Electric Thermal Storage (ETS) – A Tool for Heat and Energy Efficiency

The topic of electric thermal storage (ETS) has been discussed in the Yukon for some time. You might be wondering, what exactly is ETS? At its core, ETS is a heating technology designed to store heat for later use. This is achieved by using heating coils embedded within a medium with good heat-retention properties, such as bricks. The stored heat is then circulated throughout the home as needed.

Common Questions

‘Will I save energy, and will I save money if I install an ETS system in my home?‘
The answer is no; you will not use less energy with ETS, and while you might save money indirectly, it does not fundamentally save you money. In the future there may be an opportunity for cost savings if Time-of-Day electricity pricing is introduced in the Yukon. Learn more about pricing structures and demand side management here.

‘Are there any rebates or incentives available if I install a system?’
Again the answer is no, although it is something that the Yukon Government is exploring.

So, what is the point of ETS? The benefit of an ETS system is not that it uses less energy but that it can utilize energy at different times. Essentially, it functions as energy storage. To understand why this matters and how it could lead to long-term savings, we first need to understand a few realties of the Yukon’s electric power grid and associated electric loads.

According to Yukon Energy’s website 86% of the electricity generated on the Yukon Integrated System (YIS) comes from renewable sources, predominantly hydroelectric power. This percentage has decreased in recent years due to lower water levels, which led to reduced generation capacity coupled with a growing demand for electricity.

Yukon Integrated System

The Yukon integrated system (YIS) is the territorial electric grid that serves the majority of the Yukon, with the exception Old Crow, Beaver Creek, Destruction Bay/Burwash Landing, Swift River and Watson Lake who are each served by an isolated grid (powered primarily by diesel generators.) Learn more about energy in the Yukon here.

This increased demand for electricity is stemming from a variety of factors; but population growth, and electrification are two of the most obvious. Population growth is necessitating more homes each of which adds additional load to the electric grid.

Coupled with this is the move away from wood, oil, and propane heat, towards the electric home heating systems. The graph below shows the percentage of homes in the Yukon who rely on electricity as their primary source of heat.

The move towards electrification is in response to climate change and is an effort to reduce our reliance on fossil fuels. Electric heating, when generated from renewable sources like hydro, produces significantly fewer greenhouse gas emissions compared to traditional alternatives like wood, oil, or propane. However since space heating accounts for the majority of electricity usage in an average Canadian home it means that demand for electricity is rising and is surpassing the generation capacity of the Yukon’s hydroelectric system.  

The Yukon’s peak winter load (the maximum amount of energy used at one time on the YIS) was 104 MW in 2021, and 116 MW in 2022. Compare this to the combined peak generation capacity of the hydroelectric facilities supplying the YIS which is 92 MW in the summer and 77 MW in the winter.

Different factors contribute to lower generation capacity, but it is primarily due to seasonal water flows being lower in the winter. Additionally, the output of the hydroelectric facility at the Whitehorse Rapids cannot be easily adjusted in the winter, as altering water flow could lead to undesirable issues such as ice dams and flooding in downtown Whitehorse. While the system does benefit from some additional generation capacity from solar and wind, it is insufficient to meet winter demand, forcing reliance on thermal generation (diesel and LNG generators), which increases greenhouse gas emissions—counteracting the goal of reducing emissions through electric heating.

This is where ETS comes in. Looking at a graph of the load (amount of electricity needed to supply demand) on the YIS over the course of a day reveals variations in energy usage. There are two major peaks: one in the morning and another in the evening. If we can adjust the timing of energy usage, it can help smooth these peaks and reduce reliance on thermal generation and make better use of existing generation capacity, reducing costs and environmental impacts.

ETS has the potential to store heat during off-peak periods and release it during peak times, shifting daily electricity consumption and smoothing out overall energy use. While overall energy consumption may remain the same, using it consistently may reduce the strain on generation capacity, leading to savings in both finances and resources.

Although ETS presents a promising tool for reducing winter energy peaks on the YIS, it is not a one-size-fits-all answer across the territory. Communities not connected to the YIS would only benefit if they have excess renewable energy generation available in the winter. For instance, Old Crow would not see significant benefits from installing ETS based on its current energy demand profile. Old Crow relies primarily on diesel generation for electricity during the winter months, and though a solar array helps to reduce diesel usage in the summer months, it does not contribute much to the system in the winter. Additionally, home heating systems in Old Crow are fueled by oil not electricity. This means that their peak energy usage is not driven by home heating. ETS would neither shift the peak nor reduce greenhouse gas emissions and only increase electricity demand in the community. ETS has the potential to offer a strategic way to manage energy demand rather than reduce overall energy consumption. By shifting electricity use from peak to off-peak periods, it can be provide a tool to help stabilize the Yukon’s power grid, minimize reliance on fossil fuel-based thermal generation, and optimize existing renewable energy resources. While not universally beneficial across all communities, ETS may be able to play a role in improving energy efficiency and reducing environmental impact in areas that have surplus renewable energy production. As the territory continues to explore options for sustainable energy solutions, ETS remains a valuable tool in the broader conversation about energy management and grid resilience.

Contributors

Author: Colleen Hammond
Reviewed By: Patrick Gilles and Maureen Charlie