Cable Oil DEcontamination by BaCteria (CODEC)

Completed

Other Power and Storage Technologies(Electricity transmission and distribution)

Applied Research and Development

BIOLOGICAL AND AGRICULTURAL SCIENCES (Biological Sciences)
ENGINEERING AND TECHNOLOGY (Electrical and Electronic Engineering)

Not Cross-cutting

Project Contact
National Grid Electricity Transmission

Network Innovation Allowance

Ofgem

01 September 2023

31 March 2025

ENA months

£2,146,310

Power

London

Network Innovation Allowance

Project Contact, National Grid Electricity Transmission

A new method to decommission fluid-filled cables via bacteria-based bioremediation is proposed. The solution would produce a bespoke bacteria combination that is highly effective and efficient at degrading and mobilising hydrocarbons to remove the oil from the cables. This solution can remove more than 95% of all the cable oil in a timeframe between 14 to 16 weeks. The remaining oil is bound to the paper matrix and does not leak. Once the purging is complete, the cables can be safely left in-situ with no risk to the surrounding environment. The bacteria used are all naturally occurring with no genetic engineering and are of risk group 1 bacteria (the same as yoghurt). The solution also conforms to all relevant EU laws and regulations. This solution would significantly reduce the need for excavation and thus reduce the disruption to local communities as it does not require oil monitoring pits to be installed, nor does it require any subsequent purging. The much shortened timeframe also reduces the risk of oil contamination to the surrounding environment. Reduced excavation is also a safety benefit. This project comprises of 4 phases.Phase 1: Oil profilingOil sampling at siteOil analysis to determine the best combination of bacteriaPhase 2: MobilisationAcquire permits from relevant landowners for hardware installationProduction of hardware and bacteria including shipment to sitePhase 3: Cable treatment Connection of hardware to cables and start the treatment processPeriodic sampling and analysis to ensure good progressWaste oil disposalDisconnection and uninstallation of hardware post treatment completionPhase 4: Reporting and finalisationSample the treated cable to confirm the oil removal percentage and generate lab reports The objective of this project is to validate the new method to decommission fluid-filled cables by using the novel bacteria purging solution. The key aspects are:Validate the efficacy of the bacteria in removing oil in cablesValidate the time needed to remove 95% of the oil in cablesValidate the much reduced environmental and community impacts from this novel solution

The decommissioning of fluid-filled cables for the transmission system is often an intense, complex and lengthy process. The conventional nitrogen purging method could only remove about 40% of the oil in cables during the initial purge and would commonly need another 5 years of subsequent purging to remove the remaining oil. The large amount of excavation required could cause significant disruption to local communities while the remaining oil could pose risk to the surrounding environment. This project would look to trial a novel, bacteria based decommissioning method that could remove more than 95% of the all the cable oil in 14 to 16 weeks and thus could substantially reduce the disruption to local communities while mitigating the risk to the surrounding environment.

18/09/24