Equinor and its partners are investing more than NOK 4 billion ($390 million) to expand the Troll field, a giant North Sea asset that supplies around 10% of Europe's natural gas and contains 40% of Norway's remaining gas reserves.The project is expected to unlock around 11 billion cubic meters of natural gas, equivalent to roughly 69 million barrels of oil equivalent (boe), further strengthening one of Europe's most important sources of energy.Known as TWIN (Troll West Increased Gas Recovery North), the development will consist of two new wells tied back to existing subsea infrastructure at the Troll field in the North Sea. Production is expected to begin as early as 2028."We have an ambition to start production as early as 2028. By simplifying, increasing standardisation and reusing existing infrastructure and equipment, we are reducing costs and enabling faster production," Gunnar Nakken, Equinor's Senior Vice President for Projects and Subsea Norway, said in a statement.The TWIN development marks the third phase of Troll Phase 3, a broader effort to maximize gas recovery from the Troll West reservoir while extending the productive life of one of Europe's most important offshore gas fields.The significance of Troll stretches far beyond Norway.The field contains approximately 40% of all remaining gas reserves on the Norwegian continental shelf and has become one of the cornerstones of Europe's energy system. According to Equinor, gas produced from Troll alone currently covers around 10% of Europe's annual natural gas demand.That makes every new volume from the field strategically important.The additional 11 billion cubic meters of gas expected from TWIN may appear modest compared with Troll's vast resource base, but the volumes are significant in a European context. The project is expected to deliver enough gas to cover roughly 2% to 3% of annual European gas demand. The volume is also roughly equivalent to Belgium's annual natural gas consumption, highlighting how a relatively small tie-back project can still deliver meaningful new supplies to Europe.The development will be built using existing infrastructure, including a new subsea template with two wells connected to current facilities. Existing umbilical and MEG systems will be extended to support production, reducing both costs and development time.The project follows a series of investments aimed at maintaining production from Troll A and the Kollsnes processing plant. The second stage of Troll Phase 3 is expected to come online in 2026 and is designed to sustain high gas production toward the end of the decade. TWIN is intended to extend that production profile even further.Unlike many gas developments around the world, Troll benefits from electrified operations. Both the Troll A platform and the Kollsnes processing facility are powered by electricity from shore, allowing the field to deliver natural gas with relatively low operational emissions.The investment also highlights a broader shift underway on the Norwegian continental shelf as operators seek to offset declining field sizes and rising development costs through standardised subsea solutions and faster project execution."Our fields are ageing, new discoveries are smaller and costs are increasing. If we are to continue delivering, we need to do something radically different," Nakken said.Equinor has set a goal of halving the cost and execution time of subsea developments while increasing activity levels across the Norwegian continental shelf. The company aims to develop six to eight subsea projects annually through 2035.That strategy forms a key part of Equinor's long-term production ambitions. Despite a maturing resource base, the company is targeting production of 1.3 million barrels of oil equivalent per day from the Norwegian continental shelf in 2035.The investment comes as Europe continues to replace lost Russian pipeline supplies and seeks to secure long-term gas deliveries from reliable suppliers. Norway has emerged as the continent's largest external supplier of natural gas, with Troll serving as the backbone of that supply system.As Europe searches for secure long-term energy supplies, Norway is doubling down on the field that already delivers one out of every ten cubic meters of gas consumed across the continent. The TWIN project shows how existing North Sea infrastructure can continue to provide meaningful new energy supplies well into the next decade.By Jan-Thore Bergsagel for Oilprice.comMore Top Reads From Oilprice.comIndia Receives First Post-Deal LNG Cargo Through Strait Of HormuzBeijing Steps Up Scrutiny of Indium Exports as AI Chip Demand SoarsHormuz Traffic Stalls as U.S.-Iran Talks Collapse