An update on the generator at the Aishihik Generating Station

A few weeks ago in a radio interview, our President and CEO shared that one of the three hydro generating units at the Aishihik Generating Station (AH1) was offline due to equipment failure. We have also indicated that we were performing repair work at the Aishihik Generating Station on our Facebook page. When the issue occurred in late October, we immediately actioned an analysis and repair. The analysis is still underway with technical experts taking the unit apart to determine the extent of the damage. We have determined that the unit will not be operational this winter.

The unit generates approximately 15 megawatts of electricity. However, it’s important to highlight that Yukon Energy plans the resources it needs for winter demand in emergency scenarios. This includes a scenario where the entire Aishihik Generating Station (i.e., all three generators, not just one) and the transmission line that connects it to the grid are not operational. Given this, Yukon Energy has enough generation for this winter without AH1.

While the loss of AH1 this winter does add pressure to the electricity system, we are not in an emergency situation. Occasionally, machines fail, and when they do we fix them.

We are currently completing repairs and expect they will be complete by the spring; however, this will depend on a number of factors including supply chain and the complexity of the repair.

In the meantime, we are:

• performing maintenance on our other generation resources to prevent failure;
• performing preventative maintenance (removing dangerous trees) on major transmission lines;
• starting the rental diesel generators earlier than we usually would have to make sure they start in cold temperatures; and
• using back-up contractors to help us restore power outages more quickly in the event of an emergency;
• re-assessing the location of our existing diesel generators to ensure there is enough generation in the north and south in the event the grid is split like it was earlier in the fall.

We are also adding infrastructure to our existing power generation site in Whitehorse to allow for the potential relocation of rental diesel generators in the event we require additional generation in the south. Currently, around 80% of electricity used in the Yukon is in the Whitehorse region, meaning this is where we need the most generation. We have more than enough generation in the north, even if there was an issue with the transmission line that connects the rest of the Aishihik Generating Station to the north. However, we would be tight on generation if there was an issue with the transmission line that connects the rest of the Aishihik Generating Station to the south. That is why we are making preparations to potentially relocate rental generations to Whitehorse.

If the grid were to split without the additional rental diesel generators in Whitehorse, we would use our mutual aid protocol with ATCO, the Government of Yukon (YG) and the City of Whitehorse. In a situation where we were getting close to the limits of our system, we would call upon ATCO to turn on their diesel generators in the communities and for the City and YG to reduce electricity use in their large buildings. We may also ask Yukoners to conserve electricity. Taking small steps like using a block heater timer and delaying the use of major appliances until later in the evening can help reduce strain on the power system.