Integration of 50 % wind power in a CHP-based ... - Ea Energianalyse

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Integration of 50 % wind power in a CHP-based ... - Ea Energianalyse

20 Characteristics of the Danish energy systemtions – or bottlenecks. Since capacities often are constraining a perfect market situation 8the transfer of power (and thereby the settlement of the supply) often results in a finalprice difference. Market price differences are therefore a symptom of bottlenecks. Insuch cases, congestions are managed by dividing the price difference equally in favor ofthe two system operators. The concept behind this: the more prices drop in one area, likein the extreme cases of electrical spillover in West-DK, the bigger the price differenceand thus the bottleneck income and the resources for further investments in additionaltransmission capacity 9 .When speaking of congestions on external transmission, it is important to distinguishbetween the physical limitation on the sea cables and the more ‘artificial’ limitation fromthe variations in announced capacities by the different TSOs 10 – a factor that varies fromcountry to country as shown in Table 3.2. As an example, the rated capacities going toWest-DK from Sweden and Germany, respectively, are (as a rule) lower than the fortransmissions going the opposite direction, and the same can be said about the averagelyannounced capacities.Capacities to: NO SE DERated physical exchange cap. [MW]Rated physical import 1000 680 950Rated physical export -1000 -740 -1700Average announced cap. [MW]Import capacity. 754 507 820Export capacity. -721 -494 -1184Period of no allowed import [%] 0.8 5.5 0.1Period of no allowed export [%] 0.9 5.1 0.1Maximum registered exchange [MW]Import 1041 810 1634Export -1913 -998 -1642Table 3.2, Average Capacities from NO, SE and DE to West-DK, respectively, showing thesometimes big differences in rated physical capacities the average announced capacities,throughout the observed five year period (2004-09), but also that there are significant differencesin the rated capacities for each direction on the same connections (data source:Energinet.dk).8A balanced market with no physical limitations on the supply and exchange of power9One could question the incentive to invest in additional transmission capacity, whereby the bottleneckincome will drop. The bottleneck income is ear marked improvements in the transmission systemthough.10 One if the typical reasons why one of the TSOs some hours announces a lower capacity on interconnectionsthan the actual rated capacity is having to protect its transmission system against inner stresslevels.

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