Stand-Alone Microgrid with 100% Renewable Energy: A Case Study with Hybrid Solar PV-Battery-Hydrogen

Multi-year techno-economic assessment of proposed zero-emission hybrid community microgrid in Nigeria using HOMER

This paper presents a novel use of the HOMER Software for the multi-year economic, environmental, and energetic assessment of a proposed multi-source standalone renewable microgrid. A rural-but-rapidly-commercializing community in Nigeria's middle belt was used as a case study, with an average power demand of 975 kW and average consumption of 23.028 MWh/day. A generation mix of flat-plate photovoltaic (PV) array (3 MW nominal), concentrated solar thermal (CSP, 9 MW nominal), and small hydropower (SH, up to 200 kW), with battery storage (200 strings), system converter (2.5 MW nominal) using the Oshin River was recommended as the optimal system for minimizing the cost of electricity (LCOE) in HOMER. A diesel-based system was also simulated and a multiyear analysis for a 25-year period shows that the Net Present Cost (NPC) of $55.7 million for the renewable microgrid is vastly superior to the $408 million for the diesel microgrid, with LCOE of $0.26 and $1.01 per kWh respectively. The system also saved up to 7540 metric tons of CO2 per year in emissions. The results of the study indicate the proposed microgrid as an economically and environmentally superior alternative to diesel generators in the long term, and as deserving consideration for similar applications.

Intensification of Acidogenic Fermentation for the Production of Biohydrogen and Volatile Fatty Acids—A Perspective

Utilising ‘wastes’ as ‘resources’ is key to a circular economy. While there are multiple routes to waste valorisation, anaerobic digestion (AD)—a biochemical means to breakdown organic wastes in the absence of oxygen—is favoured due to its capacity to handle a variety of feedstocks. Traditional AD focuses on the production of biogas and fertiliser as products; however, such low-value products combined with longer residence times and slow kinetics have paved the way to explore alternative product platforms. The intermediate steps in conventional AD—acidogenesis and acetogenesis—have the capability to produce biohydrogen and volatile fatty acids (VFA) which are gaining increased attention due to the higher energy density (than biogas) and higher market value, respectively. This review hence focusses specifically on the production of biohydrogen and VFAs from organic wastes. With the revived interest in these products, a critical analysis of recent literature is needed to establish the current status. Therefore, intensification strategies in this area involving three main streams: substrate pre-treatment, digestion parameters and product recovery are discussed in detail based on literature reported in the last decade. The techno-economic aspects and future pointers are clearly highlighted to drive research forward in relevant areas.

Technical Control and Optimal Dispatch Strategy for a Hybrid Energy System

Optimal dispatch is a major concern in the optimization of hybrid energy systems (HESs). Efficient and effective dispatch models that satisfy the load demand at the minimum net present cost (NPC) are crucial because of the high capital costs of renewable energy technologies. The dispatch algorithms native to hybrid optimization of multiple energy resources (HOMER) software, cycle-charging (CC) and load-following (LF), are powerful for modeling and optimizing HESs. In these control strategies, the decision to use fuel cell systems (FCs) or battery energy storage systems (BESs) at each time step is made based on the lowest cost choice. In addition, the simultaneous operation of a FC with a BES reduces the operating efficiency of the FC. These deficiencies can affect the optimal design of HESs. This study introduces a dispatch algorithm specifically designed to minimize the NPC by maximizing the usage of FCs over other components of HESs. The framework resolves the dispatch deficiencies of native HOMER dispatch algorithms. The MATLAB Version 2021a, Mathworks Inc., Natick, MA, USA Link feature in HOMER software was used to implement the proposed dispatch (PD) algorithm. The results show that the PD achieved cost savings of 4% compared to the CC and LF control dispatch strategies. Furthermore, FCs contributed approximately 23.7% of the total electricity production in the HES, which is more than that of CC (18.2%) and LF (18.6%). The developed model can be beneficial to engineers and stakeholders when optimizing HESs to achieve the minimum NPC and efficient energy management.

Enhancing Transient Response and Voltage Stability of Renewable Integrated Microgrids

Integration of renewable generation coupled with an energy storage system (ESS) in a power system increases the complexity of networks’ stability analysis and control. Therefore, an accurate stability assessment of power networks is expected to become a big challenge in the future. In this work, an effective approach to prevent power outage by controlling the source voltage of the power network is formulated to mitigate the effects of grid faults. Small signal stability studies are conducted on a renewable integrated IEEE 9 bus system as a case study with optimized size and allocation of ESS for reducing output power variability of renewables. An assessment is performed to study the effects of load-sharing devices on parallel generators under 6-cycle three-phase fault disturbances. The damping of the power network is increased at nominal and light loading conditions with 6-cycle three-phase fault disturbances through coordinated power system stabilizer (PSS) and static VAR compensator (SVC) at bus 9. The developed framework is extensively analyzed in steady-state conditions using a load flow program. Based on the results obtained, the proposed coordinated PSS-SVC device proves to possess comparatively better performance in terms of enhancing most of the system response rate under various load conditions with overall improved stability.

Techno-Economic Analysis of the Hybrid Solar PV/H/Fuel Cell Based Supply Scheme for Green Mobile Communication

Hydrogen has received tremendous global attention as an energy carrier and an energy storage system. Hydrogen carrier introduces a power to hydrogen (P2H), and power to hydrogen to power (P2H2P) facility to store the excess energy in renewable energy storage systems, with the facts of large-scale storage capacity, transportability, and multiple utilities. This work examines the techno-economic feasibility of hybrid solar photovoltaic (PV)/hydrogen/fuel cell-powered cellular base stations for developing green mobile communication to decrease environmental degradation and mitigate fossil-fuel crises. Extensive simulation is carried out using a hybrid optimization model for electric rnewables (HOMER) optimization tool to evaluate the optimal size, energy production, total production cost, per unit energy production cost, and emission of carbon footprints subject to different relevant system parameters. In addition, the throughput, and energy efficiency performance of the wireless network is critically evaluated with the help of MATLAB-based Monte-Carlo simulations taking multipath fading, system bandwidth, transmission power, and inter-cell interference (ICI) into consideration. Results show that a more stable and reliable green solution for the telecommunications sector will be the macro cellular basis stations driven by the recommended hybrid supply system. The hybrid supply system has around 17% surplus electricity and 48.1 h backup capacity that increases the system reliability by maintaining a better quality of service (QoS). To end, the outcomes of the suggested system are compared with the other supply scheme and the previously published research work for justifying the validity of the proposed system.

Stationary Hybrid Renewable Energy Systems for Railway Electrification: A Review

This article provides an overview of modern technologies and implemented projects in the field of renewable energy systems for the electrification of railway transport. In the first part, the relevance of the use of renewable energy on the railways is discussed. Various types of power-generating systems in railway stations and platforms along the track, as well as in separate areas, are considered. The focus is on wind and solar energy conversion systems. The second part is devoted to the analysis of various types of energy storage devices used in projects for the electrification of railway transport since the energy storage system is one of the key elements in a hybrid renewable energy system. Systems with kinetic storage, electrochemical storage batteries, supercapacitors, hydrogen energy storage are considered. Particular attention is paid to technologies for accumulating and converting hydrogen into electrical energy, as well as hybrid systems that combine several types of storage devices with different ranges of charge/discharge rates. A comparative analysis of various hybrid electric power plant configurations, depending on the functions they perform in the electrification systems of railway transport, has been carried out.

Optimal Synergy between Photovoltaic Panels and Hydrogen Fuel Cells for Green Power Supply of a Green Building—A Case Study

Alternative energy resources have a significant function in the performance and decarbonization of power engendering schemes in the building application domain. Additionally, “green buildings” play a special role in reducing energy consumption and minimizing CO2 emissions in the building sector. This research article analyzes the performance of alternative primary energy sources (sun and hydrogen) integrated into a hybrid photovoltaic panel/fuel cell system, and their optimal synergy to provide green energy for a green building. The study addresses the future hydrogen-based economy, which involves the supply of hydrogen as the fuel needed to provide fuel cell energy through a power distribution infrastructure. The objective of this research is to use fuel cells in this field and to investigate their use as a green building energy supply through a hybrid electricity generation system, which also uses photovoltaic panels to convert solar energy. The fuel cell hydrogen is supplied through a distribution network in which hydrogen production is outsourced and independent of the power generation system. The case study creates virtual operating conditions for this type of hybrid energy system and simulates its operation over a one-year period. The goal is to demonstrate the role and utility of fuel cells in virtual conditions by analyzing energy and economic performance indicators, as well as carbon dioxide emissions. The case study analyzes the optimal synergy between photovoltaic panels and fuel cells for the power supply of a green building. In the simulation, an optimally configured hybrid system supplies 100% of the energy to the green building while generating carbon dioxide emissions equal to 11.72% of the average value calculated for a conventional energy system providing similar energy to a standard residential building. Photovoltaic panels account for 32% of the required annual electricity production, and the fuel cells generate 68% of the total annual energy output of the system.

Optimal Design of an Isolated Hybrid Microgrid for Enhanced Deployment of Renewable Energy Sources in Saudi Arabia

Hybrid microgrids are presented as a solution to many electrical energetic problems. These microgrids contain some renewable energy sources such as photovoltaic (PV), wind and biomass, or a hybrid of these sources, in addition to storage systems. Using these microgrids in electric power generation has many advantages such as clean energy, stability in supplying power, reduced grid congestion and a new investment field. Despite all these microgrids advantages, they are not widely used due to some economic aspects. These aspects are represented in the net present cost (NPC) and the levelized cost of energy (LCOE). To handle these economic aspects, the proper microgrids configuration according to the quantity, quality and availability of the sustainable source of energy in installing the microgrid as well as the optimal design of the microgrid components should be investigated. The objective of this paper is to design an economic microgrid system for the Yanbu region of Saudi Arabia. This design aims to select the best microgrid configuration while minimizing both NPC and LCOE considering some technical conditions, including loss of power supply probability and availability index. The optimization algorithm used is Giza Pyramids Construction (GPC). To prove the GPC algorithm’s effectiveness in solving the studied optimization problem, artificial electric field and grey wolf optimizer algorithms are used for comparison purposes. The obtained results demonstrate that the best configuration for the selected area is a PV/biomass hybrid microgrid with a minimum NPC and LCOE of $319,219 and $0.208/kWh, respectively.

A Comprehensive Approach to the Design of a Renewable Energy Microgrid for Rural Ethiopia: The Technical and Social Perspectives

In view of Ethiopia’s significant renewable energy (RE) potential and the dynamic interactions among the components of the Water–Energy–Food (WEF) Nexus, we attempted to incorporate solar and small-scale hydropower into the optimal design of an environmentally friendly microgrid with the primary goal of ensuring the sustainability of irrigation water pumping, while taking advantage of existing infrastructure in various small administrative units (kebele). Any additional generated energy would be made available to the community for other needs, such as lighting and cooking, to support health and food security and improve the general quality of life. The novelty of the study stems from the utilization of in situ social data, retrieved during fieldwork interviews conducted in the kebele of interest, to ascertain the actual needs and habits of the local people. Based on these combined efforts, we were able to formulate a realistic energy demand plan for climatic conditions typical of Sub-Saharan Africa agricultural communities and analyze four different scenarios of the microgrid’s potential functionality and capital cost, given different tolerance levels of scheduled outages. We demonstrated that the RE-based microgrid would be socially and environmentally beneficial and its capital cost sensitive to the incorporation of individual or communal machines and appliances. Ultimately, the social impact investigation revealed the design would be welcomed by the local community, whose members already implement tailor-made solutions to support their agricultural activities. Finally, we argue that extended educational programs and unambiguous policies should be in place before any implementation to ensure the venture’s sustainability and functionality.

Techno-Economic Optimization Analysis of an Autonomous Photovoltaic Power System for a Shoreline Electrode Station of HVDC Link: Case Study of an Electrode Station on the Small Island of Stachtoroi for the Attica–Crete Interconnection

A lot of autonomous power systems have been designed and operated with different power levels and with special requirements for climatic conditions, availability, operation/maintenance cost, fuel consumption, environmental impacts, etc. In this paper a novel design of an autonomous power system with photovoltaic panels and electrochemical batteries for a shoreline electrode station is analyzed. This station will be constructed on the small island of Stachtoroi for the new high voltage direct current (HVDC) link of Attica–Crete in Greece. The general guidelines of the International Council on Large Electric Systems (CIGRE) and of the International Electrotechnical Committee (IEC) for the power system of lighting and auxiliary loads for these HVDC stations are supplied from the medium voltage or the low voltage distribution network, whereas they do not take into account the criticality of this interconnection, which will practically be the unique power facility of Crete island. The significance of Crete power system interconnection demands an increased reliability level for the power sources, similar to military installations and hospital surgeries. In this research a basic electrical installation design methodology is presented. First, the autonomous photovoltaic power system with the energy storage system (ESS) consisting of electrochemical batteries is preliminary designed according to the relative bibliography. The station power and energy consumption are analytically determined taking into consideration the daily temperature variation annually. Afterwards, a techno-economic optimization process based on a sensitivity analysis is formed modifying the size/power of photovoltaic panels (PVs), the type and the energy capacity of the batteries taking into consideration the operation cycle of PVs—batteries charge and discharge and the battery ageing based on the relationship between battery cycles—the depth of discharge, the daily solar variation per month, the installation cost of PVs and batteries, the respective maintenance cost, etc., while the reliability criteria of expected loss of load power and of load energy are satisfied. Using the proposed methodology the respective results are significantly improved in comparison with the preliminary autonomous power system design or the connection with the distribution power system.

Optimal Integration of Hydrogen-Based Energy Storage Systems in Photovoltaic Microgrids: A Techno-Economic Assessment

The feasibility and cost-effectiveness of hydrogen-based microgrids in facilities, such as public buildings and small- and medium-sized enterprises, provided by photovoltaic (PV) plants and characterized by low electric demand during weekends, were investigated in this paper. Starting from the experience of the microgrid being built at the Renewable Energy Facility of Sardegna Ricerche (Italy), which, among various energy production and storage systems, includes a hydrogen storage system, a modeling of the hydrogen-based microgrid was developed. The model was used to analyze the expected performance of the microgrid considering different load profiles and equipment sizes. Finally, the microgrid cost-effectiveness was evaluated using a preliminary economic analysis. The results demonstrate that an effective design can be achieved with a PV system sized for an annual energy production 20% higher than the annual energy requested by the user and a hydrogen generator size 60% of the PV nominal power size. This configuration leads to a self-sufficiency rate of about 80% and, without public grants, a levelized cost of energy comparable with the cost of electricity in Italy can be achieved with a reduction of at least 25–40% of the current initial costs charged for the whole plant, depending on the load profile shape.

Assessment of Energy Storage from Photovoltaic Installations in Poland Using Batteries or Hydrogen

This paper presents a series of economic efficiency studies comparing three different investment variants: without energy storage, with energy stored in batteries and hydrogen installation with a PEM fuel cell stack for a location in Poland. To reach a target, the current solar potential in Poland, the photovoltaic (PV) productivity, the capacity of the energy storage in batteries as well as the size of the hydrogen production system were calculated. The solar potential was determined using archival meteorological data and the Krieg estimation method. A laboratory scale PV system (1 kW) was used to estimate the decrease in real solar installation power during the last 10 years of operation. All analyses were made for a 100 kW photovoltaic array located in Poland using static and dynamic methods of investment project assessment, such as Simply Bay Back Period (SPBP) or Net Present Value (NPV). The results showed that the SPBP amounted to 8.8 years and NPV 54,896 € for non-storage systems. Whereas, for systems with energy stored the economic indexes were, as follow: SPBP = never, NPV = 183,428 € for batteries and SPBP = 14.74 years, NPV = 22,639 € for hydrogen/fuel cell installation. Storage in hydrogen is more advantageous than batteries due to the smaller investment outlays.

The Economic Viability of a Progressive Smart Building System with Power Storage

The increased smartness of the built environment is expected to contribute positively to climate change mitigation through energy conservation, efficient renewable energy utilization, and greenhouse gas emission reduction. Accordingly, significant investments are required in smart technologies, which enable the distributed supply of renewables and increased demand-side energy flexibility. The present study set out to understand the cash flows and economic viability of a real-life smart system investment in a building. The data collection process was threefold: First, a case building’s level of (energy) smartness was estimated. Second, the semi-structured interviews were held to understand the building owner’s motives for a smart investment. Third, the investment’s profitability was analyzed. The study found that the progressive smartness investment was technically feasible, and surprisingly also economically profitable. The original EUR 6 million investment provided over 10% return-on-investment and, thus, increased the property value by more than EUR 10 million. Moreover, the commercial partners also emphasized the strategic value gained by renewable energy and environmental performance. The high level of smartness with a good return on investment was accomplished mainly through new income generated from the reserve power markets. However, the results implied that financial profitability alone was not enough to justify the economic viability of a smart building system investment.

Technical Evaluation of a PV-Diesel Hybrid System with Energy Storage: Case Study in the Tapajós-Arapiuns Extractive Reserve, Amazon, Brazil

In 2018 the number of people without access to electricity dropped to less than 1 billion. However, the difficulty of serving these people became higher, as the locations are in the most remote areas of the world. Brazil, for example, needs to bring electricity to around 1 million people who, in the vast majority, live within the Amazon region. In this way, hybrid energy systems (HESs) count as an attractive alternative for power generation, especially in remote areas. Therefore, this article analyzes a case study of a hybrid photovoltaic-diesel system installed in the Tapajós-Arapiuns Extractive Reserve in the Brazilian Amazon region. The studied plant is composed of a photovoltaic (PV) system, a lead-acid electrochemical battery bank, a diesel generator, and electro-electronic loads with highly variable demand throughout the year. The HOMER PRO software is used as the simulation tool. The results show that the load following dispatch strategy is the best option, with 85.6% of the load demand being supplied by PV energy and only 14.4% by the diesel generator set. As a result, the system is technically feasible to be replicated as a reliable energy source in other areas of the reserve to supply schools, public health places, and other community services.

Hybrid Renewable Energy Microgrid for a Residential Community: A Techno-Economic and Environmental Perspective in the Context of the SDG7

Energy, being a prime enabler in achieving sustainable development goals (SDGs), should be affordable, reliable, sustainable, and modern. One of the SDGs (i.e., SDG7) suggests that it is necessary to ensure energy access for all. In developing countries like India, the progress toward SDG7 has somewhat stagnated. The aging conventional electric power system has its dominant share of energy from fossil fuels, plagued with frequent power outages, and leaves many un-electrified areas. These are not characteristics of a sustainable and modern system in the context of the SDG7. Promoting renewable-based energy systems, especially in the context of microgrids (MGs), is one of the promising advances needed to rejuvenate the progress toward the SDG7. In this context, a hybrid renewable energy microgrid (HREM) is proposed that gives assurance for energy access to all in an affordable, reliable, and sustainable way through modern energy systems. In this paper, a techno-economic and environmental modeling of the grid-independent HREM and its optimization for a remote community in South India are presented. A case of HREM with a proposed configuration of photovoltaic/wind turbine/diesel generator/battery energy storage system (PV/WT/DG/BESS) was modeled to meet the community residential electric load requirements. This investigation dealt with the optimum sizes of the different components used in the HREM. The results of this model presented numerous feasible solutions. Sensitivity analysis was conducted to identify the best solution from the four optimized results. From the results, it was established that a PV + DG + BESS based HREM was the most cost-effective configuration for the specific location. In addition, the obtained optimum solutions were mapped with the key criteria of the SDG7. This mapping also suggested that the PV + DG + BESS configuration falls within the context of the SDG7. Overall, it is understood that the proposed HREM would provide energy access to households that is affordable, reliable, sustainable, and modern.