Osun State

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

Irewole has 35,920 buildings with a viable rooftop and 824 MWp of roof capacity. 17% run a generator, and together they spend ₦11.1bn a year on energy.

Viable buildings

35,920

Usable roof area

3.66 km²

824 MWp roof capacity

Energy spend

₦11.1bn/yr

8.89 GWh/yr burned on generators

Median payback

4.4 yr

Median IRR 25% (cash saved)

The savings bracket for Irewole

Approach B

Cash saved

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

Current energy spend₦11.1bn/yr

Year-one cash saved₦10.2bn

Lifetime cash saved₦572bn

NPV₦81.2bn

Median IRR25%

Median payback4.4 yr

Unlocked energy12.4 GWh/yr

Approach A

Energy value (upper bracket)

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

Installed capacity57.8 MWp

Capex₦57.2bn

Year-one energy value₦43.7bn

Lifetime energy value₦2.06tn

NPV₦339bn

Median IRR81%

Median payback1.4 yr

Three ways to size Irewole'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: 57.8 MWp
Capital cost: ₦57.2bn
Year 1 savings: ₦43.7bn/yr
NPV: ₦339bn
Median IRR: 81%
Median payback: 1.4 yr

The odds a rooftop in Irewole pays back quickly

Of the 35,092 buildings in Irewole with a modelled payback, 63.4% pay back inside five years and 16.8% inside three.

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How much of Irewole's demand actually gets met

Buildings in Irewole consume 22.1 GWh/yr but want 34.5 GWh/yr. The 36% they cannot buy is suppressed demand — load that appears the moment supply is reliable.

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Electricity billing bands in Irewole

Loading band economics…

How many rooftops in Irewole 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 35,092 buildings with a modelled result out of 35,920 in Irewole. 27,929 clear a positive NPV.

Payback

Under 3 years5,912 (17%)

Under 5 years22,242 (63%)

Under 7 years27,864 (79%)

Under 10 years30,610 (87%)

Return (IRR)

Above 10%30,239 (84%)

Above 15%27,929 (78%)

Above 20%24,166 (67%)

Above 25%11,515 (32%)

CO₂ avoided

21.3 kt/yr

Fuel avoided

4.31 million litres/yr

Energy unlocked

12.4 GWh/yr

Demand that is suppressed today

People served

119k

What hardware costs right now

Median advertised rates from our Nigerian market tracker — the same prices used to cost a system in Irewole.

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 Irewole

Electricity billing band

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
D	28,042	5,036	₦6.91bn	₦6.91bn	25%	4.4 yr
E	7,607	918	₦3.68bn	₦2.83bn	25%	4.4 yr
C	271	168	₦501m	₦501m	59%	1.9 yr

Load profile

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Residential	34,420	5,068	₦7.5bn	₦6.65bn	25%	4.4 yr
Commercial General	654	490	₦1.71bn	₦1.71bn	41%	2.6 yr
Industrial	366	221	₦475m	₦473m	49%	2.1 yr
Anchor	243	186	₦1.32bn	₦1.32bn	47%	2.4 yr
Commercial Retail	195	124	₦19.9m	₦19.9m	37%	2.9 yr
Filling Station	26	19	₦33.4m	₦33.4m	43%	2.4 yr
Worship	9	9	₦9.5m	₦9.5m	53%	2.1 yr
Hospitality	5	4	₦5.66m	₦5.66m	41%	2.6 yr
Mall Retail	1	0	₦662k	₦662k	33%	3.1 yr
Productive Use	1	1	₦16.9m	₦16.9m	59%	1.9 yr

Roof size band

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
100 250m2	15,879	2,635	₦4.24bn	₦4.11bn	25%	4.4 yr
Under 30m2	7,342	1,147	₦166m	₦165m	7%	13.1 yr
50 100m2	6,015	819	₦458m	₦458m	23%	4.9 yr
30 50m2	3,544	552	₦168m	₦164m	15%	7.1 yr
250 1000m2	3,103	952	₦5.24bn	₦4.51bn	25%	4.4 yr
Over 1000m2	37	17	₦821m	₦821m	39%	2.9 yr

Settlement type

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Urban Centre	28,315	4,999	₦6.64bn	₦6.64bn	25%	4.4 yr
Unclassified	5,648	459	₦2.88bn	₦2.03bn	23%	4.6 yr
Rural	1,016	233	₦355m	₦355m	23%	4.6 yr
Urban	941	431	₦1.22bn	₦1.22bn	33%	3.1 yr

Building type

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Residential Formal	18,213	1,625	₦1.28bn	₦1.28bn	23%	4.6 yr
Residential	3,983	1,309	₦4.87bn	₦4.02bn	25%	4.4 yr
Residential Small	3,411	675	₦319m	₦315m	25%	4.4 yr
Shed	3,063	504	₦75.9m	₦75.9m	7%	14.9 yr
Apartment	2,940	283	₦236m	₦236m	25%	4.4 yr
Duplex	1,561	128	₦106m	₦106m	25%	4.4 yr
Residential Informal	1,212	538	₦604m	₦604m	25%	4.4 yr
Institutional	312	206	₦1.02bn	₦1.02bn	41%	2.6 yr
Commercial	287	247	₦764m	₦764m	41%	2.6 yr
Kiosk Shop	195	124	₦19.9m	₦19.9m	37%	2.9 yr
Industrial Site	188	111	₦284m	₦283m	49%	2.1 yr
Commercial Corridor	86	56	₦262m	₦262m	41%	2.6 yr

Land use

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)
(Unset)	35,920	6,122	₦11.1bn	₦10.2bn

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	34,908	5,391	₦8.22bn	₦7.36bn	25%	4.4 yr
Enterprise	609	407	₦1.8bn	₦1.79bn	47%	2.1 yr
SME High	403	324	₦1.08bn	₦1.08bn	41%	2.6 yr

Demand tier

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)
4.0	21,420	2,341	₦3.31bn	₦3.31bn
3.0	7,517	2,260	₦6.17bn	₦5.42bn
0.0	3,098	509	₦78.2m	₦78.2m
2.0	2,794	626	₦445m	₦347m
1.0	732	93	₦41.2m	₦41.1m
5.0	290	233	₦651m	₦651m
6.0	69	60	₦396m	₦396m