What would happen if Ontario flipped the switch and powered the grid only with renewable energy?
For starters, says Paul Acchione, a consultant and engineer who has worked with nuclear energy and fossil fuels for more than 40 years, it couldn’t be done.
“Because the wind doesn’t always blow and the sun doesn’t always shine, (they) can only have 40-55 per cent capacity factor and the grid operates at closer to 70 per cent,” according to Acchione.
Ontario needs power around the clock, with a minimum demand around 4 am (“base-load power”) and a peak demand around 4 pm or 5 pm. Solar power can help meet demand as it rises during the day, but shuts down toward sunset. And wind power varies with the weather. Neither wind nor solar power can meet base-load demand on their own, and need back-up from a reliable, ready-when-needed energy source like natural gas.
Some renewable energy advocates look forward to the day that electricity can be stored on a scale large enough to power Ontario’s grid. Storage innovators like Tesla are making progress, and storage prices are coming down. But Acchione points out that they’re still not economically viable. He says that storage for renewable energy is about 2,000 times more costly than using gas as a backup, which means nuclear energy still has a role to play. “Current storage rates are expensive and simply not available which means renewable energy must be backed up with nuclear, gas or coal. Of the three, nuclear is the cleanest.”
Acchione predicts storage will become more affordable in 40 or 50 years. Until then, he says, Ontario’s power puzzle is easily solved:
“Take all the hydroelectric we can get economically and then fill in the base with as much nuclear as we can. The incremental, we can do with renewables, but you will need to invest a little bit in storage 6-8 hours so that they can fill in the peak load (times when power demands are greatest).”
In other words, the goal of all-renewable energy for Ontario won’t be met for decades, and nuclear energy will remain the foundation of the province’s electrical system.