Gombe State

Rooftop solar in Billiri, Gombe: what the roofs are worth

Billiri has 77,057 buildings with a viable rooftop and 587 MWp of roof capacity. 11% run a generator, and together they spend ₦22.2bn a year on energy.

Viable buildings

77,057

Usable roof area

2.65 km²

587 MWp roof capacity

Energy spend

₦22.2bn/yr

19.7 GWh/yr burned on generators

Median payback

6.6 yr

Median IRR 15% (cash saved)

The savings bracket for Billiri

Approach B

Cash saved

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

Current energy spend₦22.2bn/yr

Year-one cash saved₦21.2bn

Lifetime cash saved₦1.12tn

NPV₦171bn

Median IRR15%

Median payback6.6 yr

Unlocked energy17.5 GWh/yr

Approach A

Energy value (upper bracket)

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

Installed capacity83.7 MWp

Capex₦88bn

Year-one energy value₦85.5bn

Lifetime energy value₦4.04tn

NPV₦691bn

Median IRR99%

Median payback1.1 yr

Three ways to size Billiri'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: 83.7 MWp
Capital cost: ₦88bn
Year 1 savings: ₦85.5bn/yr
NPV: ₦691bn
Median IRR: 99%
Median payback: 1.1 yr

The odds a rooftop in Billiri pays back quickly

Of the 76,703 buildings in Billiri with a modelled payback, 37.0% pay back inside five years and 11.4% inside three.

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How much of Billiri's demand actually gets met

Buildings in Billiri consume 40.3 GWh/yr but want 57.8 GWh/yr. The 30% they cannot buy is suppressed demand — load that appears the moment supply is reliable.

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Electricity billing bands in Billiri

Loading band economics…

How many rooftops in Billiri 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 76,703 buildings with a modelled result out of 77,057 in Billiri. 39,069 clear a positive NPV.

Payback

Under 3 years8,733 (11%)

Under 5 years28,356 (37%)

Under 7 years39,121 (51%)

Under 10 years44,780 (58%)

Return (IRR)

Above 10%43,106 (56%)

Above 15%39,069 (51%)

Above 20%31,134 (40%)

Above 25%25,238 (33%)

CO₂ avoided

39.3 kt/yr

Fuel avoided

9.6 million litres/yr

Energy unlocked

17.5 GWh/yr

Demand that is suppressed today

People served

276k

What hardware costs right now

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

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 Billiri

Electricity billing band

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
B	22,811	5,255	₦12.5bn	₦12.1bn	29%	3.9 yr
C	20,499	1,140	₦4.26bn	₦4.23bn	7%	14.4 yr
D	13,294	368	₦2.44bn	₦1.91bn	5%	15.9 yr
E	12,555	325	₦1.06bn	₦1.02bn	5%	16.1 yr
A	7,898	1,288	₦1.94bn	₦1.94bn	25%	4.4 yr

Load profile

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Residential	74,799	6,787	₦14.7bn	₦13.7bn	15%	7.1 yr
Commercial Retail	769	366	₦155m	₦155m	37%	2.9 yr
Commercial General	715	562	₦4.19bn	₦4.16bn	53%	2.1 yr
Anchor	467	413	₦3.01bn	₦2.99bn	63%	1.6 yr
Worship	261	216	₦148m	₦148m	57%	1.9 yr
Industrial	38	28	₦53.5m	₦53.5m	57%	1.9 yr
Filling Station	7	3	₦6.51m	₦6.51m	37%	2.9 yr
Hospitality	1	1	₦940k	₦940k	63%	1.6 yr

Roof size band

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Under 30m2	42,622	2,783	₦457m	₦457m	5%	15.9 yr
30 50m2	14,861	1,390	₦596m	₦596m	19%	5.6 yr
50 100m2	11,759	1,787	₦2.11bn	₦2.05bn	29%	3.6 yr
100 250m2	6,770	1,883	₦8.48bn	₦7.68bn	31%	3.6 yr
250 1000m2	996	498	₦7.8bn	₦7.61bn	39%	2.6 yr
Over 1000m2	49	35	₦2.8bn	₦2.78bn	63%	1.6 yr

Settlement type

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Urban	31,751	1,104	₦5.03bn	₦4.65bn	7%	14.6 yr
Urban Centre	30,710	6,635	₦14.3bn	₦14.1bn	27%	3.9 yr
Unclassified	9,285	452	₦2bn	₦1.67bn	5%	17.4 yr
Rural	4,079	107	₦710m	₦504m	5%	16.1 yr
Dense Urban	1,232	78	₦218m	₦218m	19%	5.6 yr

Building type

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Shed	43,842	2,167	₦306m	₦306m	7%	15.6 yr
Residential Small	14,343	2,431	₦2.71bn	₦2.39bn	29%	3.6 yr
Residential	8,298	1,389	₦10.6bn	₦9.88bn	29%	3.6 yr
Residential Formal	6,327	0	₦117m	₦117m	19%	5.6 yr
Residential Informal	1,896	799	₦964m	₦964m	31%	3.6 yr
Kiosk Shop	769	366	₦155m	₦155m	37%	2.9 yr
Commercial	364	249	₦2.66bn	₦2.64bn	53%	2.1 yr
Institutional	357	311	₦2.4bn	₦2.39bn	55%	1.9 yr
Educational Facility	142	131	₦450m	₦450m	85%	1.1 yr
School	115	103	₦172m	₦172m	79%	1.4 yr
Place Of Worship	88	74	₦13.5m	₦13.5m	59%	1.9 yr
Healthcare Facility	87	75	₦389m	₦389m	53%	1.9 yr

Land use

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)
(Unset)	77,057	8,376	₦22.2bn	₦21.2bn

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	76,136	7,632	₦15.7bn	₦14.7bn	15%	6.9 yr
Enterprise	483	427	₦3.03bn	₦3.02bn	63%	1.6 yr
SME High	438	317	₦3.5bn	₦3.47bn	53%	2.1 yr

Demand tier

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)
0.0	43,895	2,210	₦308m	₦308m
2.0	11,055	1,932	₦2.26bn	₦2.14bn
3.0	10,927	3,064	₦14bn	₦13.1bn
4.0	5,932	245	₦2.02bn	₦2.01bn
1.0	4,926	694	₦414m	₦380m
5.0	249	170	₦1.33bn	₦1.31bn
6.0	73	61	₦1.91bn	₦1.9bn