Two of the three 305MW electricity furnaces at the country's biggest coal-fired power plant, Moneypoint, are back online after being out of action for a number of months.
However, while units 1 and 3 are back in service since earlier this month, work is continuing on Unit 2.
According to the ESB, which runs the Co Clare-based plant, the units were out of service due to planned maintenance and Unit 2 is still offline pending "further investigation and resolution".
A spokesperson added that while Moneypoint was offline, electricity demand was met by the island of Ireland wholesale electricity pool market and by two interconnectors to Northern Ireland and to Wales.
It is understood that when the coal furnaces were offline, only electricity from the Moneypoint wind farms was supplying the grid. When it is firing on all cylinders, Moneypoint is one of the most environmentally unfriendly plants in Europe and is due to be decommissioned in 2025 when its current licence expires.
It is not clear whether the temporary shutdown of the coal-burning furnaces improved Ireland's situation with regard to potential EU pollution fines. It is also not clear what will replace the coal-burning portion of the plant when it is decommissioned with different plans under consideration, including its transformation into a biofuel station.
Sunday Indo Business