The Impact of the District Heating System Thermal Inertia on the CHPP Operation Mode

About 8% of all the world's electricity is generated by means of combined heat and power plants (CHPPs). The main thermal load for CHPPs in Nordic countries is constituted by the district heating system. In operation according to the heat schedule during the heating season, CHPP operation mode forecasting inaccuracy is often observed. Heat consumption foremost depends on outdoor temperature. Forecasting of the temperature, which lies at the basis of the CHPP operation mode forecast, is a complicated task even for a period of 24 hours and always involves forecasting inaccuracy, which in turn leads to CHPP operation mode forecasting inaccuracy. The problem is that, based on the heat load forecast, a calculation of the electricity produced by the CHPP in cogeneration mode is announced to the Nord Pool Spot. In this study, we will investigate what changes in building indoor temperature may occur if the CHPP operates according to the forecast heat load mode instead of operating based on actual heat demand.