Here in the Pacific Northwest, we have quite a few wind turbines generating electricity as well as lots of hydroelectric dams. Also one coal burning generator and a number of natural gas turbine plants.
The Bonneville Power Administration owns a big transmission line network and runs most of the big hydro dams. Last year in May during certain times, the BPA took the wind generators off-line in favor of electricity from the hydro dams. The wind turbine owners squawked, since they lost revenue. Here’s an article about the situation and the deal they’re trying to make this year.
My question is, if the BPA can take the wind generators off-line, why can’t they take the thermal generators off-line? OK, I know they can’t do it quite the same way as they did for the wind. The wind was taken off-line for a few hours at a time, during the late night when demand was low. They can’t do that for thermal plants (except for gas turbines that are designed for that) but couldn’t they take an entire generator off-line for a month or two during the high runoff period? I’d really like to see the Boardman plant (the coal burner) taken off-line as much as possible.
Bumpity-bump bump bump! Come on, someone should know something about this.
Well, to hazard a guess, the coal plant is owned by the same company that actually handles the residential delivery in (parts of) Portland. Are you sure the BPA actually has anything to do with the coal plant? It could be that PGE owns the plant and the transmission lines and only buys power from the BPA when necessary. Or if they’re putting power into the BPA pool on one end and buying it on the other, maybe by being the delivery customer they have more say in which power plants get shut down than the 3rd party that owns the wind farms.
I think you got it right with bumpity bump bump
That’s what might happen to your voltage level if the thermal plants come off line.
I’m not privy to the exact reasons BPA adjusted their dispatch but I can take an educated guess.
The big reason is output control which the utility refers to as load following.
So one reason some thermal plants remain on line is so that the operators can adjust the output of electricity to match the demand. Demand changes second by second and since electricity is an instantly manufactured and consumed product the output of the plants has to match the input of the loads.
Another reason is that some thermal plants like coal can take almost a whole day to start up and aren’t designed for frequent on/off use. It stresses the the high heat components too much if they are frequently cooled and heated.
So it makes sense (economics and system stability) to keep some fossil fuel units running.
Why choose hydro over wind? Hydro is pretty well a constant output. Wind generation changes minute to minute. If you have to choose between two renewable sources the best choice is the one with the stable output.
Wind power is a fantastic resource but it’s application also can cause problems. Remember that comment I made about load following? The utility has to have generation that can respond quickly (damn near instantaneously) to second by second changes in the load. When wind power is on line the load following task becomes harder. Wind generators can’t produce a reliable amount of power. Their output varies minute by minute with the wind speed. So the Utility has to have other dispatchable generation on line to compensate. Overall the wind strategy is a good one because the value of having a very low variable cost energy source is much greater than the cost of extra stringent load following. But on the occasion that hydro is available with its low cost and reliable dispatchability (The operators know how much water per day/week is available) - wind and its unreliable output get dumped out of the mix.
There is an over-capacity of power generation and limited transmission lines within the Columbia River Basin. The private wind companies knew this before they set up their wind turbines, hoping to force BPA (a government agency) to accommodate them (Big, bad government vs. always perfect private enterprise, so to speak.). The transmission line issue cannot be easily resolved since it involves federal politics and the politics of two states, along with some contentious environmental issues within the Columbia River Gorge. The issue was made worse with the high snow-pack levels, and subsequent spring runoff, as stated in the article.
The dams and gas turbines have been here for a long time. Wind generation is exploiting the unique characteristics of weather and geography in the Columbia River Basin, something that really does offer a positive sustainable, alternative energy program. However, as I said, the wind companies are new, mostly out of the Northwest power companies (I believe Florida and possibly Texas-based power companies) who apparently chose to muscle in on Northwest energy production. At the same time the Northwest was severely burned by the California energy crisis a few years back (later by a Bush Administration proposal that was shot down) and people around here don’t want it happening again.
Now there are concerns being raised the large wind turbine blades may be dangerous to birdlife. Given the strong environmental attitude of the Northwest, the attitude of the absent owners of the wind generators and past experience with “outsiders” and you have an issue that is not going to be resolved anytime soon.
Bubbsdog, you missed the point. It has nothing to do with load following. And I’m aware that thermal plants generally can’t go down and up quickly, which is why I suggested they be taken down for a month or two. Try reading the article I linked to before commenting again.
Duckster, What we really have in the NW is not so much an overcapacity, but rather an undercapacity of transmission lines to California.
All three west coast states have requirements that a certain percentage of their power come from renewable sources. California has the highest requirements. So all the California power companies have gone out to secure renewable sources, often from neighboring states. Many of the wind farms in Oregon (as well as other western states) have contracts to supply power to California. But they’re going to have to build more long distance transmission lines to get it there.
In the meantime it leaves us with a temporary overcapacity which is compounded by the limits to how much water they can spill over the dams. During high runoff periods, the only way they can get rid of the water is by generating power. And I believe the high runoff period (late spring to early summer) is the same time of year that wind power is at its highest.