Peak & Energy Demand

Living in the Yukon, I’m sure everyone has had some experience with unplanned power outages before. The most frustrating ones happen during a cold snap in the winter. If you rely solely on electricity for your heating, these outages can also be the scariest.

Power outages can be caused by several different reasons. Some outages are planned by the utility company for maintenance or system upgrades, while others could be caused by external factors such as a tree branch falling across the distribution lines or an animal exploring somewhere it shouldn’t. However, an unfortunate and all too common reason for winter power outages is a sudden spike in electricity demand that the grid simply cannot handle.

Where Does Our Energy Come From?

To help us understand why this happens, first let’s look at where our energy comes from.

In the Yukon, most communities are connected to a single electrical network called the Yukon Integrated System (YIS). Over 80% of the electricity on the YIS is generated by three renewable hydro generation stations, with the remainder supplied by thermal generation in the form of diesel and liquid natural gas generators.
However, five Yukon communities remain disconnected from the grid generating most, or all, of their power from diesel generators.

If you’re interested in learning more about power generation in the Yukon, check out our blog post A Yukon Energy Landscape.

What is Energy Demand

Now let’s take a look at what we mean by energy demand.

Energy demand refers to the amount of electricity we consume over a specific period of time. Every electronic device we use contributes to this demand, which includes electricity usage across homes, businesses, industries, and public infrastructure.

Yukon Energy’s real-time electrical generation data is available on their website for those interested in tracking it.

On the YIS, energy consumption follows a predictable daily pattern. Demand starts low while most people are asleep. In the morning, it surges as people wake up, turn up their heat, make breakfast, and take showers. Then, as people leave for work, school, or errands, demand decreases and remains relatively steady until the evening around 5 pm. Energy spikes again as people return home, turn up their heat, make dinner, do the dishes, watch TV, do the laundry. Finally, around 10 pm, demand drops again as people go to bed.

What is Peak Demand and What Does it Mean For Me?

You may have heard utilities talk about peak demand. But what does that mean?

Simply put, peak demand refers to the times when electricity usage is at its highest. Our energy demand fluctuates with the seasons. It is lower in the summer when heating needs are minimal and peaks in the winter due to increased heating demand. This is the opposite of more southern grids where peak demand occurs during the summer when air conditioning usage is higher. As we saw earlier, peaks also typically occur twice daily, once in the morning and again in the evening.

How Does This Cause Power Outages?

Now that we understand where our power comes from, what energy demand is, and how our daily routines impact it, let’s explore how peak demand can lead to blackouts.

To better understand this, let’s examine Yukon Energy’s load consumption data over the past year. During the summer and shoulder months, nearly all of our power comes from hydroelectricity. However, in winter, lower water levels limit how many hydro generators we can run, while electricity demand rises. As a result, we rely much more on thermal generation. Although it may seem like we could generate more hydro power in winter, our maximum capacity is lower. In contrast, during summer, demand isn’t high enough to utilize our full hydro generation potential.

Reduced hydro generation combined with peak electricity demand creates the perfect storm. During extreme cold events, our demand can reach such high levels that it can overload equipment causing them to overheat or malfunction and trip safeguards in the system.

Additionally, outages can happen when our energy demand is higher than our production, in other words, when we try to use more power than we can generate. To address this issue, Yukon Energy rented 22 diesel generators in 2023/2024 to help meet demand during winter peak times, this was an increase from the 17 generators rented in previous years. Unfortunately, despite best efforts, the system can’t always respond with enough energy to prevent blackouts.

To improve reliability and reduce reliance on diesel, Yukon Energy is also working on installing a 7 megawatt / 40 megawatt-hour grid-scale battery energy storage system in Whitehorse. This battery will help manage peak demand and decrease the need for additional diesel generators.

Additionally, you may have noticed that more thermal energy is being used in the 2024/25 winter compared to previous years. That’s because one of the hydro generators at the Aishihik hydro plant has been offline all winter for repairs

How Can You Reduce Peak Demand?

There are several ways you can help reduce energy consumption during peak demand periods.

First, shifting energy intensive activities to off-peak hours can make a big difference. For example, running your dishwasher or doing laundry later in the evening or early in the morning helps ease demand during critical times. Additionally, turning down electric heaters one or two degrees, or preheating our houses when we expect colder temperatures can help reduce strain on the grid. Yukon Energy is currently running a peak smart program, where you can install smart devices in your home, like smart thermostats or hot water tank controllers, so they can make small adjustments to shift consumption away from critical times.

Second, having multiple heating options, such as a mix of electric, wood, or fuel, can lower your electrical demand during extreme cold snaps. The Yukon Conservation Society recently studied the use of electric thermal storage heaters, which store heat during off peak hours for use later, like a battery but for warmth.

Finally, with over 60% of our home energy use going towards heating, keeping heat inside your home is one of the most effective ways to reduce overall consumption. By upgrading our windows, walls, and doors, sealing up air gaps, and installing heat recovery ventilation systems, we can significantly cut down on energy waste. The government of Yukon offers several home energy rebates to upgrade your homes energy efficiency.

By reducing peak energy consumption, we not only help prevent blackouts but also lessen our dependence on backup diesel and natural gas generators. This leads to a cleaner energy system with fewer greenhouse gas emissions, benefiting both our communities and the environment.

Contributors

Author: James Tlen
Reviewed By: Maureen Charlie and Simon Kerkhof