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

Building the Mathematical Model 67The start-up costs is another rather unknown factor (this goes for generation costs ingeneral) mainly connected long power-up periods – especially in case of cold-starts. It isthus assumed 1323 €/startup (10,000 Dkk) for central units in order for them to havemarginal influence on the commitment problem, and zero costs for the remaining units.For simplifications, no economic distinguishes have been made between cold and hotstart-ups.Until now, the generation costs of the specific utilities have been calculated in relation tofuel consumption and not for el. and heat individually. In this connection, Table 5.6shows the marginal productions of el. and heat when assuming that the bi-product isvalueless. The third column is marginal CHP-generation costs in a balanced market.Heatel (condensing) (el.price = 0)co-generation(balanced price)unit (i ) [€/MWh] [€/MWh] [€/MWh]G1 35,17 31,19 17,97G2 35,17 31,19 17,97G3 35,17 31,19 17,97G4 35,17 31,19 17,97G5 35,17 31,19 17,97G6 35,17 31,19 17,97G7 35,17 31,19 17,97G8 33,06 - -G9 33,06 - -G10 66,14 - -G11 86,81 47,90 30,87OthersBoiler dc - 30,87 -Boiler c (i ) - 30,87 -CHP c (i ) 86,81 47,90 30,87Table 5.6, Generation costs of el., heat and CHP production individually. Inthe case of backpressure units (G11), which have fixed heat-el. ratio, condensingrefers to el. production with zero heat price (data source: Energistyrelsen).From Table 5.6 is seen, that the central extraction units by far are the most economicefficient when it comes to CHP production. It is also seen that boilers are more competitiveat heat production when el. prices is zero, and vice versa, and that condensing unitsare best at electricity production when heat price is zero. Although all three productionscenarios rarely occur, the table however gives a good illustration of the economy ofthermal units in the modeled system.Heat pumpsThe selected capacities for central and decentralized production areas are accessed onbasis of the results of a model sequence with infinite heat pumps capacity. As illustratedin Figure 5.8 , a duration curve on the production has been processed and then, the suitablecapacities found where the curves break and start to flatten. The result of this methodis the installation of a total heat pump capacity of 350 MW in the central heat

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