Techno-Economic Assessment of Renewable Hybrid Systems for Rural Electrification and Distributed Generation in Selected Sites across Nigeria

The study considered the potentials and economic feasibility of solar and wind energy resources for rural-electricity and distributed generation from six selected sites of Nigeria. Remote communities cut off from the central grid and made up of 200 homes, a school and health centre were conceived a site per geopolitical zone was investigated. A specific electrical load profile was then developed to suite the rural communities. In view of this, the design that will optimally meet a daily load demand with 1% LOLP was carried out by considering standalone PV, Wind and Diesel systems design, as well as a Wind-PV hybrid system design. Further to this, an analysis covering the same sites was carried out to determine the commercial viability of generating and distributing electricity in the Megawatt range via distributed generation. The 24 years’ (19872010) solar, wind and other meteorological data utilized in this study was obtained from the Nigeria meteorological centre, Oshodi. The results of the study revealed that wind standalone system is the most economically viable substitute for power generation at most of the sites with costs ranged between $0.129/kWh and $0.327/kWh for Jos and Benin City respectively. More so, a huge potential for profit making by willing investors in line with the present tariff order for wind and PV distributed generation was discovered with all sites being viable on both configuration. The optimum LCOE for distributed generation ranged between -$0.021/kWh and $0.158/kWh for PV distributed generation in Iseyin and Maiduguri respectively. This is very much competitive with grid electricity. Thus, renewable electricity could be adopted and included into the federal rural development strategy, thereby reducing the energy deficit being experienced in Nigeria.


Introduction
Access to modern energy supply is requisite to sustainable development.However, a population of about 1.3 billion people worldwide are deprived of access to electricity and over 2.6 billion people worldwide rely on traditional biomass for cooking and heating.More so, between 2011 and 2013, access to sustainable electricity generation remained static in growth rate.Although, some countries like those of the Latin America and certain Asia made great leaps forward, other regions fell largely behind, with India regressing in the number of people with access to electricity by 17 million.Half of the world's population without access to electricity reside on the African continent (Renewables Global Status Report, 2014) In most remote communities of developing nations, connection to the central electric grid is usually prohibitive due to its noneconomic viability.Moreover, the major use of energy in these rural communities is for heating and cooking purposes.Such energy resources are derived from repeated biomass burning.The byproducts of such burning have been found to be deleterious to both humans and the environment.Based on this, renewable energy systems (RES) present an exceptional prospect to hasten the transition from deleterious biomass based energy supply to modern energy services in remote and rural areas.It has the potential of escalating access to sustainable energy for cooking and heating, inexpensive lighting, communications, food preservation, improved public health, and also for agro-processing and other productive activities.
The conventional electrical power system model in use in Nigeria involves a system that mainly revolves around centrally generated electrical power and a massive system of transmission and distribution networks.Albeit, this system has been in use for many decades and the shortcomings associated with these model has led to economic volatility as well as diverse threats to public health (Walker, 2008;Wustenhagen, et al 2007;Rogers et al, 2008;Bayod-Rujula, 2009;Clark & Eisenberg, 2008).Moreover, the conventional systems are decrepit and outmoded, ineffective, and regularly strained, resulting in high utility fee variations payable by the general public (Ipakchi and Albuyeh, 2009;Mamo et al , 2009).Thus, to gradually shift emphasis from centrally generated electricity that operate on deleterious fossil based generation systems to RES, there would be the need to establish and strengthen institutional, financial, legal, and regulatory support mechanisms for renewable energy deployment must.Once established, these mechanisms will help improve access to financing, growth in necessary infrastructure, and increased awareness about renewable energy.Some of these mechanisms have been put in place in Nigeria.One notable policy thrust, is the positive feed-in tariff law on wind and solar electricity enabling.It enables consumers deliver additional green energy to a mini-grid network at prices higher than that of network electricity (Ohijeagbon and Ajayi, 2015).The regulation describes a form of generation where excess renewable energy generated by a consumer above the 1 MW mark may be sold to a nearby minigrid system at prices higher than grid electricity.These feed-in tariffs are captured under provisions for embedded (distributed) generation as presented in the multi-year tariff order for 2012-2017(Nigerian Electricity Regulatory Commission, 2012; Overview of the NERC regulations, 2012).Therefore, willing investors may take advantage of this regulation in order to provide cheap access to electricity at rural communities and also help to meet the Millennium Development Goals (MDGs) while also sustaining themselves as profitable ventures through proceeds from sales to a mini-grid in proximity of the rural communities.
Therefore, this study offers a design approach that will establish the potentials and economic feasibility of solar and wind resources for rural-electricity and distributed generation for six selected sites of Nigeria.A site per geopolitical zone was considered.
Rural communities unconnected to the national grid and made up of 200 homes, a school and health centre were considered.A specific electrical load profile was then developed to suite the rural communities.Further to this, an analysis covering the same sites was carried out to determine the commercial feasibility of generating and distributing electricity in the Megawatt range via distributed generation.

Potential of Renewable Energy Resources in Nigeria
A number of indigenous researchers have studied the potential of Renewable Energy (RE) resources in Nigeria in view of demonstrating their viability in the country.Onyebuchi (1989) projected the technical potential of solar energy in Nigeria by means of a device with 5% conversion efficiency.The study concluded that 15.0 × 10 14 kJ of useful energy can be generated annually.Chineke et al. (2008) disclosed that Nigeria receives copious supply of solar energy that can be valuably harvested.The yearly average daily solar radiation was evaluated to 5.25 kWh/m 2day, with specific values ranged between 3.5 kW h/m 2 -day, in the coastal regions of the south and 7.0 kWh/m 2 -day at the northern boundaries.Mean duration of sunshine hours within the country was estimated at 6.5 hours with yearly average solar energy intensity being 1,935 kWh per m 2 per year, which approximately equals 1,770 TWh of solar energy retrievable on a yearly basis.This is roughly equivalent to a multiple of 120,000 of the total annual average electrical energy produced by the Power Holding Company of Nigeria (PHCN) prior to privatization (UNDP, 2012).It is therefore reasonable to integrate solar energy in the nation's energy mix.
A number of research reports present the potentials for wind-to-electricity projects in Nigeria.For instance, Adekoya and Adewale (1992) looked into wind speed data of 30 stations in Nigeria and found the annual mean wind speeds and power flux densities to fluctuate between 1.5 -4.1 m/s and 5.7 -22.5 W/m 2 respectively.Fagbenle and Karayiannis (1994) also studied the 10year wind data from 1979 to 1988 taking into cognizance surface and higher winds as well as upper limit of guts.Ajayi (2010) hinted that inland, the wind is superlative in mountainous regions of the North, while moorland topographies of the middle belt and northern precincts of the nation have enormous prospect for massive wind energy production.Mean wind speeds in the north and south were revealed to lie between 4.0 − 7.5 m/s and 3.0 − 3.5 m/s respectively at 10 m height.In view of the above, most researchers concluded that wind energy is principally of excelent abundance in core northern states, the hilly and mountainous parts of the central and eastern states, and also the country's offshore areas (Adekoya et al, 1992 These information points to the fact that, Nigeria is richly endowed with huge natural supply of solar and wind energy resources and has good prospect for improved sustainable electricity production.Nonetheless, the energy need of the populace in remote areas is still centered on traditional biomass (Ajayi et al, 2010) because this group of fuels have been discovered to supply more than 50% of total energy usage in Nigeria (National Energy Policy, 2003).In furtherance to this, the disparity in fuel wood supply and demand in many remote locations is now a threat to the energy security of these communities  (Ajayi, 2010).Hence, a diversification of the nation's energy mix is cogent if the country is to achieve its target of energy security by the year 2020.This is with the clear understanding that RE resources has the advantage of being employed as a standalone facility besides its potential for grid connectivity.

Present Work
In Nigeria, only a few research studies subsist depicting the prospect of hybrid RE system for power generation (Nwosu et Agajelu et al, 2013).These were also only focused on small scale generation for remote telecom applications and also for individual buildings.Research studies on the design and economic viability of hybrid systems that can provide sustainable power for remote communities are uncommon.More so, those that capture distributed generation analyeis for potentially viable sites in Nigeria are very rare.Part of these includes the study by Ohijeagbon & Ajayi (2014).It focused the prospect and economic viability of standalone hybrid systems for rural community utilization and distributed generation at a site in Northwest Nigeria.The results revealed that distributed generation was viable for wind and PV systems rated above 7.5MW in Sokoto.This study therefore focused on the techno-economic assessment of hybrid RE for rural electrification and distributed generation in six selected sites across the geopolitical zones of Nigeria.The sites are spread across the country.

Data Collection
The twenty-four years (1987 -2010) daily global solar radiation, daily wind speed data, sunshine hours, minimum and maximum air temperature, and minimum and maximum relative humidity that were employed for this research were supplied by the Nigeria Meteorological agency (NIMET), Oshodi, Lagos, Nigeria.The solar radiation data employed for a few of the sites were consequent upon the model proposed by (Ajayi et al, 2014).This was as a result of inadequate data for some sites.The location parameters of the selected sites are as presented in Table 1.Wind turbines ranging from two to four 25 kW turbines, with single 3MW turbines in series were optimally designed for community utilization and distributed generation respectively.The cumulative solar panels employed ranged between 105 kW & 190 kW for community utilization with optimal solar arrays ranged between 25MW -35MW for distributed generation.A diesel generator of 35 kW was utilized for the study covering conventional power systems for the communities.An econometric analysis of the diesel system is presented in Table 2.
RETScreen ® software was used as a feasibility tool.This software receives average air temperature and relative humidity, which is significant, owing to the dependence of PV module efficiency on close by air temperature and relative humidity (RETScreen 4 Software, 2013; Omubo-Pepple et al, 2013; Skoplaki et al, 2009 ;Fesharaki, 2011).Also, most cell types show evidence of a reduction in efficiency as their temperature rises, while an increase in relative humidity has been found to act in such a way as to diminish the magnitude of solar radiation retrievable ( Consequently, each home is estimated to consume as 1.4kWh/day, based on the analysis of Tables 3 and 4, with a calculated primary peak load value of 46 kW.Fig. 1 presents the 24 hours hourly load profile for the communities.

Description of the solar radiation algorithm
The solar radiation algorithm utilized is described as a progression of three basic steps presented in the figure below (see Figure 2) (

Calculation of Hourly Global and Diffuse Irradiance
Solar radiation can be considered to be of two parts: beam radiation, and diffuse radiation.Therefore, the tilting algorithm utilized, uses the knowledge of beam and diffuse radiation for every hour of an average day.

PV Array Model
The model created by Evans served as the PV array model (Evans, 1981).

Wind Energy Model
Since weibull probability density function (WPDF) has been found to significantly fit with experimental long-term distribution for various sites (Ajayi et al, 2011), the wind speed profile characterization and analysis for each site was carried out using the WPDF.

Cost Benefit Analysis
Economics plays a critical role in selecting potential energy sources.Renewable and non-renewable energy sources have proven to be very diverse in cost characteristics.Renewable sources are usually higher in initial capital costs and low in operating costs, while conventional non-renewable sources usually tend to be vice-versa.The life-cycle cost (or NPC) analysis consists of, costs of initial construction, component replacements, maintenance, fuel, cost of buying power from the grid, and miscellaneous costs.On the other hand, revenues include, income retrieved from sales to the grid, in addition to any salvage value occurring at the end of the project lifetime.When evaluating the NPC, costs are taken as positive and revenues are seen as negative.Therefore, a negative NPC value signifies a net present value (NPV).
The annualized cost for each component is made up of, the capital, replacement, maintenance, and fuel costs, as well as salvage value and other costs or revenues.Further to this, the annualized costs are summed for each component, plus any miscellaneous costs, thus resulting in the total annualized cost of the system.The total net present cost is: , = total annualized cost, the project lifetime, and CRF( • ) is the capital recovery factor, given by the equation: where, i, is the annual real interest rate (the discount rate) and N is the number of years.
The annualized capital cost of each component is evaluated as follows: To determine the annualized replacement cost of a system component, the salvage value at the end of the project lifetime is subtracted from the annualized value of all replacement costs that occurred throughout the lifetime.It is noteworthy that the annualized replacement cost may be negative since it includes the annualized salvage value.
Each component's annualized replacement cost is evaluated as follows: ( ' , is a factor that takes into account the fact that the component lifetime can be different from the project lifetime: ' , the duration of replacement cost, is given by: Where, INT ( ) is the integer function, that returns the integer part of a real value.
The salvage value S of each component is given by:

7
'* , is the remaining life of the component at the end of the project lifetime: The sinking fund factor is a ratio used to calculate the future value of a series of equal annual cash flows and it is given as; The total O&M cost is a sum that comprises of: the system fixed O&M cost, any penalty for capacity shortage and penalty for emissions (if any).
The total annual O&M cost is given as: The capacity shortage is calculated using the following equation: where: ? $> = capacity shortage penalty ($/kWh) @ $> = total capacity shortage (kWh/yr) Therefore, the total annualized cost is: The levelised cost of energy (LCOE) is therefore: Where, , is the total annualized cost, @ * and @ <': are the total amounts of primary and deferrable load, respectively, that the system serves per year, and @ J <,> 9'> is the amount of energy sold to the grid per year.

Specifications of Wind Turbines and Solar Panel Used in this Study
PGE turbines (HOMER Software, 2013) were cumulatively utilized for this research to study the wind standalone system (WSS), each having the specification indicated in Table 6, while the Enercon turbine is employed for edistributed generation.
It is noteworthy that when revenues from the project far surpasses other incurred costs, i.e. *, 9 (the annual operating cost of the project), and the summation of ( $ , 9 + ' , 9 ).It results in a negative total annualized cost, that reflects in a negative LCOE which is termed levelised value of energy (LVOE) (Ohijeagbon & Ajayi, 2015); which reveals the profitability of the project from an investors' stance.Hence, where: Vc = cut-in wind speed, VFi = low wind cut-out speed, VFo = high wind cut-out speed, VR = rated wind speed, PeR = rated power at rated wind speed.shows that the solar radiation profiles for all sites in Nigeria can be grouped broadly in two, namely; Northern Nigeria and Southern Nigeria, with very eristics within each group.The similarity in characteristics is a result of similar weather and climatic conditions within the same geographical region.
Taking into consideration the hours equaled or exceeded for a series of mean measured solar radiation (Fig. 5) across the studied period, the study revealed that the corresponding power generated for each site from the designed PV array is between about 49.2% -51.1% of the hourly duration in a whole year.This however is due to solar radiation occurring only at daytime, unlike wind speed.Hence, Iseyin has a twenty four year average sunshine daily duration of about 5. 46  ) across the studied period, the study revealed that the corresponding power generated for each site from the designed PV array is between 51.1% of the hourly duration in a whole year.This however is due to solar only at daytime, unlike wind speed.Hence, Iseyin has a twenty four year average sunshine daily duration of about 5.46 hours, while Jos has 7.33 hours.correlates the annual average solar radiation and PV module size for the 6 sites studied.Upon analysis, it was found that a good correlation subsists between incident irradiation and PV size.This relationship was observed to be inverse in y between the two quantities, with the PV requirement growing with decline in solar radiation intensity.This can be attributed to the prevailing weight of daily global solar radiation on the sizing of photovoltaic systems.unequivocally gives rise to an excess in energy generated annually when the period of higher sunshine duration is balanced with those of lower duration over an entire year.This excess can easily be harnessed in the form of generation known as embedded generation, which is defined as a form of generation where excess renewable energy generated by a consumer above 1 MW may be sold to a nearby distribution network (Overview of the NERC regulations, 2012; Multi-Year Tariff Order, 2011).This sales to the grid have the advantage of reducing the LCOE, as revealed by equation 13.It is also noteworthy that the excess may not be sold to the grid at all times, as it will be wasted when lower than 1 MW, if the optimum battery capacity by design could not take care of this excess.The battery specification employed in the study is presented in table 9.It reveals the optimized rated capacity (or nominal capacity) of the battery, which is the amount of energy that could be pulled out from it at a particular constant current, starting from a fully charged state.The life cycle cost (NPC), which captures all the cost all through the operational life (25 years) of the system is presented in Fig. 7. Firstly, a project life of 25 years was specified in the analysis due to the average life span of solar panels.However, including replacement cost for each component within the analysis, makes design setup project beyond the required twenty five years' module lifetime.Hence, this makes the design setup more affordable for higher operational life cycle periods, and since each component cost is expected to reduce over the years, the LCOE is projected to further decline.This study reveals that the influence of solar panel on the total NPC is approximately 52% for the Kano site, 73  7 presents a comparison between total NPC and initial capital cost, and it reveals a similar pattern for both costs.However, this similarity is due to the use of the same technology by all sites, though the initial costs are less than NPC for each site.

Fig 7: Comparison between Net Present Cost (NPC) and Initial Capital for PV
An econometric ranking for all studied sites is presented in Table 10.The PV economics reveals that the LCOE is directly proportional to total NPC for all sites.More so, Fig. 8 shows the most excellent location in Nigeria by LCOE.It reveals that Iseyin the poorest in terms of LCOE at $0.579/kWh and Kano is the finest with $0.398/kWh.

: Comparison between Net Present Cost (NPC) and Initial Capital for PV System
An econometric ranking for all studied sites is presented in Table 10.The PV economics reveals that the LCOE is directly proportional to total NPC for all sites.More shows the most excellent location in Nigeria by LCOE.It reveals that Iseyin is the poorest in terms of LCOE at $0.579/kWh and Kano is the finest with $0.398/kWh.Hence, the use of PV standalone systems equates to savings of 7.1% and 56% respectively on an equivalent DSS that will cover the same load for this communities, with the added advantage of savings in 279 tons of CO2 green house gas emissions (GHG).The results of wind profile analysis at the and 10.A few of the sites have missing wind speed values for 2010).Fig. 9 shows the average monthly wind speed profiles for a period spanning between 1987 and 2010.The figure reveals that the 24 years monthly wind speed varied between 3.476 (m/s) in November for Benin City (SS) and 10.062 in December for Jos (NC).Fig. 10 reveals the average yearly wind speed profiles for the period covering 1987 and os (NC) is observed to have the highest yearly average wind speed -11.783 m/s in 1993, while Iseyin (SW) had the lowest -1.842 m/s in 1999.Moreover, the hours equaled or exceeded for a range of mean measured wind speeds across the period (Fig. 11) revealed that 67.2% of the data spread are values above 3.0 m/s for the poorest site in terms of wind profile, and 91.9% for the best wind profile in Jos.This discovery proves that majority of the sites are well-suited to contemporary wind turbines, since recent wind turbines for power generation have a cut m/s.Therefore, this reveals that wind power can be harnessed throughout the year with corresponding higher returns on investment.The hours equaled for power generated for each site from their respective turbine sizing based on particular wind speed profiles is presented in Fig. 12.The SS requires the highest turbine size of 100 kW, thereby generating more excess power than any other site, howbeit, for a very short period as it only generates power for equal or less than about 68% of the time.On the other hand, a site like Kano in the NW is sized at 50 kW because of a very favorable wind profile that makes this site consistently generate for 90% of the hourly duration in a year.As a result, Table 11 reveals that Benin city has the peak battery capacity requirement, which is to balance for approximately a third of the yearly hourly duration without turbine production.11).This gives rise to wind energy generation over twothirds of every hour of the day, thus, an average optimal battery size of 30.8 hours of autonomy suitably matches the load requirement.Also, it is revealed that for an average of about 24% of the annual hourly duration, the turbines can produce at the rated capacity since the rated speed for the PGE 20/25 turbines used in the design is 9 m/s (Fig. 11).This will certainly encourage good returns on investment and an opportunity for embedded generation (Overview of the NERC regulations, 2012; Multi-Year Tariff Order, 2011).From table 12, it is observed that Wind Standalone System (WSS) is in general, more cost efficient due to an average savings of 80% on battery requirement in comparison to PV Standalone System (PSS).12 shows the NPC of utilizing only WSS for power generation in each community, which reveals differential in NPC for all sites as a result of all sites having different wind speed profiles.This is because the wind energy resource is very close to the turbines' rated speed at some locations, while others are a bit far off.Thus, those close in value to the turbines' rated speed produced at the turbines' rated speed Comparing the total NPC and sites as presented in table 12 reveals that the LCOE correlates for all sites with the NPC values.Hence, Fig. 13 ranks these sites by LCOE, with Benin city being the poorest at $0.327/kWh and Jos the best with $0.129/kWh.This v equates to 89.6% and 380% savings respectively on a comparable DSS applied to meet the same load requirement for these communities.This comes with an added advantage of an additional savings in 279 tons of CO2 greenhouse gas (GHG) emissions which is equivalent to planting 25 hectares of forest for CO2 absorption.12 shows the NPC of utilizing only WSS for power generation in each community, which reveals differential in NPC for all sites as a result of all sites having different wind speed profiles.This is because the wind energy resource is very e turbines' rated speed at some locations, while others are a bit far off.Thus, those close in value to the turbines' rated speed produced at the turbines' rated speed for up to 47 % of the time in Jos, which has the best wind speed profile.Hence, this s required a lower capacity rated turbine of 50 kW in comparison to a site such as Benin city which required 100 kW to meet its load demand.After the analysis, the total NPC averaged 142% less for the WSS than that for the PSS when all sites were consid and the greatest differential of NPC by cost type was associated with capital cost.

NPC) Summary -Comparison between Wind Standalone Systems
Comparing the total NPC and LCOE for all sites as presented in table 12 reveals that the LCOE correlates for all sites with the comparatively ranks these sites by LCOE, with Benin city being the poorest at $0.327/kWh and Jos the best with $0.129/kWh.This values equates to 89.6% and 380% savings respectively on a comparable DSS applied to meet the same load requirement for these communities.This comes with an added advantage of an additional savings in 279 greenhouse gas (GHG) emissions which is equivalent to planting 25 hectares

Evaluation of the Potential of Solar Hybrid System
The logical advantage of hybridizing renewable energy resources over respective RE system is in the fact that the base load will be covered by the most copious and firmly available energy source, thereby sinking the technical requirements and the cost of the storage batteries.The economic costs of employing wind and systems, as standalone or in hybrid format are presented in Tables 13 of Econometrics Analysis for the Deployment of Solar-Technology (Ranking By Total NPC) for up to 47 % of the time in Jos, which has the best wind speed profile.Hence, this site required a lower capacity rated turbine of 50 kW in comparison to a site such as Benin city which required 100 kW to meet its load demand.After the analysis, the total NPC averaged 142% less for the WSS than that for the PSS when all sites were considered and the greatest differential of NPC by cost type was associated with capital cost.

Comparison between Wind Standalone Systems of the Potential of Solar-Wind
The logical advantage of hybridizing renewable energy resources over each respective RE system is in the fact that the base load will be covered by the most copious and firmly available energy source, thereby sinking the technical requirements and the cost of the storage batteries.The economic costs of employing wind and PV systems, as standalone or in hybrid format ed in Tables 13-15 and Fig. 14.
- As revealed in tables 13 and 15, the total NPC and LCOE for solar-wind hybrid in the selected sites did not produce any considerable improvement in terms of LCOE for the hybrid system over the WSS, although it is advantageous over the PSS for all sites.Thence, the WSS proves to be the best RE generation system for all the sites, which can adequately cater for the energy needs of the rural poor.Table 14 reveals the optimum combination of hybrid systems for this study.makes a comparison by LCOE for the WSS, PSS and hybrid energy system for all was found to be the least viable site at $0.356/kWh and Kano, excellent with $0.153/kWh.This equate to 74% and 305% savings respectively on a comparable DSS designed to meet the same load demand for this In addition, Table 15 reveals that the solar resource, though very much viable for all selected sites falls beneath the potential of wind energy.Nonetheless, all renewable technologies performed better than the conventional DSS without batteries for all ites.The percentage improvement ranged between 74% to 380% by LCOE.
In conclusion, for the analysis covering standalone community based designs, the most excellent renewable technology that fulfills all the technical requirements, in e most economically viable substitute for power generation at the rural community of 200 homes in Jos (NC), Maiduguri (NE), Kano (NW), Iseyin (SW), Enugu (SE), and Benin City (SS) is the wind standalone system.Also, with the government of Nigeria's prese electric tariff regime with grid electricity prices rising (Owonubi et al, 2009; Overview of the NERC regulations, 2012 and also based on the fact that research is ongoing to lower the price of wind turbine materials and solar panels, the competitiveness of RE generation will be on the increase.

Econometrics of Distributed Generation
The Federal government has made available the very much needed favorable environment that encourages growth in renewable energy (RE) generation by producers and consumers alike ( 2010) through distributed generation.The design adopted in

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Fig. average 24 years annual solar radiation th ranged between Iseyin (SW) (kWh/m².day)and Maiduguri (NE) (kWh/m².day)with a matching PV rating of 190 kW and 115 kW respectively.Plot of 24 Years' Annual Average Hours Equaled or Exceeded for Nigeria be attributed to the prevailing weight of daily global solar radiation on the sizing of photovoltaic systems.Fig. 6 also reveals an 4 years annual solar radiation that ranged between Iseyin (SW) -4.45 and Maiduguri (NE) -6.07 with a matching PV rating of 190 kW and 115 kW respectively. .O, Ohijeagbon O.D, Ajanaku, K.O, Aasa, S.A and Omotosho, O. A. (2015), Journal of African Research in Business & Technology, DOI: 10.5171/2015.124767

Fig 6 :
Fig 6: Correlation between the Monthly Average Solar Radiation and Solar Panel Size for Nigeria FromTable 9, considering the most cost effective PV standalone system design having a Loss of Load Probability (LOLP) of 0.01 (Hontoria et al, 2005; Shen, 2009; Khatib et al, 2013), produced an average excess electricity corresponding to 26.3% of annual generation.The reason for this excess however, is due to a reduction in daily hours of sunshine during the rainy season period, when average sunshine duration ranges between 3 and 4 hours in the north and 1 to 2 hours in the south.Consequently, a design that will cater for a load profile of 200 rural homes must necessarily include a realistic battery charging requirement to account for the days of limited solar radiation.Hence, the battery days of autonomy ranged between 48.7 hours for NW and 68.9 hours for SS at a 50% initial state of charge, which was chosen in order to extend battery life (Hund et al, 2010; Hund, 2009; Hunt, 2009; Overview of the NERC regulations, 2012; Multi-Year Tariff Order, 2011; Branker et al, 2011; Lorenz et al, 2008).However, this (kWh/m2 Day) PV Panel rating (kW) Fig

Techno-Economic Analysis Showing Grid Sales and LVOE for WSS Distributed Generation for Benin City Fig 26: Techno-Economic Analysis Showing Grid Sales and LVOE for PSS Distributed Generation for Benin City Conclusion Renewable
energy systems covering PV and wind energy resources were assessed for six meteorological locations within the six geopolitical zones of Nigeria as standalone and in hybrid format for sites in these regions for remote community utilization as well as for distributed generation.Since the DSS is the only conventional means of generating power for these remote locations, due to their isolation from the national grid, it was taken as the basis of comparison.This study showed that the most economically feasible substitute for power generation at these rural communities of 200 homes in Jos (NC), Maiduguri (NE), Kano (NW), Iseyin (SW), Enugu (SE), and Benin City (SS) is the wind standalone system.This is in comparison to the present cost of grid electricity, at a cost of about $0.09/kWh, which makes the WSS, PSS and hybrid system quite competitive.Consequently, RE systems of PV and wind