Norway's gas system enters peak maintenance to prep for heavy duty winter

OSLO (Reuters) -Maintenance at major gas fields and onshore processing plants will curb Norwegian natural gas supply by around a third during the first half of September, as Europe's biggest supplier readies the system for the busy winter demand season.

"We are a getting close to the period with the major planned shutdowns for this season," said Alfred Skaar Hansen, head of system operation at Norway's gas infrastructure operator Gassco.

The work involved many field operators and onshore facilities as well as receiving terminals in Britain and the European Union, and was planned carefully to minimise the downtime for Norwegian deliveries, he added.

The European gas winter season, when consumption is highest due to heating demand, starts on October 1 and ends on March 31.

Norway became Europe's largest supplier of natural gas following Russia's invasion of Ukraine in 2022, providing about 30% of all gas imports to the EU.

Gassco operates an 8,800-km (5,468-mile) pipeline network connecting Norwegian gas fields to Germany, Belgium, France, Britain and Denmark and deliveries are typically around 340 million cubic metres (mcm) per day.

With some maintenance starting earlier this week, including at the Nyhamna processing plant, nominations have already dropped to 255 mcm/day on Friday, Gassco data showed.

Unavailable capacity will surge from Saturday and remain at about 120 mcm/day of lost volumes until September 18, led by bigger cuts at Europe's largest gas field - Troll - and the Kollsnes onshore processing plant.

The drop in Norwegian supply is already priced into European gas contracts but unplanned extensions or delays could impact the market, analysts said.

Gassco's Hansen said the company is monitoring and coordinating all work closely and will inform of any changes via its transparency platform.

(Reporting by Nora Buli in Oslo; editing by Terje Solsvik)