All areas were hit – but parts of the South, West and Midlands are the worst affected.
ESB crews began work again at first light – it hopes to have power restored by this evening however, it's warning there may be more outages before the day is out.
Cork has been badly hit – Bandon, Macroom and Glanmire have all reported serious flooding.
Southern Correspondent with the Irish Independent Ralph Riegel says people are worried the River Bandon may burst its banks.
The ESB will decide later whether to increase the flow of water through the Parteen Weir on the River Shannon.
Levels in Lough Derg are likely to increase to 2009 levels today and tomorrow – prompting fear of more widespread flooding along the River.
Meanwhile, Ballinasloe is said to be 'safe for now' as flood prevention measures in the town are so far proving effective.
A temporary flood barrier has recently been installed, extra sandbags have been distributed, and water pumps have been running.
Businesses in the St Michael's Square area were badly affected in the aftermath of Storm Desmond, and the army had to be drafted in to assist council workers.
