Price ranges
ZEUS reports prices as observed ranges, never as single figures. For each component class (panel wattage, battery type and size, inverter rating, installed system size) an editor collects the prices shown on published Nigerian retailer and price-guide pages on a given date, discards listings that lack a wattage or capacity, and records the lowest and highest credible listing. "Credible" excludes obviously mis-labelled products (a "550 W" panel priced like a 100 W panel) and used equipment.
Every price table states: the date checked (currently 16 September 2026), the price type (published retail listings in naira; solar equipment is VAT zero-rated; delivery and installation excluded unless stated), and the sources by name and URL. Installed-system ranges combine sellers' package prices with itemised component ranges plus 10–15% labour.
Sources currently used: Solar Energy Supply Stores, Nigeria Housing Market, SolarDecide, Mercury Direct, Rayspark, Kara.com.ng, BusinessDay. Marketplaces that block automated retrieval (Jiji, Jumia) are not used; ZEUS does not scrape listings and does not fabricate averages. Prices ZEUS could not observe are marked "—".
ZEUS has no commercial relationship with any seller or brand it names, takes no referral fees, and lists sources because they were the observation points, not as recommendations.
Solar resource data
All solar yield figures come from the Global Solar Atlas 2.0 (Solargis, for the World Bank Group, funded by ESMAP), queried through its public long-term-average endpoint for city-centre coordinates. ZEUS uses the PVOUT_csi layer (specific PV output of a fixed, optimally tilted, small crystalline-silicon system including typical losses), plus GHI, DNI, optimum tilt and air temperature, and the monthly PVOUT profile. Data version 2.2.68, updated 1 April 2026, fetched 16 September 2026; licence CC BY 4.0. The exact query and the raw values are on the resource page.
ZEUS sizes on the worst month by default because a household system must work in August in Lagos, not on the annual average. Where the average is used it is labelled.
Tariff, fuel and exchange rate
Grid tariff: the Band A rate from the NERC Multi-Year Tariff Order in force (₦209.5/kWh for ten DisCos and ₦160 for EEDC from 7 December 2025), taken from NERC's published orders and cross-checked against a compilation site. Fuel: gantry prices announced by the Dangote refinery and pump prices surveyed by named national press on named dates (petrol ₦1.350 gantry / ₦1.400–1.450 pump; diesel ₦1.850 gantry). Exchange rate: the CBN NFEM closing rate (₦1.326,3/$ on 14 September 2026). All are shown with their date wherever used; none is updated automatically.
Sizing formulas
E_daily_kWh = Σ qty × W × hours × duty ÷ 1000
// array
PV_kWp = E_daily ÷ PVOUT_design ÷ η_batt η_batt 0.87 LiFePO₄ (0.92 round trip × 0.95 charge path), 0.80 lead-acid
Panels = ceil(PV_kWp × 1000 ÷ Panel_W)
Roof_m² ≈ Panels × panel_area × 1.15
// battery
E_nominal = E_overnight × nights ÷ DoD ÷ η_inv DoD 0.9 LiFePO₄, 0.5 lead-acid; η_inv 0.92
Runtime_h = E_nominal × DoD × η_inv ÷ Load_kW
// inverter
kVA = P_simultaneous × 1.25 ÷ 0.8 ÷ 1000 pf 0.8 unless the datasheet says 1.0; check surge separately
// generator
₦/kWh = L/h × ₦/L × (1 + servicing 0.15) ÷ kW_out_at_75%_load
// solar economics
₦/kWh = (capex + 1%/yr maintenance × years + battery replacement) ÷ (kWp × PVOUT_year × utilisation × years)
Constants (η, DoD, duty cycles, headroom) are typical values from manufacturer datasheets and installer practice; they are editable in every calculator and stated on every page that uses them.
Appliance wattages
Running watts are typical nameplate values for appliances common in Nigerian homes (LED lighting, ceiling fans, LED TVs, inverter and non-inverter refrigeration and air conditioning, 1 HP pumps). Starting factors: 3× for compressors and pumps, 1.5× for inverter compressors and fans. Duty cycles: 40% for refrigeration, 70% for air conditioning. Users are told to replace them with label values.
Refresh policy
| Data | Cadence | Shown as |
|---|---|---|
| Component and system prices | Quarterly, or after a >10% naira move | "Prices checked" date on each page and table |
| Fuel prices | Monthly, or after a refinery price change | Date next to each figure |
| Grid tariff | On each NERC order | Order name and effective date |
| Exchange rate | With each price refresh | CBN rate and date |
| Solar resource | When Global Solar Atlas publishes a new data version | Data version, update date, fetch date |
| Editorial content | On review | "Updated" date in the page header, changed only when content changes |
The "Updated" date is edited by hand when a page's content is reviewed; it is not regenerated on build. Sitemap lastmod mirrors it.
Known limitations
- Price observation covers published listings, not negotiated or wholesale prices, and cannot see marketplaces that block retrieval.
- City yields are for city-centre coordinates; rooftop shading and orientation are not modelled.
- Generator fuel-use figures are typical values from published guides, not measurements.
- Battery cycle-life figures are manufacturer claims at 25 °C.
- ZEUS currently covers Nigeria only; other countries are listed on the countries page with the criteria for adding them.
Corrections: write to [email protected]. See the corrections policy.