Primary reserve

The primary reserve is the capacity that is activated by the primary control system.

The primary control system is an automated device (installed locally on production equipment with a capacity of 5 MW or more), which ensures a constant ratio between frequency changes and production (capacity) changes in no more than 30 seconds.

Context

• The requirements for the primary reserve and the delivery of the primary control contribution have been laid down in the System Code.
• The settings of the primary control systems on the production equipment are based on the values laid down in the document on UCTE agreements.
• In accordance with UCTE policies, TSOs are held responsible within the UCTE for the quality of the primary control contributions after disruptions www.ucte.org. Each TSO analyses and reports on the quality of its own primary response after a European disruption of over 1000 MW.
           

Compensation for primary reserve

The maintenance of the primary reserve and the provision of the primary control contribution are not compensated for.

Explanation

The purpose of the primary reserve is to stabilise frequency disruptions in the entire (internationally) interconnected high-voltage grid, regardless of the cause and location of these disruptions. Serious frequency disruptions can result in automatic load shedding and in the worst case initiate a black-out.

The minimum size required for primary contributions is determined annually at UCTE level and is in proportion to the total production volume in the areas controlled by the TSOs. For 2008 the frequency bias for the Netherlands has been set at 737 MW/Hz. This value equals 3.5% of the frequency bias for the entire interconnected UCTE grid.

The above means that in the event of a production failure of 1000 MW somewhere in Europe, a contribution of approximately 35 MW will be expected from the Netherlands. In the synchronous UCTE system, the maximum possible production failure is deemed to be 3000 MW. Taking the percentage of 3.5% into account, this means that the Netherlands must have a primary reserve of around 106 MW.

Year	Share in UCTE production (%)	Minimum primary reserve (MW)
2007	3,6	110
2008	3,5	106

These Dutch data for 2008 were calculated proportionally on the basis of the total known Dutch electrical energy production (sources: Statistics Netherlands and TenneT) in 2006.