Assessment of autonomous renewable energy system operability under extreme events and disasters

Autonomous, hybrid renewable energy systems (HRES) are increasingly being deployed in geographically challenging terrains, often lacking adequate resilience planning for natural disasters. An assessment framework is developed to evaluate sustainable HRES design for remote off-grid application, ensuring its operability under an extreme event, i.e. its ability to absorb the shock event and continue operating. Optimal HRES configurations are obtained for different extreme events, applying Pareto optimality with key criteria of minimising the number of black outs constrained by Net Present Cost (NPC). The framework is demonstrated for a remote location in Chile. Operability of an HRES under an extreme event is found to involve a trade-off between the investment decision to reduce the vulnerability of RET components and to enhance its energy storage. The optimised HRES is found to be cost-effective for resilience against seasonal events (for flooding and snowstorm the additional NPC is 4.6%, 7.4% respectively) but unsustainable for low probability-high impact events (for earthquakes the additional NPC of 20.5% largely from increase investment in storage capacity). The study also highlights the role of the dispatch strategy in enabling a micro hydro as a secondary storage component for both fulfilling the unmet loads and for charging batteries.