Dimensioning and rule-based control of thermal energy storage for a finnish hybrid-heated energy community

Reliance on high peak district heating (DH) power demand constrains the cost-effective operation of community-level hybrid heating systems. The study evaluates tank thermal energy storage (TTES) as a peak-shaving solution for a Finnish energy community heated by a dual source heat pump and DH produced from hydrogen production waste heat. A novel simulation-based parametric analysis framework was developed and utilized to determine the cost-optimal TTES dimensioning for the analyzed community. It jointly assessed peak-shaving effectiveness and economic feasibility by varying threshold power of tank discharging, tank charging power, and tank size (500–1500 m 3 ). Results indicated that effective peak shaving required a balanced combination of threshold power of tank discharging and tank charging power. Lowering the threshold alone was ineffective with a 700 m 3 tank, and performance became less sensitive to control settings at 1500 m 3 . Cost savings were mainly from reduced DH power fees rather than energy costs, with diminishing returns beyond 700 m 3 once the shaved peak approached the threshold power of tank discharging. The cost-optimal dimensioning (1416 kW threshold power of tank discharging, 730 kW tank charging power, and 600 m 3 tank size) reduced the maximum three-hour average DH power demand by 40% from 2452 kW in the baseline without TTES. Correspondingly, the total operating cost was lowered by 17%. It decreased the LCC over a 25-year period by 13% and achieved a discounted payback period of 10.3 years. These findings provide actionable guidance for TTES dimensioning and control in hybrid-heated energy communities under hourly tariff structures. • Community hybrid heating combines dual source heat pump and renewable DH. • Renewable DH is produced utilizing waste heat from hydrogen production. • TTES integration shaves peak DH power demand for lower operating costs. • Cost-optimal TTES is identified through simulation-based parametric analysis. • TTES design and operation are evaluated under hourly renewable DH prices.