Unreliable electricity supply remains a persistent challenge in many developing countries, disproportionately

affecting low- and middle-income households through frequent power outages and rising energy costs. This

study assessed household electrical energy demand and determined the optimal sizing of stand-alone

A total of 100 households participated in the study, comprising 50 low-income households (monthly income of

₦50,000–₦150,000) and 50 middle-income households (monthly income of ₦150,000–₦500,000). A structured

load survey was conducted to collect data on household appliances, including their quantities, rated power, and

average daily operating hours. Daily energy demand was estimated from the load survey, and PV systems were

designed using standard engineering procedures based on daily energy consumption, average peak sunshine

hours, system de-rating factor, battery storage requirements, and inverter capacity. The economic viability of the

attractive, with estimated payback periods of approximately three years, depending on household energy

The findings confirm that household income level significantly influences electricity demand and PV system

sizing requirements. The study demonstrates that properly designed stand-alone photovoltaic systems provide a

technically feasible, economically viable, and environmentally sustainable solution for improving residential

electricity access in semi-urban Nigeria. The results provide practical design guidelines for engineers,

Nigeria's per capita electricity consumption is also very low, at about 149 kWh, far behind countries like Brazil

and South Africa (Enongene et al., 2019). This shows that the problem is not just about access but about how

little power is actually available to those who are connected. Expanding the grid to reach everyone by 2030

would cost tens of billions of dollars, an amount well beyond what government budgets can currently support

(Ohiare, 2015). As a result, off-grid and decentralized power solutions are increasingly seen as more practical

Solar photovoltaic (PV) technology is one of the most promising of these alternatives, given Nigeria's strong and

consistent solar irradiation. Studies on residential PV systems show how much household energy needs can vary.

For example, a study in Lagos found that required PV system sizes ranged from as small as 0.3 kW to as large

as 76 kW, depending on the type of building and how much electricity each household used (Enongene et al.,

profiles, with little attention given to how income differences within the same community affect energy demand

This gap is especially important for semi-urban and peri-urban towns in southeastern Nigeria, where living

conditions and spending power differ significantly from those in major cities. Established methods for sizing PV

systems typically use daily energy consumption, peak sunshine hours, and system efficiency as the key variables

in determining required capacity (Kamalapur & Udaykumar, 2011). Applying this method to income-

Beyond system sizing, affordability is equally important. Even a well-designed PV system is only useful if a

household can afford it and recover the cost within a reasonable time. In Nigeria, installation costs, import duties,

and currency fluctuations all affect the price of solar equipment, making the payback period a critical factor in a

Afikpo is a semi-urban town located in Ebonyi State, southeastern Nigeria. The town comprises a mixture of

urban and rural settlements with varying levels of access to electricity supplied through the national grid. Like

many communities in southeastern Nigeria, households in Afikpo experience frequent electricity interruptions,

The area receives abundant solar radiation throughout the year, with an average peak sunshine duration of

approximately 5.2 hours per day, making it suitable for stand-alone photovoltaic system deployment. The choice

of Afikpo for this study was informed by its representative socio-economic characteristics and the increasing

The study population comprised residential households within Afikpo, Ebonyi State. A total of 100 households

participated in the survey. To enable a balanced comparison between income groups, the respondents were

occupants were willing to participate and belonged to either the low- or middle-income category were included

in the study. Monthly household income was used as the basis for classification, with households earning

₦50,000–₦150,000 classified as low income and those earning ₦150,000–₦500,000 classified as middle

Completed questionnaires were checked for completeness before analysis. The collected appliance inventory

was used to estimate daily household energy consumption by multiplying the rated power of each appliance by

Representative household load profiles for both income groups were subsequently developed from the survey

A total of 100 households participated in the study, comprising 50 low-income households and 50 middle-income

The battery bank is determined using

The photovoltaic array capacities were determined using the average daily household energy demand, an average

peak sun hour value of 5.2 h/day, and an overall system efficiency of 80%. The calculated capacities of 517 W

and 1,317 W were rounded to commercially available module ratings of 600 W and 1.5 kW, respectively. Battery

storage requirements were estimated using a one-day autonomy period, a maximum depth of discharge of 50%,

a battery efficiency of 85%, and system losses of 10%. The resulting battery bank sizes of 48 V, 150 Ah and 48

(4)