(Bloomberg) -- Britain’s exposure to supply risks and price spikes is likely to persist next winter after talks between the UK government and the nation’s biggest energy supplier on funding the expansion of its natural gas storage stalled.

Centrica Plc, which re-opened the UK’s biggest storage facilty — Rough — late last year at about a fifth of its former capacity, wanted consumer-funded minimum revenue guarantees to assist its investments in the facility. But negotiations with the government have seized up for now, according to people with knowledge of the matter. 

The issue is vital because curbed Rough capacities leave the country with just nine days of gas storage — a fraction of Germany’s at 89 days — highlighting Britain’s vulnerability to prolonged cold snaps or supply disruptions. The risk hasn’t materialized so far this winter thanks to mostly mild weather both in the UK and continental Europe, but there’s no guarantee the next heating season won’t be more difficult given record-low gas exports to Europe from Russia. 

The British government has been widely criticized in the past over its decision to rely heavily on daily supplies of liquefied natural gas from across the globe, as well as pipeline flows from Norway, rather than expanding storage. Rough was closed in 2017 after serving as a gas storage site for more than three decades — before it was partially brought back last year.

A Centrica spokesperson said the talks had not progressed last autumn, when Rough was re-opened, but the door is “always open in the future.” 

“We will continue to work with gas storage operators to look at options to further boost our security of supply,” a UK government spokesperson said. The future expansion of Rough “is a matter for Centrica.”

The Financial Times was first to report that discussions over Rough expansion have collapsed. Centrica has said that without the funding measure it won’t be able to invest £150 million to double the storage capacity for the next heating season. 

“It would not make economic sense to invest without some form of government guarantee given the significant uncertainty in the market,” RBC Capital Markets said in a note.

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