Abia State

Rooftop solar in Isiala-Ngwa South, Abia: what the roofs are worth

Isiala-Ngwa South has 55,708 buildings with a viable rooftop and 1.13 GWp of roof capacity. 16% run a generator, and together they spend ₦23bn a year on energy.

Viable buildings

55,708

Usable roof area

5.03 km²

1.13 GWp roof capacity

Energy spend

₦23bn/yr

24.7 GWh/yr burned on generators

Median payback

5.1 yr

Median IRR 21% (cash saved)

The savings bracket for Isiala-Ngwa South

Approach B

Cash saved

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

Current energy spend₦23bn/yr

Year-one cash saved₦22.8bn

Lifetime cash saved₦1.21tn

NPV₦184bn

Median IRR21%

Median payback5.1 yr

Unlocked energy22.5 GWh/yr

Approach A

Energy value (upper bracket)

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

Installed capacity127 MWp

Capex₦122bn

Year-one energy value₦101bn

Lifetime energy value₦4.79tn

NPV₦800bn

Median IRR97%

Median payback1.1 yr

Three ways to size Isiala-Ngwa South'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: 127 MWp
Capital cost: ₦122bn
Year 1 savings: ₦101bn/yr
NPV: ₦800bn
Median IRR: 97%
Median payback: 1.1 yr

The odds a rooftop in Isiala-Ngwa South pays back quickly

Of the 55,491 buildings in Isiala-Ngwa South with a modelled payback, 47.9% pay back inside five years and 16.3% inside three.

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How much of Isiala-Ngwa South's demand actually gets met

Buildings in Isiala-Ngwa South consume 41.1 GWh/yr but want 63.6 GWh/yr. The 35% they cannot buy is suppressed demand — load that appears the moment supply is reliable.

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Electricity billing bands in Isiala-Ngwa South

Loading band economics…

How many rooftops in Isiala-Ngwa South 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 55,491 buildings with a modelled result out of 55,708 in Isiala-Ngwa South. 37,962 clear a positive NPV.

Payback

Under 3 years9,063 (16%)

Under 5 years26,569 (48%)

Under 7 years37,829 (68%)

Under 10 years45,328 (82%)

Return (IRR)

Above 10%43,789 (79%)

Above 15%37,962 (68%)

Above 20%29,628 (53%)

Above 25%10,357 (19%)

CO₂ avoided

41.4 kt/yr

Fuel avoided

9.92 million litres/yr

Energy unlocked

22.5 GWh/yr

Demand that is suppressed today

People served

205k

What hardware costs right now

Median advertised rates from our Nigerian market tracker — the same prices used to cost a system in Isiala-Ngwa South.

Solar panels

₦250

₦/W

Inverters

₦127,419

₦/kVA

Batteries

₦177,500

₦/kWh

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Building mix in Isiala-Ngwa South

Electricity billing band

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
D	23,139	2,963	₦5.47bn	₦5.47bn	19%	5.4 yr
E	21,091	3,820	₦7.87bn	₦7.78bn	21%	5.1 yr
C	10,915	1,923	₦8.11bn	₦8.05bn	23%	4.6 yr
B	563	337	₦1.54bn	₦1.49bn	53%	2.1 yr

Load profile

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Residential	51,959	6,242	₦8.93bn	₦8.79bn	19%	5.4 yr
Commercial General	2,162	1,615	₦9.95bn	₦9.89bn	53%	1.9 yr
Commercial Retail	908	652	₦233m	₦233m	45%	2.4 yr
Anchor	386	324	₦3.15bn	₦3.13bn	73%	1.4 yr
Industrial	237	160	₦598m	₦597m	67%	1.6 yr
Worship	33	31	₦107m	₦107m	61%	1.6 yr
Filling Station	22	18	₦38.4m	₦38.4m	65%	1.6 yr
Hospitality	1	1	₦970k	₦970k	65%	1.6 yr

Roof size band

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
100 250m2	19,429	3,154	₦7.92bn	₦7.84bn	25%	4.6 yr
50 100m2	14,625	2,124	₦1.53bn	₦1.52bn	19%	5.9 yr
Under 30m2	9,474	1,440	₦278m	₦275m	7%	14.4 yr
30 50m2	8,201	1,211	₦427m	₦379m	11%	9.4 yr
250 1000m2	3,952	1,094	₦11bn	₦10.9bn	25%	4.4 yr
Over 1000m2	27	20	₦1.88bn	₦1.87bn	61%	1.6 yr

Settlement type

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Urban	36,905	5,360	₦11.3bn	₦11.3bn	21%	5.4 yr
Unclassified	7,695	887	₦1.89bn	₦1.79bn	19%	5.6 yr
Dense Urban	5,661	2,008	₦7.99bn	₦7.96bn	25%	4.4 yr
Urban Centre	5,447	788	₦1.78bn	₦1.78bn	21%	5.1 yr

Building type

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Residential Small	20,967	2,653	₦1.39bn	₦1.33bn	19%	5.9 yr
Residential	17,874	2,338	₦7.35bn	₦7.27bn	25%	4.6 yr
Shed	13,005	1,238	₦183m	₦183m	9%	13.6 yr
Commercial	1,143	840	₦5.33bn	₦5.32bn	47%	2.4 yr
Kiosk Shop	908	652	₦233m	₦233m	45%	2.4 yr
Commercial Corridor	522	394	₦2.99bn	₦2.94bn	59%	1.9 yr
Institutional	438	346	₦2.5bn	₦2.49bn	55%	1.9 yr
Industrial Site	226	154	₦553m	₦553m	67%	1.6 yr
Educational Facility	142	124	₦717m	₦717m	81%	1.4 yr
Agricultural	113	13	₦8.76m	₦8.76m	23%	4.9 yr
School	99	86	₦212m	₦212m	79%	1.4 yr
Healthcare Facility	79	62	₦1.09bn	₦1.08bn	53%	2.1 yr

Land use

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)
(Unset)	55,708	9,043	₦23bn	₦22.8bn

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	53,408	7,312	₦10.9bn	₦10.8bn	21%	5.4 yr
SME High	1,688	1,253	₦8.36bn	₦8.3bn	51%	2.1 yr
Enterprise	612	478	₦3.73bn	₦3.72bn	69%	1.6 yr

Demand tier

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)
3.0	27,357	4,424	₦13.9bn	₦13.8bn
0.0	13,120	1,254	₦192m	₦192m
2.0	11,785	1,879	₦1.4bn	₦1.35bn
1.0	2,297	686	₦262m	₦261m
5.0	538	322	₦1.9bn	₦1.88bn
4.0	504	418	₦4.51bn	₦4.5bn
6.0	107	60	₦829m	₦791m