As part of the Chesterfield to High Marnham project we propose to build and operate two new substations - one 400 kV substation (“the scheme”) near Chesterfield (“the site") and another 400 kV substation (“the scheme”) in High Marnham near Normanton on Trent in Nottinghamshire (“the site”). The substations would enable us to uprate the existing Chesterfield to High Marnham overhead lines in the region and connect future electricity transmission network projects as part of  The Great Grid Upgrade.  

The delivery of this Project would ensure that we continue to deliver electricity safely, reliably and efficiently to the customers and communities we serve - all while working towards building a cleaner, fairer and more affordable energy system for the future. 

Chesterfield

The site is approximately 14.5 hectares (ha) and comprises two parts; the existing 275 kV substation (located within the western part of an existing 132 kV substation compound) with the majority of the remainder of the site being agricultural land, located to the south of the existing 132 kV substation compound. A number of existing pylons are within the boundary. 

The site is bound to the north by Calow Lane and to the east by Hallflash Lane with the A617 to the south west.  

There are a number of Public Rights of Way (PRoW) that go through the site. NE5/25/1 runs east to west, south of the existing substation, NE5/16/1, goes around the north and east side of Furnace Hillock, heads south of the substation and joins Hallflash Lane and NE5/17/2 and NE5/17/1, follow Hallflash Lane. The scheme would require the temporary closure and diversion of these footpaths during construction and a permanent realignment of NE5/25/1 and NE5/16/1 once the scheme is operational, details of which have been provided as part of our planning application. 

The new substation would be within a compound of approximately 150m x 210m and include a new Switchgear Hall building, up to three new supergrid transformers, which increase or decrease the voltage of electricity between different circuits, six overhead line gantries, which are bridge-like structures with platforms used to support equipment and cabling, and three additional buildings. 

The substation building would be the highest structure within the compound at approximately 15m. 

There would be extensive landscaping for this proposal that has been designed to provide environmental mitigation and satisfy the required 10% Biodiversity Net Gain (BNG). The landscaping design comprises: 

• species rich hedgerow along PRoW routes; 
• native scrub planting along the eastern boundary; 
• wetland species planting around attenuation ponds; 
• native species rich woodland planting in the west of the site; 
• native hedgerow with intermittent broadleaved tree planting; and 
• reinstatement of hedgerow and woodland habitat. 

We also propose overhead line connections to the new 400 kV substation near Chesterfield to the wider network. This will include the installation of short stretches of overhead line between the new 400 kV substation and the existing overhead line, as well as the removal of some existing stretches of overhead line, together with the temporary works (such as temporary masts) required to make these permanent changes.