Osun State

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

Ila has 27,198 buildings with a viable rooftop and 668 MWp of roof capacity. 26% run a generator, and together they spend ₦9.76bn a year on energy.

Viable buildings

27,198

Usable roof area

2.97 km²

668 MWp roof capacity

Energy spend

₦9.76bn/yr

9.15 GWh/yr burned on generators

Median payback

4.1 yr

Median IRR 25% (cash saved)

The savings bracket for Ila

Approach B

Cash saved

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

Current energy spend₦9.76bn/yr

Year-one cash saved₦9.65bn

Lifetime cash saved₦513bn

NPV₦78.7bn

Median IRR25%

Median payback4.1 yr

Unlocked energy7.45 GWh/yr

Approach A

Energy value (upper bracket)

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

Installed capacity35.5 MWp

Capex₦36.5bn

Year-one energy value₦31.7bn

Lifetime energy value₦1.5tn

NPV₦252bn

Median IRR87%

Median payback1.1 yr

Three ways to size Ila'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: 35.5 MWp
Capital cost: ₦36.5bn
Year 1 savings: ₦31.7bn/yr
NPV: ₦252bn
Median IRR: 87%
Median payback: 1.1 yr

The odds a rooftop in Ila pays back quickly

Of the 26,312 buildings in Ila with a modelled payback, 60.4% pay back inside five years and 26.2% inside three.

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How much of Ila's demand actually gets met

Buildings in Ila consume 15 GWh/yr but want 22.4 GWh/yr. The 33% they cannot buy is suppressed demand — load that appears the moment supply is reliable.

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Electricity billing bands in Ila

Loading band economics…

How many rooftops in Ila 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 26,312 buildings with a modelled result out of 27,198 in Ila. 19,408 clear a positive NPV.

Payback

Under 3 years6,885 (26%)

Under 5 years15,892 (60%)

Under 7 years19,385 (74%)

Under 10 years22,061 (84%)

Return (IRR)

Above 10%21,640 (80%)

Above 15%19,408 (71%)

Above 20%16,899 (62%)

Above 25%13,959 (51%)

CO₂ avoided

17.4 kt/yr

Fuel avoided

4.91 million litres/yr

Energy unlocked

7.45 GWh/yr

Demand that is suppressed today

People served

65k

What hardware costs right now

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

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 Ila

Electricity billing band

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
E	17,016	5,734	₦8bn	₦7.94bn	25%	4.1 yr
D	10,182	1,268	₦1.77bn	₦1.72bn	21%	4.9 yr

Load profile

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Residential	26,493	6,465	₦6.78bn	₦6.72bn	25%	4.4 yr
Anchor	259	219	₦1.95bn	₦1.9bn	55%	1.9 yr
Commercial General	228	167	₦532m	₦532m	49%	2.1 yr
Industrial	188	128	₦380m	₦380m	55%	1.9 yr
Filling Station	16	13	₦23.5m	₦23.5m	53%	1.9 yr
Worship	12	8	₦6.99m	₦6.99m	43%	2.4 yr
Hospitality	2	2	₦89.7m	₦89.7m	51%	2.1 yr

Roof size band

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
100 250m2	11,112	2,915	₦3.72bn	₦3.66bn	25%	4.1 yr
Under 30m2	5,385	1,201	₦156m	₦155m	7%	14.1 yr
50 100m2	4,398	919	₦428m	₦428m	19%	5.6 yr
250 1000m2	3,451	1,327	₦4.24bn	₦4.24bn	27%	4.1 yr
30 50m2	2,826	623	₦139m	₦139m	11%	8.4 yr
Over 1000m2	26	17	₦1.08bn	₦1.04bn	63%	1.6 yr

Settlement type

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Urban Centre	20,348	5,599	₦6.02bn	₦5.97bn	25%	4.1 yr
Unclassified	4,393	575	₦1.62bn	₦1.62bn	19%	5.6 yr
Urban	2,059	632	₦1.83bn	₦1.77bn	25%	4.1 yr
Rural	398	196	₦295m	₦295m	27%	1.9 yr

Building type

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Residential Formal	10,829	1,913	₦1.09bn	₦1.09bn	23%	4.4 yr
Residential	5,096	2,202	₦4.95bn	₦4.89bn	27%	4.1 yr
Shed	3,385	909	₦154m	₦154m	7%	13.6 yr
Residential Small	3,081	1,052	₦370m	₦370m	25%	4.4 yr
Residential Informal	1,905	0	₦16.6m	₦16.6m	13%	6.9 yr
Apartment	1,604	300	₦150m	₦150m	25%	4.1 yr
Duplex	547	84	₦42.3m	₦42.3m	25%	4.1 yr
Institutional	255	194	₦1.08bn	₦1.08bn	51%	2.1 yr
Industrial Site	129	81	₦254m	₦254m	59%	1.9 yr
Educational Facility	66	62	₦256m	₦256m	73%	1.4 yr
School	60	56	₦183m	₦183m	69%	1.4 yr
Healthcare Facility	53	39	₦565m	₦561m	47%	2.4 yr

Land use

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)
(Unset)	25,932	6,777	₦9.38bn	₦9.28bn
Farmland	1,266	225	₦388m	₦378m

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	26,733	6,641	₦7.41bn	₦7.35bn	25%	4.4 yr
Enterprise	447	347	₦2.33bn	₦2.28bn	55%	1.9 yr
SME High	18	14	₦24.3m	₦24.3m	53%	1.9 yr

Demand tier

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)
4.0	13,656	2,359	₦2.52bn	₦2.47bn
3.0	7,916	3,168	₦6.78bn	₦6.72bn
0.0	3,144	763	₦116m	₦116m
2.0	1,801	483	₦235m	₦234m
1.0	669	220	₦67.2m	₦67.2m
5.0	11	8	₦31.7m	₦31.7m
6.0	1	1	₦13.2m	₦13.2m