Plans for a huge wind farm in the outer Forth estuary are in doubt after the project hit a series of delays and lost a vital subsidy deal.
The Neart na Gaoithe wind farm is the subject of a legal challenge by RSPB Scotland, which argues the scheme is an unacceptable threat to seabirds.
The Court of Session is carrying out a judicial review.
The Low Carbon Contracts Company (LCCC) can terminate subsidy deals if schemes fail to meet agreed timetables.
But Mainstream Renewable Power, the company behind the project, said it was "currently in arbitration" with LCCC over the terms of the deal and had served a "notice of dispute".
A spokesman said: "On 29 March 2016, LCCC issued a notice which, in its view, terminated the project's CFD [Contract for Difference]. Neart na Gaoithe strongly disputes the validity of the termination notice."
The spokesman added that the company would continue to work hard to ensure the £2bn project was built as planned.
RSPB Scotland said its "primary concern" was ensuring renewable energy could be delivered without harming wildlife.
Aedan Smith, the charity's head of planning and development, said: "The Neart Na Gaoithe project is one of four which were consented conjointly by Scottish ministers in 2014 and collectively they would result in thousands of seabirds being killed each year.
"The manner in which these consents were issued meant that we had no option but to challenge the decision in the courts and the court's judgement is currently awaited."