Abu Dhabi energy company TAQA said on Wednesday it had started injecting natural gas into its partially built Bergermeer storage facility in The Netherlands.
Europe is seeking to diversify its energy supplies away from Russia and boost its storage capacity to prepare for a potential disruption to its gas supplies.
Scheduled to be completed next April, Bergermeer will nearly double the Netherlands' gas storage capacity, said TAQA, which has invested in the project alongside Dutch energy company EBN.
Energy suppliers will be able to store natural gas underground in the depleted Bergermeer gas reservoir and draw it down when demand rises.
TAQA said it had sold all of the facility's long-term capacity and plans to auction the remaining short-term capacity in September.
Once complete, it will provide 46 terawatt hours or 4.1 billion cubic metres of gas storage capacity, equivalent to the average annual gas consumption of 2.5 million Dutch households.
Companies that have booked capacity include Statoil , EDF, Vattenfall and Gazprom , the company said.