Monday, June 12, 2017
Are two overhead lines more at risk of an incident, and should one be put underground for safety reasons?
By Gavin Crook, Lead Project Manager
I wanted to take the opportunity to explain how we consider security when developing new connections.
Some people have questioned whether two overhead lines in close parallel would leave our connection more vulnerable to sabotage or extreme weather. That’s led to concerns about what would happen at Wylfa Newydd if one of the connections was lost. Will it continue to generate power? Will it be able to shut down quickly and securely?
Let me say first that the connection will be reliable and secure. Over many decades the electricity network has been 99.9 per cent reliable and extreme incidents are very rare. It’s also worth noting that other nuclear power stations in the UK have been connected using two sets of overhead lines for a number of years. For example, Sizewell A nuclear power station in Suffolk was connected with two parallel overhead lines for 50 years.
To a certain extent all forms of connection, whether subsea, underground, or overhead are theoretically vulnerable to an extreme incident. It’s therefore not a strategic reason to choose one connection technology over another.
Indeed, in the event of a problem with an underground connection, it would be much more difficult to identify a fault and restore the connection, when compared to an overhead line. As well as additional time and resource, excavating the cable to fix the fault would cause a great deal more disruption to the surrounding landscape and environment.
We take the safety and resilience of our connection very seriously. It’s our job to make sure we get the electricity that Wylfa Newydd generates to the millions of homes and businesses that need it. That’s a responsibility we don’t take lightly and we have various safeguards in place to ensure that we’re prepared to deal with every eventuality.
We’re not responsible for the operation of Wylfa Newydd, but we are in regular consultation with Horizon Nuclear Power to make sure they have all the details of our proposals that they need for their own assessments. Like us, they will be meeting their own internal quality and security standards, as well as working in close collaboration with the Office for Nuclear Regulation.
It’s for these reasons that we’re confident we can operate a resilient connection for Wylfa Newydd with two overhead lines.
If you’d like to find out more about undergrounding, take a look at this blog by our Senior Consents Officer, Jacqui Fenn.