It says 348,000 customers have been restored since Monday
Some 37,000 homes, farms and businesses remain without power from Storm Ophelia.
However 348,000 of these have had their power supply restored since Monday.
The utility says: "The rate of progress numbers-wise from here will slow down as each individual fault restores a smaller number of customers.
"Also, with the weather forecasted to deteriorate, the conditions that the crews are working in makes the restoration effort more difficult and slower."
It says a total of 3,800 staff are now working on the ground.
Customers can check their estimated reconnection time on the PowerCheck website.
While Irish Water say just 2,300 customers are still without drinking water.
It says the affected customers are on small schemes, including nine schemes in Cork affecting 488 people; 12 schemes in Waterford affecting 533 people; five schemes in Wexford affecting 757 people; and one scheme in Kilkenny affecting 500 people.
And there are still 100 people on one scheme in Tipperary who are at risk of running out of water.
The company has also deployed 50 generators to keep water flowing for 51,000 customers.
The National Emergency Coordination Group says 25 members of the Defence Forces are assisting Limerick County Council with the preparation of flood defences in Limerick City.
It comes as people are being urged to take care as Storm Brian approaches Ireland.