Whitehorse Daily Star

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Photo by Chuck Tobin

CONCEPT EXPLAINED – Yukon Energy engineer Goran Sreckovic explained how pump storage works as an alternative form of renewable energy. He told the audience while it isn’t used in Canada, it is used extensively in Europe, Japan, China and the U.S.

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Photo by Photo Submitted

OLD BUT NEW – The practice of pump storage – like filling up the bathtub and pulling the plug later – is used extensively throughout the world to store water for the generation of power later. Yukon Energy is looking at pump storage as a new alternative. Above is a simplified concept presented to an alternative energy workshop Wednesday. Graphic courtesy YUKON ENERGY

Yukon Energy looking at new renewable energy concept

There’s a new renewable energy concept being floated to assist with the Yukon’s needs.

By Chuck Tobin on October 1, 2015

There’s a new renewable energy concept being floated to assist with the Yukon’s needs.

Pump storage is what its called, and it’s being looked at by Yukon Energy as the Crown corporation begins to update its 20-year resource plan to address the territory’s future demand for electricity.

The Yukon Conservation Society has also hired a local engineer to conduct a desktop exercise to examine potential for pump storage.

While pump storage is a relatively simple proposal widely used elsewhere in the world, its application is somewhat complicated, Yukon Energy engineer Goran Sreckovic explained to a workshop Wednesday sponsored by the conservation society.

Pump storage involves the use of surplus energy to pump water into a storage area hundreds of metres above, so that the water can be released later into a penstock or pipeline to drive the turbines sitting 100s of metre below.

It’s like filling up a bathtub and then pulling the plug.

Purely as a hypothetical example: Yukon Energy spills huge amounts of water – potential energy – through the Whitehorse Rapids Dam every summer, because it’s not allowed to raise water levels in the Southern Lakes anymore than it already does.

Under the pump storage principle, the summer water could instead be used to generate electricity to power large water pumps that would push the water high up into a valley or natural depression where it could be stored – on top of Grey Mountain, strictly hypothetically.

In the cold winter months when there’s not enough water left in the river to meet generation demand, and backup diesel generation is required, the plug is pulled on the storage area. The water flowing down at great pressure because of the high elevation drives more turbines, reducing the need for diesel.

Sreckovic said pump storage generally requires two storage areas or reservoirs: one at the bottom from which the water will be pumped up, maybe Schwatka Lake, hypothetically, and one at the top, Grey Mountain.

“So the system is very simple,” Sreckovic told the 85 participants at yesterday’s day-long workshop. “Having said that, it is not exactly cheap because there are two reservoirs and the units (turbines) are more complex than regular hydro.”

The Yukon Conservation Society scheduled its workshop for Sept. 30 in hopes of providing alternate concepts to another major hydro dam the Yukon government is currently searching for through its Next Generation Hydro project. The Next Generation team – under the guidance of the Yukon Development Corporation – had scheduled a two-day workshop for today and tomorrow. It was cancelled last month after the invitations were out and the hall had been booked, as the project is months behind schedule. The publicly owned development corporation was to submit a recommendation for the next major hydro site to Premier Darrell Pasloski and his cabinet before the end of the year.

In addition to pump storage, workshop participants heard about smaller hydro projects that supply the needs of Skagway, Haines and Atlin. They listened to representatives of First Nations who spoke of the ill-effects left by the Yukon’s hydro dams in Whitehorse, Aishihik and Mayo.

The Yukon Energy engineer told the audience pump storage is huge in Europe and substantial in Japan, China and the U.S. There’s only one example in Canada, built in 1957 at Niagara Falls, known as the Sir Adam Beck Station.

In Europe, Sreckovic explained, when they began looking at pump storage, coal was a primary fuel for thermal generation, but coal generation needs to be stable and constant, just as nuclear generation used in Japan.

So when demand is down during the night in Europe, the excess coal energy is used to pump water and the water is used to drive generation during the day.

Sreckovic said pump storage can be used to address fluctuations in demand either daily or seasonally. For the Yukon, its application would be seasonally, he said.

“It is capable of shifting huge amounts of energy from one season to the other, so that is good,” said Yukon Energy’s director of resource planning. “And it is renewable.”

He said currently in Canada there is one pump storage proposal on the books, involving a generating capacity of 400 megawatts, or two and a half times greater than all of the generating capacity in the Yukon.

The estimated cost of the project is between $670 and $750 million, or somewhere around $18 million per megawatt, which is not cheap when considering some hydro projects in Alaska are coming in at $5 million or less per megawatt, Sreckovic said.

Sreckovic said a pump storage system also loses about 25 per cent of the potential energy just to run the system – pump the water up the hill.

Ideally, he said, the upper reservoir would be at least 400 metres above the lower reservoir, and no less than 200.

The closer the system is to existing transmission lines, the less costly it will be to tie in, he noted.

“The higher, the closer, the better.”

Sreckovic said there’s also the environmental footprint left by the two reservoirs, but there’s also the potential to replace diesel generation with renewable energy.

Yukon Energy will be looking at pump storage as an option in a review of its 20-year resource plan, he said.

Yukon Energy president Andrew Hall, who was at the workshop for the whole day, told the audience his staff was meeting yesterday with First Nation leaders to introduce the review of the resource plan.

Yukon Energy will be rolling it out publicly next week, he said.

Whitehorse engineer John Maissan was retained by the conservation society to conduct a desktop exercise to look at potential sites which could accommodate pump storage.

Maissan said he purposely stayed away from the potential energy corridor linking Whitehorse and Skagway because he knows Yukon Energy is already looking at a couple of sites along the corridor.

In his examination along the Robert Campbell Highway between Carmacks and Faro – where the transmission line already runs – he did identify what he described as five ‘A’ sites.

Maissan said there are of course challenges to each site, such as distance to the transmission line, and a couple did involve crossing the Yukon or Big Salmon rivers.

The exercise, however, did indicate to him that it’s worth looking for pump storage sites throughout the Yukon because the potential is there.

Comments (3)

Up 1 Down 0

wundering on Oct 6, 2015 at 1:01 pm

Store the water in fish lake? Is water not being pumped to Granger subdivision, when it could be gravity fed to same location.

Up 8 Down 6

Josey Wales on Oct 1, 2015 at 4:29 pm

OK I never read this article, this comment is for the photo.
If ever there was a photo illustrating the posture of the 4:20 crews killing a roach...this is it.

Up 11 Down 1

north_of_60 on Oct 1, 2015 at 4:24 pm

This isn't "a new renewable energy concept", it's been widely used since the 1800s.
A simple calculation shows that water could be easily stored in Fish Lake to offset the need for fossil fuel in the winter.
A small percent of fossil fuel back-up is still cheaper, and that's why it's used instead of pumped storage.

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