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

80 Model resultspacities and some do not. The single, decentralized area has been modeled with boilercapacity (as an option for hours where switching to full heat production is more profitable),but the installed capacity of 500 MW it not enough for full coverage at all time. Iwill go into further details on this later on in section 6.3 on the production patterns.In chapter 4 it was statistically proven that in West-DK, central power plants continueto generate electricity despite of low prices, and it was assumed that this production isforced by the additional heat demand. One could wonder, whether not reacting to the el.market is due to lack of boiling capacity (the amount of decentralized boiling capacity ofthe current system is presently unknown), perhaps plain conservatism among local CHPoperators, or due to some third reason. Nevertheless, it could be interesting to discussthe sense in keep letting local heat consumer co-finance low electricity prices for thebenefit of all consumers (including the ones in external power systems). In practice, decentralizedproducers are often in a position of natural monopoly when it comes to thesupply of district heating. Heat-consumers are therefore obligated to pay whatever pricemight be.6.2.3. Price formations in the by‐pass scenarioIn the current project, running in bypass mode means bypassing the high-pressure turbineand, by doing so, giving central CHP plants an opportunity to run entirely as a boilerin times where heat is more valuable than electricity.As mentioned in the beginning of this chapter, the modeling of the bypass scenario hasbeen divided into two system scenarios. The first is a full-scale scenario, where the systemhas optional turbine-bypass on all seven extraction units. This scenario is very computeheavy, and has therefore been limited to one-week operation samples as mentionedabove. The samples have been modeled on the basis of profiles of the first week of January,April and November, in order to cover different times of the year. July was optimizedtoo, but did not result in any bypass operation and does therefore not differ fromthe reference scenario. In addition, the samples have been subjected to the ‘windy’ andnon-windy’ profiles presented in the beginning of the chapter. In the second scenario, thesystem is modeled with optional bypass for just one unit and has therefore been modeledfor the entire year.Turbine bypass in the full‐scale scenarioWhen focusing on the electricity and heat price alone, the main objective of the full-scalemodel is to see how optional BPO potentially affects the total system, and thus the formationof electricity prices, whereas the objective of the single-unit BPO system is tostudy the heat-price formations in the particular distribution area being affected by it.The six plots presented in Figure 6.9 below shows the results of the full-scale-bypassscenario with all seven units with optional turbine-bypass. However in the figures, theheat price is only plotted for one of the seven distribution systems (all price formationsturned out the same because of their individual sizes being scaled according to the CHPcapacities). The grey bar above the price curve indicates if the extraction unit of the particularsystem is operating in BPO-mode. The numbers at the upper left corners of thegraphs indicates the solution gabs (the margin of which the optimal solutions are to be

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