SeasonalGridStorage - Innovative seasonale thermal storages for urban district heating grids
Starting point / motivation
In order to achieve the objectives in terms of energy efficiency, reducing CO2 emissions and increasing the share of renewables, heating networks have a central role to play, especially since about half of the final EU energy volume is thermal energy.
Energy supply and heat demand don't always match regarding place and time. That is why solutions must be found to eliminate costly capacity. Urban heat networks have to be adapted to the market conditions, in order to integrate new energy sources into existing systems to allow a sustainable operation of networks.
Thermal storage can balance supply and demand allowing a greater role to renewable energy in heating networks. Seasonal thermal energy storage systems can store heat for several months and thus they allow the customers to use in winter the energy that has been produced during the summer months. In some pilot plants, seasonal storages are already used to supply energy to heating networks. However, the sensible heat storage technologies currently used have some disadvantages (large volumes and high storage temperatures are necessary, problems with Temperatures >100°C, heat losses, high investment costs).
Contents and goals
It shows that the seasonal storage of heat is associated with a number of challenges, which is why technological advances are necessary in this area. The integration of innovative (especially thermochemical) storage technologies / materials in heat networks could therefore help to improve the energy and economic performances of these systems. The various properties of innovative heat storages (high energy density, pressure and loss-free storage, easy transportability of materials, etc.) can improve their operation for thermal networks.
In the project SeasonalGridStorage, new innovative storage technologies were analyzed using the principle of thermochemical energy storage and possible integration concepts in urban networks are identified. For this purpose, 3 representative urban heat networks and their requirements were analyzed and dynamic scenario calculations are performed.
The project SeasonalGridStorage was divided in 4 work packages. The distribution of the work packages is shown in Figure 1.
Result of the project is the identification of economic technologies and operation conditions and the description of economically and energetically reasonable approaches to the integration of thermochemical storage in heating networks. From the results of the energetic, economic and ecological assessments, guidelines can be set about the required properties of a system with thermochemical seasonal district heating storage in order to provide competitive energy for heating network on different scales.
Markus Köfinger, MSc.
AIT Austrian Institute of Technology GmbH
Project or cooperation partners
Energyinstitute - Johannes Kepler Universität Linz