The Ontario Power Authority has said that Ontario has close to 2,000 megawatts of wind power in operation with another 3,800 megawatts under development. …

That meant wind supplied 3 per cent of the province’s power last year, out-producing coal at 2.8 per cent. …

But wind’s increase presents some challenges to the province’s power system, which sometimes has too much power flowing onto the grid.

… when there’s a surplus, wind turbines continue producing power but the system operators throttle back production at Bruce Power’s nuclear plants – while still paying them for the lost production.

Meanwhile, Ontario Power Generation also spills water at some of its hydro-electric stations to make room for the wind power on the grid. In effect, he said, that replaces low-cost hydro power with higher-priced wind power.

Nuclear power is still the mainstay of Ontario’s power supply, making up almost 57 per cent of last year’s supply compared with 55 per cent the year before.