Decarbonising energy supply: the potential impact on district heating networks of the integration of thermal energy storage and substitution of peak load with base load

Abstract

In 2021, district heating networks provided 6.4 TWh of thermal demand in Switzerland, representing a market share of about 6%. This share is forecast to reach 38% by 2050. More than 50% of those networks rely on base load provided by biomass, complemented by fossil fuel peak load. This paper describes a strategy that would see storage being integrated to substitute peak load with base load. A university campus in Scotland acts as the reference use case to test the suggested fixed-order control strategy. Given these study conditions, the capacities of different storage systems are varied, and their potential for substitution and decarbonisation is accounted for. The study indicates that the integration of small storage volumes seems very promising albeit leading to limited results pertaining to decarbonisation. Depending on fossil fuel prices, a full decarbonisation potential depending on large seasonal storage volumes could be found and a value of 0.14 €/kWh could be calculated as economic threshold to fully decarbonise the reference case.