Economic controls co-design of hybrid microgrids with tidal/PV generation and lithium ion/flow battery storage

TL;DR

This paper presents a controls co-design approach for hybrid microgrids combining tidal and solar power with lithium-ion and flow batteries, optimizing cost and performance for islanded renewable energy systems.

Contribution

It introduces a novel optimization framework for hybrid microgrid design, emphasizing controls co-design, battery failure modeling, and cost sensitivity analysis.

Findings

Hybrid microgrid can reduce energy costs significantly.

Flow batteries can lower costs and increase renewable energy share.

Controls co-design improves system robustness and efficiency.

Abstract

Islanded microgrids powered by renewable energy require costly energy storage systems due to the uncontrollable generators. Energy storage needs are amplified when load and generation are misaligned on hourly, monthly, or seasonal timescales. Diversification of both loads and generation can smooth out such mismatches. The ideal type of battery to smooth out remaining generation deficits will depend on the duration(s) that energy is stored. This study presents a controls co-design approach to design an islanded microgrid, showing the benefit of hybridizing tidal and solar generation and hybridizing lithium-ion and flow battery energy storage. The optimization of the microgrid's levelized cost of energy is initially studied in grid-search slices to understand convexity and smoothness, then a particle swarm optimization is proposed and used to study the sensitivity of the hybrid system configuration to variations in component costs. The study highlights the benefits of controls co-design, the need to model premature battery failure, and the importance of using battery cost models that are applicable across orders of magnitude variations in energy storage durations. The results indicate that such a hybrid microgrid would currently produce energy at five times the cost of diesel generation, but flow battery innovations could bring this closer to only twice the cost while using 100% renewable energy.