The provincial government-owned utility said Friday that the $66-million drop in profitability was primarily due to lower earnings at a fund set up to pay for nuclear waste removal and management.
OPG said the decrease at the funds was largely due to the lower values of global equity markets.
Ontario Power Generation also says its bottom line was affected by lower hydroelectric revenue.
OPG says its unregulated hydroelectric stations received lower prices for their electricity on spot markets.
In addition, hydroelectric output was reduced due to low water levels in the Ottawa and northwestern Ontario river systems. The lower hydro output was partially offset by more electricity from thermal and nuclear power plants.
Its overall second-quarter revenue fell by $75 million from a year earlier and cash-flow from operations fell to $101 million from $151 million.
OPG'r revenue from all sources fell to $1.125 billion from $1.202 billion in the second quarter of 2011.