Although Indonesia’s electrification ratio reached 99.2% in 2020, it has shown stagnating electrification since 2018. This is because most of the remaining areas that need to be electrified are remote and have unique characteristics that hamper implementation of microgrids for providing energy access. Furthermore, not only the deployment but also the long-term sustainability of microgrids is crucial for ensuring continuity of energy access. This paper aims to investigate the scaling and sustainability challenges of remote microgrid development in Indonesia by analyzing microgrids in the Maluku and North Maluku provinces. This study is a two-part publication; the first part focuses on identifying challenges in Indonesia’s remote microgrid development, while the second part focuses on potential technology solutions. In the first part, an assessment of energy access within a multi-tier framework was conducted, which was then analyzed using a multi-dimensional (institutional, social, technical, economic, environmental, and policy) approach adapted from the literature. The framework was expanded by mapping the challenges onto specific phases of the microgrid development, which is intended to be helpful for the parties involved in specific phases. It is shown that the challenges related to unclear land status, lack of social engagement, preliminary survey, technical and practical knowledge, and O&M procedures—especially for remote microgrids with renewable energy sources—are the most prominent issues. Additionally, issues caused by electrical events and environmental conditions such as relatively humid and high-temperatures, and uncontrolled vegetation, rodents, insects, and lizards are often found. Furthermore, a high-level technological outlook to address some of these issues is presented.

This paper presents a systematic review of microgrid interoperability focusing on energy access. Drawing upon 59 studies and reports, it delves into interoperability issues and technologies across various microgrid applications. This study aims to provide a synthesized overview of the current discourse on microgrid interoperability, particularly contextualized within the realm of energy access. This objective is accomplished through a process that involves clarifying terminologies, exploring potential interoperability issues in microgrids, identifying the technologies for interoperability, and examining promising pathways to achieve interoperability. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) method was used in this study. Through data extraction and content analysis, the review found that studies on interoperability in the energy field primarily focus on the smart grid topic, where information and communication technologies are regarded as key elements to facilitate interoperability. There is less emphasis on physical or electrical interoperability, with the literature primarily focusing on interoperability in the communication domain. Furthermore, interoperability in the energy access context is uncommon, as indicated by a lack of literature in remote, rural, or community settings. Adopting common industry standards is one of the strategies for ensuring interoperability, enabling microgrid systems to function effectively and reliably. This paper contributes to describing research insights, identifying gaps in knowledge, and proposing future research directions regarding microgrid interoperability.

This paper is the companion paper of Remote Microgrids for Energy Access in Indonesia “Part I: scaling and sustainability challenges and a technology outlook”. This part II investigates the issues of photovoltaic (PV) systems with respect to the planning, design, and operation, and maintenance phases in microgrids in Indonesia. The technology outlooks are also included as PV has an important role in providing electricity in the underdeveloped, isolated, and border areas. The data in this paper are from PV microgrids located in Maluku and North Maluku, which are two provinces where there is barely any grid connection available and thus very dependent on remote microgrids. The data are obtained from interviews with Perusahaan Listrik Negara (PLN) and NZMATES, which are an Indonesian utility company and a program for supporting role for the PV systems in Maluku funded by New Zealand respectively. Common issues with respect to reliability and sustainability are identified based on the provided data. Advanced technologies to increase reliability and sustainability are also presented in this paper as a technology outlook. Among these solutions are online monitoring systems, PV and battery lifetime estimation, load forecasting strategies, and PV inverters technology.

Powerquality (PQ) is part of low-frequency electromagnetic interference (EMI), which could be present in any system. It is known that nonlinear loads pose PQ problems in large grids, but this problem is even more prevalent in smaller grids. However, the typical methods in addressing PQ problems might not be feasible in remote areas because of their challenging characteristics; hence, alternative approaches are needed. This letter investigates the significance of the cable characteristics and the nonlinear load current amplitude $(I_{\mathrm { load}})$ on the power losses $(P_{\mathrm { loss}})$ , voltage drop $(V_{\mathrm { drop}})$ , and total voltage harmonic distortions (THD $_{V}$ ) to effectively minimize them. The investigated cable parameters were based on the typical cable $2\times 16$ mm2 NFA2X. A high value of $P_{\mathrm { loss}}$ , $V_{\mathrm { drop}}$ , and THD $_{V}$ was found when the loads were highly nonlinear and the cable length was 1 km. A sensitivity showed that $R_{\mathrm { cable}}$ and $I_{\mathrm { load}}$ were more significant than $L_{\mathrm { cable}}$ and $C_{\mathrm { cable}}$ to the increase of $P_{\mathrm { loss}}$ , $V_{\mathrm { drop}}$ , and THD $_{V}$ . Therefore, using more parallel conductors ( $4\times 16$ mm2 NFA2X) as a simple approach was proposed to reduce $R_{\mathrm { cable}}$ and $I_{\mathrm { load}}$ per cable, which resulted in 53%, 53%, and 28% reduction in $P_{\mathrm { loss}}$ , $V_{\mathrm { drop}}$ , and THD $_{V}$ , respectively. The additional cable investment can be recovered by the savings from the $P_{\mathrm { loss}}$ reduction, which was estimated at four years. Moreover, complying with the recommended THD $_{V}$ value (below 8%) was more difficult than keeping $V_{\mathrm { drop}}$ below 10%, because it requires lower $R_{\mathrm { cable}}$ and $I_{\mathrm { load}}$ .

Electromagnetic compatibility (EMC) challenges arise in generator and inverter-based power supplies due to the presence of inrush currents and rapid load changes among other electromagnetic interference sources. Inrush currents and rapid load variations have shown to cause EMC issues in the form of poor power quality. In this article, the fundamental principle of elements containing the energy are discussed where energy of rotational inertia is compared to electrical energy stored in capacitors and inductors. The investigated microgrids which include a mobile generator (rotational energy) powered military ground vehicle and an off-grid inverter (electrical energy) are measured and analyzed with respect to rapid load changes. This will identify challenges and inherent difference between generator based inverter based microgrids, as well as the benefits of each with respect to different load characteristics. This lays a foundation of determining the optimum between the quality of supply and the quality of demand, where inertia is a key factor in stability. The primary conclusion drawn from the measurement and analysis underscores the significance of load rising edge and amplitude in resulting instability due to transient load fluctuations. Measurements from real world applications show $\pm$ 12–13% voltage deviations for a generator based system and up to 20% for a inverter based system on a rapid load change event.

Sustainable Development Goal 7 aims to ensure universal access to affordable and reliable energy, including for remote communities beyond the main grid. Microgrids offer a promising solution but sustaining them long term remains challenging. One contributing factor to early failures is poor conducted electromagnetic compatibility, i.e., power quality (PQ). Although PQ issues in remote microgrids are similar to those in large grids, their effects are often more severe due to high source impedance, a substantial proportion of nonlinear loads, less robust equipment, limited skilled operators, and harsh environment. Conventional PQ mitigation (e.g., filters, oversizing, power factor correction) are often impractical for these resource-constrained areas, hence requiring a more pragmatic approach. Consequently, understanding PQ from both supply and demand sides is critical in this context, as cost-efficient solutions can only be identified by assessing both sides together. Measurements highlight the necessity of real-time PQ monitoring at multiple points in the system, while simulations show that adjusting system impedance and load composition can improve PQ. These findings show the importance of coordinated action among system owners, operators, appliance manufacturers, and users in managing PQ in resource-constrained environment.