Hybrid Hydrogen and Mechanical Distributed Energy Storage

Abstract

Effective energy storage technologies represent one of the key elements to solving the growing challenges of electrical energy supply of the 21st century. Several energy storage systems are available, from ones that are technologically mature to others still at a research stage. Each technology has its inherent limitations that make its use economically or practically feasible only for specific applications. The present paper aims at integrating hydrogen generation into compressed air energy storage systems to avoid natural gas combustion or thermal energy storage. A proper design of such a hybrid storage system could provide high roundtrip efficiencies together with enhanced flexibility thanks to the possibility of providing additional energy outputs (heat, cooling, and hydrogen as a fuel), in a distributed energy storage framework. Such a system could be directly connected to the power grid at the distribution level to reduce power and energy intermittence problems related to renewable energy generation. Similarly, it could be located close to the user (e.g., office buildings, commercial centers, industrial plants, hospitals, etc.). Finally, it could be integrated in decentralized energy generation systems to reduce the peak electricity demand charges and energy costs, to increase power generation efficiency, to enhance the security of electrical energy supply, and to facilitate the market penetration of small renewable energy systems. Different configurations have been investigated (simple hybrid storage system, regenerate system, multistage system) demonstrating the compressed air and hydrogen storage systems effectiveness in improving energy source flexibility and efficiency, and possibly in reducing the costs of energy supply. Round-trip efficiency up to 65% can be easily reached. The analysis is conducted through a mixed theoretical-numerical approach, which allows the definition of the most relevant physical parameters affecting the system performance.

Assessment of Potential Barriers to the Implementation of an Innovative AB-FB Energy Storage System under a Sustainable Perspective

“…The higher the round-trip efficiency, the less energy is lost in the storage process. The AB-FB RTE is equal to 65%, which is lower than the VRFB (75%) [12], although it seems to be higher than the one reached using hydrogen as energy storage vector [24,25]. It is expected that the AB-FB RTE will reach values higher than 70% (based on preliminary and not-yet-published research studies).…”

Optimized Modeling and Design of a PCM-Enhanced H2 Storage

“…The exploitation of renewable energies has attracted a growing number of efforts in recent years [1], ranging from the theoretical physical aspects to the engineering implementation of novel energy systems. However, efficient and economically convenient implementations require the presence of energy buffers, due to the aleatory nature of renewable energies, especially from solar and wind sources [2,3].…”

Development of an efficient and sustainable energy storage system by hybridization of compressed air and biogas technologies (BIO-CAES)

“…This process increases the efficiency of the system reducing the consumption of fossil fuels and, therefore, CO 2 emissions [70]. To reduce the handicaps of conventional CAES, different approaches have been considered such as reducing the target depth of the storage cavities [43] or the hybridization of energy storage technologies, such as the integration of CAES and hydrogen [63], and others [3,19,58,4].…”