TORONTO - Ontario Power Generation has been given approval to increase its electricity rates by about one per cent.

The government-owned utility, which supplies about 70 per cent of Ontario's electricity, had applied to increase the payments it gets from hydroelectric and nuclear stations by 6.2 per cent.

The Ontario Energy Board denied OPG's request for recovery of costs associated with the refurbishment of the Darlington nuclear station.

The board also told OPG to conduct a number of studies on staffing, compensation, performance and other issues in an effort to address future costs at the utility.

Consumer prices for electricity will be adjusted May 1, as they are every six months, but for consumers not on the regulated price plan, the new rate increases are retroactive to March 1.

OPG earned $649 million on revenue of $5.4 billion in 2010, up from $623 million profit in 2009.