UK’s Biggest Gas Storage Site Cuts Capacity for Six Months

Centrica Plc will limit natural gas storage at the UK’s biggest facility for six months to test wells at the site 9,000 feet below the North Sea, cutting the amount of stored fuel available next winter by more than 10 percent.

The Rough storage site, able to hold more than 70 percent of the U.K.’s total capacity, will limit the amount of gas in its wells by as much as 29 percent after reducing their maximum pressure, Centrica Storage Ltd. said. The move is “part of CSL’s assurance program and as a responsible operator and given the age of the field and installation,” the unit of the UK’s biggest retail gas supplier said in a statement late Thursday.

The UK has less natural gas storage space in relation to demand than most other countries in Europe, exposing its reliance on one site for most of total inventories. Centrica said March 18 that it identified a potential well integrity problem at the site and announced the possible restriction, boosting UK winter prices by as much as 6.2 percent.

Rough’s stock capacity will be limited to 29 terawatt-hours to 32 terawatt-hours after maximum operating pressure was restricted to 3,000 pounds per square inch, according to Centrica. The site had a record working gas capacity of 41.1 terawatt-hours in 2014. The facility can meet as much as 10 percent of peak winter demand.

The UK is able to store almost 4.7 billion cubic meters (166 billion cubic feet) of gas, equal to about 6.3 percent of its gas use in 2013, according to data from Eurogas. That compares with 30 percent in Germany, 28 percent in France and 15 percent in the Netherlands. Britain needs less storage than other European nations because of its diverse supplies, according to National Grid Plc, the nation’s network operator.

Long Range

Rough is the UK’s only so-called long-range storage facility, primarily injecting gas during lower demand in summer for use during the winter months.

Rough supplied 34,351 gigawatt-hours of gas this winter through March 25, National Grid data show. That compares with 20,208 gigawatt-hours in the winter of 2013-14, the mildest in seven years, and 39,377 gigawatt-hours in the winter of 2012-13, the biggest volume on record.

The site, located 27 kilometers (17 miles) offshore Easington, near Hull in northeast England, injects fuel through 24 wells on a three-platform installation into a sandstone reservoir about 2,743 meters (9,000 feet) under the sea floor. Withdrawals are done through the same wells and six others located on a second installation 2 kilometers from the first, according to Centrica.

Other Supplies

Other sources of gas remain more important. Rough provided an average of 19 million cubic meters a day since the six-month winter season started Oct. 1, National Grid data show. That compares with total average supplies of 275 million, 31 million of which from the nation’s liquefied natural gas terminals and 21 million from the Netherlands. Norway, the UK’s biggest foreign gas source, shipped an average of 97 million cubic meters a day in the period.

Higher imports of LNG into the UK this year will mitigate any impact of Rough capacity limitations, an energy risk manager said Thursday. The UK is set to import 11 cargoes of LNG this month, the most since July 2014 and the most for a winter month since December 2011, according to port and ship-tracking data.