CASE STUDY: Powering Up Britain’s Aircraft Carriers

QEC Shore Power Upgrade


His Majesty’s Naval Base Portsmouth is home to the two Queen Elizabeth-class (QEC) aircraft carriers and whilst Britain’s largest Naval platforms spend a large amount of time on deployment, the availability, resilience and reliability of shore supplied power when alongside in Portsmouth is key.
The 280m-long and 74m-wide carriers operate at a frequency of 60Hz, whilst the National Grid runs at 50Hz. To enable the ships to have the required frequency when using shore-supplied power, a conversion is carried out through two Rotary Frequency Converters (RFCs) housed in a purpose built substation before finally reaching the ship via hydraulic boom.


Managed by the KBS Maritime Project Execution team, the QEC Shore Power Upgrade project, commencing in October 2022 and spanning across six months, delivers increased environmental
resilience and increased life expectancy through improvements to the cooling systems of the two Rotary Frequency Converters.
Operating 24/7 when the carriers are alongside at Portsmouth, the project saw KBS Maritime, working with expert partner organisations, change the air cooling units (CACA) to make space for the new closed air cooling water units (CACW). The new water cooling units were installed to regulate the temperature of the new system.
Prior to going live, full commission testing was carried out on the new system, with simulated vessel load before connecting live to the carriers.


Efficient shore-supplied power connections bring significant environmental advantages across Portsmouth Naval Base, which is working towards becoming Net Zero Carbon in the coming years. By increasing the reliability and availability of the shore-supplied power to the carriers for future years, the likelihood of having to resort to alternative back-up power sources is significantly reduced.
What’s more, the project has been carried out to complement the deployment calendar of the Royal Navy ensuring shore power is always available to the carriers when alongside throughout the lifecycle of the project.
This forward thinking approach not only benefits the environment but also helps the Portsmouth Naval Base operate more efficiently and sustainably in the long run.
Managing the asset going forward is also key, with our Control Engineers being fully trained to not only operate the new system effectively but also to troubleshoot and maintain optimal efficiency.