The Scottish government, which once pushed an independence bid in part on oil revenue, said every option is on the table for staying in the European Union.

The Scottish government under First Minister Alex Salmond pushed a bid for independence from the United Kingdom in 2014, betting its financial future in part on revenue from oil and gas. Boasting one of the more ambitions low-carbon platforms in the world, Salmond's government would've powered the country on renewable energy resources.

Nicole Sturgeon, his successor, said after the British vote in June to leave the European Union that economic momentum for Scotland rested within the bloc.

"That's why my task today and tomorrow and throughout the length of the coming negotiations will be to protect Scotland's relationship with and interests in the European Union, and to explore every avenue and every option for doing so," she said.

With crude oil prices down 50 percent from what they were in the wake of the Scottish vote for independence two years ago, energy companies like BP and Royal Dutch Shell, which merged with British energy company BG Group this year, are cutting back and, as a result, thousands of jobs have been lost in the British oil and gas sector so far in 2015.

In early July, Scottish Cabinet Secretary for the Economy Keith Brown said the government in Edinburgh would do everything in its power to preserve the wealth left in the North Sea. The government, meanwhile, estimates the renewable energy sector employed more than 21,000 people and had a market value of $7.3 billion last year.

Ahead of a Tuesday speech outlining strategies to remain tied to the EU, Sturgeon said she would continue to push for interests that matter.

"Democracy, economic prosperity, social protection, solidarity and influence -- these are the vital interests that we now seek to safeguard," she said.

The majority of the Scottish voters taking part in the June referendum opted to stay in the EU.