Beyond Seasonal Arbitrage—Structured Review on Distributed Long Duration Energy Storage and Its Benefits to the Distribution Grid

The rapid rise in variable renewable energy sources such as wind and solar introduces significant volatility and uncertainty into electricity grids, underscoring the critical need for increased system flexibility to ensure stability and reliability. Long-duration energy storage (LDES) technologies are emerging as essential solutions for meeting needs by enabling the storage and dispatch of energy over extended periods—from several hours to days or even weeks. The existing literature and system studies focus predominantly on centralized LDES providing seasonal arbitrage under idealized “copper plate” grid assumptions, while the broader distribution grid services and the specific role of distributed LDES and its benefits to the distribution grid remain largely underexplored. This paper presents a structured literature review on studies published between 2015 and 2025 that explicitly address grid-connected LDES at the distribution level. The review synthesizes the portfolio of services provided by distributed LDES—ranging from seasonal arbitrage, curtailment reduction, and hosting capacity enhancement to T&D deferral, resilience, and hydrogen co-products—and compares techno-economic characteristics, modeling approaches, and optimization objectives across studies. On this basis, the review identifies the main research gaps and contribution areas and gives direction for future research.