i-stormy
Interoperable, modular and Smart hybrid energy STORage systeM for stationarY applications
Context
The ongoing energy transition requires new paradigms including new assets capable of addressing novel grid needs. Storage units can address several of these system requirements, especially when these units are composed of different sources, such as batteries, supercapacitors, electrolysers, thermal storage or pumped hydro plants. In this context, hybrid power plants can leverage heterogeneous capabilities in a collocated manner, in order to identify and exploit synergies between different sources, such as PV and wind.
Trends and Opportunity
Among all these new system needs, the transition from conventional generation to inverter-based generation is creating a trend towards the provision of ancillary services from units that interface the grid via power electronics. This implies that inverters will be required to provide a certain amount of active and reactive power, based on, for instance, frequency and voltage. Ideally these services are provided in an optimal way, that is, maximizing the efficiency of the units composed of inverters and storage. At the same time, since storage units are becoming larger, they are now typically composed of different units with different characteristics to address different needs, e.g., they can be composed of a high-energy and a high-power module and their correspondent submodules.
Objective
The main goal of the iSTORMY project is to develop a low cost, modular, efficient, (industrial) solution for stationary hybrid energy storage systems, with an optimal configuration to maximize reliability, safety and lifetime to provide different services in the electricity grid at the lowest cost. While most hybrid battery Research and Development focuses on novel battery chemistries or on providing optimized battery solutions, iSTORMY looks at the entire system in which it integrates innovation on the power electronics, the battery stack and the Energy Management System level, including the possibility to use 2nd life EV batteries.
Findings
The contributions from AIT have focused on the provisions of grid services using hybrid storage. Given that typical grid services were designed before hybrid power plants (or hybrid storage systems) were envisaged, there are some uncertainties on how to leverage the capabilities of each module, and how to distribute the setpoints among the different modules present in a hybrid unit. In the scope of this project this uncertainty has been reduced by spelling out possible methods to coordinate the different modules within the unit.
Use Cases
Three use cases are being assessed for specific insight:
- First, the coordinated provision of frequency and voltage support (that is, the simultaneous provision of active and reactive power), which is expected to be needed in weak grids.
- Second, peak shaving at an industrial site, and by extension, any kind of service that can be framed as an optimization problem, with a well-defined cost to be minimized and where forecast for prices and/or demand are available.
- Third, the impact of primary frequency control on the aging of the different modules of a HESS has been evaluated, considering a typical frequency evolution in continental Europe. Two different criteria are used to define the primary frequency service, namely the Nordic criterium and the CE regulation.
