National Grid uses ‘smart valves’ to unlock 1.5GW of network capacity

National Grid Electricity Transmission is deploying a “cutting edge” power flow control technology to unlock 1.5GW of additional network capacity in the North of England.

The company said it will alleviate bottlenecks on the transmission network, allowing more renewable power to be transported to customers and reducing the amount that needs to be curtailed.

“When we’re taking huge quantities of green renewable energy and we’re transporting that across a number of parallel circuits, obviously some circuits will get overloaded before other ones,” National Grid chief engineer David Wright told Utility Week.

“This technology then gives you the opportunity to equalise out those power flows and take power off the overloaded circuits, put it onto other circuits where you’ve got more capacity and ultimately therefore transport a lot more energy through the system.”

The technology was developed by US-based company Smart Wires, which said its Smart Valve works by detecting the current on a power line and injecting a voltage waveform that is offset in phase by 90 degrees – or “in quadrature” – to raise or lower its reactance.

As current follows the path of least impedance – a function of both resistance and reactance – the firm said it can therefore a make a power line more or less attractive in comparison to others.

Wright said the technology has already seen limited usage on distribution networks, but this is the first time it has deployed on a transmission network anywhere in the world.

National Grid Electricity Transmission (NGET) is initially installing it on five circuits at three of its substation sites in the North of England – Harker in Carlisle, Penwortham in Preston and Saltholme in Stockton-on-Tees – unlocking 500MW of additional network capacity in each area. The company is also looking to further increase its capability to control power flows at Harker and Penwortham in the Autumn, freeing up another 500MW of capacity.

Wright said this will represent “a substantial increase in percentage terms”, adding: “There’s potentially 20 other deployments that we can see a forward pipeline for across Great Britain”.

He said the technology has also been designed to be “mobile” and “modular” meaning that “depending on the requirement you can put more devices together on a particular circuit so it’s really scalable and deliverable to wherever it’s needed in the country.”

“It enables the acceleration of the decarbonisation of Britain, but you’re also able to do it at a much lower cost, so it’s more capacity at lower cost and quicker delivery,” he said.

Smart Wires chief executive Peter Wells said: “With these projects, NGET have pioneered a new way to think about planning and operating the grid – leveraging flexible investments to deliver gigawatts of impact in incredibly short timeframes.”

Julian Leslie, head of networks at National Grid Electricity System Operator, added: “Managing constraints on the transmission network is an important part of our work operating the electricity system so it’s great to see Smart Wires’ technology being utilized.

“Developments such as this, and the steps outlined in our five-point congestion management plan, will reduce the impact of constraints, allowing us to harness the full potential of renewable generation and lower costs for the end consumer – all helping towards our ambition of being able to operate the system at zero carbon by 2025.”