The impact of solar on the Yukon grid

Dec 15, 2023  Comment

There’s been a lot of discussion and news lately about the role solar plays in the Yukon’s electricity system. As the primary generator of electricity in the territory, we wanted to provide some information about the impacts of solar on the Yukon grid.

The microgeneration program managed by the Government of Yukon has been extremely successful, with targets set for 2030 met in 2023. The current program is oversubscribed with hundreds of potential solar projects approved to move forward next year.

Achieving these targets so rapidly has made achieving our reliability and affordability goals more challenging.

What is the current state of our electricity system?

Our existing hydro resources combined with renewable energy projects put us in an admirable position, where more than 90% of the electricity we generate each year is renewable. But we know that as we grow, we need to increase our supply of renewable electricity to maintain this position. To do this requires more renewable winter electricity.

As a utility, providing Yukoners with safe and reliable electricity is always our top priority. To understand the current state of our operations, there’s two main things that are important to keep in mind.

First, there is a surplus of renewable electricity in the Yukon in the summer. This is because that is when electricity demand is lowest, and our supply of hydroelectricity is highest. For context, Yukoners use between 30 and 50 megawatts of electricity on an average summer day. On those days, we can generate about 55 to 88 megawatts of hydroelectricity depending on the number of hydro units available. We perform most of our maintenance on our hydro units in the summer, which is why the number of units available can vary.

Second, as we all know, solar power generation is highest during the spring and summer. It provides very little winter energy. The Yukon needs to be laser-focused on investing in projects that increase the supply of winter energy and capacity and decrease peak demands for power in the winter. That’s because Yukoners use about three times more electricity in the winter than they do in the summer. As an isolated grid, which means we are not connected to the larger North American grid, we cannot buy winter electricity or sell surplus summer electricity to other places.

So, how does more solar power impact the Yukon grid?

Too much solar power on the electricity system affects our ability to deliver reliable and affordable electricity to Yukoners.

Impacts to reliability

If there’s too much solar power on the electricity system, it puts our job of delivering reliable electricity at risk. Our ability to deliver reliable electricity depends on keeping the electricity system in a constant state of balance, where the amount of electricity being generated is always equal to the amount of electricity Yukoners need. Too much solar power in a particular place can cause fluctuations in the supply and demand of energy, resulting in grid instability. This instability reduces reliability and can cause power outages. 

This past summer, as more solar power has been added to the grid, our control room has seen more instability on the system. Other isolated grids tend to cap generation from intermittent renewables to about 10-20% of their system load as a way to ensure system reliability. Next year, we expect intermittent energy sources to account for 30-50% of the amount of electricity Yukoners need on a summer day. While we have been able to manage the level of solar on our system so far, increasing the amount of solar energy is a concern for safety and reliability. That is why we recommended that the microgeneration program be put on hold.

Impacts to affordability

By its nature, solar power is a variable source of energy. The amount of solar power available quickly drops when a storm rolls in, or the sun goes behind a cloud. To account for this and to keep the grid in a constant state of balance, we keep an adequate supply of spinning reserve, or “instantaneous backup power” available. To do this, available hydro units are operated below their capacity and efficiency zone, or thermal assets are run, to supply electricity quickly when the amount of solar power being generated suddenly drops. This causes us to waste hydropower, use fossil fuels, contemplate shutting off renewable electricity generated by independent power producers, and pay for energy we can’t use. Ultimately, it costs us money to manage solar on the grid, and these costs are passed on to ratepayers.

Can solar be safely integrated into the grid?

Adding more sources of solar will require a system approach. This system can include firm backup capacity, system upgrades, and seasonal storage. While batteries would help smooth out the variability of solar generation in the short-term, we need seasonal storage to store the solar electricity generated in the summer for use in the winter. Our battery project that is currently underway will help smooth out the fluctuations we’re seeing now with the solar that’s already installed on the grid. However, investments in seasonal storage are key to maximizing the use of solar power.

Updates to our resource plan will provide us with the opportunity to identify and advance seasonal storage projects. However, there aren’t any seasonal storage projects that have the financial or social licence certainty to proceed at this time. Batteries on their own cannot be the only solution to adding more solar to the grid. As mentioned above, we have a surplus of summer electricity and need to focus on sources of electricity in the winter.

What’s next?

The targets of the Government of Yukon’s microgeneration program have been met. Now, we need time to assess. The first step is a grid stability study with ATCO Electric Yukon, Yukon Development Corporation, and the Government of Yukon’s Energy, Mines & Resources. This study will help us confirm the sources of instability we’re seeing and help us to assess and understand what grid investments are needed.

We are also interested in modernization of the grid. An example of grid modernization could be the installation of smart meters, so that we can have greater visibility of the system. Greater visibility will allow us to problem solve more effectively.

Finally, we are embarking on a two-step approach to our next phase of energy planning.

Step one will involve developing an electricity supply plan, which is scheduled for release in spring 2024. This plan will determine the Yukon’s electricity needs in the next 10 years and determine the resources we need to meet winter peaks that can be built in a short timeframe.

Step two will involve updating our integrated resource plan, which is scheduled for release by the end of 2025. This plan will address broad questions about what new electricity supply resources should be advanced to meet customers' needs in the next twenty years, and where, when, and how much of those resources are needed. Both steps will consider different resource options that are best suited for the Yukon. You can learn more about our energy planning here.

What we do know now is that significant investments in Yukon’s electricity system are needed to support the integration of more intermittent renewables. We are advancing grid improvements to support this increase and are planning to implement a large capital program over the coming years to meet these demands.

We also know that we need to focus on winter energy. We are advocating for all levels of government to shift their focus to supporting winter energy demand.

Ultimately, the Yukon’s energy needs don’t fit with what solar power can provide. While having some solar power on the grid is manageable, exceeding what our current grid can safely integrate is not responsible from a reliability, affordability or safety perspective.


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