The French energy giant officially opened the Shetland Gas Plant in Britain's northernmost outpost, which cost USD 5 billion to build.
Bringing in gas from the Laggan-Tormore fields, the plant began production on February 7, which has since been ramped up to its full capacity of 500,000 cubic feet of gas (90,000 barrels of oil equivalent) per day.
The fields are expected to last for about 20 years.
The Scottish North Sea oil and gas sector has been reeling from a plunge in oil prices since mid-2014, leading the British government to cut taxes for the industry.
The plant was "creating jobs and providing secure, affordable energy to the UK's families and businesses for decades to come", she said in a statement.
"North Sea oil and gas is crucial to our energy mix.
"We are 100 percent committed to helping our oil and gas industry attract investment, unlock new potential and remain competitive for the future."
The Laggan-Tormore fields lie around 80 miles (125 kilometres) northwest of Shetland.
Total chief executive Patrick Pouyanne said the project demonstrated the company's "commitment" to Britain and said it would help the country's long-term energy security.
