Garreg Lwyd-Knighton Grid Connection

Disciplines involved:

EDP were commissioned to assist Western Power Distribution (WPD) with proposals to install a 23km 66kV grid connection between the consented Garreg Lwyd Hill windfarm, and the existing electricity distribution network at Knighton substation, Powys, mid-Wales.


The grid connection comprises overhead and cabled (subterranean) components. It is situated in a remote landscape that transitions from semi-urban to upland agricultural land.

EDP provided a complete technical service throughout the entire project life cycle from route design to installation. This included securing the necessary principal and secondary environmental consents, and supervising on-site environmental mitigation during construction.


Novel and pragmatic solutions, involving a large multi-disciplinary project team, were required to address unforeseeable project issues that arose.

Specifically, EDP undertook a lead role in the following activities:

• Environmental constraints mapping and route options appraisal;

• Detailed environmental surveys;

• Site visits and consultation with Natural Resources Wales, Cadw, and Powys County Council;

• Obtaining Section 37 consent from the Department for Energy and Climate Change (DEEC) for two overhead sections;

• Obtaining Scheduled Monument Consent and a protected species licence;

• Obtaining Hedgerow Removal Consent and Ordinary Watercourse Crossing Consents; and

• Design and implementation of environmental mitigation, supervised by a Clerk of Works.

EDP also attended several public exhibitions.


The project was one of the largest and most challenging projects undertaken by EDP and WPD, with a complex project history. EDP’s work ensured that significant environmental effects were avoided/minimised and ensured that WPD was able to successfully meet its obligations as a responsible statutory undertaker.


The grid connection is installed and was energised in March 2017.



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