**1. Introduction**

The Armed Forces operate in remote locations for training and military operations, even under natural disaster conditions or in foreign territories during conflicts, and must be ready to deploy on short notices, in any climate and for prolonged periods. As such, they currently rely on relocatable temporary camps (RTCs) for their deployments through extreme operational and environmental conditions. To sustain operations, as there is no utility grid, RTCs depend on logistics for the continuous supply of fossil fuel (primarily diesel) as the main source of energy. Ine fficiencies in current practices lead to vulnerabilities in energy infrastructures, such as shortfalls in power generation and higher requirements for fuel resupply, with the knock-on e ffect of greatly increasing the transportation logistics during operations. Moreover, RTCs typically use spot generation by connecting loads to a common set of generators, where each generator is oversized to satisfy peak loads, even when these loads are infrequent. Consequently, generators typically are selected at a significantly higher capacity, resulting in an ine fficient and costly source of power, increased maintenance, and wet sacking, a condition resulting from poor fuel combustion.

In recent years, military engineers have therefore encountered several operational challenges associated with energy logistic convoys and infrastructure, limited supplies, and climate change. Scientific literature identified a spectrum of approaches and technologies to address energy consumption under these conditions. Few combinations of components have been proposed according to the site-specific characteristics [1–3], however, the definition of further integrated configurations remains rarely investigated, although it is evident that the Armed Forces could benefit from holistically assessing these approaches as integrated systems.

Significant gains in the e fficiencies of RTC utility systems (renewable energy systems; improved generators and energy storage or grid e fficiency) and energy conservation measures (e.g., insulation of the camp tent fabric, building controls, etc.) would have an overall increasing benefit on the deployed operations. Meanwhile, stand-alone hybrid energy systems have been proposed as valuable means of supplying energy to remote areas, such as isolated rural villages [4–7], and for various other purposes, such as medical clinic practices [8] or military operations [9–11].

Some researchers investigated solutions aiming at reducing the dependency on fossil fuels during prolonged emergencies by proposing self-contained demonstration units that make use of hybrid generation from solar, wind, and biomass and, minimally, fossil sources [12]. Some of these systems have already been introduced to the market, as described below. Besides microgrids, clusters of electricity sources and load operating systems are being used to improve the reliability of electrical grids, manage the addition of distributed clean energy resources like wind and solar photovoltaic generation, reduce fossil fuel emissions, and provide electricity in areas not served by centralized electrical infrastructure [13].

Some models described the components of a microgrid [5,9,14,15], but not much is known about its behavior as a whole system. Some studies aimed to model microgrids at steady-state and study their transient responses to changing inputs [16]. However, researchers have built a full-scale microgrid model, including the power sources, power electronics, and load and mains models [5].

One of the main challenges towards the development of isolated microgrids is the managemen<sup>t</sup> of various devices and energy flows to optimize their operations, particularly regarding the hourly loads and the availability of power produced by renewable energy systems. Energy managemen<sup>t</sup> systems could be a solution to tackle these issues [16–18]. Regarding the provision of energy services with modular and transportable systems by making use of microgrid technology, some examples can be found in the market. For example, examples of possible technical solutions include the following:


The Cross-Power unit, e.g., uses modular hybrid wind and solar systems, integrated with battery storage, to produce electricity in remote locations. However, most of the existing solutions use black box intelligent energy managemen<sup>t</sup> systems to ensure a continuous supply and avoid shortfalls in power generation.

This paper presents a scalable and transportable solution, named Smart Hybrid Energy System (SHES), for providing energy-e fficient services to soldiers in protracted displacement situations. The SHES combines the existing diesel generators with solar power generation, energy storage, and waste heat recovery technologies, all connected to a microgrid, ensuring uninterrupted electricity and hot water supplies. The reliable and energy-e fficient system helps to manage generator output. By transforming an independently operating system of generators into a demand-managed microgrid, SHES provides power only where and when it is needed, instead of completely relying on fuel-burning generators. The system also provides the Armed Forces with critically needed power surety by utilizing intelligent load managemen<sup>t</sup> technologies to prevent grid collapse in the event of generator fault, as the SHES prevents a stoppage of energy flow by shifting demand onto supporting generators if one generator fails. The system is designed to manage the energy needs of a 150 to 1500-person RTC, operating in a temperate climate zone and allowing for the occasional deployment to extremely hot or cold climatic zones. Finally, this paper considers the energy savings achievable through technologies that improve the accommodation's insulation, such as a thermoreflective multilayer system developed for emergency architecture, or that provide additional layers of solar protection, reducing the heat transfer through the shelter exterior thus reducing the daily air conditioning loads and reliance on diesel fuel [19,20].
