Energy Resilience in Presence of Natural and Social Uncertainties

The resilience of energy systems is gaining more importance under the threat of pandemics, extreme weather, natural disasters, military conflicts, trade wars, energy supply shortages, rising energy demand, etc. [1]. Energy is an essential for both economic and social activities as well as all production and transportation operations. Unexpected and uncontrollable significant events hinder the normal operations of an energy system. However, an energy system with resilience can maintain its operation under adverse conditions or recover faster from disruptions [2]. Resilience thus becomes an essential element for a modern energy system.

There have been articles published articles in Energies to respond to the uprising issues of energy resilience. Son et al. [2] define power system resiliency as the ability to prepare for, adapt to, and recover rapidly from disruptive events. They suggest that the microgrid planning should be resilience-oriented. That is, the resilience of an energy system should be promoted from the planning stage. They propose a framework that considers the capacity and installation locations of distributed generators (DGs). It is shown that the resilience of the power system can be raised by good planning.

Bae et al. [3] show that repair capability is a factor in the resilience of an energy system. A natural disaster may damage multiple components at the same time. These damaged components may not be repaired simultaneously. Therefore, the recovery priority rule is very important to effectively shorten the expected duration of system failure. The resilience of an energy system can be increased if the ability to repair is improved by using an appropriate repair priority rule.

Al-Rubaye et al. [4] point out that a reliable electricity supply and emission reductions can be achieved by resilient hybrid energy systems (RHESs); that is, an energy system with resilience can have double dividends not only with respect to reliable energy supply but also environmental protection. Multiple evaluation techniques should be adopted for such an RHES, including design and implementation, the use of microgrids, and the application of cradle-to-grave life cycle analysis (LCA). Such an RHES can be applied worldwide, in order to enhance energy resilience to achieve both energy supply and environmental protection targets.

Singh and Hachem-Vermette [5] suggest that an energy system should be equipped with a self-sufficient approach to deal with inevitable changes generated by disasters. They hence propose layout optimization of resilience; that is, the resilience of an energy system should be enhanced from the layout stage. For instance, they demonstrate that energy planners can estimate the sizing of battery banks for shelter buildings in order to increase energy resilience and eliminate vulnerability. Therefore, layout optimization is an effective tool to promote the resilience of an energy system.

Liu et al. [6] indicate that networked microgrids can help reduce total operating costs as well as improve the resilience of the power supply. The independent microgrids should be connected and globally optimized by a network.

Cao et al. [7] find out that infrastructure resilience is very important for reducing the potential vulnerability and exposed fragility in urban areas. Infrastructure resilience should protect against climate change, natural disasters, financial crises, epidemic diseases, terrorist attacks, etc. They call it ‘resilient civil infrastructure’, which can bring benefits to support the resilience of the energy system.

Gong and Ionel [8] show how a stationary battery energy storage system (BESS) can enable self-sustained full-level electricity supply during power outages. This is an example to increase energy resilience of buildings. Solar power generation is available during the hours of sunshine, which will be affected by weather and seasonal conditions. The energy storage device can provide stored power during hours of no sunshine, hence helping enhance the resilience of a solar power supply. They use the case of California climate zone 9 to demonstrate how BESS can help increase the resilience of a regional solar power system.

Even though the future cannot be ensured in advance, Huang et al. [9] demonstrate how the resilience of a power dispatch system can be enhanced by incorporating a contingency assessment. They implement case studies on the modified IEEE 30-bus, 118-bus, and Polish 2382-bus systems under possible blackouts. In their new dispatch model, the added security constraints only make sure that the operation is safe for possible contingency events. They show that the average power losses can be reduced up to 40% by applying their new dispatch model.

We are living in a risky world where no one can 100% guarantee that disruptions in an energy system will never take place. Resilient restoration of a disrupted power supply system is hence an important ad hoc issue. Xin et al. [10] build up a multi-period model taking into account both reconfiguration and multiple distributed energy resources (DERs). Their model facilitates rapid restoration of an energy system by reducing prediction errors and speeding up computation. Consequently, rapid recovery is a key component of energy resilience.

Aiming at promoting the resilient smart city development in Poland, Baran et al. [11] believe that a smart city should be resilient and that resilience can be enhanced by installing multi-component capacity. The responses of an urban system to changes are not certain, such that a smart city must be resilient at all times to deal with unexpected impacts and challenges. Participatory planning and governance are required for building a resilient smart city. Technological, institutional, and human components must be taken into account to build up resilient smart cities.

From the above eleven papers published in Energies, we can summarize four pillars of the resilience of energy systems: planning, infrastructure, restoration, and governance. For the planning aspect, layout optimization, contingency assessment, life cycle assessment, etc., are key factors. For the infrastructure aspect, networks, microgrids, civil engineering, hybrid energy sources, global optimization, etc., are key factors. With respect to the restoration aspect, repair capacity, reconfiguration ability, computational speed, etc., are the key factors. In regard to the governance aspect, participatory governance, incentive compatibility, institutional regulations, etc., are key factors. More pillars and key factors can be found in future research because the studies of energy resilience are still on-going. Moreover, the translation of academic research on energy resilience into practical application is also in progress.

Resilience should be a major concern for future energy system developments. The world is facing uncertainties from both natural and social perspectives. We are not 100% sure about the future. However, we can be resilient for the future, and so too the energy systems.