CrystalClear - Lifecycle Analysis of SF6 Alternative Technologies and Crystal Formation Impacts

Completed

Other Power and Storage Technologies(Electricity transmission and distribution)

Applied Research and Development

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

£500,000

Power

London

Network Innovation Allowance

Project Contact, National Grid Electricity Transmission

NGET is investigating alternative technologies as replacements for SF6 at transmission voltages and has identified that there is a need for independent benchmarking of the overall environmental impacts of the different products available. In addition, one of the technologies already in service requires investigation of an issue reported by other researchers.We will investigate the environmental impact of SF6 alternative technologies through comprehensive independent life cycle analysis. This will enable NGET to evaluate the best alternatives to SF6 to select under different scenarios.Other investigators have noted the presence of crystals forming in gas mixtures based on C4F7N and this has been replicated in other laboratories but producing them in sufficient quantity to understand their significance to asset integrity has been difficult. This project will synthesise crystals in a chemical laboratory. The impact of these crystals on dielectric strength of the gas mixture can then be evaluated. Equipment that contains SF6 can develop leaks over time resulting in loss of SF6 to the atmosphere. SF6 emissions have an impact on global warming over a period of thousands of years because it is very stable as well as having the highest known GWP. The scope of this project is to support decision making about alternative technologies to replace SF6 and this requires an understanding of all possible and environmentally friendlier solutions. The total environmental impact of the different technologies over their lifetime will be assessed, this will attempt to take into account the future technology landscape and compensate for lack of operational experience with the new technologies. One of these new technologies has been reported to produce solid materials in crystalline form during laboratory testing. These have proved difficult to produce in large quantities in realistic conditions but this may happen in service. To understand the materiality of such products, this project will generate them synthetically to enable electrical testing to be carried out. This project seeks to understand the environmental impact of different technologies proposed as alternatives to SF6 for switchgear.This project also aims to understand the potential damaging effects of producing crystalline by-products in certain gas mixtures proposed as an alternative to SF6.

NGET is investigating alternatives to SF6 for use in gas insulated electrical switchgear. Two areas of investigation are combined within this project to further the understanding of alternative technologies.The project will consider how lifecycle analysis of new technology options may be approached and conducted. This will provide understanding of the relative merits of different technologies and the potential benefits of selecting one over anotherA second workstream will involve testing the dielectric strength of fluoronitrile based gas mixtures in the presence of crystalline materials to understand whether they pose a risk to the function of assets.

02/10/24