Nord Pool Spot has recieved the following message from Nordel:
The Nordic transmission system operators (TSOs) have decided to harmonize the so-called ramping rules for commercial trade between the Nordic synchronous system and the Continent (UCTE). Ramping means a restriction of how much flow is allowed to change between two hours. A ramping restriction in planned flow of a maximum 600 MW difference from one hour to the next will be applied separately on all HVDC connections between the two systems.
In practice this will introduce new restrictions for Kontek, SwePol, Baltic cable, and the coming HVDC connection NorNed. For KontiSkan and Skagerrak cables similar restrictions exist since a few years. The EstLink cable is not affected by ramping, neither is the Denmark West-Germany (AC) connection.
In terms of the connections included in the Elspot market these changes are to take effect at the earliest 9 October when the new Elspot system, SESAM, has been launched. The restriction on NorNed will be implemented as soon as the cable is taken in to commercial operation.
The reasons for ramping restrictions
Changes in trade have increased over the last years due to tighter market integration and with more connections between the areas. As a consequence, the balancing control has become increasingly difficult.
Frequent large changes in production and flow in fully loaded corridors in the grid make it more difficult to control the frequency. The security of the power system is threatened in the synchronous Nordic system. Local voltage problems also occur frequently.
Without restricting the maximum change of flow per hour (ramping) on interconnectors, very large ancillary services and operational reserves would be needed to handle imbalances within the operative hours. The coming commercial opening of NorNed via, initially explicit auctions, and the planned market coupling between Denmark and Germany will presumably make the balancing even more challenging.
The ramping restriction between the Nordic synchronous system and the Continent (UCTE) will be imposed separately on the 6 DC links listed below. However, for KontiSkan and Skagerrak the restriction is not only separate, but also jointly, i.e. Denmark West to/from Sweden and Norway.
- SwePol (Sweden <-> Poland)
- Baltic Cable (Sweden <-> Germany)
- Kontek (Denmark East <-> Germany)
- KontiSkan (Sweden <-> Denmark West)
- Skagerrak (Norway <-> Denmark West)
- NorNed (Norway <-> The Netherlands)
In Nordel there is an ongoing work on finding solutions on the balancing and local voltages problems due to large changes in the power flow on the HVDC links. The long-term goal (2010) of this work is to be able to reduce the ramping restrictions by introducing new balancing products. The Nordic TSOs will monitor the market impact of the ramping restrictions and investigate cost-effective initiatives that could lead to reductions in the need for ramping.
Lysaker, 7 September 2007
For further information, please contact:
Øivind Rue, Statnett SF, firstname.lastname@example.org, +47 22 52 72 95
Mikael Engvall, Svenska Kraftnät, email@example.com, +46 8 739 78 78
Per Sörensen Energinet.dk, firstname.lastname@example.org, +45 76 22 42 11