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On New Year’s Day the scene was set for an over-run of electricity
By Per Andersen

On New Year’s Day the watch in Eltra’s control room had to use the new emergency plan for the first time to avoid threats to the system from critical over-run. This was accomplished by stopping a total of c.115 MW of Elsam’s wind farms. Elsam’s wind farms are not subject to the legislation on “prioritised production”.

It took about 30 minutes to shut down the many turbines, but this was enough time to avoid a further rise in electricity over-run caused by increasing wind speeds.

Low demand on New Year’s Day
Tuesday the 1st January constituted a classical over-run situation. True to tradition the people of Jutland and Funen relaxed on the first day of the year. They did not use strong lights and kept the use of electrical machines to a minimum. So the load was light, even though the weather was cold. Around mid-day about 1.400 MW was produced from wind, the central heat and power plants registered about 1,150 MW and the decentralised heat and power plants contributed about 1.250 MW - a total production of about 3.800 MW. Against this, there was a demand for about 1.900 MW as well as a maximal export to Norway and Sweden of 1.650 MW.

Reduced German nuclear electricity 
Northern Germany could only take about 200 MW, because of its own over-production problems and a low demand. Nuclear electricity north of Hamborg had even been reduced to limit production. This is something that seldom occurs.

With fully loaded connections to neighbouring countries and prospects of both lower demand and increased wind production in the afternoon, the watch in Eltra’s control room decided to step in.

“According to our new emergency plan we would normally turn down Elsam’s large plants first, and let them operate on “by-pass” – heat production. Thereafter we would stop those of Elsam’s decentralised heat and power plants that are not “prioritised” (about 20 MW). However, Eltra’s watch first chose to intervene in Elsam’s centrally controlled wind turbines. This happened for management and communication reasons, but especially because the situation could rapidly get worse”, points out Carl Hilger, Eltra’s operations manager.

Running-in phase
“We are in a running-in phase. Communications must be improved because contact to individual production plants is still maintained with the help of telephone lists. It is difficult to get the necessary over-view. It is all rather primitive, and the “handles” are neither smart nor economic. For this reason we are putting a lot of effort into establishing closer collaboration with the grid companies and production plants, as well as getting the cost and subsidy rules changed so that we can handle the over-run of electricity most economically for society”, says Carl Hilger.