|European Union Electricity Market Glossary|
According to Article 2(2)(c) of the Commission Regulation (EU) 714/2009 on conditions for access to the grid for crossborder exchanges in electricity ‘congestion’ means a situation in which an interconnection linking national transmission networks cannot accommodate all physical flows resulting from international trade requested by market participants, because of a lack of capacity of the interconnectors and/or the national transmission systems concerned.
TSO – DSO Report on an integrated approach to an Active System Management (p. 14, 15) observes that the “concept was generalised afterwards, due to lack of capacity in any element of the grid”, in the Commission Regulation (EU) 2015/1222 establishing a Guideline on Capacity Allocation and Congestion Management (the CACM Regulation).
The CACM Regulation laid down in Article 2 the following definitions:
- ‘market congestion’ - a situation in which the economic surplus for single day-ahead or intraday coupling has been limited by cross-zonal capacity or allocation constraints (Article 2(17));
- ‘physical congestion’ - any network situation where forecasted or realised power flows violate the thermal limits of the elements of the grid and voltage stability or the angle stability limits of the power system (Article 2(18));
- ‘structural congestion’ - congestion in the transmission system that can be unambiguously defined, is predictable, is geographically stable over time and is frequently reoccurring under normal power system conditions (Article 2(19)).
In the European Commission’s Winter Energy Package (Proposal for a Regulation of the European Parliament and of the Council on the internal market for electricity (recast, 30.11.2016, COM(2016) 861 final 2016/0379 (COD), Article 2(2)(c)) 'congestion' meant a situation in which all requests from market participants to trade between two bidding zones cannot be accommodated because they would significantly affect the physical flows on network elements which cannot accommodate those flows.
Identical definition has been finally included Article 2(4) of the Regulation (EU) 2019/943 of the European Parliament and of the Council of 5 June 2019 on the internal market for electricity (recast).
The definitive text of the recast Regulation introduced, moreover, in Article 2(6) the definition of ‘structural congestion’, which means congestion in the transmission system that is capable of being unambiguously defined, is predictable, is geographically stable over time, and frequently reoccurs under normal electricity system conditions.
The EU Network Code on System Operation in Article 55(c) lists congestion management services among services provided by third parties, through procurement when applicable, that each Transmission System Operator (TSO) uses for ensuring the operational security of its control area.
ACER/CEER Annual Report on the Results of Monitoring the Internal Electricity and Natural Gas Markets in 2017 Electricity Wholesale Markets Volume October 2018 (p. 8) indicates that where sufficient information is available (e.g. in the CWE region), it confirms that congestion most often relates to intra-zonal critical network elements (CNEs) rather than to interconnectors.
ACER/CEER refers to the example, when congestion occurred in the CWE region, internal lines constrained available capacity much more often (86% of occurrences) than cross-zonal lines (14%) in 2017. More than half of these occurrences related to CNEs located inside Germany.
According to the ACER/CEER this shows that capacity calculation methodologies often lack rules to avoid internal exchanges being unduly prioritised over cross-zonal ones.
Network Code on System Operation, Article 55(c)
|Last Updated on Friday, 13 September 2019 22:24|