Independent research from consultancy Ramboll and commissioned by DESNZ shows that overhead transmission lines on pylons remain considerably cheaper than undergrounding electricity cables.

Ramboll was tasked to undertake the study to identify if there is potential for cost reduction in underground transmission lines over long distances of 20km and 50km by using innovative methods, against a baseline of traditional burial in a trench using ‘cut-and-cover’.

The assessment compared cut-and-cover as a baseline (being the incumbent undergrounding method) versus cable ploughing, horizontal directional drilling (HDD), microtunnelling (pipe jacking), auger boring, Direct Pipe, E-Power Pipe and Pipe Express.

The assessment identified cable ploughing, HDD and microtunnelling (pipe jacking) as having the most potential to have costs approaching those of cut-and-cover, and whilst these methods are already commercially available, they have to date been limited to short distances or applications largely outside the UK.

However, Overhead cables on pylons remain the cheapest, and faster, way to deliver an expanded grid. A finding backed up by another recent study from Deloitte.

Minister for Energy, Micael Shanks, commented: “New independent research published today shows that overhead transmission lines on pylons remain considerably cheaper than undergrounding electricity cables, and are often the fastest way to deliver the upgrades we need. We’ll continue to follow the evidence as we expand the grid for clean power, energy security and growth, while ensuring communities hosting infrastructure see direct tangible benefits.”

---