Imo State

Rooftop solar in Nwangele, Imo: what the roofs are worth

Nwangele has 33,633 buildings with a viable rooftop and 810 MWp of roof capacity. 43% run a generator, and together they spend ₦24.7bn a year on energy.

Viable buildings

33,633

Usable roof area

3.6 km²

810 MWp roof capacity

Energy spend

₦24.7bn/yr

23.2 GWh/yr burned on generators

Median payback

4.4 yr

Median IRR 25% (cash saved)

The savings bracket for Nwangele

Approach B

Cash saved

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

Current energy spend₦24.7bn/yr

Year-one cash saved₦24.5bn

Lifetime cash saved₦1.28tn

NPV₦201bn

Median IRR25%

Median payback4.4 yr

Unlocked energy23.3 GWh/yr

Approach A

Energy value (upper bracket)

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

Installed capacity106 MWp

Capex₦107bn

Year-one energy value₦93.8bn

Lifetime energy value₦4.47tn

NPV₦751bn

Median IRR99%

Median payback1.1 yr

Three ways to size Nwangele'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: 106 MWp
Capital cost: ₦107bn
Year 1 savings: ₦93.8bn/yr
NPV: ₦751bn
Median IRR: 99%
Median payback: 1.1 yr

The odds a rooftop in Nwangele pays back quickly

Of the 33,612 buildings in Nwangele with a modelled payback, 76.0% pay back inside five years and 43.4% inside three.

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How much of Nwangele's demand actually gets met

Buildings in Nwangele consume 35.4 GWh/yr but want 58.7 GWh/yr. The 40% they cannot buy is suppressed demand — load that appears the moment supply is reliable.

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Electricity billing bands in Nwangele

Loading band economics…

How many rooftops in Nwangele 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 33,612 buildings with a modelled result out of 33,633 in Nwangele. 29,405 clear a positive NPV.

Payback

Under 3 years14,599 (43%)

Under 5 years25,556 (76%)

Under 7 years29,371 (87%)

Under 10 years30,974 (92%)

Return (IRR)

Above 10%30,451 (91%)

Above 15%29,405 (87%)

Above 20%26,830 (80%)

Above 25%18,205 (54%)

CO₂ avoided

45.9 kt/yr

Fuel avoided

12.9 million litres/yr

Energy unlocked

23.3 GWh/yr

Demand that is suppressed today

People served

225k

What hardware costs right now

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

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 Nwangele

Electricity billing band

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
C	12,647	5,248	₦8.55bn	₦8.55bn	25%	4.4 yr
D	10,434	4,702	₦7.82bn	₦7.73bn	25%	4.4 yr
E	8,667	3,883	₦7.41bn	₦7.29bn	25%	4.4 yr
B	1,885	761	₦921m	₦921m	25%	4.4 yr

Load profile

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Residential	31,771	12,895	₦18.4bn	₦18.2bn	25%	4.4 yr
Commercial General	1,107	1,009	₦4.46bn	₦4.46bn	61%	1.6 yr
Commercial Retail	403	379	₦106m	₦106m	61%	1.6 yr
Anchor	208	187	₦1.36bn	₦1.33bn	63%	1.6 yr
Worship	91	81	₦233m	₦233m	61%	1.6 yr
Industrial	38	30	₦108m	₦108m	67%	1.6 yr
Filling Station	13	11	₦28.6m	₦28.6m	53%	2.1 yr
Hospitality	2	2	₦40.4m	₦40.4m	55%	1.6 yr

Roof size band

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
100 250m2	13,274	5,596	₦10.5bn	₦10.5bn	25%	4.4 yr
50 100m2	7,597	3,298	₦1.77bn	₦1.68bn	25%	4.4 yr
Under 30m2	4,803	2,120	₦226m	₦226m	17%	6.4 yr
30 50m2	4,162	1,768	₦331m	₦331m	21%	5.4 yr
250 1000m2	3,757	1,780	₦11bn	₦10.9bn	25%	4.1 yr
Over 1000m2	40	32	₦837m	₦829m	75%	1.4 yr

Settlement type

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Urban Centre	31,918	13,934	₦23.4bn	₦23.4bn	25%	4.4 yr
Unclassified	1,715	660	₦1.28bn	₦1.11bn	25%	4.4 yr

Building type

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Residential	13,033	5,344	₦15.6bn	₦15.5bn	25%	4.4 yr
Residential Small	12,154	5,041	₦2.55bn	₦2.45bn	25%	4.4 yr
Shed	6,582	2,510	₦224m	₦224m	11%	9.1 yr
Commercial Corridor	702	644	₦2.63bn	₦2.63bn	63%	1.6 yr
Kiosk Shop	403	379	₦106m	₦106m	61%	1.6 yr
Commercial	246	227	₦1.22bn	₦1.22bn	59%	1.9 yr
Institutional	163	144	₦691m	₦691m	57%	1.9 yr
Educational Facility	65	58	₦269m	₦269m	83%	1.4 yr
School	56	51	₦164m	₦164m	81%	1.4 yr
Worship Center	33	29	₦50.3m	₦50.3m	63%	1.6 yr
Healthcare Facility	32	28	₦676m	₦650m	53%	2.1 yr
Clinic	30	25	₦116m	₦116m	49%	2.1 yr

Land use

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)
(Unset)	33,633	14,594	₦24.7bn	₦24.5bn

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	32,425	13,494	₦19.3bn	₦19.1bn	25%	4.4 yr
SME High	962	883	₦3.9bn	₦3.9bn	63%	1.6 yr
Enterprise	246	217	₦1.47bn	₦1.44bn	65%	1.6 yr

Demand tier

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)
3.0	21,193	8,880	₦19.7bn	₦19.6bn
0.0	6,582	2,508	₦224m	₦224m
2.0	4,444	2,125	₦1.23bn	₦1.14bn
4.0	604	416	₦2.84bn	₦2.84bn
1.0	568	425	₦113m	₦113m
5.0	221	220	₦494m	₦494m
6.0	21	20	₦118m	₦118m