Mini-grids Research Articles

Carbon footprint of solar based mini-grids in Africa: Drivers and levers for reduction

The massive development of mini-grids (MGs) is seen as a promising alternative to the extension of national grids to achieve universal access to electricity. MGs based on solar photovoltaic are often recognized fully consistent with net-zero CO2 emissions objectives. However, if they have low or even no direct emissions from diesel consumption, they embed indirect carbon emissions due to solar panels and batteries manufacturing. Electrification policies, mainly based on the levelized costs of electricity (LCOE), should likely account for the carbon footprints (CFP) of possible electrification strategies.In this work, we assess the CFP of hybrid MGs (solar, battery, diesel) for rural electrification in Africa. We consider a large number of MG configurations for many locations across the continent. For each location, we identify the lowest CFP and LCOE, and estimate their dependency to meteorological and socio-economic factors.Our results show that: (i) the lowest CFP depends on location and is around 200gCO2/kWh; (ii) it can be higher than the CFP of certain African national grids; (iii) the CFP of hybrid MGs can be lower than the CFP of MGs relying only on solar PV; (iv) for most techno-economic and environmental assumptions, moderate LCOE increases allow significant CFP reductions.

The political economy of mini-grid electricity development and innovation in Kenya

Accessible and affordable energy services are a prerequisite for socioeconomic growth and poverty reduction. Yet it is estimated that 600 million people in sub-Saharan Africa will not have access to electricity in 2030. Recent research suggests that universal access to electricity will be achieved through a mix of centralized and decentralized systems and that the diffusion of these technologies is a socio-technical process involving multiple actors. These actors include firms, networks, energy users, and government agencies that interact within a political landscape to deliver innovation within energy service systems. Thus, factors related to the political economy can impact the process of innovation and warrant analysis. This study aims to provide an analysis of the political economy factors that can influence the emergence of mini grid electricity development in the African context exemplified in Kenya as a case study. The study uses the Technology Innovation Systems (TIS) lens as an analytical framework to provide a critical analysis of how political economy factors have influenced the development of mini grid electricity in Kenya. The result shows that despite the presence of some favorable conditions for innovation, political economy factors significantly impede the deployment of mini grids in Kenya. Power and vested interests have created negative competition between public and private developers, limiting knowledge and information diffusion between actors and stalling mini grid developments where they are most needed.

Coordinated, Centralized, and Simultaneous Control of Fast Charging Stations and Distributed Energy Resources

The growing penetration of fast charging stations (FCSs) to electric vehicles (EVs) and distributed energy resources (DERs) in the electrical power system brings technical issue changes in the voltage profile throughout grid nodes and feeder current overload. The provision of ancillary services by DERs and FCSs arises as an appealing solution to reduce these adverse effects, enhancing the grid hosting capacity. The control of microgrids is essential for the coordinated implementation of these services. Although microgrid control is widely applied to DERs, few studies address the coordinated control of DERs and FCSs to obtain benefits for the electrical power system. This paper proposes a coordinated and simultaneous control of DERs and FCSs based on the power-based control (PBC) strategy, efficiently exploiting FCSs in a microgrid model previously unaddressed in the literature. The results show that, with the coordinated control of DERs and FCSs, the control of the power flow in a minigrid (MG) is achieved both in moments of high generation and in moments of high load, even with the maximum operation of DERs. This method allows for the maintenance of voltage levels within values considered acceptable by technical standards (above 0.93 pu). The maintenance of voltage levels is derived from reducing the overload on the point of common coupling (PCC) of the minigrid by 28%, performing the peak shaving ancillary service. Furthermore, the method allows for the control of zero power flow in the PCC of the minigrid with the upstream electric grid in periods of high generation, performing the ancillary service of valley filling. The method performs this control without compromising vehicle recharging and power dispatch by DERs.

Sizing isolated mini-grids in Kenya: Risk transfer to deal with multidimensional uncertainties and constraints

Isolated mini-grids (MG) can be an efficient option for rural electrification worldwide. Nonetheless, a large share of MG fail after a few years and inadequate sizing has been identified as a major risk. Academia, public authorities and funding agencies tend to consider the sizing of mini-grids mostly from a technical and economic angle, looking to optimize performance for MG developers and operators with tools such as HOMER. This paper proposes a different approach. We study the strategies adopted by different MG stakeholders to deal with their own uncertainties and constraints in the sizing process. Based on field work in Kenya, we detail how MG funders and regulators transfer risks to private MG developers and operators. As a result, the latter face risks regarding demand estimation, funding and regulatory aspects when sizing MGs. In turn, they adapt their methods and business models, sometimes transferring risks to end users. While flexible sizing might be a solution, we show that regulatory and funding issues limit MG modularity, leading low-income customers to eventually bear the consequences of ill-suited sizing.

Contribution of green hydrogen vector to guarantee electricity feeding in remote areas- Case study

This paper examines the potential of solar-hydrogen hybrid renewable energy systems as a solution for off-grid applications in areas with heavy rainfall. This study highlights the immense potential of renewable mini grids as a solution to Africa's energy access challenges helping to achieve the sustainable development goal SDG 7. Associated to Photovoltaic primary source (PV), the combination of Lithium-Ion batteries and Alkaline hydrogen system emerges as an effective approach for ensuring uninterrupted electricity supply, especially in rainy seasons. This solution mitigates the need for Diesel Generator, offers protection against fluctuations in diesel fuel prices, and concurrently results in significant reductions in CO2 emissions while optimizing the utilization of PV energy. The uniqueness of this approach is the use of hydrogen as a backup solution. Hydrogen, generated through electrolysis, serves as a reliable energy reservoir during periods of low renewable energy production. This capability enhances the mini-grid's resilience, guaranteeing continuous electricity feeding to off grid critical facilities where power outages can have significant consequences. However, the exclusive use of hydrogen in conjunction with PV energy requires further cost reductions for broader competitiveness, especially concerning Solid Oxide Cell (SoC) electrolyzers. Furthermore, fuel cells, across all hydrogen technologies explored, require continuous development to improve their cost-efficiency and streamline their widespread adoption. Nevertheless, the improvement that can be made to reduce the Hydrogen system CAPEX and enhancing its efficiency would make green hydrogen as a competitive and reliable primary storage solution.

Techno-Economic Feasibility Analysis of 143kW Solar Mini Grid for Rural Electrification in Gokule Village - A Case Study

Techno-Economic Feasibility Analysis of 143kW Solar Mini Grid for Rural Electrification in Gokule Village - A Case Study

Power struggles: Advances and roadblocks of solar powered mini grids in Tanzania

Rural energy poverty persists in Tanzania, with 77% of the population not having access to electricity. A combination of high solar radiation and slow extension of the national energy grid has raised off-grid solar PV based mini-grids as a potential solution. In this paper, a novel extension to the Technological Innovation System (TIS) function approach is used to analyze the positive and negative trends of solar PV based mini-grid diffusion in the country. This framework, adapted for a Global South context, considers key dynamic processes (functions) and structural components (actors and institutions) that are considered essential for diffusion of technological systems, along with the general institutional infrastructure, informal institutions and other contextual factors that may influence the development and implementation of solar PV based mini-grid systems. Based on a combination of semi-structured interviews with key stakeholders and secondary data, the paper identified negative trends in several functions such as market formation, entrepreneurial activities and guidance of the search. The paper demonstrates a clear link between the worsening conditions for solar PV mini-grids with institutional changes as a result of the new political direction for the energy sector that followed the 2015 presidential election in Tanzania.

Quantifying impacts and benefits of advanced remote monitoring solutions for the operation of mini grids in sub-Saharan Africa

As of 2022, 675 million people do not have access to electricity globally. The large majority of this underserved population lives in Sub-Saharan Africa. Mini grids systems play a central role to close this energy access gap. The adoption of latest technologies such as remote monitoring solutions can contribute to strengthen mini grids business case by improving their operation, maintenance and performance. In this study we present the latest trends, opportunities and challenges of remote monitoring solutions for mini grids and we illustrate the potential of this technology in optimizing mini grids operations, making the case for wider adoption in the sector. The analysis is developed assessing primary data collected from seven mini grids developers, covering 49 photovoltaic autonomous hybrid rural mini-grids across seven sub-Saharan Africa countries. To better understand the advantages of remote monitoring solutions we present a classification based on their related benefits compared to manual/local monitoring options. Orientation toward the adoption of remote monitoring solutions by mini grids developers highlights the advantages from a market and from the operational and maintenance perspectives. Through a cost-benefit analysis of remote monitoring solutions, we show that can have a positive impact on mini grids operations, leading to an overall operational expenditures reductions of up to 17 %, with an investment payback time as short as 1 year. Finally, we provide an estimation of operational costs savings at country level by using remote monitoring solutions in future rural electrification efforts.

Exploring the connections between mini-grid market regulation and energy access expansion: The case of Nigeria

About 140 million people across Africa are expected to gain access to electricity from mini grids by 2040. Nigeria, with the least dependable electricity supply on the continent, stands to benefit significantly from this boon. Accordingly, the government has put in place clear regulations to incentivise private investment and drive market growth. While the techno-economic dimensions of the growing mini-grid sector and the broader electricity industry have been extensively studied, less attention has been paid to analysing the impacts of the regulatory framework on the achievement of rural electrification and universal energy access goals. Drawing on qualitative data obtained from key regulatory and market actors in the Nigerian mini-grid sector, this paper interrogates the premise of pursuing widespread rural electrification through a regulatory framework that is primarily geared toward increasing market efficiency. The study finds that, while the current framework has enabled growth in the sector, complementary mechanisms are required to achieve equitable distribution of access, especially among the mainly rural populations dwelling on the fringes of mainstream electricity markets. The findings are instructive for practitioners and policy makers seeking evidence-informed approaches to achieving the goal of universal energy access in Africa.

Long-term optimal capacity expansion planning for an operating off-grid PV mini-grid in rural Africa under different demand evolution scenarios

Using real-time load data and HOMER Pro's ‘multi-year’ optimization tool, this paper investigates the long-term cost optimal capacity expansion planning (CEP) for an overloaded photovoltaic (PV) mini-grid (MG) with storage batteries in off-grid rural Ethiopia over a 20-year planning horizon. Three distinct annual energy demand growth scenarios were considered: 0 % (fulfils the minimum load requirement), 5 %, and a 15 % from productive users only. In all scenarios, the generation mix consists of only solar energy and the maximum allowable capacity shortage (MACS) is limited to 10 %. The findings reveal that, in all scenarios, the largest capacity expansion is performed on the battery and PV systems, covering up to 73 % and 35 % of the total expansion costs, respectively. The annual unmet load fraction of the expanded MG system ranges from 5.9 % in scenario-3 to 9.4 % in scenario-1, and the cost of electricity (LCOE) ranges from $0.404/kWh in scenario-3 to $0.887/kWh in scenario-1. The results indicate that the scenario-3 expansion path is comparatively cost-effective and has the highest reliability; but it still falls short of fully satisfying the required load demand and is not financially viable. Surprisingly, increasing the reliability of the scenario-3 capacity expansion from 94 % to 100 % raises the MG's Net Present Cost by 37 %. The sensitivity analysis shows that the MACS, ambient temperature, and battery's depth of discharge significantly affect the cost and performance of the capacity expansion. The study demonstrates (a) there are significant trade-offs between minimizing MG expansion costs and maximizing reliability levels; (b) capacity expansion based solely on cost-minimization without considering key constraints and uncertainties (demand, cost, PV, and battery degradations) may not provide a practical and robust solution to severe reliability issues, (c) capacity expansion that supports demand from productive users increases the cost-effectiveness and bankability of isolated MGs.

Techno-Economic Assessment of a Hybrid Solar Photovoltaic – Diesel Genset for Rural Electrification, Case study of Namabasa Village – Uganda

In recent time, hybrid renewable energy systems are increasing being utilized to provide electricity in remote areas especially where the grid extension is considered very expensive. This study presents a techno –economic analysis of a Mini grid solar photovoltaic system for five (5) typical Zonal Communities in Namabasa ward Mbale District while promoting renewable energy system adaption and rural electrification. The assessment technique includes the establishment of the socio-economic state of the rural community through a field survey. The cost of system development ,electricity tariffs and sizing of energy production are realized via the Levelized Cost of Electricity ( LCOE) technique Sensitivity analysis was carried out to identity the parameters that affect the evolution of the (LCOE) during the life of the project, the results have shown that the annual energy production at a rate of 12,693.2 Mwh/year and capacity of 1449kW, while the lowest is predict at Namabasa Zone II at the rate of 2847MWh/year a capacity of 325KW where business consumers. The standard (LCOE) for system during the 15-year lifespan in the five (5) zones is estimated 350/= per KWh except at Doko II, this cost per Kilowatt Hour is more attractive and competitive compared with the current rate charged by the National electricity company.

Challenges in the operational performance of six 15-19kWp photovoltaic mini-grid power plants in the Jharkhand State of India

Solar photovoltaic (PV) based mini-grid systems are effective solutions for the supply of clean electricity in areas where the electricity supply is erratic or inadequate. About 14,000 mini and microgrid systems installed in India are operated and maintained by the government, companies, and not-for-profit organisations. The objective of the present study is to investigate the performance of PV mini grids to ascertain technical design, system utilization, and consumer requirements to identify the potential barriers and technical and operational challenges. In this study technical and management concerns related to six functional mini grids of capacity 15 kW to 19 kW in the Indian state of Jharkhand are presented. A detailed analysis is carried out considering sizing, system utilization, operation and maintenance (O&M), safety, and plant management, required skill and training of manpower. These issues are then compared with different developer types. The results of mini-grid user feedback survey are also presented. The study shows that the operational and commercial success of mini-grid projects can be achieved through optimal system design and utilization, effective operation, and maintenance and by addressing technical, commercial, and social issues.

Battery-hydrogen vs. flywheel-battery hybrid storage systems for renewable energy integration in mini-grid: A techno-economic comparison

Decentralized renewables power production is rapidly growing because of environmental concerns. With the purpose of maximizing renewable exploitation, energy storage systems integration in Mini-Grids (MGs) is needed. Hybrid energy storage systems (HESSs) are promising to obtain enhanced performances in terms of both capacity and responsiveness, yet their feasibility may be hindered by design and management choices impacting the economic competitiveness. In this paper, two HESSs are analysed and compared in a real case-study, namely reversible solid oxide cell (rSOC)/Li-ion battery and flywheel/Li-ion battery systems. The analysis here developed handles annual photovoltaic generation and electric load actual dataset and includes: i) a statistical analysis to obtain the most representative days, ii) dynamic modeling of the HESSs, iii) simulations to define components sizing and to extrapolate the evolution of annual battery state-of-charge, iv) battery lifespan assessment through application of the rainflow cycle counting algorithm, and v) a detailed economic evaluation (Levelized Cost of energy LCOE, Levelized cost of Storage LCOS and their sensitivity to electricity market price) including subsidies for self-consumption. For both HESSs, performance indexes of reduction of energy withdrawal from the grid and self-consumption increase are fixed at about 30 % and 70 % respectively, with reference to the features of the investigated MG. As main outcomes for this integrated methodology, it appears that self-consumption rewards (i.e.110 €/MWh) let the flywheel/Li-ion battery HESS reach a LCOS agreeing with 2021 average market parity. On the contrary, LCOS is more than two-fold for the rSOC/Li-ion battery HESS, being equal the impact on the MG management and its energy independence from the main power grid. The integrated methodology is adequate for critically reviewing design and management choices and understanding the impact of the market on the profitability of a sub-system, with insight on energy storage units.

The Artificial Neural Network Approach for Determining the Futuristic Capacity of Power Supply in the Central Parts of Edo State, Nigeria

The need for the estimation of the future state of electric power supply in the power system can no longer be avoided. This is due to the inevitable operational, maintenance, planning and expansion obligations of the power sector. In this work, the future trend of power supply by the 33kV feeders that supply power to the customers in the central part of Edo State, Nigeria was forecasted from 2020 to 2030 using Artificial Neural Network. The findings showed that there will be a 13.84% reduction in the power supplied by the utility provider by 2030 if the current trend was sustained. To avoid the adverse impact of such a negative performance by the power supplier, there is a need to increase system capacity by constructing mini grids and implementation of other contingency plans within the study area.

Transmission infrastructure, interconnection of mini and main grids and energy storage for grid stability

Transmission infrastructure, interconnection of mini and main grids and energy storage for grid stability

Leaving no aspect of sustainability behind: A framework for designing sustainable energy interventions applied to refugee camps

The issues of forced displacement and energy for sustainable development are convergent: an estimated 90% of displaced people globally have no access to electricity, while 85% of refugees are hosted in developing countries. However, few tools to plan and design sustainable energy access interventions have been transposed to displacement settings. This paper presents a novel framework for the holistic planning of energy projects which considers both sustainability aspects and the specificities of displacement settings. The framework is the result of a review of literature which aimed to define a “sustainable energy intervention” in displacement contexts and an assessment of relevant planning tools against this definition. The framework includes the use of an energy delivery model toolkit, an inclusive design approach, an assessment of the desired impacts, energy system modelling, business model design, and an assessment of economic viability. We apply the framework in the design of a solar mini grid of Holl Holl refugee camp in Djibouti, in which a sustainable intervention and business model are proposed that could be compatible with the local conditions. We highlight issues that arise from the humanitarian sector status quo and propose that this framework could help to enhance sustainable energy practices in the humanitarian and development sectors.

Determinants of Uptake of Industrial Solar in Nairobi Metropolitan

Sub-Saharan Africa countries have abundant solar energy estimated in terawatts which can be harnessed to meet ever rising energy needs. Yet there are barriers affecting uptake of industrial solar by industries. This research aimed to establish determinants and how they effect of uptake of industrial solar mini grids in Nairobi Metropolitan area. The study objectives were; to explore the effect of financial capability, influence of Energy Act (2019), effect of business model and influence of public policy awareness on uptake of industrial solar. Descriptive research design was used. Target population was 30 industrial consumers in Nairobi Metropolitan area and three officials; a representative from Ministry of Energy, Kenya Association of Manufactures and one of the developers. The study established that energy regulations had a significant relationship with uptake of industrial solar resulting to delays, corruption and bureaucracy in implementation of energy regulations. Business model had also a significant effect towards uptake of industrial solar due to reliability and investment cost involved. Public policy awareness had a significant effect towards uptake of industrial solar and that promotion of the policy awareness was largely done by developers. The study recommends adoption of net metering, central publicly available database for industrial solar for planning purposes and need to offer affordable interest rates to investors in industrial solar with favourable loan application terms. Keywords: Uptake of Industrial solar, Financial capacity, Business model, Public Policy awareness, Net Metering. DOI: 10.7176/JETP/12-2-02 Publication date: April 30 th 2022

Analysis of Control-System Strategy and Design of a Small Modular Reactor with Different Working Fluids for Electricity and Hydrogen Production as Part of a Decentralised Mini Grid

Hydrogen is increasingly being viewed as a significant fuel for future industrial processes as it offers pathways to zero emission. The UK sees hydrogen as one of a handful of low-carbon solutions for transition to net zero. Currently, most hydrogen production is from steam reforming of natural gas or coal gasification, both of which involve the release of carbon dioxide. Hydrogen production from mini decentralised grids via a thermochemical process, coupled with electricity production, could offer favourable economics for small modular reactors (SMRs), whereby demand or grid management as a solution would include redirecting the power for hydrogen production when electricity demand is low. It also offers a clean-energy alternative to the aforementioned means. SMRs could offer favourable economics due to their flexible power system as part of the dual-output function. This study objective is to investigate the critical performance parameters associated with the nuclear power plant (NPP), the cycle working fluids, and control-system design for switching between electricity and hydrogen demand to support delivery as part of a mini grid system for a reactor power delivering up to approximately 600 MWth power. The novelty of the work is in the holistic parametric analysis undertaken using a novel in-house tool, which analyses the NPP using different working fluids, with a control function bolt-on at the offtake for hydrogen production. The results indicate that the flow conditions at the offtake can be maintained. The choice of working fluids affects the pressure component. However, the recuperator and heat-exchanger effectiveness are considered as efficiency-limiting factors for hydrogen production and electricity generation. As such, the benefit of high-technology heat exchangers cannot be underestimated. This is also true when deciding on the thermochemical process to bolt onto the plant. The temperature of the gas at the end of the pipeline should also be considered to ensure that the minimum temperature-requirement status for hydrogen production is met.

A generic GHG-LCA model of a smart mini grid for decision making using the example of the Don Bosco mini grid in Tema, Ghana

Ghana’s population is in a steady growth, which is accompanied by increasing energy demand. At the same time a significant proportion of the population lack access to the electricity grid. Within the framework of the United Nations Sustainable Development Goals (SDGs) access to energy shall be available for everyone (SDG 7). Solar Mini Grids can be used to meet this growing energy demand and give environmentally friendly access to energy in remote regions. Since Solar Mini Grids can be complex systems that require many components such as photovoltaic modules, charge controllers, cables, and battery storage it is crucial to analyze the environmental impacts of these Mini Grids considering the full life cycle. For this purpose, a generic Excel based LCA model has been created to show the optimization potentials of individual system components of Solar Mini Grids and analyze the most environmentally friendly construction. Results for the first case study at the Don Bosco Mini Grid in Tema show that the emissions are highly dependent on the technology and capacity of the energy storage as well as the utilization rate. The utilization rate describes the ratio of the consumed electricity to the produced electricity for cases where a feed in to the national grid is not possible. Therefore, it is important to design the Mini Grid and the energy storage beforehand considering local conditions in a way the environmental impact over the Solar Mini Grid life cycle can be optimized. This can be achieved by using the generic LCA model developed in this paper.

Environmental Impact of Solar Home Systems in Sub-Saharan Africa

Solar home systems (SHS) represent one of the most promising technologies for a rapid and independent electrification in those areas of Sub-Saharan Africa (SSA) without access to electricity. This study addressed the environmental impact of SHS in SSA through updated life cycle inventories and five impact categories: greenhouse gases (GHG) emissions, fossil fuels, metal and water depletion and human toxicity. Sixteen scenarios were considered, including manufacturing, transportation, recycling and user-related variables, such as the installation site, adequacy of SHS user operation and battery lifespan. The results showed that lead-acid batteries were the largest contributor to environmental impact among the SHS components, accounting for up to 36–76% of the environmental impact indicators. Apart from the components, user training for SHS operation, with the goal of maximizing usable energy and battery lifetime, proved to be critical to achieve improvements in the energy payback time and GHG emissions, which (under scenarios of high solar resources) can reach the range of 5.3–7.1 years and 0.14–0.18 kgCO2 eq/kWh, respectively. In addition, SHS GHG emission factors were benchmarked with those of other electrification approaches, such as national grids, 100% PV and hybrid PV-diesel off-grid mini grids and off-grid diesel generators. SHS achieved GHG emission factor values equivalent to PV-based mini grids in most scenarios and was strikingly lower compared to SSA national grids and diesel generators.