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Wondering what's happening with Revelstoke 6?

Revelstoke Dam
We're planning to install the final generating unit at Revelstoke Dam but with growing electricity demand and an increasing population, the increased capacity from another unit at Revelstoke won’t be enough. Enter Site C.

Project manager Chris Waite explains why we’re preparing to add another unit, even with Site C

By now you've probably heard the news that BC Hydro is building the Site C Clean Energy Project, a third dam on the Peace River that will generate enough electricity to power 450,000 homes each year.

And if you've been wondering how our existing dams, like Mica and Revelstoke, fit into our plans, you're not alone.

When Mica and Revelstoke were completed, they each had enough space for six generating units, but only four were installed. We essentially built the dams with room to grow.

Mica is now fully complete with six units in service, but what about Revelstoke?

Why, you might ask, can't we just 'finish' Revelstoke with a sixth generating unit, instead of building a whole new dam with Site C?

Well, as it turns out, we are planning to install a sixth unit at Revelstoke; it's an important part of how we'll meet the growing electricity demand.

But as Revelstoke 6 project manager Chris Waite explains – it won't be enough.

Why, you might ask, can't we just 'finish' Revelstoke with a sixth generating unit, instead of building a whole new dam with Site C?

The critical piece comes in understanding the difference between energy and capacity, as Chris explains in the video above. Although Revelstoke 6 will offer us increased capacity, Site C provides both energy and capacity. And B.C. will need both in the long term as our demand continues to grow, especially since we need to do maintenance on units at Mica in the coming years.

Reservoir size means capacity, not energy

Once you've got a handle on the fact that Revelstoke only offers additional capacity (not energy), you might be wondering why again. That is, why don't we just run Revelstoke at 'full power' all the time?

The answer is the size of our reservoirs.

The amount of electricity that we can generate from our dams over the year is limited by the amount of water that we have available. And the amount of water that we have available depends on the weather; we get more in a wet year than a dry year. But the amount of water in the reservoir stays the same, whether we have five generating units or six.

So in any given year, the total amount of electricity that we can generate from Revelstoke is the same. Installing the extra generating unit allows us to produce more power at any given time from Revelstoke Dam – increasing our capacity – but it also means that we'll use more water.

So if we decide to produce more power from Revelstoke at some times of the day to help meet peak demand periods, it limits what we have available for other times. Running all the units all the time would just mean running out of water.

But as Chris explains, that peak demand (often dinnertime on the coldest day of the year) is where Revelstoke 6 can help. Adding a generating unit is another way that we can meet that spike in demand with clean electricity.