Bruce Power says the site's flexibility is a valuable asset as it has adjusted output over 200 times this year to respond to Ontario's fluctuating demand.
In May, Unit 4 was returned to service, after a Station containment outage.
All four Bruce A units were removed from service to ensure Bruce A's layers of safety systems are at the highest standards.
"The successful completion of the Unit 2 outage marks a major milestone in Bruce Power’s 2016 Business Plan, as we plan to have a significant portion of our investment program behind us with a large volume of output ready to meet the summer demands," said Kevin Kelly, Acting President and Chief Financial Officer. "So far in 2016, Bruce Power has produced over 18 Terrawatt-hours (TWh) of carbon-free electricity – that’s 30 per cent of Ontario’s energy at 30 per cent less than the average residential price of power," Kelly added.