BE24221 - Research Study of the Potential for Cost Reduction in Undergrounding Transmission Lines over Long Distances

**Please note this is an Award Notice and not a call for competition, this Contract has been awarded via the CCS Research and Insights (RM6126) Dynamic Purchasing System.**

The Department for Energy Security and Net Zero (DESNZ) is appointing a Contractor to to conduct a research study of the comparative costs of different methods of undergrounding transmission lines in a GB context, and the potential for these costs to be reduced if scaled up to longer distances. Its purpose is to update and improve the evidence base for undergrounding costs and identify potential for further innovation to reduce costs.

Depending on the study findings, the research may have implications for innovation funding in this area and potentially influence related policy.

The objectives are:

• To list undergrounding methods that could be used for transmission lines.
• To qualitatively assess all methods of undergrounding with respect to their suitability for undergrounding transmission lines over long distances of order 20-50km and shortlist three methods with the most potential for further study.
• To document published evidence for the lifetime cost of the counterfactual of undergrounding in shallow trenches using 'cut-and-cover' and sensitivity to distance per km in a UK context.
• To engage with specialist suppliers for the three shortlisted undergrounding methods chosen for further study to quantify and validate current installation costs and sensitivity to distance of these methods using a basis consistent with that for the counterfactual.
• To work with specialist suppliers to identify areas where innovations in shortlisted undergrounding methods such as in equipment or methodology might help to reduce costs when scaling-up to longer distances.
• To analyse and compare costs with the counterfactual and identify the main cost

components.

• To identify if choices about cable technology such as voltage and whether AC or DC impacts the comparative costs of undergrounding methods.
• To qualitatively assess wider aspects of the shortlisted non-traditional undergrounding

methods including constraints, environmental impact, deliverability, and energy security

• To write a final study report collating the above research and analysis with conclusions on whether there is scope to reduce undergrounding costs using nontraditional undergrounding methods and recommendations for further work