Impacts of thermal energy storage on the management of variable demand and production in electricity and district heating systems: a Swedish case study

Petra Holmér,Jonathan Ullmark,Lisa Göransson,Viktor Walter,Filip Johnsson

doi:10.1080/14786451.2020.1716757

Petra Holmér, Jonathan Ullmark + Show 3 more

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https://doi.org/10.1080/14786451.2020.1716757

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Abstract

ABSTRACTThis study investigates how thermal energy storage (TES) influences the cost-optimal investment and operation of electricity and district heating (DH) systems in different scenarios. Greenfield energy system modelling for Year 2050 with a high time resolution shows that sensible TES strategies have a strong impact on the composition and operation of the DH system in all investigated scenarios. The introduction of TES displaces to a significant extent the heat-only boilers in all scenarios and can promote solar heating in small DH networks. The modelling shows that TES also promotes the use of power-to-heat processes and enables combined heat and power plants to increase full-load hours, with simultaneous adaptation to the variable production in the electricity system. A major benefit derived from TES is the ability to respond to rapid variations in the electricity system. Thus, the pit and tank storage systems with higher (dis)charging capacities are preferred over borehole storage.

Highlights

In response to the global threat posed by climate change and dramatic reductions in the costs of variable renewable energy (VRE) sources, in particular wind and solar power, the use of VRE is expected to increase and become more widespread over the coming decades (IEA 2017)
The results show that thermal energy storage (TES) is more effective at reducing the system cost than either batteries or demand-side management (DSM), even if power-to-heat is not available; heat pumps (HPs) are even more effective, in terms of both reducing the system cost and increasing the wind energy share
This is achieved by modelling different scenarios, as described in the Model scenarios section, applying the single-region, Greenfield investment model presented by Göransson et al (2017), which in this work is expanded to include a description of the district heating (DH) sector

Summary

Introduction

In response to the global threat posed by climate change and dramatic reductions in the costs of variable renewable energy (VRE) sources, in particular wind and solar power, the use of VRE is expected to increase and become more widespread over the coming decades (IEA 2017). The available VMS in the electricity sector include the use of batteries, demand-side management (DSM), pumped hydro, flexible thermal generation, and power-to-fuels processes, e.g. hydrogen production from electrolysis. The most common TES system, tank TES (TTES), is frequently used in combination with conventional heat generation technologies, in order to meet short-term load variations, and is sometimes used as seasonal storage (Sarbu and Sebarchievici 2017). Pit TES and borehole TES (PTES and BTES) are mostly used for seasonal storage, often in combination with solar heating (PlanEnergi n.d.; Sibbit et al 2012)

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