The Ontario government’s Long-Term Energy Plan, updated yesterday, continues to place a strong, justified reliance on nuclear power to meet Ontario’s electricity requirements.
Nuclear power is a safe, affordable and reliable way to generate the province’s “base load” power. Base load refers to the power supply that operates continuously through the day and night, and is always available.
Base load electricity in Ontario is produced by nuclear generating stations and large hydroelectric generating stations. It differs from “peaking” generation provided by smaller hydro stations, gas plants and renewable power sources (mostly wind and solar), from which Ontario draws electricity as demand rises during the day.
The main differences between base load and peaking generation arise from the cost per unit of electricity and the certainty of delivery.
Base load power produces the majority of electricity in the province. It provides all, or almost all, of the electricity when daily demand is at its lowest point, near 4 am (See graph).
Demand rises through the day as people wake up and begin to draw more electricity for their needs – at home, the office, at school, in industry, and so on. As demand rises, other generation sources begin producing power to meet the rising demand. The Independent Electrical System Operator balances demand and supply to ensure the province has sufficient power at the lowest price.
With coal disappearing from Ontario’s energy mix in 2014, the province’s most-affordable energy sources are hydro ($0.035/kWh) and nuclear ($0.056/kWh). Both energy sources require very large up-front investments in generating equipment, but these are paid off over periods ranging from 20 to 60 years.
It’s the same idea that drives consumers to buy houses rather than stay in hotels – the house needs financing, but the benefits are worth the investment.
Recently, declines in the price of natural gas have made it seem an attractive alternative to coal, hydro and nuclear energy. Some advocates contend that natural gas could displace all three – and especially nuclear, given the significantly lower investment needed to build gas plants.
This perspective omits two important facts. First, gas prices are volatile; they have risen before and will eventually rise again whenever supplies tighten up. Uranium prices have also proved volatile, but they make up a very small part of the total cost of nuclear energy. Nuclear generators don’t have the same need to pass price spikes along to the consumer.
Second, burning natural gas emits carbon dioxide and other greenhouse gases, compounding the challenge of climate change. According to the UN Intergovernmental Panel on Climate Change, gas emits 29 times more greenhouse gas than nuclear energy (and coal 62 times more than nuclear).
A decision to use gas for base load generation would create carbon emissions around the clock. It would also reverse the progress Ontario has made in reducing carbon emissions by substituting nuclear energy for coal.
These are the reasons to favour nuclear energy as a source of base load power, and to add a diverse mix of other sources—gas, hydro, wind, solar and others—to ensure Ontario can meet peak demand.