(((Because *all* forms of power are risky. But wind has its own risk characteristics: sometimes it doesn't blow, sometimes it blows enough to roast the grid.)))
Date: Mon, 3 Mar 2008 08:03:47 +0900
From: "Charles Wood"
Subject: Wind Power Risks
It is now becoming more common to hear of wind power caused outages. The outages are either a loss of service because the wind has stopped blowing or, surprisingly, because there is too much wind.
These problems were not so apparent when the percentage of wind power was low compared to the overall capacity, and in particular to rapid response generators such as hydro.
It seems that wind power has become too successful and the engineering required to integrate it into different grids has lagged behind. In particular, the correct balance is not being achieved between wind power capacity in a region and the available replacement power sources -
transmission and local non-base load sources.
A recent outage in Texas illustrates the low wind example. An *IEEE
Spectrum* article by Peter Fairley explains the overload scenario.
The Texas outage on February 27 as reported by Reuters:
http://www.reuters.com/article/domesticNews/idUSN2749522920080228?feedType=RSS&feedName=domesticNews&rpc=22&sp=true
"Electric Reliability Council of Texas (ERCOT) said a decline in wind energy production in west Texas occurred at the same time evening electric demand was building as colder temperatures moved into the state.
The grid operator went directly to the second stage of an emergency plan at
6:41 PM CST (0041 GMT), ERCOT said in a statement.
System operators curtailed power to interruptible customers to shave 1,100
megawatts of demand within 10 minutes, ERCOT said. Interruptible customers are generally large industrial customers who are paid to reduce power use when emergencies occur."
The IEEE article on power surges from wind farms is at http://spectrum.ieee.org/feb08/5943
and the key paragraph is this:
Wind-farm installation in Europe grew an estimated 38 percent last year, up from 19 percent in 2006, bringing the total capacity to about 67
gigawatts (roughly the equivalent of 20 to 25 standard-size nuclear power plants). At those rates, European grid operators report, windmill construction is outstripping growth in transmission capacity. The result is that in wind-farm-rich countries such as Germany and Denmark, high winds cause large and unanticipated power flows that saturate the grids of neighboring nations. In recent years this has forced grid operators to curtail scheduled transfers of power between grids. In 2008, the grid operators warn, the unanticipated power flows could overload lines anywhere from the Czech Republic to the Netherlands.
