Transcript Ramping Constraints

IG meeting, December 5th, 2012, DERA premises, Copenhagen
NWE Day Ahead Price Coupling
Further clarifications on the algorithm
Ramping Constraints
• 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
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:
http://www.statnett.no/Documents/Nyheter_og_media/Nyhetsarkiv/2010/Rampi
ng%20report.pdf
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
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
Handling of price differences
• The algorithm can support different price bounds on different markets.
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.
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:
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–
–
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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:
http://www.statnett.no/Documents/Nyheter_og_media/Nyhetsarkiv/2010/Ramping%20report.pdf