Cost-optimal control for a small energy community heated with dual source heat pump and district heating

• Buildings are heated by parallel low-temperature and district heating (DH) networks. • Heat pump for low-temperature heating utilizes outdoor air and waste heat. • Validated energy community model supports dynamic analysis of hybrid heating system. • Energy community is cost-optimally controlled based on dynamic energy prices. • Hydrogen production waste heat enhances cost-effectiveness of current DH. Control strategies are crucial for reducing energy costs in hybrid heating systems using multiple energy carriers. The study analyzed the impact of three control strategies on energy usage and costs in a small energy community heated with a hybrid heating system. The system comprises a low-temperature heating network powered by a dual source heat pump and a district heating network. The control strategies included a low-temperature heating-prioritized and two cost-effective control strategies based on different electricity and district heating prices. The analysis was implemented by dynamic simulations based on the customized heating network model for the years 2022 and 2023. The cost-effective control strategy based on hourly electricity prices and the estimated cost of district heating produced by utilizing waste heat from hydrogen production resulted in the lowest annual costs. It reduced the annual costs by 25 % in 2022 and by 5 % in 2023 compared to the low-temperature heating-prioritized control strategy. The major difference between the two years was the variations in energy prices and the structure of the district heating power fees. As price differences between electricity and district heating in 2023 were less than those in 2022, the drop in energy costs upon adopting the cost-effective control strategy was smaller in 2023. Different power fee charging policies resulted in an increased power fee cost in 2023 even if the maximum district heating power slightly decreased. The increased power fee cost weakened the positive impact of energy cost saving brought by the cost-effective control strategies in the total costs.