The Hydro Question

Boy, I go away for a few hours and all of the sudden the big question is why I didn't mention hydroelectric dams. I assume many of you don't click through to the comments, so:

Declan:

One question though, you don't mention large hydroelectric plants.... Is this because you consider them a worse option than nuclear / coal / gas, or just because you figure we don't need them if we build enough wind/solar/small hydro/conservation?

Wonderdog:

A lot of people (not necessarily here) treat hydro as benign, and it ain't.

LeoPetr:

Do we have suitable river basins for hydroelectric plant construction? I suppose we should, at least for the small ones. Are there hydroelectric dams currently under construction in Ontario (ignoring the new Niagara Falls turbines)?

And finally, Westacular:

I assumed you omitted it because we've already tapped all the best/most immediately available sites for large hydro plants, but I have no reason to actually assume that's the case.

As far as Hydroelectric goes generally, the fact is most of the best-placed dams in the industrialized world have inconveniently already been built. I don't consider large-scale hydroelectric dams to be worse than a similar-sized coal, nuclear, or gas plant, but that's not saying much. There's some obvious negative impacts from building large dams with the attending disruptions. And large-scale hydro suffers from the same lack of nimbleness that nuclear does - for engineering and regulatory reasons, we can't build it quick or cheap.

I suppose if I had to rank large hydro I'd put it somewhere between nuclear and wind, though closer to nuclear. Not my preferred option, certainly. Basically, large hydro is still labouring under the old paradigm of centralized generation, with huge projects to get economies of scale. But if necessary - and that's always a big if - then I suppose I'd have to say large hydro is better than the alternatives of coal, nuclear, or gas. It is inferior to wind, solar, or small hydro (see below.)

I don't know of any current projects to build hydro in Ontario. Certainly I can't think of any large projects, though LeoPetr notes that we're adding a bit of capacity to Sir Adam Beck in Niagara Falls. For those market-forces fans out there, we should note that like Nuclear, large hydro plants tend to be built by big government (see Ontario Hydro here, The TVA in the US, or many different Communist governments.)

Actually, Ontario is an interesting test case for the future of hydroelectric power. We've got three large rivers that remain untapped in the northern parts of the province, as well as a variety of other smaller sources, according to OPA's power supply mix report. (PDF) However, the vast majority of the potential waters (about 6 Gw out of 7.5 Gw potential) are either Federal or First Nations lands, or part of provincial parks and reserves. What's left amounts to just under 1.5 gw, or about as much as the proposed additions to Darlington. What's really interesting is that the report says that about 567 Mw of that is in relatively small sites, from 10-100 Mw. This is almost as much as exists in the very large (+100 Mw) sites. (p. 22 of the above link.) So we could either try and build a few large plants that we'd have to screw the First Nations to build, or we could concentrate on the small-scale hydro which is almost as plentiful.

An additional wrinkle is that large transmission lines will need to be built for any tapping of the northern hydro potential. There is, however, a chance for some double-dipping, as most of Ontario's wind potential is also in the north. If we're going to build those transmission lines, there's more than enough opportunity up north.

There are some interesting developments in small-scale hydroelectric generation, too. One of the most interesting is so-called "underwater windmills". Because water is obviously denser than wind, even a small current can deliver as much or more force to the blades of a windmill-style turbine. Alternately, in a fast-moving river the turbines can be much smaller. This kind of technology is lower-impact than a Niagara- or Three Gorges-style dam. It's also modular and scaleable in a way that dams aren't. As a bonus, it doesn't ruin the river for recreational use or wildlife, so long as boaters stay away from the turbines. I think we could post a sign on a buoy, don't you?

These underwater windmills do, of course, suffer the same problems of the air-pushed kind - they're intermittent, though less so than wind. I can only repeat what I've said before - storage! Of course, even with aggressive conservation and a theoretical deployment of storage technologies, we will need actual generation. There's every reason to believe that small-scale hydro can meet part of that, especially if we take the opportunity to build up our wind potential as well.