The amount of fossil fuels Yukon Energy is burning to generate power has more than quadrupled in the last three years, according to numbers provided by the Crown corporation.

Yukon Energy president Andrew Hall said this morning the dependency on hydrocarbons will rise again this winter because of low water in the Aishihik Lake reservoir.

In 2016, while 98.4 per cent of power for the grid was produced by renewable hydro, 1.4 per cent came from generators powered by natural gas and diesel fuel – with a sprinkling of contribution from wind.

In 2017, dependency on fossil fuels jumped to 3.2 per cent, according to the numbers.

It’s expected that by the end of this year, 6.3 per cent of the electricity on the grid will have been produced by natural gas and diesel, with more than two-thirds of that coming from the LNG plant at the Whitehorse Rapids Dam.

This morning, for instance, 27 per cent of all the power on the grid was coming from a combination of diesel and natural gas.

Hall told the Star that low water last winter in the Mayo Lake reservoir that supplies the Mayo hydro facility required a higher degree of dependency on hydrocarbons to make up for the loss in hydro production.

As this winter begins, the water level in the larger Aishihik Lake reservoir that supplies the Aishihik hydro facility is a metre below normal, he explained.

Aishihik, Hall said, is usually the bread and butter for the supply of winter hydro in the Yukon, contributing 50 per cent.

“So when we saw the freshet coming in the spring and the lack of summer rain, it became clear that the Aishihik watershed just did not receive as much precipitation as normal,” he said.

“What that means is we are going to produce less energy out of Aishihik than we would normally.”

As a result, he said, they made a decision to begin burning natural gas and diesel in October to offset the low storage of water in Aishihik, and they will be burning it through the winter.

Having backup generation powered by hydrocarbons is not only there to help meet peak loads in the winter, but also to help meet demand in years of low water like this year, he explained.

As it did last year, Yukon Energy is renting four additional diesel generators capable of producing two megawatts each to provide for emergency backup generation if required, at a total cost of $1.5 million – not including fuel costs.

Under Yukon Energy’s 20-year-old resource plan finalized in 2016, there are a number of options to provide additional renewable and non-renewable generation, including increasing the storage of water in the Southern Lakes at a cost of $15.5 million.

The corporation is also looking at building a new diesel generation plant, or a combination of diesel and natural gas, at a cost of $62 million.

The territorial cabinet has also instructed the Yukon Development Corp. to investigate the feasibility of running a transmission line down the Stewart-Cassiar Highway to hook into B.C.’s grid. The cost is estimated at $1.7 billion.