The Impact of Stand-Alone Systems in Nigeria’s Energy Distribution Sector and Present-Day Challenges Faced

The electricity situation in Nigeria has become alarming, with the population increasing over the years, the supply of electricity has failed to reach the demand. With over 223 million residents in the country, 95 million people lack an adequate supply of electricity. 91% of the supply is allocated to the urban areas while 30% at most reaches the rural economy due to constraints in the electrical grid. This has caused overdependence on other sources of generation such as diesel generators, and other means of generation. Using these other sources of generation has contributed to the nation’s carbon footprint and global warming. This paper aims to study the impact of stand-alone microgrids and how they could curb the electricity deficit in Nigeria, there is also a brief background on renewable energy as it forms the foundation of microgrids. This paper concludes that though microgrids could mitigate global warming and curb the country’s electricity deficit, factors such as security and management are preventing the successful implementation of these means.


Introduction
Nigeria has a land mass occupying 923,768 km2 with abundant non-conventional and conventional energy sources potential [1].Nigeria has a position as the leading oil producer in Africa, it currently holds the sixth spot among the world's largest oil consumers and has the highest possible daily generation capacity of 5.3 trillion cubic meters of natural gas,2.5 million barrels of unrefined oil, 379 million short tons of gas, and 37 million barrels of undiscovered crude oil are all estimated to be in Nigeria, but the country still depends on oil for 9% of its GDP [2].The frequent use of fuel or diesel to power generators as a result of the absence of an electrical supply has added to noise pollution.The pollutants and noise levels from the aforementioned generators produced emissions that were greater than the suggested permitted levels by the world health organization, in 2015, the world health organization made a report which confirmed that the main cause of death of 290.2 thousand people in 2012 was as a result of lower respiratory infections caused by air pollution from diesel generators [3].To promote the country's development and ensure an ecologically friendly environment, it is imperative to deliver an ample supply of energy to both rural and urban areas [4].However, this goal often needs more transmission lines and the remote location of the interconnected grid, which leads to constraints in energy distribution.[5].The anticipated energy shortfall is 170 MW, and this gap can be closed via the use of nonconventional energy sources, such as wind, hydropower, solar, and biomass [6].
In markets such as Africa and India, what is commonly referred to as a 'micro grid' in North America may be referred to as a 'mini grid'.A mini-grid is a renewable-based energy system that has a potential of 10 kW or more, while a micro-grid is also alike but its potential is below 10 kW in agreement with the Ministry of New and Renewable Energy located in India.These systems have an independent operation, but they can also be connected to the power system to trade power which in these cases are called grid-connected mini or microgrids [7].The World Bank provides a different explanation about the mini-grid system to be a medium of providing electricity to rural areas through the use of isolated generation systems, these microgrids are found to be in span from several kilowatts to numerous megawatts and can also exist in three medium which includes an on-grid operation, an isolated mode, or fused into the grid system legally [8].In this paper, the terms microgrid and mini grid are used interchangeably.
By inculcating distributed generation such as microgrids into the nation, it reduces the constraints on the national grid while still providing electricity to rural communities.It plays a significant role in the United Nations Sustainable Development Goals such as Clean Energy (SDG 7), SGG 13 known as Climate Action, SDG 3 targeted at Good Health and Well-Being and SD4 focused on improving Quality Education while lowering the nation's carbon footprint.
This paper aims to analyze the impact of renewable energy stand-alone systems in Nigeria and present-day challenges.These objectives are as follows: firstly, to understand the available renewable energy sources in Nigeria.Secondly, a review of deployed renewable energy systems in Nigeria and the impact and barriers faced in implementation.

Literature review
Due to the rising concerns about increasing climate change and the release of carbon emissions into the atmosphere, countries and researchers have done continuous research on renewable energy and how to access its potential in their own countries.Energy demand has rapidly grown over the years and while countries have been heavily dependent on conventional sources of generation such as fossil fuels, many developed and developing countries are switching to cleaner sources of generation due to continuous greenhouse gas emissions being released into the atmosphere from fossil fuels.The release of greenhouse gases into the atmosphere has caused individuals to further investigate the outcome of nonrenewable energy sources, this has also led countries to form national policies and alliances such as the United Nations Framework Convention on Climate Change of 1992, the 1997 Kyoto Protocol and the Paris Agreement of 2015 which are all concerned towards reducing greenhouse gas emissions in the atmosphere [9].
The limited supply of electricity is a growing concern, especially in rural communities in Nigeria as two-thirds of this population is found to be in this range.Therefore mini-grids have been suggested as this would serve as a more cost-effective option considering the ambiguous cost concerning restoring grids and transmission line costs [10].Furthermore, the authors in the paper [11] employed the use of the Hybrid Optimization Model for Electric Renewables to analyze several hybrid energy system concepts that rely on the unit fee of producing power, the running cost and the reduction in greenhouse gases for an Indian country.The several systems analyzed include a photovoltaic and diesel generatorbased system, only a grid-connected system, and a photovoltaic and grid-connected system.The optimal system chosen consisted of a 200 kW PV array, an 850 kW Grid, a 200 kW Inverter and a 200 Kw.It was discovered that the photovoltaic and Grid connected system was the most feasible, with it producing the lowest cost of energy, carbon emissions are at their peak in the grid-connected system but when renewable energy sources such as photovoltaic are introduced, the carbon emissions are reduced, and power shortage is met.
Table 1 shows various renewable energy systems that have been implemented currently, proposed renewable energy models and various assessments of optimum systems carried out globally and locally.

Year of Publication
Aim of research Result [12] To discuss several mechanisms to forecast energy demand for various regions of microgrid implementation They were able to establish a forecasting mechanism such as exponential smoothing to predict energy consumption in Kenya up to four months ahead of time. [13] To develop a means of electrifying developing countries in Africa through the use of microgrids.
They proposed a microgrid consisting of photovoltaic panels, storage batteries, a generator set and utility for a test bed located at the Electronic Development Institute, Anambra, Nigeria.The system also consists of an energy management system.[14] To model an isolated hybrid nonconventional energy system to provide power to a public Nigerian structure They employed the use of HOMER Pro to design a hybrid non-conventional energy system while using Evaluation based on distance from the average solution for the multiple criteria.The proposed system consists of 70 kW PV modules, 70, 3000 Ah batteries, a 20 kW diesel generating set and a 40 kW converter [15] To discuss the viability of the framework involved in transporting energy from transformers to the electric meter of the consumer and further explain obstacles that must be conquered to fastrack the energy transformation.
They were able to discover that off-grid solutions, with energy storage systems, enhance the efficiency rate of energy facilities.Bus configurations are usually used at the distribution level and the standardization rates are 48V and 380V.[16] To provide a techno-econosocial-environmental study to address challenges in sustainability in the Korean Energy Sector They employed deep neural networks to get the time series data for the country, proposed hybrid renewable energy sources using HOMER Pro then employed an algorithm to generate a renewable energy map of the country.[17] Nigeria's electrical system uses several kinds of smart grid technologies and these are addressed and analyzed in this study, along with their effects, distribution, and incorporation with the nation's conventional electrical infrastructure.
They were able to discuss the features that would aid the successful implementation of smart grid systems in Nigeria, barriers that affect its implementation and the issues the grid systems would encounter when implemented in the country.[18] To obtain a review of the applications, operations & modelling of microgrid They were able to realize that a microgrid can work on its own or in conjunction with other grids.[19] To propose a suitable size of an isolated mode of providing electricity to consumers using hybrid non-conventional energy The wind and battery system from the simulation results suggests it is the most suitable option for fulfilling the load requirements of Kano.The photovoltaic and battery system is seen to be the most suitable option for fulfilling the load requirements of Abuja.
[20] 2021 To present the design of a hybrid microgrid and perform a dynamic analysis of the suggested system.
To estimate the load consumption and climate conditions of the location, System Advisory Model software was utilized.The system proposed for the location included a hybrid of non-conventional energy sources hybrid comprising a wind turbine farm rated at 3000kW and a solar photovoltaic array rated at 1000 kWp, which was coupled with a storehouse system using pumped hydro with a capacity of 166,532 m 3 volume capacity [21] 2021 The focus of this study was to examine how graphene can be utilized in energy storage devices, absorbers, and electrochemical sensors.
The advantages of graphene oxide and graphene in comparison to other forms of carbon allotropes were also deliberated upon.These advantages comprise factors such as a large surface area, easy synthesis, high conductivity, solubility, and economical sourcing of the material.[22] 2020 To propose a form of systematic study that provides better insights into industrial and smart microgrid systems.
They were able to propose five research questions targeted to specific areas in the grid and appropriate findings in those areas such as incorporating RES and DES into working grid systems, the obstacles faced in its implementation, the regions actively conducting research in this area, the policies affecting the technology and lastly the current state of research concerning the topic.[23] 2020 The objective of this study is to employ the Genetic Algorithm and Homer Pro software to minimize energy expenses, unmet load, and total system net present value, with CO2 emissions.
The outcomes of these two techniques are analyzed and it is seen that Genetic based algorithm coupled with a hybrid renewable energy system provides the most optimal solution using fuel cells with battery, biogas, biomass, solar and wind rendering the lowest cost of energy to be $0.163 per KWH.

Year of Publication
Aim of research Result [24] 2019 To discuss the system operation of wind/biomass/diesel/battery stand-alone microgrids energy management and dispatch issues They were able to come up with an optimization strategy known as organic Rankine cycle (ORC) technology combined with biomass power plants (BPGs) which improves power generation.
[25] 2019 To model a hybrid power framework that considers heat loss and satisfies the hourly energy requirement of the place.
They employed the thermal modelling of a house in Benin City, Edo state Nigeria using Building Energy Optimization software in which they found the energy needs of the house to be (17,485 kWh), used HOMER Pro to determine the optimal energy system of the house consisting of a diesel generator and a stand-alone photovoltaic system and finally used MATLAB to test the power quality, harmonics, load impact, and voltage transients of the system.
[26] 2019 To propose a smart microgrid model that is suitable for meeting demand.
The proposed system consisted of a solar photovoltaic, battery and diesel generator [27] 2019 To design a smart grid that ensures no loss of power supply.
They used HOMER Pro to obtain an optimal solution of a smart grid consisting of a 15 kVA Biogas generator, 10 kWP solar PV, and 1 kW wind integrated with vanadium redox flow battery storage 1 kW running for six hours.To guarantee the presence of a power outage, they also used a power systems computer-aided design-based energy management system.
[28] 2019 To determine the most suitable option to provide electricity to a community called Itele in Nigeria through the use of hybrid nonconventional energy sources to satisfy the load requirements of the group.The most optimal system was discovered through the use of Hybrid Optimization for Electric Renewables.This system entails a standalone system and a partially connected system.The standalone system incurred a total net present cost of $29.9 million with the lowest carbon emission while the partially connected system incurred a total net present cost of $22.7 million offering carbon, nitrogen and sulfur emissions.
[29] 2018 To model a hybrid alternating current/direct current (AC/DC) microgrid for a community system, located on an island without connecting it to the grid later on.
They employed the use of HOMER Pro to design the most optimum system that would have the lowest Net Present Value (NPV) A power system that combines several nonconventional energy sources was proposed to meet this demand which included lead-acid batteries rated at 57 kWh, a photovoltaic array rated at 15.3 kW diesel generator rated a 17 kW, and a converter rated at 6.93 kW.The total cumulative price for this system amounts to £56,264.
Electricity is produced using basic energy sources through a process known as energy generation.This is most frequently produced at a power plant where rotating electromechanical generators are used.Combustion, nuclear fission, or other non-stationary non-conventional sources of energy, such as water and wind, are used to power the generators.The two main categories of energy generation which are discussed below:

Conventional sources of energy generation
2.1.1.Fossil fuels.Hydrocarbons vary from natural gas to coal, oil, and petroleum goods.These are classified as fossil fuels.They are primarily made of decomposing plants and animals.Because of its abundant natural resources, most developing nations, including Nigeria, are heavily reliant on fossil fuels [34].The majority of Nigerians also possess energy production equipment such as diesel generators which significantly worsens climate change and global warming in Nigeria and globally [35].The utilization of fossil fuels has far-reaching consequences, extending beyond global warming and climate change to encompass air pollution, water pollution, and the formation of smog through the release of nitrogen oxides.These environmental implications have significantly impacted Nigeria, resulting in various issues such as land degradation, landslides, and flash floods.Moreover, climate change has brought about more intense rainfall patterns, leading to damage to infrastructure such as houses, pipelines, and roads.[36].Fossil fuels have a major contribution to carbon emissions globally as shown in Table 2. Fossil fuels, including hydrocarbons, coal, and non-renewable energy waste, undergo a process called combustion when exposed to oxygen, resulting in the release of heat.This heat, in turn, raises the temperature of the water, leading to the production of steam.The motion of the steam generates

Year of Publication
Aim of research Result [30] 2018 To design a model that provides electricity to a segment of people living in St. Martin's Island, Bangladesh using nonconventional energy sources renewable The proposed microgrid system consists of a solar photovoltaic array farm, alternating current loads and a wind turbine farm with a doubly-fed induction generator.[31] 2018 To perform an assessment using economics and technology for a hybrid non-conventional energy source using thermal energy as its storehouse and solar power The simulated results using HOMER Pro showed that the levelized cost of energy for the photovoltaic-concentrated solar energy is 0.524$ per kWh system and 0.51$ per kWh for the photovoltaic-battery network.The capital cost is a critical factor for the photovoltaicconcentrated solar power system, while operation and maintenance are important factors in the photovoltaic-battery system.
[32] 2015 To model a controller-integrated system for managing energy in a power network with different energy sources.
They provided a system to regulate energy for a model using photovoltaics, wind power, biomass gasifier and a battery set-up using Matlab/Simulink, they also used a fuzzy logic controller to maintain the battery state of charge.
[33] 2009 To review battery energy storage systems and discuss their impact on power systems.
They identified various types of battery energy storage devices which include Metal Air, Flow Batteries Lead Acid, Sodium Sulphur and Lithium-ion and they provide ancillary services, balance renewables etc kinetic energy, which is harnessed to rotate the turbine's rotor.As the rotor spins, it generates electrical energy but due to factors such as declining investments, oil theft, and sabotage, Nigeria's oil production -the largest in Africa -has decreased by 38% since 2010, reaching 79 Mt in 2021, which represents a 22% decline since 2019.Although there was a slow increase of 3% per year from 2016 to 2019, following a 14% drop in 2016, attacks on oil and gas infrastructures were partly responsible for the fluctuation.To offset this decline, Nigeria is emphasizing the exploitation of fields situated in deep and very deep offshore locations.The majority of the country's oil production is exported, with 92% of it being exported in 2021.The primary recipients of Nigerian crude oil exports by value in 2021 were India (20%) and Spain (13%).The energy demand of the country is increasing at a very expedient rate while crude oil production has reduced over the years [37].This is what led to an interest in further ways of meeting the ever-increasing energy demand of the nation.[4] examined the frequent use of Nigerian remote diesel generators' noise and pollution levels.where it was established that 60% of Nigerians have no direct contact with the power supply, with the remaining 80% producing between 8,000 and 14,000 MW of electricity individually using their own utilizing diesel generator and solar inverters.According to [4] the nation uses over 60 million generators, with an estimated N3.5 trillion in fuel expenses annually.Nigeria presently imports more diesel and gasoline-powered electric generators than any other country in Africa.
Excessive and repeated exposure to this has resulted in various health issues, including heart and breathing problems, eye irritation, nausea, fatigue, headache, dizziness, unconsciousness, and even fatalities of people staying in that particular area.

Gas.
Nigeria is fortunate to possess significant natural resources as a country.As of January 2013, Nigeria boasted the ninth-largest proven gas reserves globally, estimated to be around 187 trillion cubic feet (Tcf) (EIA, 2013) [38].Nigeria's natural gas has a predominant methane content of approximately 90%, accompanied by carbon dioxide ranging from 1.5% to 2.0%.It also contains ethane within the range of 3.9% to 5.3%, propane ranging from 1.2% to 3.4%, heavier hydrocarbons between 1.4% and 2.4%, and trace amounts of sulfur, as noted in a study by Delta and Udo in 2013.Despite its low sulfur content, which classifies it as "sweet," natural gas flaring in the Niger Delta region produces sulfur dioxide (SO2) as one of its byproducts, as revealed by research on flaring operations [39].Methane, an essential fuel source found in coal beds and methane clathrates, is interconnected with other hydrocarbon fuels.Natural gas, predominantly a non-renewable fossil fuel, originates from the decomposition of ancient sea animals and plants that occurred more than 300 million years ago (The NEED Project, 2017) [40].When these organisms perish, they sink to the ocean floor and become covered by layers of sediment, eventually forming rock over an extended period.As time passes, the sedimentary rock accumulates, subjecting the energy-rich remains of these organisms to immense pressure.The combination of high pressure and heat within the Earth causes chemical transformations in the organic matter, resulting in the formation of gas and petroleum.Gases become trapped within the layers of rock.
Notably, gas, known for its clean-burning properties, is abundantly available in Nigeria.Nigeria is capable of generating about 11,788 MW of electricity from gas power stations in Nigeria, but the gas produced in the country is not fully utilised for power production because most of the gas produced is exported [40].

Non-conventional sources of energy generation
To ensure a sustainable [41] future and environment, organizations and the government began making conscious efforts to replace fossil fuel energy sources with renewable based energy sources such as hydropower, geothermal energy, bioenergy, wind, and ocean energy due to the release of greenhouse gases and global warming.This motivation led to the development of sustainable development goal 7 on affordable and clean energy and sustainable development goal 13 targeting climate change.[42].The efforts to inculcate renewable energy sources into the national grid system have had a slower growth rate in recent years [37].

Solar energy.
Nigeria has an inexhaustible supply of solar energy as a green energy source, with an intensity of solar radiation in the span of 4000 W h/m2 in the southern belt to 7000 W h/m2 in the far northeast [43], with an average load requirement being 2324 W h/m2 /day, solar radiation varies from the northern to the southern regions but is stronger in the north-eastern axis [44].According to estimates by experts, if solar PV panels are placed strategically on only 1% of the land area in Northern Nigeria, they can generate and utilize 207,000 GWh of electrical energy per annum.This amount is comparable to approximately 4.6 million barrels of oil per day, as reported by Heinrich Boll Stiftung, Nigeria.This represents a favourable and advantageous situation [10].At an average solar irradiation of 5.535KWh/m2 per day, Nigeria has access to a significant potential for solar energy.The vast Sahel Savanna region offers a considerable expanse of land for a solar project.If covered adequately with solar PV panels over an approximate radius of 3000 kilometres, this area could generate 6000 Mega Watts of power.The experts also suggest an off-grid solution, where one million homes in Nigeria could have a 1000W solar power system installed on their rooftops, which could result in a total power production output of 7000MW, a figure that is in proximity to the enormous target set by the present administration known as Vision 30:30:30 to generate 9,000MW of renewable energy.This is a valuable opportunity for leapfrogging, especially considering the suboptimal condition of the country's on-grid network and transmission lines and the nation's grid framework [45].There are chances for using solar energy as a renewable energy source in the country, according to studies that have been done assessing its potential in the nation [46].Solar PV has the technological advantage of requiring relatively lower amounts of input, cost, manpower, and resources compared to other renewable energy sources such as geothermal, wind, biomass, and hydropower as reported by [47].This is particularly beneficial for Nigeria, an emerging and developing economy with limited experience in infrastructure technology and the intricacies involved in acquiring, installing, utilizing, and maintaining equipment.

Wind energy.
Whereas hybrid systems combining solar and wind energy have also been realized, wind energy systems have been developed in regions of the world like several locations in Asia, Europe and America.The marketing strategies implemented by the Energy Commission of Nigeria will determine how successfully these energy sources are implemented in the country.Wind power generation has not been used in the country due to a lack of government backing and inadequate knowledge.According to [43] wind energy has the potential to boost national economic growth rates by 7% and 13%, respectively.in both dry and rainy seasons, the mean wind speed in various states of Nigeria was nothing less than 3 m/s and had a maximum value of 8 m/s old [48].At present, the use of wind power in Nigeria is restricted to a handful of water pumping operations, some of which have been deserted.In Sokoto state, specifically in Sayyan Gidan Gada, there is a 5-kW wind power generation system.However, it is worth noting that there are several inoperative projects in northern Nigeria.The wind power potential of the country is being examined to determine the capacity of wind power to generate electricity for Nigeria, and they generally concur that the capacity energy produced from wind in Nigeria ranges from poor to moderate [49].Amongst all the renewable energy sources, wind energy stands out as a highly efficient source but can only be harnessed in areas with high wind speeds.Despite increased global investment in wind farms, African countries have not made significant investments in wind energy technology or its utilization.In contrast, countries such as the United Kingdom [50], China [51], Belgium and Germany [52], and the United States [53] use wind energy for electricity generation.In a paper [54] the Global Wind Energy Council in 2011 observed that the worldwide deployed capacity of wind power had reached a significant milestone such that it increased from 6,100 MW in 1996 to approximately 237,669 MW in 2011.While countries in North Africa, such as Tunisia have an installed capacity of 114MW, Egypt has an installed capacity of 550MW, and lastly, Morocco has an installed capacity of 291MW, they have all made significant contributions to wind energy generation [54], but progress in sub-Saharan Africa has been relatively slow.The authors in the paper [55] analyzed daily time wind series data for offshore communities in Koko located in Warri, Abonemma located in Rivers state and Victoria Island located in Lagos using three statistical models -Weibull, Rayleigh, and Exponential distribution.This analysis was carried out for 10 years spanning from 2002 to 2011.The study determined that the annual average wind speeds for Abonemma, Victoria Island, and Koko were 7.29,6.25,7.32, m/s, discretely, while the annual mean wind power densities were 171.47, 240.43, and 237.60 W/m2, respectively.The wind speeds having the highest energy destiny were seen to be 8.96,7.43,and 8.37 m/s discretely.Based on the analysis, it was concluded that the variety of wind speeds for the three sites was appropriate to generate power.A site housing an annual wind speed of 5m/s or more is required for large wind speed installation [56].

Biomass energy.
The term "biomass" refers to plant-based materials such as wood, agricultural waste, and household, commercial, and industrial waste."Bioenergy" is a renewable energy source that is generated from these microbial sources and is used to produce electricity, heat homes, businesses, and power vehicles.Biomass is discovered to be in the third rank of the world's third-largest principal energy source after coal and oil [57].It includes all organic matter from plants and animals that can be utilized for energy production and can be categorized into agricultural sources, forests and their by-products such as animal excrement and city waste.Heat, electricity or biofuels are sources of energy gotten from biomass energy sources after they have passed through modern technologies such as hydrolysis, pyrolysis etc.These modern technologies ensure higher efficiency and reduce air pollution [58].In recent years, both developed and developing countries have increasingly prioritized utilizing biomass as a source of power generation.As seen in [57] this has led to a widespread recognition of biomass as a viable renewable energy source, with Brazil at the forefront of this trend.Nigeria also has a wealth of sustainable bioenergy resources that can be utilized for power generation.[59] did a study in Nigeria and it was discovered that the country can generate 2.01 EJ (47.97 MTOE) of energy from the 168.49 million tons of agricultural waste and the residue it produces yearly.[60] in which the potentials of biomass and solar energy were accessed for Kaduna state in Nigeria.

Micro Grid
A small group of electricity network users with a local source of supply is usually called a microgrid.This microgrid is usually attached to a consolidated national grid but can operate autonomously if needed.It is a set of electricity networks which generates electricity closest to its place of consumption.
The international energy agency estimates that 350,000 mini grids would be needed to provide universal access to power at the lowest possible cost.The majority of small grid solutions typically use solar, or wind power supplemented by batteries and diesel generators to offer continuous electricity [61] When utilized as a stand-alone system, Microgrids (MGs) offer avenues to integrate Renewable Energy Sources (RESs) into distribution networks and supply power to isolated rural regions [62].
The solution to Nigeria's inconsistent power supply lies in the digitization of its power system, which has necessitated the implementation of a grid such as a smart grid as well.This is a grid that has a bidirectional form of communication that's backed up with the use of digital technology.It is a resilient power framework which efficiently integrates all linked components by operating at the same frequency or acting in synchronism to improve all connections of everyone present in the power framework [63].Bi-directional communication capabilities of the smart grid enable remote control of equipment and data collection devices.Its automated device management technology and support for informed decisionmaking by stakeholders are key features [64].

Barriers associated with implementing microgrids in Nigeria.
The power generation industry confronts a variety of obstacles, which include the utilization of outdated machinery and instruments, unregulated maintenance of facilities, and insufficient power output [65].Nigeria's installed electricity generating capacity is around 13 gigawatts (GW), however, due to gas shortages, only approximately half of this capacity is operational.Due to these restrictions and insufficient infrastructure, the installed producing capacity is currently 64% lower than the real generation potential of 7 GW.In 2018 The Power Sector Performance Survey, the industry incurred losses of NGN 51.519 billion in September 2018 in the transmission and distribution lines due to a shortage of gas supply, which adversely impacted power supply in conjunction with infrastructure restrictions.7 gas-fired generating stations in remained inactive in June 2019, resulting in a significant decline in the average on-grid power generation to about 3.4 GW from the peak generation of 5.4 GW in February 2019 [27].

The lack of concern, insufficient knowledge within society, awareness-raising, and collaborations.
Awareness in a community is one vital factor in introducing renewable energy sources into a community, if the community in which a microgrid is to be situated has no prior or fundamental knowledge as to what a microgrid is, there would be negative acceptance of present or further installation going on.The authors in this paper [10] carried out an informal survey in Oyo state which shows that an average Nigerian lacks awareness about the concept of Renewable Energy, the benefits of renewable energy and most importantly the ability of renewable energy to provide an alternative power supply for the community.This is the driving force behind this lack of concern as only a few government officials, policymakers, and energy consultants make the most noise about renewable energy sources in Nigeria today, while the average citizen, who is the main beneficiary and consumer, contributes little or nothing to the discussion.Creating a policy or plan in isolation without involving stakeholders such as youth, activists, civil societies, media, educational institutions, remote regions, non-profit groups, and prospective shareholders would hinder collaboration and project ownership.This is because the knowledge and understanding required to appreciate and participate would be lacking.To address this issue, raising awareness is not solely the government's responsibility.Citizens who recognize the advantages of renewable energy for our nation can also play a vital role by assuming responsibility and spreading awareness within their communities, among their fellow students at school, and among their friends.Additionally, the government can organize seminars and conferences to raise awareness among citizens, thereby encouraging their acceptance of the transition to new energy sources.
3.1.2.Acts of cybercrime, theft of infrastructure, and terrorist activities.Cyber-attacks are worldwide situations that affect nations, businesses, organizations, security services, and infrastructure, and can cause harm to the smart grid's computer programs and physical control systems.Electricity can be stolen majorly in two different ways in Nigeria such as meter tampering which is known as being directly connected to the grid through the distribution lines and inserting various objects into rotating disks to cause inaccurate readings of the energy meter [66].They are more ways in which electricity theft has contributed to the ₦30 billion that's lost monthly by the Distribution companies [67] such as formatting the readings of the meter, stealing electricity cables, destroying the power infrastructure and lastly corrupt utility employers collecting money illegally from consumers to connect them directly to the grid [68].Due to their dependence on information technology, microgrids, and smart grid are susceptible to cyber threats [69].An estimated 445 USD billion is used worldwide each year to fight cybercrime [70], but many developing countries like Nigeria allocate little to no resources towards countering cybercrime.Therefore, the implementation of standalone systems in Nigeria must include well-structured cybersecurity measures to ensure a secure and resilient system [71].To address this issue effectively, it is crucial to prioritize the implementation and enforcement of laws and regulations to combat electricity theft in Nigeria.Although laws on electricity theft, such as Section 94 (3) of the Electric Power Sector Reform Act and the draft of the Nigerian Electricity Regulation Commission's Electricity Theft [68], already exist, their weak enforcement has allowed electricity theft to persist in the country.Furthermore, introducing smart grids integrated with demand response and smart meters can serve as an additional measure to curb the misappropriation of electricity.This would minimize the need for manual readings, reduce instances of theft, and enhance transparency within the system.

Corruption.
Corruption is a prevalent issue that has set Nigeria back compared to other countries.It has had a destructive impact on all aspects of Nigeria's economy, including the power sector.The power industry has experienced various instances of corruption, leading to widespread outcry [75].In many countries, including some developed nations, corruption has become a pervasive issue among government officials and influential individuals in the private sector.This problem also exacerbates theft, and implementing strict government penalties against corruption could facilitate the deployment of renewable energy-connected grid systems [71].To address this issue, mediums such as Enhancing Transparency and Accountability and Strengthening Regulatory Frameworks could be implemented.Enhancing Financial Management and Audit includes implementing sound financial management practices such as having regular audits of power sector finances and operations.This helps identify and address financial irregularities, mismanagement, and embezzlement while Enhancing Transparency and Accountability including implementing measures to improve transparency and accountability in the power sector.This can include publishing regular reports on project contracts, expenditures, and outcomes, ensuring public access to relevant information, and establishing mechanisms for oversight and scrutiny by independent bodies and civil society organizations.

Impact of standalone systems in Nigeria.
Various renewable energy sources are available in Nigeria for the generation of electricity as seen in the previous section.Photo-voltaic panels which utilize solar energy are mostly used as stand-alone systems in Nigeria [76].Other renewable energy sources available in Nigeria have many limitations as compared with Solar such as hydropower needing large bodies of water such as rivers and waterfalls.Utilization of biomass leads to the felling of trees, soil erosion and also food competition and wind energy has inconsistent nature of wind speed ranging from 3 m/s to a value of 8 m/s [48].The majority of studies carried out on the impact of the standalone system considered mostly solar energy as little research is carried out on the impact of other renewable sources in Nigeria.The following are various impacts of mostly solar-installed stand-alone systems.

Improved standard of living.
Deploying these technologies in Nigeria could significantly improve their standard of living.Access to energy has the potential to accelerate development, resulting in better living conditions for rural communities.This, in turn, could dissuade rural residents from migrating to urban centres in search of better opportunities.It is widely known that people migrate to cities mainly to improve their standard of living, but once the same amenities they seek in urban areas are provided in rural areas, they may be more inclined to remain and engage in productive activities.It is important to note that the cost of living in rural areas is significantly lower than that of urban centres [77].

Increase in Health Care
Services.Improving rural healthcare services is a critical national and global priority.Although health is considered to be wealth, Nigeria faces significant challenges in providing adequate electricity to support proper rural health services.As a result, the utilization of nonconventional energy options has the potential to improve the provision of essential healthcare services and vaccines in remote areas.Renewable energy can power a range of equipment and devices, such as lighting, fans, solar refrigeration, radio and telecommunications, medical appliances (such as microscopes, centrifuges, nebulizers, and oxygen concentrators), sterilization equipment, and water treatment systems for healthcare centres.Solar photovoltaic (PV) technology can serve as a reliable source of energy to power DC refrigerators that are crucial for storing vaccines and medications that require specific temperature conditions.Furthermore, sterilization can be carried out using renewable energy sources [78].

Generation of revenue.
In cases where the government permits the concept of allowing community-based microgrids to consume and produce electricity at the same time, there is a generation of revenue.Households equipped with solar PV systems can function not only as electricity consumers but also contribute their surplus electricity to the microgrid.Such parties that both produce and consume electricity simultaneously are referred to as prosumers, and they can monetize the excess electricity they provide [7].In a paper [7] they proposed a medium of providing electricity to the business community via solar energy and He shares that the government can support the model presented in the paper such that households equipped with solar PV systems come together to create a solar home system-based microgrid system, they can function as a Generating Company (GenCo) and receive similar benefits previously exclusive to privately-owned GenCos that generate power from ground-mounted photovoltaic plants that require a vast land area.In cases where solar home systems-based microgrids can benefit from the government's proposed commitment to purchase surplus power generated, it would be advantageous.This is especially beneficial for generating stations that are stationed in the city as they have a direct connection to greater rates charged for their buy-back rate.It's worth noting that the wholesale contract prices for GenCos utilizing feed-in tariffs for electricity generated from photo-voltaic plants are consequentially more than those for other conventional energy sources [79].

Education.
The education sector can benefit from renewable energy technologies as well.To enhance the education of rural residents, hybrid renewable energy systems could be introduced to familiarize them with computer use and related devices in information technology.Solar photovoltaic (PV) systems can be utilized to power computers in schools as this would even lead to the establishment of cyber cafes in rural areas.Furthermore, placing solar PV technology in schools is an effective way to raise energy awareness within a community.Since schools are central locations for community gatherings, installing a renewable energy project in such a centralized location can enhance the profile of renewable energy and promote conservation in general [64].

Relationship between standalone systems and the gross domestic product (GDP) of a nation.
The utilization of non-conventional energy sources could positively grow the Nigerian economy.The authors in [80] utilized the value-at-risk methodology and the Johansen test to examine the causal connection between electricity consumption and economic growth in Nigeria.Their findings indicate a positive relationship between economic growth and electricity consumption in the long run.A statistical approach called a Granger causality test examines the antecedent existing among elements in a time series, and it provides the contingent description of the antecedent by analyzing empirical data sets to identify particular trends in complementation.The authors in [81] employed the Granger test in the Nigerian context, revealing the one-way sporadic alliance between electricity use and the development of the economy.In light of these results, the authors advised that there should be an increase in power demand, as well as the use of alternative power sources to enhance the competitiveness of the national grid and promote economic growth.They went through a bivariate analysis to examine the relationship between the growth of an economy and consumed electricity in Nigeria.The authors in the paper [82] arrived at a comparable outcome.Their research demonstrated that electricity consumption has a positive correlation with real gross domestic product in Nigeria in the long run.

Conclusion
There is vast potential for abundant renewable energy sources distributed around the world, depending on the geographical location of each nation.The continuous use of fossil fuels creates an over-reliant system on the consistent need of extracting crude oil which also harms the environment as well.
Developed countries and developing countries have leaned towards the renewable energy area but due to a lack of policies and cognizance, implementation of non-conventional energy sources implementation in Nigeria still requires a lot of structuring.Distributed generation such as mini-grids hybrid mini-grids, microgrids and smart grids pose a better alternative to centralized distribution systems as it reduces the restraints imposed by the transmission network.In addition, further investigation should be done on accessing the potentials of microgrids in different parts of the world to assist developers in implementing on-ground solutions and the government needs to create more efforts to raise awareness concerning necessary stakeholders.This paper also addresses barriers associated with implementing renewable energy systems and their impact as well.Several constraints exist in this paper which provoke ground for future inquiry as to how the gross domestic product of a nation correlates to the implementation of the grid systems in African countries as well as other grid systems which have been implemented in various countries as well.

Table 1 .
Comparative result of distributed generators.
2.1.2.Diesel generators.To provide the immediate need for electricity demand, diesel and gasolinepowered electric generators are now often used around the country.Around 16TWh of power was provided by generators in sub-Saharan Africa in 2012, with nearly 75% of that energy being used in Nigeria.The authors in paper