CWE day-ahead FBMC went live in May 2015, thereby replacing the former ATC-method for coupling the day-ahead markets in the CWE region. Contrary to ATC, FBMC makes it possible to optimize the zonal net positions of the relevant bidding zones simultaneously, based on an optimization algorithm to maximize CWE social welfare while respecting network constraints. CWE FBMC makes it possible to be far less conservative than the ATC-method. This potentially allows a more efficient use and allocation of the existing network capacity.
In 2018, CWE FBMC performed notably better than in the previous 2 years in terms of maximum and average CWE cross-zonal exchanges. In December 2018, the combination of long-term and day-ahead cross-zonal exchanges in the CWE region reached 10,813 MW, i.e. 13% more than the maximum of 9,536 MW reached in October 2017, 22% more than the maximum of 8,829 MW reached in 2016 and even 54% more than the maximum of 7,023 MW reached in 2012 with ATC (Figure 54). Compared to ATC, however, CWE FBMC still results in lower minimal exchanges. While the minimum CWE cross-zonal exchanges during congested hours amounted to 2,348 MW before CWE FBMC implementation, it went down to 1,456 MW with FBMC in 2017. In 2018, the lowest value of CWE exchanges recorded during congested hours amounted to 1,620 MW (Figure 54).
-3962 -3322
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3218 3209
2821
-4,500 -3,500 -2,500 -1,500 -500 500 1,500 2,500 3,500 4,500
200701 200704 200707 200710 200801 200804 200807 200810 200901 200904 200907 200910 201001 201004 201007 201010 201101 201104 201107 201110 201201 201204 201207 201210 201301 201304 201307 201310 201401 201404 201407 201410 201501 201504 201507 201510 201601 201604 201607 201610 201701 201704 201707 201710 201801 201804 201807 201810
Monthly Max Physical Flow FR=>BE Mean Physical Flow BE=>FR Monthly Max Physical Flow BE=>FR MW
BE => FR
FR=>BE
Figure 54: Maximum, average and minimum monthly values of CWE cross-border volume (day-ahead + long term) during congested hours for 2011 – 2017. The vertical line indicates the start of FBMC for day-ahead market coupling.
Sources: CWE TSOs, CREG
In annual terms, the yearly averaged cross-zonal exchanges in the CWE region reached 4,590 MW i.e. 20% more than the 3,736 MW yearly average achieved in 2017. The yearly averaged cross-zonal exchange during congested hours reached 4,684 MW, an increase of 17% compared to 4,018 MW in 2017. Based on these indicators, 2018 outperformed all previous years (see Figure 56). The monthly averaged CWE cross-zonal exchanges are shown in Figure 55, together with the average net positions of the different bidding zones.
7,023
7,745
8,829
9,536
10,503
5,145 5,596
2,348
1,634
1,456
1,620
0 2,000 4,000 6,000 8,000 10,000 12,000
Series4 Monthly Max Monthly Average Monthly Min
ATC FBMC
MW
Figure 55: Monthly averaged Zonal Net Positions and CWE cross-zonal exchanges in day-ahead, including long term nominations, before and after the introduction of FBMC on 21 May 2015. By way of comparison, the net positions of the DE/LU and AT bidding zones after the DE/AT/LU bidding zone split on 1 October 2019, are lumped together.
Figure 56: Yearly averaged day-ahead cross-zonal exchange in the CWE-region, including long-term nominations. The blue and gray bars indicate, respectively, the evaluated results over all hours and over congested hours only. The darker bars show the results with ATC, the lighter ones the results with FBMC. By way of comparison, exchanges between the DE/LU and AT bidding zones after 1 October 2018 are not included in the figures. As such, the net positions of the DE/LU and AT bidding zones after the DE/AT/LU bidding zone split on 1 October 2019, are lumped together.
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201101 201104 201107 201110 201201 201204 201207 201210 201301 201304 201307 201310 201401 201404 201407 201410 201501 201504 201507 201510 201601 201604 201607 201610 201701 201704 201707 201710 201801 201804 201807 201810
Zonal Net Positions / Total CWE exchange (MW)
NEP BE NEP NL NEP FR NEP DE/AT/LU XB-vol CWE congested hours only
2011 2012 2013 2014 2015 2016 2017 2018
Total CWE Exchange between zones (MW)
All hours (ATC/FBMC) Congested hours (ATC/FBMC)
The results of CWE FBMC in 2018 were in contrast with its initial years of implementation, from 2015 to 2017, when CWE FBMC was clearly underperforming due to the presence of highly loaded internal network constraints defining the flow-based domain. In the CREG study 1687, the CREG identified the role of collective and individual TSO discretionary actions which led to the observed situation with cross-zonal exchanges being on average below the values promised by the parallel runs – and even below ATC-values. As discussed in this study, in a majority of hours the capacities offered in the day-ahead market often merely corresponded to the capacities determined by the long-term transmission rights, which in turn were only guaranteed thanks to the application of the LTA-inclusion patch (see also Section 4.2 in the CREG Market Monitoring Report 2016). In essence, CREG concluded that the risks for non-efficiency and discrimination identified in the CREG Decision 1410 of April 2015 had materialized.
The recovery of CWE FBMC started in October 2017 thanks to a reduction of the size and number of network constraints. During winter 2017-2018, CWE exchanges were significantly higher than in winter 2015-2016 and winter 2016-2017 thanks to - among other things - the increase in Fmax-values of frequently congested internal critical branches with the application of seasonal ratings and/or DLR, and thanks to lower loop flows. Further performance improvement was obtained during 2018 by the 20% minRAM measure implemented at the end of April 2018, the introduction of the DE/AT-LU bidding zone split in October 2018, the removal of the French and DE/AT/LU export limits and the increase of the Belgian import limit. Those structural changes were included in the updated CWE FBMC approval package submitted by CWE TSOs in June 2018 in view of the inclusion of the DE/LU-AT bidding zone border, and approved by the CREG in its Decision 1814 of August 2018. Discussions on the impact and concrete implementation of the Clean Energy Package on the CWE FBMC methodology are still ongoing.