Rivers State

Rooftop solar in Gokana, Rivers: what the roofs are worth

Gokana has 34,269 buildings with a viable rooftop and 700 MWp of roof capacity. 45% run a generator, and together they spend ₦73bn a year on energy.

Viable buildings

34,269

Usable roof area

3.12 km²

700 MWp roof capacity

Energy spend

₦73bn/yr

63.2 GWh/yr burned on generators

Median payback

4.6 yr

Median IRR 25% (cash saved)

The savings bracket for Gokana

Approach B

Cash saved

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

Current energy spend₦73bn/yr

Year-one cash saved₦70.4bn

Lifetime cash saved₦3.6tn

NPV₦537bn

Median IRR25%

Median payback4.6 yr

Unlocked energy34.6 GWh/yr

Approach A

Energy value (upper bracket)

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

Installed capacity176 MWp

Capex₦179bn

Year-one energy value₦128bn

Lifetime energy value₦6tn

NPV₦977bn

Median IRR75%

Median payback1.4 yr

Three ways to size Gokana'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: 176 MWp
Capital cost: ₦179bn
Year 1 savings: ₦128bn/yr
NPV: ₦977bn
Median IRR: 75%
Median payback: 1.4 yr

The odds a rooftop in Gokana pays back quickly

Of the 34,000 buildings in Gokana with a modelled payback, 81.2% pay back inside five years and 43.6% inside three.

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How much of Gokana's demand actually gets met

Buildings in Gokana consume 108 GWh/yr but want 142 GWh/yr. The 24% they cannot buy is suppressed demand — load that appears the moment supply is reliable.

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Electricity billing bands in Gokana

Loading band economics…

How many rooftops in Gokana 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 34,000 buildings with a modelled result out of 34,269 in Gokana. 31,357 clear a positive NPV.

Payback

Under 3 years14,837 (44%)

Under 5 years27,610 (81%)

Under 7 years31,308 (92%)

Under 10 years32,755 (96%)

Return (IRR)

Above 10%32,569 (95%)

Above 15%31,357 (92%)

Above 20%28,785 (84%)

Above 25%15,663 (46%)

CO₂ avoided

121 kt/yr

Fuel avoided

37.5 million litres/yr

Energy unlocked

34.6 GWh/yr

Demand that is suppressed today

People served

269k

What hardware costs right now

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

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 Gokana

Electricity billing band

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
C	22,862	10,654	₦47.2bn	₦45.6bn	25%	4.6 yr
D	7,382	2,964	₦13.6bn	₦13bn	23%	4.6 yr
E	3,387	1,755	₦6.61bn	₦6.27bn	63%	1.6 yr
B	638	178	₦5.59bn	₦5.43bn	23%	4.6 yr

Load profile

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Residential	33,585	14,984	₦61.2bn	₦59.4bn	23%	4.6 yr
Worship	280	225	₦580m	₦580m	45%	2.4 yr
Anchor	210	187	₦9.47bn	₦8.6bn	57%	1.9 yr
Commercial General	168	137	₦1.22bn	₦1.22bn	43%	2.4 yr
Industrial	24	18	₦591m	₦561m	59%	1.9 yr
Mall Retail	2	0	₦84.9k	₦84.9k	31%	3.4 yr

Roof size band

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
100 250m2	10,584	5,279	₦27bn	₦26.3bn	31%	3.4 yr
50 100m2	8,782	3,674	₦4.36bn	₦4.32bn	23%	4.6 yr
Under 30m2	6,739	2,746	₦557m	₦550m	21%	4.9 yr
30 50m2	5,322	2,097	₦986m	₦971m	23%	4.6 yr
250 1000m2	2,776	1,704	₦30.3bn	₦29.1bn	47%	2.4 yr
Over 1000m2	66	51	₦9.85bn	₦9.1bn	53%	2.1 yr

Settlement type

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Urban Centre	25,179	11,194	₦41.2bn	₦39.9bn	23%	4.6 yr
Dense Urban	5,928	3,324	₦22.1bn	₦21.1bn	39%	2.6 yr
Unclassified	1,985	543	₦4.01bn	₦3.92bn	23%	4.6 yr
Urban	1,177	490	₦5.68bn	₦5.51bn	25%	4.6 yr

Building type

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Residential Informal	9,798	2,776	₦7.52bn	₦7.51bn	23%	4.6 yr
Residential Small	7,542	4,344	₦5.77bn	₦5.7bn	51%	2.1 yr
Residential Formal	6,067	2,139	₦5.11bn	₦5.08bn	23%	4.6 yr
Residential	5,667	3,591	₦42.4bn	₦40.7bn	57%	1.9 yr
Shed	4,431	2,095	₦286m	₦286m	21%	5.1 yr
Institutional	216	180	₦6.89bn	₦6.75bn	43%	2.4 yr
Worship Center	94	75	₦147m	₦147m	47%	2.4 yr
Place Of Worship	93	75	₦92.1m	₦92.1m	45%	2.4 yr
Educational Facility	80	71	₦1.28bn	₦1.28bn	61%	1.9 yr
School	62	52	₦240m	₦240m	55%	1.9 yr
Duplex	53	20	₦42.7m	₦42.7m	23%	4.6 yr
Unknown	43	32	₦150m	₦150m	43%	2.4 yr

Land use

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)
(Unset)	34,179	15,493	₦72bn	₦69.4bn
Industrial	89	58	₦975m	₦958m
Farmyard	1	0	₦6.81m	₦3.58m

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	34,033	15,346	₦62.9bn	₦61.2bn	25%	4.6 yr
Enterprise	232	203	₦10.1bn	₦9.16bn	57%	1.9 yr
SME High	4	2	₦44m	₦44m	31%	1.6 yr

Demand tier

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)
2.0	12,803	5,393	₦7.34bn	₦7.3bn
3.0	9,221	5,241	₦55.1bn	₦52.7bn
4.0	5,547	2,024	₦9.61bn	₦9.38bn
0.0	4,433	2,097	₦286m	₦286m
1.0	2,258	789	₦231m	₦224m
5.0	7	7	₦460m	₦432m