Cogeneration plant and electric heat pump on fixed tariffs
This project includes two gas fired CHPs, an electric heat pump, gas fired boilers and a thermal storage. These different production units must at all times cover the total heat demand which is divided into “Total sale of heat” and “Network loss”. Produced and consumed electricity is traded on a fixed tariffs market with a high day-time tariff and a low night-time tariff. The weekend is also a low tariff period.
An overview of the model is given in the below picture.
The optimal operation is calculated in energyPRO, which in this case is achieved by minimizing the net heat production cost. In order to do so, the two CHPs must be operated in hours with high electricity prices (Day tariff) and the heat pump in hours with low electricity prices (Night tariff and weekends). The storage tank will be used to support this strategy by storing excess heat from the CHPs and the heat pump to be used at a later time.
In the below figure, a graphical representation of the operation can be seen. The figure is composed of three graphs: The top graph shows the heat production of the different units and the total heat demand. The middle graph, shows the electricity production and consumption, and the last graph shows the storage capacity and content.
From the figure it can be seen that the two CHPs (red and green colors) are producing in the day-time in the weekdays, while the heat pump (blue color) is operated during night-time and in weekends. The gas boilers are operated when the heat pump cannot cover the heat demand and storage tank is empty.