Decentralized hydrogen-based stationary energy storage systems complemented by smart control can provide increased operational flexibility in the energy system

While the electrification of the energy system implies a reduction of greenhouse gas emissions greatly beneficial to society, it can also pose technical challenges. The most notable among these are that the capacity of the local electric grid may be exceeded, along with the occurrence of imbalances between decentralized renewable energy production and final consumption. Hydrogen-based energy storage systems (HESS) are regarded as promising solutions to address these challenges. However, the feasibility has not been demonstrated and the involved processes are not well characterized on a technical relevant power level, so far. 

With this motivation, in this study a stationary energy storage based on hydrogen complemented by smart control is demonstrated on the sub-MW power level. Specifically, it is shown that with a H2 energy storage of 4 MWh, this combination of HESS and controls can peak-shave the stochastic electricity demand of an electric vehicle charging site (EVCS). 

LEC December 2024 Highlight
Figure 1: The Energy System Integration platform (ESIP) is a container-based demonstrator platform. The hydrogen-based energy storage system on the sub-MW power level is part of this platform.
LEC Highlight December 2024
Figure 2: The impact of the combination of the HESS with smart controls is shown in this figure. Compared to the nominal charging policy (NCP) the performance was substantially improved using the chance-constraint charging policy (CCP) with the HESS and a value function design (VF). The performance gets close to the ideal charging policy’s one with full information (ICP) and outperforms the NCP with prior information (NCPP).

The HESS consists of real-world facilities including a PEM electrolyzer, a gas cleaning unit, a fuel cell system and pressurized gas-storage vessels that are operated at the Energy System Integration Platform of the Paul Scherrer Institute (PSI, Switzerland – see Fig. 1) This is a first-of-its-kind HESS using pure oxygen in the re-electrification process of the fuel cells, and it can be operated in a fully autonomous manner with the option of receiving higher-level control reference setpoints from smart control (model predictive control).

Following the demonstration of the technical feasibility for peak shaving, including the characterization of the involved systems, the potential to minimize the load peaks was determined. In the investigated setting, an average peak reduction of up to 49 % (blue vs. green bars in Fig. 2 was achieved). Ultimately, such hydrogen-based energy storage systems (even if not necessarily based on the use of pure oxygen) will help to minimize the costs of future electric grid expansions and avoid excessive curtailment.

Contact

Christian Peter
Paul Scherrer Institute
Forschungsstrasse 111
5232 Villigen PSI
Switzerland

Phone: +41 56 310 55 88
E-Mail: christian.peter@psi.ch

Sources

Fochesato M., Peter C., Morandi L., Lygeros J., (2024). Peak shaving with hydrogen energy storage: From stochastic control to experiments on a 4 MWh facility. Applied Energy, doi: 10.1016/j.apenergy.2024.123965