Decentralized Thermal Energy Storage for District Cooling: A techno-economic case study on the feasibility of small scale latent thermal energy storage in Gothenburg

Sammanfattning

District cooling (DC) networks are expanding. To accommodate future network expansion and mitigate increasing peak demand, thermal energy storage (TES) can beincorporated into the DC networks. Decentralized storage has the potential to relieve production and network capacity during peak demand hours by storing coolingenergy at individual customer sites. This thesis investigates the theoretical potentialof decentralized TES containing phase change materials, called latent thermal energystorage (LTES), both from the perspective of the customer and producer. The analysis uses mixed integer linear programming (MILP) together with operational datafrom a critical section of Gothenburg’s DC network (2025). The results indicatedthat peak demand in the Almedal area could be reduced by 6.1% using measureddata, and by 10.0% with optimized operating conditions. Network flow reductionswere also evaluated, showing a decrease of around 3.2% using measured data, creating potential for new customers to connect to the network. Optimizing operatingconditions alone reduced the flow by 34.9%, while the addition of storage provideda reduction by 10.0%. The economic analysis showed that profitability is highlycase-dependent and primarily driven by achieved peak reduction. While customersgenerally benefit more economically from LTES implementation than producers, acost-sharing approach improved the profitability for both parties if sufficient peakreduction is achieved. With the calculated investment cost of 2149 SEK/kWh, theproducer would be willing to cover between 45-81% of the investment to remainprofitable, depending on discount rate. In contrast, the customer could, independently of discount rate, pay for the full storage and still remain profitable over a 10year project period.