What happens when electricity use exceeds the grid’s capacity?
5 minutes reading
Hydro-Québec produces enough clean electricity to supply the entire province, except during . But what happens when the demand exceeds the grid’s capacity? And what if we were all part of the solution?
These are winter periods during which we anticipate that the electricity demand will be very high. They occur on cold days when everyone uses a lot of electricity at the same time.
In Québec, water and wind power generate nearly 40,000 megawatts (MW) of electricity, a considerable contribution to Québec’s prosperity. During most of the year, the demand for electricity is well below what Hydro-Québec can produce, so it exports the surpluses to neighboring markets. That clean energy enables other provinces and US states to meet their net-zero goals and helps Québec fill its coffers!
But that isn’t the case in a cold snap. When temperatures plummet, the demand for electricity skyrockets: Québec consumes nearly twice as much electricity in winter than it does in summer. Those few hours in the mornings and evenings when everyone’s using a lot of electricity at the same time and the demand exceeds the power system’s capacity are called winter peaks.
On cold days, heating can account for up to 80% of an average household’s daily electricity use.
Over the next few years, the electrification of the transportation and industrial sectors will further drive demand and exert even more pressure on the grid. Hydro-Québec estimates that it will take between 150 and 200 additional terawatthours of clean electricity to reach net zero by 2050. So more shortfalls are likely.
What happens when the demand for electricity exceeds the system’s capacity?
Take February 3, 2023, for example. That day, temperatures in Québec hit all-times lows of -48°C in the city of Québec and -52°C at Le Massif mountain in the Charlevoix region, and Hydro-Québec recorded a historic peak in power demand of about 43,124 MW! But even though these arctic conditions maxed out our capacity, there’s no reason to anticipate a widespread outage.
To contend with winter peaks and manage the high demand they give rise to, Hydro-Québec crews maintain the system year-round. When all the power system’s resources are operating at full capacity, Hydro-Québec buys electricity from its neighbors. The only problem is that energy prices on the open market, which fluctuate with supply and demand, are higher in winter. Not to mention that the electricity produced elsewhere isn’t as clean as our own. That’s why it’s so important to aim for self-sufficiency, even during the winter peaks, which we estimate at about one hundred hours each year.
Are there ways to avoid exceeding the system’s capacity?
We all have a role to play in conserving electricity and limiting the investments in the system. Small changes, like turning down the thermostat by a few degrees and postponing your laundry and EV charging, are all it takes. The good news is that Hydro-Québec has created two offers to help you contribute to the collective effort. All you have to do is choose the one that works best for you!
The key is to be energy wise during winter peaks, which occur from December 1 to March 31, between 6 and 9 a.m. and 4 and 8 p.m.
With Rate Flex D, you can save quite a bit of money, since most of the time in winter, you’ll be charged less than the base rate, except during occasional peak demand events, when you’ll be charged more than the base rate. All you need to do is take a few steps to use electricity more wisely and at the right time.
Hilo makes life even easier by transforming your residence into a smart home that manages devices like your thermostats for you. All you have to do is let Hilo look after the thermostat settings (depending on the participation mode you’ve chosen) so that they are turned down during challenges, which take place during winter peak events! You’ll earn cash rewards for every kWh saved.
All these little actions can really make a big difference for Québec. So much so that, in winter 2023‑2024, households signed up for Rate Flex D or Hilo and companies that reduced their consumption during peak periods helped lower power demand by 999 MW—the equivalent of the installed capacity of Outardes‑3 generating station! If all Quebecers pitch in, we’ll grow our collective wealth and ensure our province relies solely on renewable energy. And those are all great reasons to be part of the solution!