Delta State

Rooftop solar in Isoko South, Delta: what the roofs are worth

Isoko South has 53,303 buildings with a viable rooftop and 1.35 GWp of roof capacity. 70% run a generator, and together they spend ₦127bn a year on energy.

Viable buildings

53,303

Usable roof area

5.98 km²

1.35 GWp roof capacity

Energy spend

₦127bn/yr

108 GWh/yr burned on generators

Median payback

2.4 yr

Median IRR 45% (cash saved)

The savings bracket for Isoko South

Approach B

Cash saved

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

Current energy spend₦127bn/yr

Year-one cash saved₦123bn

Lifetime cash saved₦6.22tn

NPV₦930bn

Median IRR45%

Median payback2.4 yr

Unlocked energy38.4 GWh/yr

Approach A

Energy value (upper bracket)

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

Installed capacity240 MWp

Capex₦252bn

Year-one energy value₦186bn

Lifetime energy value₦8.76tn

NPV₦1.43tn

Median IRR81%

Median payback1.4 yr

Three ways to size Isoko 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: 240 MWp
Capital cost: ₦252bn
Year 1 savings: ₦186bn/yr
NPV: ₦1.43tn
Median IRR: 81%
Median payback: 1.4 yr

The odds a rooftop in Isoko South pays back quickly

Of the 53,191 buildings in Isoko South with a modelled payback, 89.6% pay back inside five years and 62.2% inside three.

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How much of Isoko South's demand actually gets met

Buildings in Isoko South consume 174 GWh/yr but want 213 GWh/yr. The 18% they cannot buy is suppressed demand — load that appears the moment supply is reliable.

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Electricity billing bands in Isoko South

Loading band economics…

How many rooftops in Isoko 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 53,191 buildings with a modelled result out of 53,303 in Isoko South. 50,861 clear a positive NPV.

Payback

Under 3 years33,111 (62%)

Under 5 years47,634 (90%)

Under 7 years50,840 (96%)

Under 10 years51,800 (97%)

Return (IRR)

Above 10%51,647 (97%)

Above 15%50,861 (95%)

Above 20%48,704 (91%)

Above 25%39,547 (74%)

CO₂ avoided

203 kt/yr

Fuel avoided

68.5 million litres/yr

Energy unlocked

38.4 GWh/yr

Demand that is suppressed today

People served

362k

What hardware costs right now

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

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 Isoko South

Electricity billing band

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
C	15,388	9,936	₦35.9bn	₦35bn	57%	1.9 yr
A	12,282	8,856	₦18.5bn	₦17.6bn	33%	3.4 yr
B	11,072	8,520	₦29.2bn	₦28.1bn	47%	2.4 yr
E	9,939	6,485	₦29.7bn	₦28.5bn	69%	1.6 yr
D	4,622	3,448	₦14bn	₦13.7bn	59%	1.9 yr

Load profile

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Residential	52,429	36,490	₦116bn	₦112bn	45%	2.4 yr
Anchor	344	303	₦7.5bn	₦7.09bn	63%	1.6 yr
Commercial General	271	238	₦3.19bn	₦3.13bn	49%	2.1 yr
Worship	187	155	₦581m	₦577m	55%	1.9 yr
Commercial Retail	34	25	₦9.21m	₦9.21m	41%	2.6 yr
Industrial	27	25	₦210m	₦207m	71%	1.4 yr
Hospitality	10	9	₦136m	₦131m	47%	2.1 yr
Mall Retail	1	0	₦79.3k	₦79.3k	33%	3.4 yr

Roof size band

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
100 250m2	19,277	13,920	₦49.1bn	₦47.6bn	47%	2.4 yr
Under 30m2	10,400	6,843	₦948m	₦943m	41%	2.6 yr
50 100m2	9,890	6,605	₦5.79bn	₦5.45bn	43%	2.4 yr
250 1000m2	7,570	5,840	₦62.5bn	₦60.4bn	47%	2.4 yr
30 50m2	6,065	3,956	₦1.16bn	₦1.16bn	43%	2.6 yr
Over 1000m2	101	81	₦7.76bn	₦7.32bn	45%	2.4 yr

Settlement type

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Dense Urban	17,865	13,103	₦36bn	₦35.5bn	57%	1.9 yr
Urban Centre	15,336	11,659	₦22.9bn	₦22.5bn	37%	2.9 yr
Urban	9,277	5,983	₦35.8bn	₦33.6bn	57%	1.9 yr
Rural	5,673	4,332	₦18.3bn	₦17.7bn	69%	1.6 yr
Unclassified	5,152	2,168	₦14.4bn	₦13.5bn	25%	4.4 yr

Building type

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Residential	16,820	12,488	₦97.2bn	₦93.7bn	59%	1.9 yr
Residential Small	12,908	9,269	₦9.58bn	₦9.23bn	57%	1.9 yr
Shed	9,689	5,692	₦873m	₦873m	45%	2.4 yr
Residential Formal	7,946	6,933	₦6.6bn	₦6.6bn	41%	2.6 yr
Residential Informal	4,038	1,151	₦634m	₦634m	25%	4.4 yr
Apartment	661	617	₦455m	₦455m	39%	2.9 yr
Duplex	366	340	₦301m	₦301m	45%	2.4 yr
Institutional	273	237	₦6.54bn	₦6.36bn	49%	2.1 yr
Educational Facility	149	132	₦1.18bn	₦1.18bn	69%	1.6 yr
School	108	97	₦474m	₦474m	65%	1.6 yr
Worship Center	63	51	₦91.5m	₦91.5m	57%	1.9 yr
Place Of Worship	60	52	₦78.7m	₦78.7m	57%	1.9 yr

Land use

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)
(Unset)	53,123	37,133	₦127bn	₦122bn
Industrial	180	112	₦483m	₦483m

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	52,884	36,878	₦119bn	₦115bn	45%	2.4 yr
Enterprise	371	328	₦7.71bn	₦7.3bn	65%	1.6 yr
SME High	48	39	₦1.02bn	₦968m	45%	2.4 yr

Demand tier

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)
3.0	24,327	18,063	₦109bn	₦106bn
4.0	10,483	7,904	₦9.02bn	₦9bn
0.0	9,412	5,632	₦867m	₦867m
2.0	7,849	5,012	₦7.24bn	₦6.13bn
1.0	1,226	628	₦377m	₦362m
5.0	5	5	₦413m	₦396m
6.0	1	1	₦284m	₦261m