PROJECT DESCRIPTION
BACKGROUND
SF₆ (sulphur hexafluoride) has properties that make it an excellent insulator and switching medium for high-voltage (HV) switchgear and other HV electrical applications. However, SF₆ is also an extremely powerful greenhouse gas (GHG): it has a 24,300 times higher global warming potential than carbon dioxide (CO2) and a half-life of approximately 1,000 years. Although the contribution of SF₆ to the overall GHG effect is less than 1%, every source of SF₆ emissions has a disproportionally large impact. The beneficiary, Grid Solutions SAS, has demonstrated the feasibility of SF₆-free technology for electrical switchgear for three types of HV equipment. These solutions are in operation in several European countries. To fulfil the EU's climate change mitigation goals, the use of potent GHGs must be prevented. Eliminating SF₆ from current use in the industry is therefore reflected in the EU F-Gas Regulation (517/2014).
The concrete goals of this regulation are to:
- limit the total amount of the most important F-gases that can be sold in the EU from 2015 onwards, to phase out one-fifth of 2009-2012 sales by 2030, and to drive research and industry towards investment in alternative solutions;
- ban the use of F-gases in many new types of equipment;
- prevent emissions of F-gases from existing equipment with proper monitoring, staff certification, and recovery at the equipment's end-of-life.
Moreover, the regulation had a provision for reviewing the situation in 2020, based on the availability of economically viable alternatives. The F-gas Regulation (EU) 2024/573 was adopted on 7 February 2024 and started to apply on 11 March 2024. The new regulation limits the GWP of the alternatives to SF6 to 1 CO2e. However, complete lifecycle carbon footprint of the switchgear (incl. its supporting structure) is considered as one criteria of derogation to GWP threshold (paragraph 13 of Article 1).
OBJECTIVES
The objective of the LifeGRID project was to replace SF₆ in Gas-Insulated Substations’ (GIS) High-Voltage Circuit Breakers (HVCB) with an environmentally friendly alternative called g³. The technical feasibility was already demonstrated for 145 kV gas-insulated substations (GIS), however, the aim was to tackle the highest grid voltage level in Europe, namely 420 kV, for which there is no solution currently available.
The transition to higher voltages and currents represents a significant challenge for SF₆-free GIS circuit breakers. To achieve a fully integrated, future-proof solution, innovative approaches are needed. These include refining gas mixtures (such as g³) and adapting key components, in particular the circuit breaker's arcing chamber. Electric arcs cause a drastic rise in temperature, pushing the gas molecules into a plasma state and triggering their decomposition. To achieve this goal, the project partners have developed successive prototypes in order to prepare an integrated 420 kV SF₆-free GIS solution for European transmission networks, with the support of Transmission System Operators (TSOs).
RESULTS
Achieved results:
- The project succeeded in developing a prototype 420 kV/63 kA high voltage circuit breaker without SF₆ (using g³ gas), testing and validating its performance to create a viable solution for the SF₆-free Gas-insulated high-voltage switchgear.
- A comprehensive database of gas properties under the appropriate operating conditions was set up. This database was then used for extensive numerical modelling, involving over 1,400 calculations on 70 different models.
- Lifecycle Assessments (LCAs) were carried out and estimated the direct reduction in GHG emissions was at 98.2% using g³ compared with SF₆ technology during the project.
- 22 prototypes of circuit breakers using g³ gas instead of SF₆ were produced, corresponding to a saving of 454 tonnes of CO₂eq during the project's manufacturing and testing phases.
- Successful involvement of a Transmission System Operator (TSO), SSEN Transmission in Scotland, which provided its technical specifications for the finetuning of the prototype.
- In 2023, Grid Solutions SAS was able to launch its new 420 kV SF₆-free GIS, the T155 Dual Gas, of which sales skyrocketed within the year.
- In 2024, once the industrialization process was in place, the first T155 Dual Gas GIS bays were manufactured and delivered.
- After project completion, 4,755 tons and 14,150 tons of CO₂eq could be saved in 2024 and 2025 with the delivery of 35 and 90 GIS bays, respectively, thus doubling the projections shared in the Project final report.
