Osun State

Rooftop solar in Iwo, Osun: what the roofs are worth

Iwo has 65,589 buildings with a viable rooftop and 1.57 GWp of roof capacity. 34% run a generator, and together they spend ₦35.1bn a year on energy.

Viable buildings

65,589

Usable roof area

6.99 km²

1.57 GWp roof capacity

Energy spend

₦35.1bn/yr

30.3 GWh/yr burned on generators

Median payback

4.4 yr

Median IRR 25% (cash saved)

The savings bracket for Iwo

Approach B

Cash saved

What these buildings stop paying — merit order, capped at current spend.

Current energy spend₦35.1bn/yr

Year-one cash saved₦34.6bn

Lifetime cash saved₦1.85tn

NPV₦267bn

Median IRR25%

Median payback4.4 yr

Unlocked energy27.3 GWh/yr

Approach A

Energy value (upper bracket)

What the energy is worth if full latent demand were met. Not cash saved.

Installed capacity118 MWp

Capex₦119bn

Year-one energy value₦84.6bn

Lifetime energy value₦3.98tn

NPV₦648bn

Median IRR67%

Median payback1.6 yr

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.

Baseline: mixed

Counterfactual: grid when available, generator otherwise, weighted by the NTL-derived grid availability. The realistic case, and what the headline numbers use. Always falls between grid and genset by construction.

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: 118 MWp
Capital cost: ₦119bn
Year 1 savings: ₦84.6bn/yr
NPV: ₦648bn
Median IRR: 67%
Median payback: 1.6 yr

The odds a rooftop in Iwo pays back quickly

Of the 64,991 buildings in Iwo with a modelled payback, 73.4% pay back inside five years and 33.2% inside three.

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How much of Iwo's demand actually gets met

Buildings in Iwo consume 63.8 GWh/yr but want 91.1 GWh/yr. The 30% they cannot buy is suppressed demand — load that appears the moment supply is reliable.

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Electricity billing bands in Iwo

Loading band economics…

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. Shares are of the 64,991 buildings with a modelled result out of 65,589 in Iwo. 56,731 clear a positive NPV.

Payback

Under 3 years21,570 (33%)

Under 5 years47,676 (73%)

Under 7 years56,671 (87%)

Under 10 years60,678 (93%)

Return (IRR)

Above 10%60,126 (92%)

Above 15%56,731 (86%)

Above 20%50,681 (77%)

Above 25%37,378 (57%)

CO₂ avoided

64.2 kt/yr

Fuel avoided

15.9 million litres/yr

Energy unlocked

27.3 GWh/yr

Demand that is suppressed today

People served

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

Full price tracker Size a home system Size a business system

Building mix in Iwo

Electricity billing band

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
C	39,358	15,504	₦16.5bn	₦16.5bn	25%	4.4 yr
D	22,501	6,372	₦10.4bn	₦10.2bn	25%	4.4 yr
E	3,489	642	₦6.92bn	₦6.67bn	23%	4.6 yr
B	241	62	₦1.24bn	₦1.24bn	25%	4.4 yr

Load profile

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Residential	63,810	21,228	₦23.9bn	₦23.5bn	25%	4.4 yr
Commercial General	732	599	₦3.42bn	₦3.42bn	41%	2.6 yr
Anchor	536	376	₦7.07bn	₦6.97bn	43%	2.4 yr
Commercial Retail	219	160	₦32.8m	₦32.8m	39%	2.9 yr
Industrial	189	152	₦457m	₦453m	51%	2.1 yr
Filling Station	50	34	₦56.7m	₦56.5m	41%	2.4 yr
Worship	28	23	₦20.4m	₦20.4m	43%	2.4 yr
Hospitality	23	6	₦69.1m	₦69.1m	35%	3.1 yr
Productive Use	2	2	₦9.09m	₦9.09m	43%	2.1 yr

Roof size band

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
100 250m2	27,423	8,647	₦13.2bn	₦13bn	25%	4.4 yr
Under 30m2	13,465	4,736	₦460m	₦452m	17%	6.1 yr
50 100m2	10,859	3,611	₦1.4bn	₦1.39bn	25%	4.4 yr
250 1000m2	6,925	3,075	₦12.8bn	₦12.7bn	25%	4.1 yr
30 50m2	6,811	2,445	₦472m	₦470m	21%	5.1 yr
Over 1000m2	106	66	₦6.72bn	₦6.64bn	49%	2.1 yr

Settlement type

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Urban Centre	55,809	19,942	₦23bn	₦22.9bn	25%	4.4 yr
Unclassified	5,650	1,301	₦4.36bn	₦4.08bn	25%	4.4 yr
Urban	3,571	1,179	₦7.15bn	₦7.03bn	25%	4.4 yr
Rural	559	158	₦567m	₦554m	25%	4.4 yr

Building type

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Residential Formal	28,121	11,414	₦7.55bn	₦7.55bn	25%	4.4 yr
Residential Informal	9,452	2,074	₦1.56bn	₦1.56bn	25%	4.4 yr
Residential	9,165	2,849	₦12.2bn	₦11.9bn	25%	4.4 yr
Residential Small	6,171	1,794	₦1.07bn	₦1.06bn	25%	4.4 yr
Shed	5,147	1,090	₦169m	₦169m	17%	6.1 yr
Apartment	3,905	1,472	₦973m	₦973m	25%	4.4 yr
Duplex	1,815	530	₦362m	₦362m	25%	4.4 yr
Institutional	354	265	₦5.72bn	₦5.64bn	41%	2.6 yr
Kiosk Shop	220	161	₦33.5m	₦33.5m	39%	2.9 yr
Commercial	201	197	₦1.27bn	₦1.27bn	45%	2.4 yr
School	140	87	₦423m	₦423m	51%	2.1 yr
Educational Facility	139	97	₦791m	₦791m	57%	1.9 yr

Land use

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)
(Unset)	65,584	22,577	₦35bn	₦34.5bn
Industrial	5	3	₦32m	₦32m

Not published for this cube: Median IRR, Median payback.

Lead segment

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Standard	64,549	21,769	₦26bn	₦25.6bn	25%	4.4 yr
Enterprise	679	494	₦7.39bn	₦7.29bn	47%	2.4 yr
SME High	361	317	₦1.67bn	₦1.67bn	41%	2.6 yr

Demand tier

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)
4.0	36,616	13,548	₦13.9bn	₦13.9bn
3.0	17,984	5,919	₦19bn	₦18.6bn
0.0	4,923	1,095	₦169m	₦169m
2.0	4,733	1,477	₦688m	₦628m
1.0	1,082	320	₦106m	₦103m
5.0	160	140	₦520m	₦520m
6.0	91	81	₦716m	₦716m