A marine licence has been granted for a plan to develop gas storage caverns underneath Larne Lough, according to the company behind it.
The project near Islandmagee, would see seven large gas storage caverns hollowed out under the lough.
Islandmagee Energy said the project would provide security of supply during peak demand for up to 14 days.
Northern Ireland's main conservation groups have previously opposed the plan on environmental grounds.
Harland and Wolff Group Holdings plc, Harland and Wolff's owner, is the firm behind the project.
Its chief executive, John Wood, said the latest announcement was "good news for consumers and businesses in the UK who are currently experiencing distressing hikes in energy prices".
"With the current energy supply crisis, everyone now understands just how important gas storage is to secure supply and protect against extreme volatility in gas and power prices in the UK," he said.
"We are delighted with this major step forward in the project's journey, paving the way for the construction of our facilities."
The firm said on Wednesday that 400 direct jobs will be created, during construction and that Islandmagee Energy also has longer-term ambitions to store hydrogen.
"The existing power grid cannot always accept all of the electricity generated from wind farms during periods of surplus wind power generation," he added.
"It is during these frequently-occurring periods that wind farms are temporarily scaled back as there is no way to store the excess electricity produced.
"Production of large-scale hydrogen and its storage is the long-term solution to this.
"Excess wind generated power can be used to produce green hydrogen which can then be stored in salt caverns for future use during peak demand periods."
Last year, Mr Wood said it had completed a "robust series of surveys and studies", which had been sent to Stormont departments.
The project would see seven large storage caverns hollowed out using solution mining.
The brine solution created would be pumped across land before being discharged into the North Channel near Islandmagee in County Antrim.
The sea at Islandmagee is a protected area, as is Larne Lough which supports tern colonies.
An umbrella group, the Northern Ireland Marine Task Force, representing a range of conservation organisations had previously said they were against the pumping of "super saline brine" into the sea and that construction of the discharge pipe could displace marine life, especially the protected harbour porpoise.
On Wednesday, the chairman of Marine Conservation Northern Ireland, Nigel Hamilton, expressed his "grave concern" over the proposal.
The North Channel is considered one of the best habitats for marine life in the UK.
High energy costs have led manufacturers across the UK to warn of higher prices for their goods as they pass on increases to consumers.
Other firms have said they may be forced to shut down factories if the rising cost of gas and electricity makes it uneconomic for them to produce their goods.