New technology set to unlock 1.5GW of capacity to UK Grid

According to National Grid, use of power flow technology at scale is a world first and boosts the transmission network’s ability to support renewable generation.

Talking to Utility Magazine, National Grid’s Chief Engineer – David Wright – highlighted the use of technology to actively balance power flows on transmission lines.  With time pressure increasing to deliver NG’s self-declared target of reaching net zero capability by 2025, the use of technology to deliver on time has become essential.

Born in the USA

This latest tech development – SmartValve – was created by US-based Smart Wires and assists the network balance transmission flow to overcome the issue of some circuits working at capacity while others are almost idle.

According to David Wright: “Installing power flow controllers such as SmartValves allows National Grid Electricity Transmission (NGET) to provide the Electricity System Operator with equipment which reduces the network congestion that otherwise limits renewable generation. This is done with minimal impact on communities and the environment.”

Perhaps, more importantly, the controllers can unlock “bottlenecks” of renewable power. Wright cited an additional 1.5GW through 500MW of energy flow across three boundaries.

Current thinking

The essence of the technology is manipulating the line current rather than the voltage and changing the reactance of the line by injecting a voltage waveform “in quadrature” with the line current. 

Wright states: “Power follows the path of least impedance. When SmartValve increases the line reactance (and therefore increases the line’s impedance), the line current reduces – this is because, relative to other electrically parallel paths, the path with SmartValve is slightly less attractive for power to flow.”

The process can be reversed where more power is needed from a particular line, thus allowing manageable transmission balance.

Scaling up

Although not new in itself, the scale of implementation and the significantly higher power capacity make it a world first in this specific use of power flow technology.  Set for initial roll-out in three areas of the North of England – near Harker, Penwortham and Saltholme – National Grid Electricity Transmission (NGET) will install 48 SmartValve units across five circuits in three substations. To date, 27 devices have been installed and there are plans for further expansion beyond the original target by the end of 2021.

According to NGET, the time taken from ground breaking to fully operational is less than a year and the units are fully mobile, which means transfer from one site to another takes around one week. 

The SmartValve technology is just part of NGET’s drive to develop a smart, flexible grid in the UK, but hopes it will be seen as a benchmark for adoption around the world – in particular Australia which is working to resolve its energy balance crisis.