Solar generation is out as an option to supply the increasing energy demand for the Yukon over the next five, 10 and 20 years.

Geothermal – using natural heat from different deep depths beneath the ground to drive steam turbines – is gone.

But holding back more water in Marsh Lake in late summer and early fall to use for generation at the Whitehorse Rapids Dam during peak demand in the winter is factored into all three scenarios Yukon Energy is using to predict future needs.

Adding a third natural gas generator at the dam is also included in Yukon Energy’s vision for the future no matter how it’s sliced, as is more diesel generation.

But so too is storing energy in batteries and making improvements to existing hydro facilities, such as upgrading one or both of the 40-year-old turbines at the Aishihik facility.

Wind is only viable as a grid-level source of generation if the territory’s economy is red-hot, concludes assessments completed by Yukon Energy to prepare its 20-year resource plan it intends to present in March to the Yukon Utilities Board.

Updating the resource plan, as it is mandated to do on a regular basis, has been ongoing for several months. It was last updated in 2011.

On Monday evening, representatives of the Crown corporation presented their draft report to a public meeting attended by approximately 50 people, many of whom were familiar faces in the ongoing debate about how to supply the territory’s mounting energy needs.

Solar was described as just too unreliable to serve as a grid-level source of generation without battery storage.

Yukon Energy president Andrew Hall and crew were in Carcross today to host a noon-hour public meeting.

Presentations will be made in Mayo and Haines Junction tomorrow, and in Dawson City on Thursday.

Members of the public have an opportunity to provide input before the publicly owned utility completes its update of the 20-year plan to submit to the board.

Goran Sreckovic, Yukon Energy’s director of resource planning, told last night’s audience that planning for the future comes down to forecasting growth and determining which suite of options is best-suited to meet the growth.

Mining drives the Yukon’s economy, and because mining is cyclic, determining how best to provide for future demand is particularly difficult because while a mine may last 10 years, assets to generate power are designed to last much longer than 10 years, Sreckovic said.

There were questions and criticisms from the audience spanning a number of topics, including what sort of allowance was made in the demand forecast for the rising popularity of electric vehicles.

There’s a window open in the summer tourist season when Yukon Energy is spilling excess water, excess energy over the dam when it could be used to promote the greater use of electric vehicles to replace vehicles burning gasoline, it was mentioned.

Why hasn’t Yukon Energy gone to greater lengths to take on the home heating industry with the use of renewable energy to heat homes instead of fossil fuels, in a battle against greenhouse gas emissions?

Yukon Energy president Andrew Hall said the answer was simple. It’s still cheaper to heat with heating fuel, and until that changes, it’s difficult to convince home owners to switch, he said.

Goran told the audience every utility in the world is struggling to forecast how great the penetration of electric vehicles will be.

For the purpose of updating the resource plan, Yukon Energy is forecasting 1,800 electric vehicles on the low side over the 20 years and 2,500 on the high side, Sreckovic said.

• Over the next 10 years, under the low-growth scenario, the Minto Mine closes down in 2021, with another mine opening up the same year.

The cost of providing for increased demand to 2026 is forecast at $207 million, with 99.8 per cent of energy being renewable.

It includes energy conservation measures beginning in 2018; the addition of the third natural gas generator in 2019; implementing battery storage in 2020; upgrading existing generating assets like the Aishihik hydro plant in 2020; enhancing water storage in the Southern Lakes beginning in 2020: adding additional diesel generation in 2021; upgrading the Mayo hydro facility in 2022 and adding more diesel in 2026.

• Under a medium-growth scenario, Minto closes down in 2021 with another two mines becoming operational, one hooked into the grid and one not.

The forecast cost of meeting the higher demand is $299 million, with 98.1 per cent of the energy being renewable.

Meeting the additional growth involves everything in scenario one except additional diesel in 2026, but includes a small hydro project between 2023 and 2026, and raising the water storage in Mayo Lake by a half a metre to a metre in 2022.

• The high-growth scenario involves two mines on the grid and two mines off the grid.

Even mines off the grid would drive an increase in economic activity, housing.... The cost of meeting the demand would be $458 out to 2026. It would include all generating options in scenario one and two, with the addition of wind generation in 2022.

Hall explained there are variables in each scenario. The forecast includes the Minto Mine closing in 2021, but it may close at the end of this year, he acknowledged.

While expanding water storage in the Southern Lakes is included in each of the three scenarios, if ultimately there’s too much resistance from the public, they’ll have to look at something else, he said.

The resource plan, Hall said, is flexible, which is why it’s updated every five years if necessary.

Hall mentioned Yukon Energy was keen on what is known as pump storage, or using excess summer hydro energy to pump water up into a storage basin high in the mountains and then releasing the water for generation in the winter – like filling the bathtub and then pulling the plug.

“As much as we like it, we have to be disciplined,” he said. “We just can’t bring something forward if it’s too expensive.”

Each of the options to provide additional generating capacity comes with an estimated price.

The price for increasing storage in the Southern Lakes works out to nine cents per kilowatt hour, which roughly compares to the 12 cents per kilowatt hour residential customers see on their bills.

The cost of wind under the high-growth scenario, on the other hand, ranges anywhere from 13 to 19 cents per kilowatt hour, while introducing battery storage comes at a cost ranging from 80 cents to a $1.31 per kilowatt hour.

Discarded along with solar generation were the options of using biomass, or burning wood such as beetle-killed timber, to power generation, as was using biogas from organic waste.