Grid-interactivity of a Solar Combined Heat and Power District Heating System

In this paper the performances regarding grid-interactivity of a conventional combined heat and power (CHP) district heating system and a solar CHP district heating system – with decentralized solar thermal systems and heat storages in the buildings – are investigated and compared for a future scenario of the energy system. For this, simulations were carried out and the subsequent results evaluated applying a recently introduced method (load-grid matching coefficient) for quantifying grid-interactivity. It is shown that the solar CHP district heating system has better grid-interactivity compared with the conventional CHP district heating system. It is also quantitatively and visually shown that there is still potential to improve the grid-interactivity of both concepts by, for instance, applying more sophisticated control strategies. Furthermore, it is shown that in the summer period the CHP unit is not required for long periods of time. This allows temporal decommissioning of the district heating station and the district heating grid and thus an avoidance of the distribution losses which are relatively high when compared with the actual heat used during this period.