Mesa contends that two of its wind projects were placed at competitive disadvantage for 20-year power purchase contracts against NAFTA free-trade regulations.

The complaint comes after provincial feed-in tariff (FIT) administrator Ontario Power Authority made “last-minute” changes to rules for awarding them spelled out in the provincial Green Energy Act .

At stake were contracts that will pay premium rates for power generated from renewable energy sources in the Bruce transmission region in western Ontario.