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The flow-based coupling method

Flow-based coupling within the CWE region went live on 21 May 2015.
Prior to that, these four bidding zones were coupled on a Net Transfer Capacities (NTC) basis, meaning that limitations on exchanges were set bilaterally for each border (one constraint per border and per direction, implicitly taking into account the state of the network).
Constraints now explicitly take into account the physical network infrastructure in the five countries. Cross-border exchanges are thus optimised to reflect the actual physical capacities of networks as accurately as possible. This requires very close coordination between transmission system operators in CWE countries.
In sum, it is no longer possible to consider borders separately, and indicators previously used for the France-Belgium and France-Germany borders have been replaced by France-CWE region indicators

France was a net exporter to the CWE region for the third year in a row


Exchanges between France and the CWE region were very balanced in 2020. France was an importer for 51 % of one-hour periods, and an importer for six months: January, July, and from September on. The balance was lower than in 2019, but France nonetheless had a net export balance of 0.7 TWh.

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Price convergence in the CWE region rose further


Instances of price convergence within the CWE region rose to 43 %, from 42 % in 2019. This was the highest level on record since markets were first coupled. The rise reflected more homogeneous market conditions in the different CWE countries and the additional interconnection capacity available, particularly for the flow-based calculation, thanks to increased coordination between TSOs.

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A first HVDC line in the CWE region

On 18 November 2020, ALEGrO (Aachen Liège Electricity Grid Overlay), a HVDC power line linking Germany and Belgium, was commissioned and integrated into the CWE capacity calculation. For the first time, this new link, operated by TSOs Elia and Amprion, will be operated allowing the market coupling algorithm to dictate how power flows over the cable, this to maximise the surplus within the region. Moreover, after the decision was approved by regulators, market coupling within the CWE region began using the “flow-based plain” methodology on 3 November, meaning that counterintuitive flows (exports to market bidding areas where prices are lower) will no longer be inhibited if they maximise overall social welfare. This change is also known as the elimination of the “intuitive patch”.

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