Stormy weather has the potential to cause disruption to our electricity system. As owners of the transmission network in England and Wales, as well as the distribution network in the Midlands, South West England and South Wales, we take the job of ‘keeping the lights on’ very seriously and have a number of measures in place to deal with potential issues that severe weather might cause.
The electricity transmission system is the physical system that we use to move electricity at high voltage across the country; we do a lot of meticulous preparation to guard against power cuts occurring at a national level, and to ensure that electricity continues to flow to reach the local electricity networks.
When planning how we manage the network, our engineers and analysts consider every detail that might impact how electricity is delivered around the country. This means that weather is one of our most important considerations, especially at times of year when we know we’re likely to face inclement or severe weather.
Power cuts on our distribution network – which connects electricity from the transmission network to homes, businesses and vital services – are also more likely during severe weather. So we have additional measures in place during the winter months to ensure we can restore supplies as quickly and safely as possible, as well as enabling customers to get the support and information they need; particularly those in vulnerable situations.
Our transmission and distribution systems must be resilient to storm conditions, and we work all year round to ensure we’re ready for all kinds of severe weather. This includes:
Our engineers and operations teams make sure the network of pylons, cables and substations is robust against weather damage and a wide range of faults.
They respond to issues during the event and follow up at all sites to complete damage assessments.
Our engineers in the field are in constant contact with our control centres, which operate 24 hours a day, 365 days a year.
The Transmission Network Control Centre (TNCC) remotely controls the operations of the high-voltage electricity transmission system in real time. Our transmission teams monitor over 7000km of overhead line, over 300 substations and over 700km of underground cable, to locate any faults or issues and take appropriate action to ensure that electricity continues to flow.
As well as managing network issues, the TNCC also coordinates with key customers who are connected to our network. TNCC colleagues are also connected to any emergency calls with the wider industry, like Ofgem or the Department for Energy Security and Net Zero (DESNZ), to provide critical network updates and support where needed.
Our Distribution Control Centre looks after our distribution network in the Midlands, South West England and South Wales. On this network we’re responsible for 225,000km of overhead line, 90,000km of underground cable and 188,000 substations to keep the lights on across our four distribution licence areas.
The TNCC is also in constant contact with the Electricity System Operator (ESO), who balance supply and demand in the electricity system. They monitor the weather and prepare by anticipating different scenarios to make sure they have enough electricity reserves available for unforeseen losses of supply or generation.
Mechanisms designed to protect the system include delayed auto reclose (DAR), which kicks in if a fault trips a circuit (not uncommon during bad storms) and brings the powerline back into service after a few seconds. During Storm Arwen in November 2021, around 45 circuits tripped with the DAR automatic protection kicking in immediately.
Our transmission teams also offer to support DNOs at a local level where possible, providing key resources to support them in re-connecting supplies to communities and infrastructure such as hospitals. This may include deploying technical staff or use of our helicopters to identify damage.
As a DNO, we provide extra support for customers on our Priority Services Register, many of whom are in vulnerable situations, in the event of a power cut. During severe weather events, this support is even more vital for these customers, who may be elderly, disabled or medically dependent on electricity. These customers receive regular updates during a power cut and, where appropriate, may be offered support from external agencies, such as the Red Cross.
Other contingencies are in place too. For example, colleagues at Thorpe Marsh substation in Doncaster set up 1.5km of temporary flood defences to successfully shield it from unusually severe floods.