
Results
- Reduced risk of unplanned outages on the transmission network
- Improved protection of nationally important infrastructure
- Greater confidence in the long-term delivery of renewable energy