Generator vs solar cost calculator

Compare what your generator costs per kWh and per year with a solar-plus-battery system over 5 and 10 years. Defaults are September 2026 Nigerian figures (petrol ₦1.400/L, diesel ₦1.850/L, Band A ₦209.5/kWh); change any of them.

Updated 16 September 2026

Generator

Fuel use from published Nigerian guides; edit below.

Fuel use

L/h

Electrical output at that fuel use

Fuel price

₦/L

Petrol pump ₦1.400–1.450, diesel ₦1.850–2.020 (13 September 2026).

Hours per day

h/day

Servicing, oil, wear

% of fuel

Generator purchase price

₦

Replaced every 4 years in the 10-year figure.

Solar system

Installed price

₦

5 kVA lithium packages observed ₦2m–₦5.5m (16 September 2026).

Array size

kWp

City

Share of solar output actually used

Surplus on sunny days is lost unless exported.

Generator hours avoided by solar

Rainy-season nights may still need the generator.

Battery replacement in year 8–10

₦

Set 0 to exclude.

Grid tariff for comparison

₦/kWh

Band A 209.5; lower bands pay less for fewer hours.

ResultsLagos

Generator, per kWh

—

₦ incl. servicing

Generator, per year

—

₦ fuel + servicing

Solar, per kWh

—

₦ over 10 years incl. battery replacement

Simple payback

—

years

5-year cost: generator vs solar

—

₦

10-year cost: generator vs solar

—

₦

Formulas and assumptions

Gen_₦/h = L/h × ₦/L × (1 + servicing)
Gen_₦/kWh = Gen_₦/h ÷ kW_out
Gen_year = Gen_₦/h × h/day × 365
Gen_10yr = Gen_year × 10 + generator price × 2.5
Solar_kWh/yr = kWp × PVOUT_year × utilisation
Solar_10yr = capex + capex × 1%/yr × 10 + battery replacement
Solar_₦/kWh = Solar_10yr ÷ (Solar_kWh/yr × 10)
Payback = capex ÷ (Gen_year × avoided share)

The comparison charges solar with a mid-life battery replacement and 1% a year maintenance, and credits the generator with nothing for noise, fumes, fuel trips or food loss during outages. Panels keep producing after year 10; the solar per-kWh figure is conservative.

What this is

An estimate from stated formulas and typical values, for planning and for checking quotations. It is not an engineering design, does not replace a load audit and site survey by a qualified installer, and does not account for shading, roof orientation, cable losses or local standards. ZEUS is not an engineering firm.