This article systematically reviews the emerging field of research on business models for renewable energies, differentiating between developing and industrialized countries. The key findings on developing countries are as follows: first, there is a lack of quantitative data; second, opportunities are driven primarily by unfulfilled basic needs and micro-finance, whereas corruption and weak electricity grids are the main barriers; and third, business models should be replicable. The key findings on industrialized countries are as follows: first, opportunities are driven primarily by climate change mitigation and energy efficiency improvements; second, stuck thought patterns and high costs of energy storage are important barriers; and third, cooperation is a key in future business models to handle increasing complexity. This review reveals implications for researchers and policy-makers. Promising avenues for future research are the analysis of intermodal business models and opportunities concerning energy self-supply and renewable district heating. Policy-makers are advised to design legal frameworks that account for the global nature of the renewable energy challenge and are simultaneously adapted to regional disparities.

Comparing drivers, barriers, and opportunities of business models for renewable energies: A review

Microgrid clustering architectures

Networked microgrids (NMGs) provide a promising solution for accommodating various distributed energy resources (DERs) and enhancing the system performance in terms of reliability, resilience, flexibility, and energy efficiency. With the penetration of MGs, the communication-based distributed control is playing an increasingly important role in NMGs for coordinating a multitude of heterogeneous and spatially distributed DERs, which feature enhanced efficiency, reliability, resilience, scalability, and privacy-preserving as compared with conventional centralized control. This article aims to provide a comprehensive survey of distributed control and communication strategies in NMGs. We provide thorough discussions and elaborate on: 1) Essential merits of MGs and NMGs, and their practical implementations; 2) Distributed communication network characteristics and specific operation objectives of NMGs; 3) Classifications of distributed control strategies in NMGs and their salient features; 4) Communication reliability issues concerning data timeliness, data availability, and data accuracy, and the development of countermeasures; 5) Advancements in several promising communication and computation technologies and their potential applications in NMGs.

Distributed Control and Communication Strategies in Networked Microgrids

DC microgrids built through a bottom-up approach are becoming popular for swarm electrification due to their scalability and resource-sharing capabilities. However, they typically require sophisticated control techniques involving communication among the distributed resources for stable and coordinated operation. In this work, we present a communication-less strategy for the decentralized control of a photovoltaic (PV)/battery-based highly distributed dc microgrid. The architecture consists of clusters of nanogrids (households), where each nanogrid can work independently along with provisions of sharing resources with the community. An adaptive I–V droop method is used, which relies on local measurements of state of charge and dc bus voltage for the coordinated power sharing among the contributing nanogrids. PV generation capability of individual nanogrids is synchronized with the grid stability conditions through a local controller, which may shift its modes of operation between maximum power point tracking mode and current control mode. The distributed architecture with the proposed decentralized control scheme enables 1) scalability and modularity in the structure, 2) higher distribution efficiency, and 3) communication-less, yet coordinated resource sharing. The efficacy of the proposed control scheme is validated for various possible power-sharing scenarios using simulations on MATLAB/Simulink and hardware-in-the-loop facilities at the Microgrid Laboratory, Aalborg University.

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A Decentralized Control Architecture Applied to DC Nanogrid Clusters for Rural Electrification in Developing Regions

We present the design and experimental validation of a scalable dc microgrid for rural electrification in emerging regions. A salient property of the dc microgrid architecture is the distributed control of the grid voltage, which enables both instantaneous power sharing and a metric for determining the available grid power. A droop-voltage power-sharing scheme is implemented wherein the bus voltage droops in response to low supply/high demand. In addition, the architecture of the dc microgrid aims to minimize the losses associated with stored energy by distributing storage to individual households. In this way, the number of conversion steps and line losses are reduced. We calculate that the levelized cost of electricity of the proposed dc microgrid over a 15-year time horizon is $0.35/kWh. We also present the experimental results from a scaled-down experimental prototype that demonstrates the steady-state behavior, the perturbation response, and the overall efficiency of the system. Moreover, we present fault mitigation strategies for various faults that can be expected to occur in a microgrid distribution system. The experimental results demonstrate the suitability of the presented dc microgrid architecture as a technically advantageous and cost-effective method for electrifying emerging regions.

Scalable DC Microgrids for Rural Electrification in Emerging Regions

The provision of energy at the local level by using renewable and local resources is increasingly acknowledged as a techno-economic solution for rural electrification. This work describes an approach for implementing microgrid projects at the institutional level by means of a specific entity that uses methods that engage the community in microgrid operation and maintenance (OM), which ensures long-run benefits. The first step, related to macro-level barriers, is addressed by building a complete cadastre of isolated communities, while the second, at the micro level, focuses on business models for covering investment and OM costs. A cadastre uncovers the key characteristics of each location (energy resources, availability, socio-economic conditions, environment, etc.). A cadastre also helps identify local needs, develop monitoring strategies, and determine benchmarks among microgrids. Its information also assists with proposing new projects, securing funding, and monitoring actual microgrids. At the micro level, local stakeholders, economic capabilities, social capital, and organizational structures are identified, which contribute to the selection of a tailored business model that can enable fundraising and OM activities. The approach is presented in a four-stage framework: 1) background data collection; 2) community profile building; 3) system design; and 4) detailed engineering. Each community is evaluated by a prioritization index that considers the electrical conditions of each residence.

Karen Ubilla

Papers

Smart Microgrids as a Solution for Rural Electrification: Ensuring Long-Term Sustainability Through Cadastre and Business Models