Katsina State

Rooftop solar in Danja, Katsina: what the roofs are worth

Danja has 89,917 buildings with a viable rooftop and 724 MWp of roof capacity. 10% run a generator, and together they spend ₦11.4bn a year on energy.

Viable buildings

89,917

Usable roof area

3.27 km²

724 MWp roof capacity

Energy spend

₦11.4bn/yr

9.21 GWh/yr burned on generators

Median payback

8.6 yr

Median IRR 11% (cash saved)

The savings bracket for Danja

Approach B

Cash saved

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

Current energy spend₦11.4bn/yr

Year-one cash saved₦11.3bn

Lifetime cash saved₦607bn

NPV₦94.2bn

Median IRR11%

Median payback8.6 yr

Unlocked energy10.8 GWh/yr

Approach A

Energy value (upper bracket)

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

Installed capacity68.7 MWp

Capex₦75bn

Year-one energy value₦85.3bn

Lifetime energy value₦4.08tn

NPV₦708bn

Median IRR113%

Median payback0.9 yr

Three ways to size Danja'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: 68.7 MWp
Capital cost: ₦75bn
Year 1 savings: ₦85.3bn/yr
NPV: ₦708bn
Median IRR: 113%
Median payback: 0.9 yr

The odds a rooftop in Danja pays back quickly

Of the 88,977 buildings in Danja with a modelled payback, 34.8% pay back inside five years and 9.9% inside three.

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How much of Danja's demand actually gets met

Buildings in Danja consume 17.8 GWh/yr but want 28.7 GWh/yr. The 38% they cannot buy is suppressed demand — load that appears the moment supply is reliable.

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Electricity billing bands in Danja

Loading band economics…

How many rooftops in Danja 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 88,977 buildings with a modelled result out of 89,917 in Danja. 39,253 clear a positive NPV.

Payback

Under 3 years8,769 (10%)

Under 5 years30,965 (35%)

Under 7 years39,360 (44%)

Under 10 years55,874 (63%)

Return (IRR)

Above 10%50,546 (56%)

Above 15%39,253 (44%)

Above 20%33,142 (37%)

Above 25%27,000 (30%)

CO₂ avoided

22.2 kt/yr

Fuel avoided

5.89 million litres/yr

Energy unlocked

10.8 GWh/yr

Demand that is suppressed today

People served

251k

What hardware costs right now

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

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 Danja

Electricity billing band

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
C	33,020	2,605	₦3.83bn	₦3.83bn	13%	7.4 yr
E	26,502	3,039	₦3.24bn	₦3.18bn	9%	9.6 yr
D	25,666	2,795	₦4.03bn	₦4.02bn	9%	9.4 yr
B	4,729	291	₦300m	₦300m	23%	4.6 yr

Load profile

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Residential	89,317	8,238	₦10.3bn	₦10.2bn	11%	8.6 yr
Anchor	256	194	₦514m	₦514m	63%	1.6 yr
Commercial General	173	137	₦495m	₦495m	63%	1.6 yr
Worship	97	91	₦55.2m	₦55.2m	69%	1.6 yr
Commercial Retail	67	67	₦37.3m	₦37.3m	75%	1.4 yr
Industrial	7	3	₦6.16m	₦6.16m	41%	2.6 yr

Roof size band

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Under 30m2	42,167	3,290	₦409m	₦409m	7%	14.6 yr
30 50m2	20,617	1,891	₦660m	₦616m	11%	8.6 yr
50 100m2	17,534	1,892	₦2.05bn	₦2.05bn	29%	3.9 yr
100 250m2	8,334	1,397	₦5.1bn	₦5.08bn	31%	3.4 yr
250 1000m2	1,250	257	₦3.08bn	₦3.08bn	31%	3.4 yr
Over 1000m2	15	3	₦94.1m	₦94.1m	33%	3.4 yr

Settlement type

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Urban	42,663	7,401	₦8.93bn	₦8.86bn	11%	8.9 yr
Unclassified	20,795	230	₦1.36bn	₦1.36bn	9%	13.1 yr
Dense Urban	18,177	1,016	₦834m	₦834m	17%	5.9 yr
Rural	8,282	83	₦268m	₦268m	9%	9.4 yr

Building type

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Shed	51,260	4,238	₦514m	₦514m	9%	13.6 yr
Residential Small	18,210	2,370	₦2.4bn	₦2.36bn	31%	3.6 yr
Residential	9,079	1,630	₦7.21bn	₦7.19bn	31%	3.4 yr
Residential Informal	8,550	0	₦115m	₦115m	15%	6.1 yr
Residential Formal	2,149	0	₦43.7m	₦43.7m	21%	5.1 yr
Institutional	170	134	₦403m	₦403m	63%	1.6 yr
Educational Facility	93	69	₦122m	₦122m	93%	1.1 yr
Kiosk Shop	67	67	₦37.3m	₦37.3m	75%	1.4 yr
School	63	45	₦67.4m	₦67.4m	91%	1.1 yr
Healthcare Facility	58	48	₦209m	₦209m	61%	1.6 yr
Apartment	56	0	₦1.68m	₦1.68m	31%	3.6 yr
Clinic	40	30	₦66.8m	₦66.8m	59%	1.9 yr

Land use

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)
(Unset)	89,917	8,730	₦11.4bn	₦11.3bn

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	89,626	8,501	₦10.7bn	₦10.6bn	11%	8.6 yr
Enterprise	257	195	₦517m	₦517m	63%	1.6 yr
SME High	34	34	₦174m	₦174m	77%	1.4 yr

Demand tier

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)
0.0	51,270	4,248	₦515m	₦515m
2.0	16,323	1,868	₦3.01bn	₦2.99bn
3.0	13,223	1,931	₦7.06bn	₦7.05bn
1.0	5,518	679	₦618m	₦573m
4.0	3,583	4	₦196m	₦196m