Imo State

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

Isu has 31,892 buildings with a viable rooftop and 743 MWp of roof capacity. 49% run a generator, and together they spend ₦29.2bn a year on energy.

Viable buildings

31,892

Usable roof area

3.31 km²

743 MWp roof capacity

Energy spend

₦29.2bn/yr

26.6 GWh/yr burned on generators

Median payback

4.4 yr

Median IRR 25% (cash saved)

The savings bracket for Isu

Approach B

Cash saved

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

Current energy spend₦29.2bn/yr

Year-one cash saved₦28.8bn

Lifetime cash saved₦1.48tn

NPV₦236bn

Median IRR25%

Median payback4.4 yr

Unlocked energy23.5 GWh/yr

Approach A

Energy value (upper bracket)

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

Installed capacity104 MWp

Capex₦109bn

Year-one energy value₦98.8bn

Lifetime energy value₦4.71tn

NPV₦795bn

Median IRR99%

Median payback1.1 yr

Three ways to size Isu'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: 104 MWp
Capital cost: ₦109bn
Year 1 savings: ₦98.8bn/yr
NPV: ₦795bn
Median IRR: 99%
Median payback: 1.1 yr

The odds a rooftop in Isu pays back quickly

Of the 31,836 buildings in Isu with a modelled payback, 77.3% pay back inside five years and 48.8% inside three.

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How much of Isu's demand actually gets met

Buildings in Isu consume 36.5 GWh/yr but want 60 GWh/yr. The 39% they cannot buy is suppressed demand — load that appears the moment supply is reliable.

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Electricity billing bands in Isu

Loading band economics…

How many rooftops in Isu 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 31,836 buildings with a modelled result out of 31,892 in Isu. 27,589 clear a positive NPV.

Payback

Under 3 years15,545 (49%)

Under 5 years24,615 (77%)

Under 7 years27,560 (87%)

Under 10 years29,507 (93%)

Return (IRR)

Above 10%28,960 (91%)

Above 15%27,589 (87%)

Above 20%25,618 (80%)

Above 25%17,626 (55%)

CO₂ avoided

52.7 kt/yr

Fuel avoided

16.4 million litres/yr

Energy unlocked

23.5 GWh/yr

Demand that is suppressed today

People served

238k

What hardware costs right now

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

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 Isu

Electricity billing band

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
D	12,255	5,654	₦11.7bn	₦11.4bn	25%	4.4 yr
E	10,316	4,444	₦9.84bn	₦9.81bn	25%	4.4 yr
C	7,627	4,322	₦6.78bn	₦6.78bn	55%	1.9 yr
B	1,694	1,126	₦799m	₦799m	49%	2.1 yr

Load profile

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Residential	31,328	15,007	₦25.1bn	₦24.8bn	25%	4.4 yr
Commercial General	274	265	₦2.05bn	₦2.01bn	61%	1.9 yr
Anchor	216	202	₦1.96bn	₦1.92bn	69%	1.6 yr
Commercial Retail	52	51	₦22.3m	₦22.3m	65%	1.6 yr
Industrial	12	11	₦45.5m	₦45.5m	69%	1.4 yr
Worship	8	8	₦18.1m	₦18.1m	63%	1.6 yr
Filling Station	2	2	₦943k	₦943k	39%	1.6 yr

Roof size band

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
100 250m2	11,998	5,814	₦12.3bn	₦12.3bn	25%	4.4 yr
50 100m2	7,592	3,672	₦2.12bn	₦2.12bn	25%	4.4 yr
Under 30m2	4,500	2,175	₦216m	₦216m	17%	5.9 yr
30 50m2	4,340	2,090	₦403m	₦403m	23%	4.6 yr
250 1000m2	3,435	1,775	₦12.8bn	₦12.5bn	51%	2.1 yr
Over 1000m2	27	20	₦1.31bn	₦1.27bn	63%	1.6 yr

Settlement type

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Urban Centre	29,569	14,627	₦27.9bn	₦27.6bn	25%	4.4 yr
Unclassified	2,323	919	₦1.22bn	₦1.22bn	25%	4.4 yr

Building type

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Residential Small	12,864	6,340	₦3.51bn	₦3.51bn	25%	4.4 yr
Residential	12,035	5,807	₦21.3bn	₦21bn	25%	4.4 yr
Shed	6,429	2,860	₦256m	₦256m	11%	8.6 yr
Commercial	144	144	₦1.54bn	₦1.5bn	67%	1.6 yr
Institutional	124	116	₦921m	₦921m	57%	1.9 yr
Educational Facility	66	60	₦411m	₦411m	83%	1.4 yr
School	53	52	₦154m	₦154m	83%	1.4 yr
Kiosk Shop	52	51	₦22.3m	₦22.3m	65%	1.6 yr
Healthcare Facility	42	39	₦717m	₦672m	53%	2.1 yr
Clinic	36	33	₦139m	₦139m	51%	2.1 yr
Industrial Site	12	11	₦45.5m	₦45.5m	69%	1.4 yr
Market	8	8	₦7.34m	₦7.34m	63%	1.6 yr

Land use

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)
(Unset)	31,892	15,546	₦29.2bn	₦28.8bn

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	31,518	15,187	₦25.6bn	₦25.3bn	25%	4.4 yr
Enterprise	228	213	₦2.01bn	₦1.97bn	69%	1.6 yr
SME High	146	146	₦1.54bn	₦1.5bn	67%	1.6 yr

Demand tier

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)
3.0	20,627	10,408	₦26.4bn	₦26.1bn
0.0	6,428	2,859	₦256m	₦256m
2.0	4,452	2,036	₦1.12bn	₦1.12bn
1.0	311	169	₦47m	₦47m
4.0	67	67	₦809m	₦809m
5.0	7	7	₦506m	₦469m