Solar glossary
Generator cost per kWh: what it means and why it matters
The all-in cost of a self-generated kilowatt-hour, at the fuel the building actually burns — petrol for most homes, diesel for commercial sites.
Why it matters in Nigeria
This is the number solar competes with in Nigeria, and it is several times the grid tariff.
How PureWatts measures it
Median Genset cost ₦
med_genset_cost_ngn_kwh
Median over the buildings in the group. Medians DO NOT COMBINE — never average these across groups; re-derive from the histograms instead. Generator cost at the segment's own fuel — petrol for residential, diesel for C&I.
Median over the buildings in the group. Medians DO NOT COMBINE — never average these across groups; re-derive from the histograms instead.
Total Genset kWh per year (vs generator)
sum_genset_kwh_yr
Sum over the buildings in the group. Energy self-generated today.
Counterfactual: self-generate every kWh, at the fuel the segment actually burns — petrol ~N1,114/kWh for residential, diesel ~N669/kWh for C&I. Upper bound. RENAMED from `diesel`, which priced households at diesel they do not burn.
Sum over the buildings in the group.
See these numbers for your area
Every state and local government area page reports generator cost per kwh for its own rooftops. Browse the Nigeria rooftop solar data.
Related terms
How these numbers are produced
Approach A — energy value (upper bracket)
Sizes the system to the building's full latent demand and values that energy at the mixed grid/generator tariff. It answers what the energy is worth — not what anyone currently pays.
Approach B — cash saved (lower bracket)
Sizes the system to demand that is actually served today, values it by merit order (solar displaces generator kWh first) and caps it at current spend. It answers what a building stops paying.
Cohort: Viable rooftops (≥0.6 kWp potential).
- Demand is modelled latent demand, not metered consumption.
- Fuel is priced at ₦1,800/litre (operator-set). NBS reported ₦3,277/litre for May 2026 — on that basis every naira figure here is roughly 1.8× understated.
- Generator ownership is a model output, not a survey result: it follows from the grid-availability scale and the 25% demand-suppression assumption.
- Approach A prices energy nobody currently buys. Its savings must never be read as cash saved.
- Demand is MODELLED LATENT demand, not metered consumption.
- Generator ownership is model output, not survey.
- Medians do not combine across groups — re-derive from the histograms.
- Per-building files are float32 with 4 significant figures; cast to float64 before summing, because polars keeps Float32 sums in Float32.
- Null scenario fields mean the roof cannot host 0.6 kWp, not zero savings.
- `genset` was previously named `diesel` and now uses the segment's real fuel.
- Ordering holds by construction: grid savings < mixed < genset.