Kraftvärmeverk som elnätsreglering för laddfordonsladdning

Sammanfattning: The use of plug-in electric vehicles (PEV) is rapidly growing in many countries. In Sweden the number of PEVs in the transport system grew from about 43 000 in December 2017 to almost 58 000 in July 2018. To fully load a discharged PEV battery in a reasonably brief time will require high charging powers, which might cause high peaks in the power grid. The purpose of this project was to investigate the possibilities for electricity production in combined heat and power (CHP) plants to balance the demand peaks in the power grid caused by charging PEV. Data were obtained from different heat production plants in two Swedish cities, Borlänge and Falun. The cities, which have interconnected district heating systems, have a broad spectrum of different types of heat producing plants, and thus functions as an example model of a “typical northern Europe” heating system. An artificial charging load profile was created for a system of a large number of PEVs forming a scalable load. The charging load profile was then used as input in CHP plant models, to generate the heat production profile for the CHP plants in the system. The heat profiles were then used as inputs in a district heating simulation software. The complete Borlänge-Falun heat production system was simulated to find out whether it is possible to operate the CHP plants based on the PEV charging load profile. The generated heat production profiles were similar and clearly followed a pattern that was in line with how the heat and electricity output relate in a CHP plant. The results showed that during periods when the heat demand is high, the CHP plants can operate at full load and are thus capable to fully regulate the charging of the PEVs. During periods when the heat demand is low, and the CHP plants are unable to operate on full load, there is a discrepancy between the CHP plants ability to produce electricity and the PEVs charging demand. If the plants are operated at full load even though the heat demand is low, the heat surplus will be lost unless the system is equipped with a large heat storage. This lost heat will lead to increased costs unless there are control means to compensate the CHP plant operator for the peak regulating services as such provided. Furthermore, constructing an energy system were heat is intentionally wasted might not be considered a sustainable solution. The CHP plant regulating system can, however, be combined with other local regulating, e.g. load control, to minimise the heat wasted.