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Dispatchability…uh, what?

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The emninetly dispatchable power of Dinorwig, a former quarry in Wales turned hydraulic storage

Today (8/8/17) SFU’s Mark Jaccard chimed in on the Site C debate with an opinion piece in the Vancouver Sun about dispatchability. Huh?

What appears to irritate Jaccard, a highly influential scholar and environmentalist, is the often repeated claim that while the costs of Site C keep climbing, those of renewables keep dropping.  By the time the Site C dam is completed, wind and solar will be so cheap that BC will be saddled with a white elephant.  Not so fast, says Jaccard: the real comparison should made on the cost of dispatchable electricity, not simply the price per kilowatt of capacity, nor that of produced electricity in kilowatt-hours.  Rather, what matters is the cost of producing electricity at the time when it is needed.  For instance, wind electricity that is only produced at nighttime, when no-one needs it, would indeed have indeed very low value; conversely, wind that reliably produces electricity at peak times (typically late afternoon), would be worth much more.  Dispatchable electricity, that is, electricity that can be matched to the demand, is indeed much more valuable.

Jaccard should be applauded for introducing this fairly arcane concept into the discussion.  As the Utilities Commission, which is finally reviewing Site C, drafts its recommendations, the concept of dispatchability is likely to get more airplay – and generate further confusion.  Forewarned…

That said, I expect this editorial to be embraced by the defenders of Site C.  Jaccard, wisely, does not pronounce himself on the issue.

That may be because, ultimately, dispatchability is unlikely to be a key issue.  Jaccard mentions that a large reservoir, such as would be created by Site C, does  provide dispatchability because of its ability to store water and release it only as needed.  A large hydro-electric reservoir is an ideal match for an intermittent source such as wind or solar.  Indeed, according to Jaccard,

As we invest in more wind and solar, the economics of dispatchable sources like Site C improves.

This is counter-intuitive, but true – in general.  But this is very unlikely to be true of Site C, itself.  This is because Site C would create just another reservoir, one among many in the province.  Site A, where the WAC Bennett was built, is a case in point: it created Williston Lake, a reservoir that dwarfs the proposed reservoir that Site C would create in the Peace valley.  And there are many more, of course: just think of Kootenay Lake or the Arrow Lakes to get an idea of the storage capacity we already have.  We are already well equipped to partner with any increase in intermittent power such as wind or solar.

Jaccard also mentions that other energy storage options, such as batteries, are much more costly than its equivalent capacity in a large hydroelectric reservoir.  But this is the same refrain as was said last decade about wind and solar: too expensive.  As larger and larger storage systems come on line (such as  the newly announced projects in Hawaii and Australia), unit costs per unit power are going to drop, just as they did for solar, because of the economies of scale in manufacturing, as well as new technical developments.  True, we’re not there yet, but there is no reason to expect that batteries would not follow a price curve similar to solar cells or computers.  In contrast, if Muskrat Falls is any indication, the price of Site C is going to keep soaring skywards.  I have not asked him, but my guess is that Jaccard’s prudence and lack of commitment on this issue comes from the fact that he knows these facts, just like Andrew Weaver does.  And like Weaver, I expect Jaccard to eventually admit, sooner or later, that Site C is unnecessary.

But if nothing else, Jaccard has the merit of introducing the concept of dispatchability to the general public, at least to those who read the papers.  If it becomes a household word, I fully expect the geothermal energy folks to start trumpeting: “Hey, we’re dispatchable! Invest with us!”

And a good thing that would be.

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Written by enviropaul

August 4, 2017 at 3:40 pm

One Response

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  1. […] to consider, which complicate the situation considerably.  The first of these points is dispatchability, that is, the ability to generate electricity at the time when it is needed.   But cars do not […]


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