TIVERTON, Ont. -- Bruce Power says it has successfully synchronized Unit 1 to Ontario's electricity grid, generating power from the unit for the first time in nearly 15 years.

With first synchronization now complete, Bruce Power says final planned commissioning activities will be carried out on Unit 1 including safety system shutdown testing.

The utility says Unit 2 continues to be on track to return to operations in the fourth quarter. Plans to reconnect Unit 2 to the grid were delayed in May due to some damage to non-nuclear equipment at the site.

Bruce Power says when both Units are in operation, they'll produce enough electricity to power cities the size of Ottawa and London, Ont., combined.

The return to service of Units 1 and 2 will bring the Bruce Power site back to its eight-unit capacity, doubling the number of operational units from 10 years ago when the company began a revitalization program.

Bruce Power has two units containing four Candu reactors each at its site in Tiverton, Ont., on the shores of Lake Huron. Six of the eight units are in full operation.

"This is a significant achievement for Bruce Power and another tangible milestone that the restart project is nearing completion and we are close to securing eight units of operation," said president and CEO Duncan Hawthorne.

"This is a big step forward as we work to return the Bruce Power site to its full generating potential."

Bruce Power is jointly owned by TransCanada, Cameco Corp. (TSX:CCO), and several pension plans.