Osun State
Rooftop solar in Iwo, Osun: what the roofs are worth
Iwo has 65,589 buildings with a viable rooftop and 1.57m kWp of roof capacity. 74% run a generator, and together they spend ₦44.1bn a year on energy.
65,589
6.99m m²
1.57m kWp roof capacity
₦44.1bn/yr
38.7m kWh/yr burned on generators
2.9 yr
Median IRR 37% (cash saved)
The savings bracket for Iwo
Cash saved
What these buildings stop paying — merit order, capped at current spend.
Energy value (upper bracket)
What the energy is worth if full latent demand were met. Not cash saved.
Three ways to size Iwo's rooftops
Solar + battery. The default headline scenario, and the one the SEO fact base quotes. Prices the energy a full solar+storage system would deliver.
Read with care: 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.
- System size
- 206k kWp
- Capital cost
- ₦196bn
- Year 1 savings
- ₦153bn/yr
- NPV
- ₦1.18tn
- Median IRR
- 73%
- Median payback
- 1.4 yr
How many rooftops in Iwo actually pay
Counted building by building on the cash-saved basis (merit-order sized, valued against what the building spends today), not read off an average. 65,589 of 65,589 clear a positive NPV.
Payback
Return (IRR)
84.1m kg/yr
21.3m L/yr
45m kWh/yr
Demand that is suppressed today
169k
What hardware costs right now
Median advertised rates from our Nigerian market tracker — the same prices used to cost a system in Iwo.
Solar panels
₦250
₦/W
Inverters
₦127,419
₦/kVA
Batteries
₦177,500
₦/kWh
Building mix in Iwo
Load profile
| Segment | Buildings | With generator | Spend ₦/yr | Cash saved yr 1 (B) | Median IRR | Median payback |
|---|---|---|---|---|---|---|
| Residential | 63,810 | 47,016 | ₦32.5bn | ₦31.8bn | 37% | 2.9 yr |
| Commercial General | 732 | 609 | ₦3.43bn | ₦3.43bn | 31% | 3.4 yr |
| Anchor | 536 | 380 | ₦7.56bn | ₦7.11bn | 39% | 2.9 yr |
| Commercial Retail | 219 | 160 | ₦32.8m | ₦32.8m | 29% | 3.6 yr |
| Industrial | 189 | 165 | ₦478m | ₦463m | 47% | 2.1 yr |
| Filling Station | 50 | 34 | ₦57.2m | ₦57m | 35% | 3.1 yr |
| Worship | 28 | 23 | ₦20.4m | ₦20.4m | 35% | 2.9 yr |
| Hospitality | 23 | 6 | ₦69.2m | ₦69.2m | 23% | 4.6 yr |
| Productive Use | 2 | 2 | ₦9.09m | ₦9.09m | 35% | 2.6 yr |
Roof size band
| Segment | Buildings | With generator | Spend ₦/yr | Cash saved yr 1 (B) | Median IRR | Median payback |
|---|---|---|---|---|---|---|
| 100 250m2 | 27,423 | 19,778 | ₦17.5bn | ₦17.2bn | 35% | 3.1 yr |
| Under 30m2 | 13,465 | 9,963 | ₦574m | ₦565m | 37% | 2.9 yr |
| 50 100m2 | 10,859 | 7,962 | ₦2.3bn | ₦2.27bn | 37% | 2.9 yr |
| 250 1000m2 | 6,925 | 5,507 | ₦15.6bn | ₦15.2bn | 39% | 2.6 yr |
| 30 50m2 | 6,811 | 5,084 | ₦630m | ₦626m | 37% | 2.9 yr |
| Over 1000m2 | 106 | 101 | ₦7.53bn | ₦7.09bn | 51% | 2.1 yr |
Settlement type
| Segment | Buildings | With generator | Spend ₦/yr | Cash saved yr 1 (B) | Median IRR | Median payback |
|---|---|---|---|---|---|---|
| Urban Centre | 55,809 | 39,246 | ₦27.1bn | ₦27bn | 33% | 3.1 yr |
| Unclassified | 5,650 | 5,158 | ₦7.51bn | ₦6.71bn | 53% | 2.1 yr |
| Urban | 3,571 | 3,432 | ₦8.66bn | ₦8.39bn | 51% | 2.1 yr |
| Rural | 559 | 559 | ₦827m | ₦815m | 65% | 1.6 yr |
Lead segment
| Segment | Buildings | With generator | Spend ₦/yr | Cash saved yr 1 (B) | Median IRR | Median payback |
|---|---|---|---|---|---|---|
| Standard | 64,549 | 47,567 | ₦34.5bn | ₦33.8bn | 37% | 2.9 yr |
| Enterprise | 679 | 510 | ₦7.9bn | ₦7.44bn | 41% | 2.6 yr |
| SME High | 361 | 318 | ₦1.68bn | ₦1.68bn | 31% | 3.4 yr |
Demand tier
| Segment | Buildings | With generator | Spend ₦/yr | Cash saved yr 1 (B) | Median IRR | Median payback |
|---|---|---|---|---|---|---|
| 4.0 | 36,616 | 23,590 | ₦15bn | ₦15bn | — | — |
| 3.0 | 17,984 | 15,312 | ₦25.7bn | ₦24.6bn | — | — |
| 0.0 | 4,923 | 4,724 | ₦289m | ₦289m | — | — |
| 2.0 | 4,733 | 3,671 | ₦1.61bn | ₦1.53bn | — | — |
| 1.0 | 1,082 | 877 | ₦263m | ₦260m | — | — |
| 5.0 | 160 | 140 | ₦521m | ₦521m | — | — |
| 6.0 | 91 | 81 | ₦717m | ₦717m | — | — |
Nearby LGAs in Osun
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.