THE north could face electricity blackouts in 2024 and 2025 unless action is taken, it has been warned.
The details from the grid operator are included in an annual capacity statement from System Operator NI (SONI).
It said the issue centres on Kilroot power station near Carrickfergus and environmental permits which place limitations on its operating hours.
SONI said it was working with the regulator and Department for the Economy to address the issue.
Kilroot is a coal-fired power station but there are plans to convert to gas turbine generation in the coming years.
While coal-fired power stations are to be effectively regulated out of existence for environmental reasons, Kilroot was given special operating dispensation during the pandemic.
"At present, the plant needs to operate at a reduced generation capacity following the expiration of the Covid-19 Regulatory Position Statement; they do this to manage and comply with their most recent environmental permit," SONI told the BBC.
"The reduction in coal plant output reduces Northern Ireland short term adequacy surplus."
Kilroot's new gas turbine system will not be fully operational until 2026.
Environmental permits mean its new turbines will only be operational for an average of 1,500 hours per year in both 2024 and 2025.
The situation is made worse in 2025 because four older "peaking" units will not be available due to maintenance.
When the new gas turbines are operational in 2026 the system is expected to return to surplus.
It has been reported that one option to deal with the shortfall would be to allow Kilroot to temporarily derogate from its environmental permits.
However, the cost and legality of this is unclear.