Peak demand facts and developments

The polar vortex that blanketed western Canada this winter made very clear how weather events can have a profound effect on energy demand in Canada: severe cold meant huge amounts of energy were needed to keep Canadians warm. It is reassuring therefore to know that energy utilities design delivery systems to handle extreme – or as the industry says – “peak” demand. In lay terms, that means systems are built to endure the coldest (or warmest) hour of the year.

In this issue, we examine the particulars of system design for peak demand – in both the natural gas, and the electricity systems in Canada.

ANNUAL DEMAND AND SEASONAL PEAKS:

Let’s start by first looking at two broader data points: annual demand and seasonal peaks for natural gas and electricity. According to the Canada Energy Regulator, Canada consumed about 580 TWh of electricity and 1230 TWh of natural gas in all of 2022. Simple math tells us that means 2.1x as much natural gas as electricity. However, this does not provide the full picture. For one thing, we know energy demand varies seasonally. So, let’s look more closely at the monthly energy consumption.

The breakdown by month in Figure 1 demonstrates much greater reliance on the gas system during the winter season, when the demand for space heating is higher. We see that during a month like January, the peak demand is more than 50% higher than that of the annual average monthly demand. Furthermore, the gap between the two systems has widened, with gas consumption growing from approximately 2.1 times to 2.5 times that of electric consumption.

FOCUSING ON DAILY PEAKS:

The significant discrepancies between the annual and monthly numbers beg questions about what happens on a daily basis? To answer them, let’s use some of the data from the polar vortex cold weather event that occurred between January 11^th – January 15^th this year in western Canada. The following is a summary of the peak energy deliveries in the provinces of British Columbia, Alberta, and Saskatchewan over that time period.

British Columbia:

On Friday, January 12^th, British Columbia was hit with extreme cold, with parts of the province reaching temperatures as low as -45°C. On the same day, BC Hydro advised that they delivered 11,300 MW of electricity, a record. On that same day, FortisBC also saw a record demand: 21,763 MW of natural gas – almost twice the electric demand.

Alberta:

In Alberta, temperatures also reached as low as -45°C. In response, the electricity consumption in the province peaked at 12,384 MW, a record according to the Alberta Electric System Operator. Throughout the weekend, ATCO Gas indicated that the natural gas system in Alberta delivered up to 110,340 MW of energy, nearly 10 times the amount that had been delivered by the electricity system.

Saskatchewan:

The weather event brought similar frigid temperatures to Saskatchewan, with parts of the province reaching lows of -44°C. The electric system in the province hit a peak of 3,810 MW on January 13^th, just 100 MW short of the all-time high. The same weekend, the province also set a new daily gas use record of 1.70 PJ/day¹ , which is roughly equal to 19,700 MW: over 5 times the electric demand of the next day.

The graph shown in Figure 2 summarizes the peak energy demands as outlined above. Furthermore, the graph also includes the annual gas and seasonal peak gas demands in each province, converted to average delivery in MW, according to the Canada Energy Regulator and Statistics Canada.

What jumps out from the data is how much more energy is delivered by the natural gas delivery system than by the electric system in these three provinces. At moments of peak energy demand – when Canadians needed energy the most – the gas systems in BC, Alberta and Saskatchewan were able to deliver as much as almost 10 times the energy that the electric systems delivered. Readers may recall Alberta was issuing alerts because of concerns that the electric system could not meet demand: no such alerts were issued about a gas system delivering over 9 times more energy.

So to answer the question “why is peak demand important?” we need only look at the graph in Figure 2. Across all three provinces, the peak demand was 20% higher than the average seasonal peak and more than 51% of the average annual demand. To put it simply, having a system capable of reliably meeting that demand is essential to preventing Canadians from freezing in the dark.

As noted earlier, peak demand is the basis on which our energy systems are designed. Though they are not running at maximum capacity for most of the year, designing for peak conditions ensures that they remain stable and reliable for those critical hours or days of the year. And there is no energy system in Canada that does this better than our natural gas delivery system.

¹https://www.saskenergy.com/about-us/newsroom/saskenergy-sets-new-daily-natural-gas-usage-record-0