Instead of curtailing excess wind power when electricity demand is low, it would be offloaded into high-power compressors and into the energy bags. When demand is high, the compressed air would be used to drive generators.
The prototype's architect is Maxim de Jong, CEO of Canadian aerospace firm Thin Red Line. "At depths of around 600 metres, there will be enough pressure in one 20-metre-diameter energy bag to store close to 70MWh of energy," says Jong. "That's around the same as 14 hours of energy generation from the largest offshore turbines currently in operation."
Seamus Garvey, project leader at Nottingham University, says the prototype is now overdue but depends on clearing some insurance hitches.