OSLO, Aug 28 (Reuters) - Norway's Troll gas field, the country's largest gas export source to Britain and continental Europe, will see its output availability cut by 1.8 billion cubic metres (bcm) in 2020, early maintenance estimates showed on Wednesday.
The estimates from system operator Gassco are lower than Troll's total maintenance in 2019 - both conducted and scheduled - which is expected to result in some 4.5 bcm of reduced gas production availability according to Reuters calculations.
Gassco's estimates are preliminary and the system operator can amend them or add additional maintenance at a later stage.
During April and May, for about 40 days, Troll is expected to see reduced availability of 17 million cubic metres (mcm) of gas per day. In June, output capacity will also be cut for 21 days, with an impact of 42 mcm/day.
Gassco has also scheduled availability cuts for September 2020, which will last half a month and will affect Troll's gas production capacity by 18 mcm/day.
Troll has a huge production capacity of up to 120 mcm/day, and Gassco's preliminary maintenance figures do not show that it will be fully shut at any given point in 2020.
The field feeds Norway's Kollsnes gas processing plant, which will also see reduced gas processing capacity when Troll's output will be unavailable, as Gassco schedules its maintenance simultaneously to optimise production.
Visund, another Norwegian field that feeds Kollsnes, will also see output cuts of 15 mcm/day from the second part of August 2020 and into September, as it will go through yearly maintenance for three weeks.
Equinor, the field’s operator, has a 30.58% stake in Troll, while state-owned Petoro holds 56%, Shell 8.1%, Total 3.69% and ConocoPhillips 1.62%. (Editing by Terje Solsvik and Deepa Babington)