Oct 28 (Reuters) - British Gas owner Centrica (CNA.L) has reopened its Rough gas storage site off England's east coast at about 20% of its previous capacity, enough to heat 1 million homes for 100 days this winter, the company said on Friday. Before it was closed, Rough represented more than 70% of UK storage and supplied 10% of peak winter demand. However, after Russia’s invasion of Ukraine and growing concerns over gas supplies this winter, Centrica upgraded the facility and started refilling the site in early autumn. Even at 20% of previous capacity, Rough is the UK's largest gas storage site and adds 50% to the UK's gas storage capacity, though this lags behind European countries, Centrica said. The long-term aim is to turn the Rough gas field into the largest long-range energy storage facility in Europe, capable of storing both natural gas and hydrogen, Centrica said.

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