Ovis Daniel Irefu

Microgrids that combine renewable generation with battery storage are being deployed in power systems worldwide to improve supply continuity and to integrate variable renewable energy, yet most evidence on their reliability comes from simulation, and field studies rarely report measured reliability indices together with the load, storage, and weather period under which they were obtained. This paper reports on the design and field evaluation of a 24 V direct-current microgrid at the University of North Texas Discovery Park, Denton, Texas, USA (33.2° N) that combines photovoltaic (PV) and wind generation with lead-acid storage and a parabolic-dish thermoelectric branch on a shared bus. Reliability was assessed from a 33-day metered campaign (696,595 records) and a design-basis suite using loss of power supply probability (LPSP), loss of load expectation (LOLE), expected energy not supplied (EENS), and two storage-independent indices. At the metered load, wind reduced battery-supplied energy by 17.9% (13.5% at night) and generation-adequacy LPSP from 47.9% to 39.4% by generating at night and under low irradiance. Under a 140 W design-basis load, wind reduced LPSP from 4.18% to 0.93% (EENS from 0.140 to 0.031 kWh/day), but the same load evaluated on the record, which covers a different period of measured weather, yielded up to 24.1%, showing that reliability indices depend jointly on load, storage, and the weather period over which they are computed. For the thermoelectric branch, characterized in seven campaigns over 32 days (19 August–19 September 2026), diagnostic elimination showed that manual-tracking dwell time and optical-interface coupling govern output; moving the thermoelectric module bank closer to the dish focal point, with the dish aiming procedure unchanged, raised delivered power from 13.11 W to 50.96 W.

Field evidence for hybrid renewable microgrids remains scarce, and reliability indices measured on operating systems are rarely qualified by their operating conditions. This paper reports on the design and field evaluation of a 24 V direct-current microgrid that combines photovoltaic (PV) and wind generation with lead-acid storage and a parabolic-dish thermoelectric branch on a shared bus. Reliability was assessed from metered field campaigns (696,595 records) and a design-basis suite using Loss of Power Supply Probability (LPSP), Loss of Load Expectation (LOLE), and two storage-independent indices. At the metered load, wind reduced battery-supplied energy by 17.9% (13.5% at night) and generation adequacy LPSP from 47.9% to 39.4% by generating at night and under low irradiance. Under a 140 W design-basis load, wind reduced LPSP from 4.18% to 0.93%, but the same load over a different resource window (calendar period of measured weather) yielded 24.1%, showing that reliability indices depend jointly on load, storage, and resource window. For the thermoelectric branch, diagnostic elimination showed that manual-tracking dwell time and optical-interface coupling govern output; repositioning the modules raised delivered power from 13.11 W to 50.96 W.

Renewable energy systems play a critical role in reducing carbon emissions and promoting energy sustainability. Conventional battery storage remains the dominant but problematic solution for intermittency management in off-grid renewable energy systems (RES), imposing high capital costs ($150-400/kWh for lithium-ion), short replacement cycles of 3-15 years, and significant environmental burdens from toxic material disposal barriers that are particularly acute in the remote and resource-limited communities that most need reliable clean energy. This paper presents a systematic review of battery-less off-grid RES, synthesizing evidence across six alternative energy storage and dispatch technologies: supercapacitors, mechanical flywheels, compressed air energy storage (CAES), pumped hydroelectric storage (PHS), hydrogen storage via PEM electrolysis, and molten salt thermal energy storage (TES). The review spans single-source, dual-source, and multi-source configurations, with documented applications in seawater reverse osmosis desalination, agricultural water pumping, rural electrification, and small-scale industrial processes. A comparative performance analysis reveals that no single battery-less technology is universally optimal; rather, hybrid approaches particularly molten salt TES paired with hydrogen storage offer the most robust solution for continuous, dispatchable off-grid power. Building on this synthesis, the paper proposes and characterizes a novel integrated battery-less microgrid combining solar photovoltaic (PV), wind turbine (WT), and concentrated solar power (CSP) with molten salt thermal storage and PEM-based green hydrogen production. The system’s defining innovation is the dual-pathway utilization of stored hydrogen: as a long-duration electricity backup via fuel cells and as a direct fuel for agricultural vehicles and equipment, eliminating diesel dependence in off-grid farming contexts. Key findings indicate that such integrated systems can reduce curtailed renewable energy by up to 79%, eliminate battery replacement costs over a 20-year operational lifespan, and provide multi-day energy autonomy without chemical battery storage. Critical challenges including electrolyzer cost reduction, small-scale CSP adaptation, and energy management system design are identified as priority directions for future research to enable widespread deployment. HOMER Pro-based techno-economic validation is identified as the immediate next step in this research work.

The energy crisis in Nigeria has continued to impede the rapid expansion of the telecommunication industry, whose operating expenditure is galloping due to over-dependence on diesel generators as an alternative source of power to its base transceiver station (BTS). This fossil-fuel power source has also increased the industry’s carbon footprint. As a solution to these problems, the objective of this work is to provide a sustainable and quality hybrid DC power supply system for BTS that would increase access to information and communication technology or ICT infrastructure. This involves the integration of solar & wind energy with the grid. The sizing of the hybrid sub-systems was designed & simulated using MATLAB Simulink to test for functionality. A prototype of the design system was then implemented with the results showing an average power output that guarantees 21 hours/day of supply. By installing this hybrid system of 1.3 kW, approximately 2.55 kg of diesel (C10H20) would be un-utilized by one BTS, thereby preventing 3.6 kg of CO2 from been emitted to the atmosphere daily. Extrapolating these values shows 930.75 kg of diesel can be saved and reduce 1314 kg of CO2 emission within a year. Hence eliminating the need for diesel-backup generator for a grid connected or non-grid BTS sited in rural areas.

Inadequate electricity supply is a global challenge that needs solutions. This situation has compelled the purchasing of fossil fuel-generating units for use in residential, commercial, and industrial sectors to generate electricity. However, using fossil fuel generating units cause greenhouse gas emissions, bringing about environmental pollution and ultimately resulting in climate change. In particular, educational institutions require adequate and reliable power supply to ensure proper learning and teaching, which is lacking in developing countries like Nigeria. Fortunately, Nigeria has enormous renewable energy sources such as solar energy, which can be utilized through photovoltaic (PV) modules to generate clean energy fed into a mini-grid. This novel approach focused on an educational institution that will enable adequate electricity from the mini-grid for proper learning and teaching, reduced negative environmental impacts, and lower energy costs. Therefore, this research is focused on developing an effective hybrid utility grid-diesel generator-solar PV mini-grid system for the Faculty of Engineering and Technology of the Nigerian Defence Academy, Kaduna. Design analysis and techno-economic evaluation of the mini-grid were carried out using the HOMER Pro software tool, which was also used to simulate and optimize the mini-grid. The results revealed that the hybrid system comprising the grid, diesel generator, PV, and converter was technically and economically viable. The net present cost (NPC) of $182,065.20, producing a total energy of 836,430 kWh/year, was obtained and gave 0.00198 $/kWh as a levelized cost of energy (LCOE). Correspondingly, a renewable fraction (RF) of 98.3% was attained, thus meeting the Faculty's daily load demand of 575.64 kWh/day, thereby providing a reliable and improved energy supply at the best cost. Therefore, a hybrid system such as this one is proposed for tertiary institutions to ensure greater electric power supply availability.

Thermochemical processes utilize heat and chemical reactions for the release of hydrogen (H₂) from organic materials, including fossil fuels and biomass. In some thermochemical processes, the combination of heat with closed-chemical cycles generates H₂ from feedstock such as lignocellulosic biomass, plastics, and aquatic plants. Some of the major challenges facing renewable H₂ production include the high-temperature requirements for biomass decomposition and water splitting as well as the correspondingly expensive thermal-resistant materials needed for these processes. An overview of the role of nanomaterials in mitigating these challenges is presented in this chapter, with emphasis placed on thermochemical water splitting, given its considerable promise. Generally, the application of nanomaterials (as catalysts) improves the overall thermochemical process efficiency. The specific improvement routes include a reduction of the high-temperature requirements, reduced tar formation, improved reactant conversion, and an increase in the H₂ yield and stability over several cycles. This chapter further discusses some of the recent advancements in renewable nanomaterial-based thermochemical water splitting and highlights crucial challenges to be addressed for the large-scale uptake and commercial implementation of this H₂ production route.

This paper presents a modified fractional-order proportional-integral-differential (MFOPID) controller for load frequency control in an Island microgrid based on an electric vehicle (EV) and renewable energy source. It tackles the intermittent energy sources and the dynamic of the load change with reduced speed and the quality of response generated on the microgrid. The MFOPID controller gains are well turned using a metaheuristic grasshopper optimization algorithm (GOA) technique to determine its robustness and optimal system performance. The controller gains are evaluated with three different searching agent populations. The proposed MFOPID with GOA improved system performance frequency by 19.485 Hz compared to 14.1151 Hz of the benchmark model. It takes 6.9068 s of the proposed model to settle compared to 16.6796 s of FOPID.