EDF is expected to give the final go ahead for the Hinkley Point C nuclear project in Somerset today.
The French-controlled energy giant is holding a board meeting for the final investment decision.
The nuclear plant is expected to provide 7% of the UK electricity needs once it is completed.
However, some environmental campaigners are against the project and are calling on the government to stop the scheme and provide more investment for renewables.
Earlier this week, reports claimed shareholders at EDF approved plans to sell shares to raise €4 billion (£3.3bn) for the nuclear project.