Solar glossary
LCOE (levelised cost of energy): what it means and why it matters
The average cost of every kilowatt-hour a solar system produces across its life, once the capital cost, replacements and maintenance are spread over the energy it delivers.
Why it matters in Nigeria
It is the only fair way to compare solar against a ₦209/kWh grid tariff or generator fuel at ₦669–₦1,114/kWh. If solar LCOE sits below what you pay today, the system saves money.
How PureWatts measures it
Median LCOE ₦ (Solar + battery)
med_sc2_lcoe_ngn_kwh
Median over the buildings in the group. Medians DO NOT COMBINE — never average these across groups; re-derive from the histograms instead. Levelised cost of energy: DISCOUNTED lifetime cost over DISCOUNTED lifetime generation, at the building's own discount rate. Cost includes capex, 25 years of O&M and every replacement, less the residual value of kit with life left at the end of the study.
Solar + battery: PV sized to cover FULL demand including round-trip losses: kwp = min(demand x (daylight + (1-daylight)/0.90) x 1.10 / net_yield, pv_max_kwp); battery = night demand / (0.80 DoD x sqrt(0.90)), capped at 2.0x PV kWp
Sized to LATENT demand — the energy the building would use if it could. Against a cash baseline that only reflects today's spend this looks oversized; that is what sc3 exists to fix.
Median over the buildings in the group. Medians DO NOT COMBINE — never average these across groups; re-derive from the histograms instead.
Median LCOE ₦ (Merit-order sized)
med_sc3_lcoe_ngn_kwh
Median over the buildings in the group. Medians DO NOT COMBINE — never average these across groups; re-derive from the histograms instead. Levelised cost of energy: DISCOUNTED lifetime cost over DISCOUNTED lifetime generation, at the building's own discount rate. Cost includes capex, 25 years of O&M and every replacement, less the residual value of kit with life left at the end of the study.
Solar + battery, merit-order sized: Same engine as sc2, but the target is what the building CONSUMES today x 1.5 (MO_SIZING_UPLIFT) rather than full latent demand.
In Osun, sizing sc2 to latent demand while crediting it only with displacing current spend produced a 6x-oversized system and a negative IRR that said nothing about solar. sc3 is the fix, not an alternative opinion.
Median over the buildings in the group. Medians DO NOT COMBINE — never average these across groups; re-derive from the histograms instead.
See these numbers for your area
Every state and local government area page reports lcoe (levelised cost of energy) for its own rooftops. Browse the Nigeria rooftop solar data.