Solar glossary
Solar sizing scenarios (sc1, sc2, sc3): what it means and why it matters
Three ways of sizing the same roof: solar only, solar plus battery sized to full demand, and solar plus battery sized to what the building spends today.
Why it matters in Nigeria
Quoting a saving without naming the scenario is meaningless. Every figure on our data pages says which scenario it belongs to.
How PureWatts measures it
Total KWp (Solar only)
sum_sc1_kwp
Sum over the buildings in the group. Installed PV capacity.
Solar only: PV sized to cover DAYLIGHT demand: kwp = min(demand x daylight_frac x 1.10 / net_yield, pv_max_kwp)
Understates value where the load is evening-peaked, which is most residential.
Sum over the buildings in the group.
Total KWp (Solar + battery)
sum_sc2_kwp
Sum over the buildings in the group. Installed PV capacity.
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.
Sum over the buildings in the group.
Total KWp (Merit-order sized)
sum_sc3_kwp
Sum over the buildings in the group. Installed PV capacity.
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.
Sum over the buildings in the group.
See these numbers for your area
Every state and local government area page reports solar sizing scenarios (sc1, sc2, sc3) for its own rooftops. Browse the Nigeria rooftop solar data.