Role of different energy storage methods in decarbonizing urban distributed energy systems: A case study of thermal and electricity storage

Aiming at identifying the difference between heat and electricity storage in distributed energy systems, this paper tries to explore the potential of cost reduction by using time-of-use electricity prices and a variety of energy storage methods. The current situation is defined as basic situation which is purchasing electricity for all loads in real-time (Scenario 1). For the Scenario 2, battery energy storage to utilize valley electricity is considered (Scenario 2). Besides, considering that the price of the battery is relatively high, heat and cold pumps are also included as well as thermal storage to provide dispatchable heat and cold (Scenario 3). Lastly, as a representation of renewable heat, the solar collector was used to collect solar heat for supplying heat and cold (via absorption refrigeration) to the building (Scenario 4). Using levelized cost of electricity (LCOE) and payback time of scenarios as the main indicators, the influence rules of key parameters is analyzed and the capacity is optimized, aiming to explore the sensitive reaction of scenarios to components and compare the performance of different scenarios on typical days in four seasons. Based on the results, the utilization of valley electricity and storage methods in different scenarios can reduce the LCOE of commercial buildings. When the lifetime is considered as 10 years, Scenarios 2, 3, and 4 can reduce the LCOE from 0.9795 CNY/kWh (Scenario 1) to 0.9183, 0.6791 and 0.7748 CNY/kWh, respectively. Scenario 2 is sensitive to the lifetime of the battery. Scenario 4 has great potential for a long lifetime such as 20 years and it is also sensitive to the price of components.