Nasarawa State

Rooftop solar in Wamba, Nasarawa: what the roofs are worth

Wamba has 28,466 buildings with a viable rooftop and 350 MWp of roof capacity. 21% run a generator, and together they spend ₦12.7bn a year on energy.

Viable buildings

28,466

Usable roof area

1.57 km²

350 MWp roof capacity

Energy spend

₦12.7bn/yr

11.8 GWh/yr burned on generators

Median payback

4.1 yr

Median IRR 25% (cash saved)

The savings bracket for Wamba

Approach B

Cash saved

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

Current energy spend₦12.7bn/yr

Year-one cash saved₦12bn

Lifetime cash saved₦630bn

NPV₦98.4bn

Median IRR25%

Median payback4.1 yr

Unlocked energy9.08 GWh/yr

Approach A

Energy value (upper bracket)

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

Installed capacity49.4 MWp

Capex₦52.2bn

Year-one energy value₦50.9bn

Lifetime energy value₦2.42tn

NPV₦412bn

Median IRR105%

Median payback1.1 yr

Three ways to size Wamba'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: 49.4 MWp
Capital cost: ₦52.2bn
Year 1 savings: ₦50.9bn/yr
NPV: ₦412bn
Median IRR: 105%
Median payback: 1.1 yr

The odds a rooftop in Wamba pays back quickly

Of the 27,895 buildings in Wamba with a modelled payback, 56.8% pay back inside five years and 21.8% inside three.

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How much of Wamba's demand actually gets met

Buildings in Wamba consume 19.3 GWh/yr but want 28.4 GWh/yr. The 32% they cannot buy is suppressed demand — load that appears the moment supply is reliable.

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Electricity billing bands in Wamba

Loading band economics…

How many rooftops in Wamba 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 27,895 buildings with a modelled result out of 28,466 in Wamba. 17,445 clear a positive NPV.

Payback

Under 3 years6,078 (22%)

Under 5 years15,839 (57%)

Under 7 years17,445 (63%)

Under 10 years19,799 (71%)

Return (IRR)

Above 10%18,905 (66%)

Above 15%17,445 (61%)

Above 20%16,388 (58%)

Above 25%14,397 (51%)

CO₂ avoided

21.6 kt/yr

Fuel avoided

6.22 million litres/yr

Energy unlocked

9.08 GWh/yr

Demand that is suppressed today

People served

135k

What hardware costs right now

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

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 Wamba

Electricity billing band

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
E	15,326	2,100	₦5.23bn	₦4.93bn	17%	5.6 yr
D	9,031	2,596	₦5.1bn	₦5.08bn	27%	3.9 yr
C	4,109	1,374	₦2.38bn	₦2.02bn	27%	3.9 yr

Load profile

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Residential	27,469	5,122	₦9.3bn	₦8.98bn	25%	4.4 yr
Worship	479	458	₦372m	₦372m	63%	1.6 yr
Anchor	299	279	₦2.03bn	₦1.67bn	71%	1.4 yr
Commercial General	202	194	₦972m	₦972m	61%	1.6 yr
Commercial Retail	11	11	₦4.42m	₦4.42m	71%	1.4 yr
Industrial	6	6	₦24m	₦24m	73%	1.4 yr

Roof size band

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Under 30m2	9,245	1,054	₦137m	₦136m	5%	16.1 yr
50 100m2	7,668	1,724	₦1.98bn	₦1.92bn	27%	3.9 yr
100 250m2	5,565	1,917	₦4.64bn	₦4.58bn	29%	3.9 yr
30 50m2	5,251	925	₦298m	₦296m	11%	8.9 yr
250 1000m2	721	440	₦4.26bn	₦4.07bn	59%	1.9 yr
Over 1000m2	16	10	₦1.39bn	₦1.02bn	63%	1.6 yr

Settlement type

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Unclassified	15,022	1,835	₦4.76bn	₦4.45bn	11%	8.9 yr
Rural	7,277	1,167	₦2.77bn	₦2.76bn	25%	4.4 yr
Dense Urban	4,784	2,355	₦3.91bn	₦3.55bn	29%	3.9 yr
Urban	1,383	713	₦1.27bn	₦1.27bn	51%	2.1 yr

Building type

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Shed	11,966	1,231	₦150m	₦150m	7%	14.9 yr
Residential Small	9,295	1,978	₦2.18bn	₦2.12bn	27%	3.9 yr
Residential	4,189	1,410	₦6.26bn	₦6.01bn	29%	3.9 yr
Residential Formal	1,156	1	₦41.3m	₦41.3m	25%	4.4 yr
Residential Informal	863	502	₦666m	₦666m	51%	2.1 yr
Institutional	327	311	₦1.26bn	₦1.26bn	59%	1.9 yr
Worship Center	161	152	₦84.2m	₦84.2m	67%	1.6 yr
Place Of Worship	156	151	₦46.6m	₦46.6m	65%	1.6 yr
Educational Facility	103	95	₦326m	₦326m	89%	1.1 yr
School	71	65	₦138m	₦138m	85%	1.1 yr
Healthcare Facility	67	63	₦1.32bn	₦961m	53%	1.9 yr
Clinic	53	52	₦108m	₦108m	53%	1.9 yr

Land use

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)
(Unset)	28,466	6,070	₦12.7bn	₦12bn

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	28,129	5,753	₦10.6bn	₦10.2bn	25%	4.4 yr
Enterprise	303	283	₦2.05bn	₦1.69bn	71%	1.4 yr
SME High	34	34	₦92.6m	₦92.6m	67%	1.6 yr

Demand tier

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)
0.0	11,981	1,245	₦152m	₦152m
2.0	7,718	2,342	₦3.7bn	₦3.63bn
1.0	4,137	1,029	₦1.14bn	₦1.08bn
3.0	3,724	1,428	₦6.64bn	₦6.44bn
4.0	906	26	₦1.09bn	₦724m