Norway is already Europe's largest supplier of natural gas after a sharp reduction in Russian deliveries since the start of the war in Ukraine in 2022.
"The gas from Troll alone meets around 10% of Europe's demands," Equinor's head of exploration and production in Norway Kjetil Hove said in a statement.
"This is a highly profitable project that will secure high gas production from the Troll field," Equinor's head of projects, drilling and procurement Geir Tungesvik said in the statement.
The new infrastructure will accelerate production equivalent to about 55 billion standard cubic metres (bcm) of gas, and at its peak the annual contribution from the additional development will amount to around 7 bcm, Equinor said.
Norway's full-year export of pipeline gas to Europe in 2023 stood at 109 bcm.
Recent upgrades at the onshore Kollsnes processing plant have already raised Troll's maximum output capacity to 129 million standard cubic metres (mcm) of gas per day from 121 mcm previously, and this will rise further with the new investments.
"Production from the new Troll wells will amount to about 20 million standard cubic metres of gas per day," Equinor said.
The new investment, known as the second stage of the Troll Phase 3 project, includes eight new wells with a new gas flowline to the Troll A platform, with the first wells scheduled to come on stream at the end of 2026, Equinor said.
Once processed at Kollsnes, the gas from Troll is sent via the Zeepipe pipelines and can be distributed onwards to receiving terminals in Germany, Belgium, France, Britain and Denmark.
Operator Equinor holds a 30.58% stake in Troll while Norway state firm Petoro owns 56%, Shell (SHEL.L), opens new tab has 8.10%, TotalEnergies (TTEF.PA), opens new tab 3.69% and ConocoPhillips (COP.N), opens new tab 1.62%.
