Analysis of Thermal Energy Storage Deployment and Operation with the Cross-sectoral Energy System Model REMix

Abstract

To date, Combined Heat and Power plant (CHP) operation is mostly heat-controlled: it consequently follows the demand for heat. With regard to energy systems with high shares of intermittent RE, a reorientation of these units towards power-controlled mode needs to be pursued [1,2]. This implies an adjustment of the operation to the current power demand and RE generation, and consequently a decoupling of production and consumption of heat using thermal energy storage (TES). In this paper, a model-based assessment of the least-cost installation and operation of TES in CHP supply systems in Germany is presented. It is particularly focused on the sensitivity of TES deployment to variations in storage costs and performance. By taking into account different grid regions within Germany, the correlation of TES installation and operation on the one hand, and RE supply structure on the other can be assessed. In addition to TES, a model endogenous installation of electric boilers in CHP supply systems is considered. The analysis relies on the application of the cross-sectoral energy system model REMix [3-5], including power, heat and transport sector (Figure 1). The model results reveal a strong dependency between least-cost deployment of TES and applied installation capital costs and storage losses. Nonetheless, also in model runs with higher costs and losses, overall storage capacities exceeding 100 GWh are installed (Figure 2). The annual heat input to the storage systems is much less sensitive to changes in the applied costs. In contrast, the impact of increased storage losses is higher (Figure 2). The REMix results suggest an important potential contribution of TES systems in CHP heat supply to the RE integration in Germany. By adjusting the CHP operation to the grid feed-in of fluctuating PV and wind power, curtailments and thus conventional power plant operation and CO2 emissions can be significantly reduced.