1. IG meeting, December 5th, 2012, DERA premises, Copenhagen
NWE Day Ahead Price Coupling
Further clarifications on the algorithm

2. The algorithm can handle following ramping constraints
Line ramping:
max changes on one line from one hour to the next hour
Cumulative flow ramping (new feature):
Limit the flow change from one hour to the next on a set of lines.
Net position ramping (implemented, not in production yet):
Limit the change in net position from one hour to the next hour

3. Line Ramping
Ramping constraint is an instrument of system operation to maintain system security (frequency management purposes).
This sets the maximum change in DC flows (Max MW/h per interconnector) on an hour to hour basis
Daily implicit allocations are expected to utilize DC capacity more fully (due to daily price differences), thereby causing greater and more frequent hour to hour variations in flow
ENTSO-E report on handling of ramping constraints:

4. Minimum stable flow
The issue has been presented to ACER 21. June where it was stated that this is a difficult requirement which has been submitted to R&D investigation
It will not be implemented by PCR/NWE launch

5. Avoidance of curtailment by local matching
Local Matching Constraint (LMC) is used in markets where the two following notions are considered:
Price Taking Orders (PTOs) i.e. hourly orders at minimum or maximum price;
Curtailment: defined as the situation when not every PTO can be executed;
LMC aims at limiting curtailment and imposes the following (supply LMC below; demand LMC is symmetrical):
If demand quantity is sufficient, supply PTO must be entirely executed
If demand quantity is not sufficient, supply PTO is executed as much as possible
Additional information was presented to ACER 21. June

6. Handling of price differences
The algorithm can support different price bounds on different markets.

7. NRAs questions
For information, a set of 27 additional questions requesting further information on the algorithm has been sent to PCR PXs by Markus Hübner on 12/11.
Answers are beeing prepared.

8. Backup slide : Ramping on Nordic DC interconnectors
Constraints on hour to hour changes of DC flows
Max 600 MW/h per interconnector (3000 MW for all Nordic interconnectors to the Continental Europe)
Ramping constraint is an instrument of system operation to maintain system security.
Evaluated to have low social costs compared to alternatives so far.
TSOs are investigating alternatives for the future:
Shorter time resolution (quarterly production plans)
Load frequency control
More efficient activation procedure of reserves
Cumulative ramping
ENTSO-E report on handling of ramping constraints: