CityStore - Sondierung des wesentlichen F&E-Bedarfs zur Optimierung von städtischen Energiespeichern in integrierten Energiesystemen
With #mission2030 (BMNT und BMVIT 2018) the Austrian government set the goal to generate electricity so that the national total electricity consumption is covered 100% from renewable energies at a yearly balance by 2030. With this goal, the country's energy system is facing a significant transformation, where expanding storage infrastructures poses one of the main focuses. However, the strategy does not clearly indicate where and which storage capacities and technologies are foreseen.
Especially cities have to deal with several environmental and energy policy challenges, such as climate change, energy security and sustainable development. Due to the increasing degree of urbanization, energy and resource requirements are increasingly concentrated on urban areas, which means that local approaches are required. The main challenge when using emission neutral energy sources lies in the incoherence between the supply of solar energy or waste heat and the electricity demand. Therefore, energy storage systems offer a solution, as they can be used to decouple the generation of energy from consumption. While conventional storage (storage power plants, gas storage) can be found in rural regions, storage potential in cities remains unused.
The goal of CityStore is to explore essential research and development (R&D) needs for optimized planning and realization of urban energy storages in an integrated energy system. In this regard, the core research questions of the project CityStore are:
- What requirements are there on the stakeholder side (local decision makers, companies, energy suppliers) concerning the implementation and evaluation of storage technologies in cities, where do they see storage potential?
- Which technologies are relevant for cities and which ones can be used?
- What are the requirements of stakeholders and experts for tools that on the one hand evaluate the effects of storage technologies in the entire energy system and on the other hand support the planning and optimal operation of the storage?
- To what extent can the existing tools cover the stakeholder requirements and what are their strengths and weaknesses, indicating future need for R&D?
- What are the advantages of energy storage systems at urban level in two concrete use case studies (Graz and Weiz)?
- How can different business models support the integration of energy storage in urban areas?
To answer these research questions, the following qualitative and quantitative analyses were conducted:
- Inclusion of relevant stakeholders and experts through workshops and interviews.
- Selection of the most promising storage technologies for cities
- Preparation of a list of technical-economic parameters of relevant technologies
- Compilation of techno-economic parameters for storage technologies, with relevance from very high to medium, based on literature research, to assess how and which storage technologies can contribute to the energy transmission in cities.
- Analysis of selected energy modelling tool through an assessment of the stakeholder requirements. A total of 70 requirements were identified, divided into six categories (technical, spatial, operational, time, sector coupling, other).
- Model-based analysis of the contributions of urban storage solutions in line with two case studies; a seasonal storage facility for district heating in Graz (331.000 inhabitants), and a photovoltaic system coupled with a battery storage facility in Weiz (11.700 inhabitants).
- Derivation of business models based on the two case studies using the so-called Value Proposition Canvas, the Business Model Canvas and the St. Gallen Business Model Navigator.
A wide range of technologies are available for the application of energy storages at an urban level. In the CityStore project the most promising technologies were grouped into four storage categories: electricity Storage (ELC), Heat Storage (HEAT), Gas Storage (GAS), and P2X technologies.
A critical element is to provide coherent techno-economic analyses of storages to be able to determine how different storage technologies can be implemented at the urban level and what impact they have on the overall energy system of the city. Such analyses require tools that can provide answers to the above stated questions by modelling defined energy systems.
The analysed tools contain extensive technology options. For the evaluation of electricity and heat storage, the strengths of the tools lie in the fact that a wide range of technologies are well represented, techno-economic parameters can be taken into account and potentials for peak load reduction can be estimated. However, the analysed tools also show weaknesses and thus future R&D requirements are identified.
The added value of energy storage in cities lies in the more efficient use of solar energy in the short term (daily storage) and in the use of summer waste heat surpluses from industry in winter (seasonal storage).
In addition to short term use, combinations of PV panels and batteries are increasingly being used in other areas, such as emergency backup (blackout protection) or for flexible coverage, often driven by various subsidy incentives. Therefore, these aspects should be taken into account in further considerations.
In this project, a first evaluation of a possible operation of cavern storages for district heating in Graz was conducted without thermodynamic simulation of the rock. Thus, this consideration lacks the heat losses and gains due to heat conduction in the rock and the feedback between storage and district heating generation. Together with the consideration of other seasonal storage options, these questions remain as topics to be investigated in follow-up projects.
AIT Austrian Institute of Technology GmbH (AIT)
Project or cooperation partners
- Grazer Energieagentur GmbH (GEA)
- Weizer Energie- Innovations- Zentrum GmbH (WEI)