Ontario Power Generation (OPG) has begun a $122 million planned maintenance and inspection outage on Darlington Nuclear Unit 4.

The 900 megawatt unit was removed from service April 8 after more than 159 consecutive days of producing reliable and clean baseload electricity.

"This work will ensure that our nuclear units are ready to deliver the power Ontarians need during the summer when electricity demand is high," says Brian Duncan Senior VicePresident Darlington Nuclear. "Our units at Darlington provide about 20 per cent of the province’s electricity every day."

In January, OPG announced a $12.8 billion investment of Darlington Nuclear Station. The refurbishment of the first of four units will begin in October and will preserve about 3,000 jobs. The refurbished station will provide 30-plus years of clean, reliable baseload power at a cost lower than other alternatives considered. In 2015, OPG’s average sale price for nuclear generation was 6.5 cents per kilowatt hour.

OPG provides about half the power Ontario relies on. The electricity OPG produces is 99.7 per cent free of greenhouse gas and smog causing emissions.