"It's a clear message that if we do energy conservation right, there is a huge potential; the reduction we've seen this year is just the tip of the iceberg," Gibbons said.
"If we aggressively promote energy conservation we will be able to phase out our dirty coal plants by 2010, four years ahead of Premier Dalton McGuinty's proposed schedule."
Even though this summer's peak demand only decreased by 4.7%, that's still the equivalent of one-third of the total output of the Nanticoke generating station, the province's biggest coal-fired power plant, Gibbons said.
He credited some of the province's electric utilities for successfully launching programs to persuade business and residential customers to reduce their energy consumption.
The programs helped reduce demand by as much as 14.5% in Wasaga during peak periods, while Hydro One had reductions of 5.3%.
Terry Young of the Independent Electricity System Operator said conservation definitely played a role in lowering this year's peak demand, although the summer was less hot and humid than the previous year, and overnight temperatures weren't as high.