1 Weight ledger: 180 t saved per platform
A 36-bay SF₆ GIS weighs 480 t including steel support and HVAC. Clean-air vacuum GIS totals 300 t—180 t less. On a floating platform, that saving translates into 1,800 m³ less concrete ballast and €14 M lower hull steel cost—cash that funds an extra 5 MW of turbines .
2 Seismic & sway: 0.3 g with 8-second period
Floating platforms sway at 0.3 g PGA with 8-second eigen-frequency. Traditional SF₆ tanks risk bellows fatigue. Vacuum bottles, welded from a single stainless billet, tolerate 0.5 g without derating. FEM analysis shows fatigue life > 100,000 cycles—12× the platform design life .
3 Salt-fog immunity: 1,000-hour ASTM B117
North Sea platforms record 1,200 mm yr⁻¹ salt precipitation. Epoxy housings molded with cyclo-aliphatic resin achieve hydrophobicity class HC1 under IEC TS 62073. After 1,000-hour salt-fog test, surface conductivity remains < 10 µS—no tracking, no flashover . Contacts live inside a hermetic bottle—salt never reaches the gap.
4 Capacitive switching: no restrike on 40 km cables
Export cables behave as capacitors when energized open-circuit. Vacuum interrupters are tested to IEC 62271-100 Class C2: 24 restrike-free operations on 185 A, 50 km cable. After 18 months, contact erosion is 0.03 mm—below the 0.1 mm limit—proving SF₆-free switchgear alternatives can switch reactive offshore networks without oversized surge arresters.
5 Helicopter-free maintenance: 30-year sealed life
Helicopter slots are weather-limited; crane lifts need wave height < 1.5 m. Vacuum bottles sealed for life ≥ 30 years eliminate gas top-ups. Torque-check is done by Bluetooth strain sensor—no crew transfer vessel needed. Maintenance cost drops from €48 k yr⁻¹ (SF₆) to €2 k yr⁻¹ (vacuum), a 96 % reduction that banks price into project finance .
6 Carbon maths: 38,000 t CO₂-eq avoided
Per platform: 180 t steel saved (2.3 t CO₂-eq t⁻¹), 1,800 m³ concrete saved (0.38 t CO₂-eq m⁻³), 850 kg SF₆ not leaked (23,500 GWP) equals 38,000 t CO₂-eq over 25 years—equal to removing 8,200 cars for the project lifetime .
7 Blockchain energy tags: MWh with coordinates
Each MWh is hashed with GPS, time-stamp and SF₆ mass (0 kg). When the cable lands in Dundee, the onshore grid retires tokens that prove zero-gas origin—satisfying UK CfD contracts and adding £2 MWh premium on power sold.
8 Specification language ready for EPC contracts
“SF₆-free switchgear alternatives 40.5 kV shall be vacuum-interrupted, SF₆ mass = 0 kg, Class C2 capacitive switching, internal arc 31.5 kA 1 s, seismic 0.3 g, salt-fog 1,000 h ASTM B117, maintenance interval ≥ 25 years, helicopter-free torque sensor, end-of-life take-back ≥ 95 % mass recovery.”
9 Conclusion: the ocean wind is green—so is the switchgear that harvests it
Offshore wind may be the poster child of decarbonisation, but if the collector platform still breathes SF₆, the story springs a leak. SF₆-free switchgear alternatives built on vacuum interrupters cut weight, cost and carbon while surviving salt, sway and helicopter constraints—turning the harshest environment on Earth into the cleanest megawatts on the planet.
Float your next gigawatt with Degatech Electric’s SF₆-free switchgear alternatives—vacuum-interrupted, salt-proof, helicopter-free—at Degatech Electric Switchgear Products.
