Friday, May 07, 2010

Worth Reading

... is this comment on the feasibility of using water to store energy from solar and wind sources.

(Don't tell Van Jones.)

3 comments:

tim eisele said...

Well, I think that the commenter might be just a *touch* over the top:

1. Their estimate that pumped storage "only recovers around 25% of the energy put into it" is wildly at variance with other estimates that it is more on the order of 70-85%.

2. The estimate that storage for 10% of US electricity production would have to have reservoir volumes equal to all of the current US hydropower reservoirs neglects the point that pumped storage only needs to store it for a few days, while conventional hydropower needs storage to tide it over from one rainy season to the next, so at least part of that volume has to store water for about a year.

I'm not really convinced about the freezing problem of shallow reservoirs, either. Even around here, anything deeper than about 4 feet doesn't freeze all the way to the bottom in the winter - as shown by the fact that one of my wife's favorite fishing lakes (Lake Bailey) is only about 6 feet deep yet supports a nice population of sunfish and pike.

Granted that pumped storage has high capital costs, and works better in some areas than others, but it isn't the level of flaming stupidity that the commenter is painting it as. And when the geography is right, it really does make sense for managing peak loads, which things like coal-fired and nuclear plants aren't really that well-suited for.

Right around our area is actually a pretty good location for pumped storage - there's quite a lot of topographic relief between Lake Superior and most of the Upper Peninsula, there are lots of places where you can get about 500 feet of drop in less than a mile. I think that it would be a grand idea to build nuclear plants here as baseline generators, with pumped storage to manage the peaking loads. And my wife would really like to see them use Lake Superior for cooling the power plants, because currently the fishing is pretty pathetic due to the cold, nutrient-poor water.

K T Cat said...

Good points, but what is it you'd want to flood in order to store energy in the form of a lake?

tim eisele said...

Well, for starters I can think of five lakes within 30 miles of here that have already been flooded by damming rivers, but that are not currently being used for hydropower because the average flowrate over the course of the year isn't high enough to warrant a dedicated power station and staff. If they were used for pumped storage instead, though, I think they are each big enough to give back a few hundred megawatts for a couple of days. They would be perfectly adequate storage facilities. For that matter, the road we live on is in a creek valley that could easily be dammed up to form a pretty good pumped-storage lake, and nobody even lives on the part of the road that would be flooded. And this whole area is so ecologically impoverished (due to so recently being under glaciers + having been completely logged off within the last 100 years) that no given valley is going to have some endangered endemic species in it. All in all, we are completely unlike, say, California.