Taraba State

Rooftop solar in Gassol, Taraba: what the roofs are worth

Gassol has 229,460 buildings with a viable rooftop and 1.06 GWp of roof capacity. 7% run a generator, and together they spend ₦11.4bn a year on energy.

Viable buildings

229,460

Usable roof area

4.86 km²

1.06 GWp roof capacity

Energy spend

₦11.4bn/yr

10.4 GWh/yr burned on generators

Median payback

16.1 yr

Median IRR 5% (cash saved)

The savings bracket for Gassol

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₦11.1bn

Lifetime cash saved₦593bn

NPV₦81.9bn

Median IRR5%

Median payback16.1 yr

Unlocked energy12.5 GWh/yr

Approach A

Energy value (upper bracket)

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

Installed capacity84.2 MWp

Capex₦91.3bn

Year-one energy value₦84.9bn

Lifetime energy value₦4.02tn

NPV₦682bn

Median IRR93%

Median payback1.1 yr

Three ways to size Gassol'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: 84.2 MWp
Capital cost: ₦91.3bn
Year 1 savings: ₦84.9bn/yr
NPV: ₦682bn
Median IRR: 93%
Median payback: 1.1 yr

The odds a rooftop in Gassol pays back quickly

Of the 223,062 buildings in Gassol with a modelled payback, 16.7% pay back inside five years and 6.9% inside three.

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How much of Gassol's demand actually gets met

Buildings in Gassol consume 22.9 GWh/yr but want 35.3 GWh/yr. The 35% they cannot buy is suppressed demand — load that appears the moment supply is reliable.

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Electricity billing bands in Gassol

Loading band economics…

How many rooftops in Gassol 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 223,062 buildings with a modelled result out of 229,460 in Gassol. 57,916 clear a positive NPV.

Payback

Under 3 years15,400 (7%)

Under 5 years37,169 (17%)

Under 7 years58,005 (26%)

Under 10 years76,770 (34%)

Return (IRR)

Above 10%72,734 (32%)

Above 15%57,916 (25%)

Above 20%41,117 (18%)

Above 25%32,030 (14%)

CO₂ avoided

21.9 kt/yr

Fuel avoided

4.59 million litres/yr

Energy unlocked

12.5 GWh/yr

Demand that is suppressed today

People served

286k

What hardware costs right now

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

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 Gassol

Electricity billing band

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
D	87,417	4,677	₦2.02bn	₦2.01bn	5%	17.4 yr
E	69,744	4,271	₦3.06bn	₦2.9bn	5%	17.6 yr
C	38,760	4,109	₦3.03bn	₦2.96bn	7%	13.4 yr
B	33,539	2,525	₦3.26bn	₦3.23bn	15%	6.6 yr

Load profile

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Residential	225,252	13,823	₦6.32bn	₦6.09bn	5%	16.4 yr
Commercial Retail	2,052	540	₦196m	₦196m	35%	3.1 yr
Commercial General	1,478	711	₦3.67bn	₦3.63bn	37%	2.9 yr
Anchor	501	373	₦1.09bn	₦1.09bn	53%	1.9 yr
Industrial	149	114	₦79m	₦79m	61%	1.6 yr
Filling Station	24	17	₦17.2m	₦17.2m	45%	2.4 yr
Worship	4	4	₦450k	₦450k	53%	1.6 yr

Roof size band

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Under 30m2	162,619	8,545	₦820m	₦817m	5%	17.9 yr
30 50m2	32,523	2,925	₦759m	₦756m	11%	9.4 yr
50 100m2	26,232	2,725	₦2.27bn	₦2.27bn	23%	4.6 yr
100 250m2	7,145	1,093	₦3.03bn	₦2.9bn	29%	3.9 yr
250 1000m2	914	278	₦3.21bn	₦3.13bn	29%	3.9 yr
Over 1000m2	27	16	₦1.28bn	₦1.24bn	57%	1.9 yr

Settlement type

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Unclassified	125,426	6,113	₦4.11bn	₦3.9bn	3%	18.1 yr
Rural	50,793	3,687	₦1.97bn	₦1.95bn	7%	14.9 yr
Dense Urban	31,442	2,675	₦3.22bn	₦3.19bn	17%	6.1 yr
Urban	21,799	3,107	₦2.06bn	₦2.06bn	15%	6.9 yr

Building type

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Shed	164,016	7,573	₦646m	₦646m	5%	17.6 yr
Residential Small	26,007	3,183	₦2.38bn	₦2.38bn	25%	4.4 yr
Residential	16,674	2,711	₦3.08bn	₦2.86bn	13%	6.9 yr
Residential Informal	11,180	350	₦177m	₦177m	17%	6.1 yr
Residential Formal	7,316	2	₦33.9m	₦33.9m	9%	9.1 yr
Kiosk Shop	2,052	540	₦196m	₦196m	35%	3.1 yr
Commercial	853	397	₦3.35bn	₦3.31bn	37%	2.9 yr
Institutional	385	290	₦567m	₦567m	51%	2.1 yr
Commercial Corridor	216	7	₦91.6m	₦91.6m	35%	3.1 yr
Educational Facility	175	134	₦140m	₦140m	73%	1.4 yr
Industrial Site	139	107	₦71.9m	₦71.9m	61%	1.6 yr
School	119	81	₦54.4m	₦54.4m	67%	1.6 yr

Land use

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)
(Unset)	229,460	15,582	₦11.4bn	₦11.1bn

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	227,726	14,680	₦6.74bn	₦6.52bn	5%	16.4 yr
SME High	1,093	421	₦3.46bn	₦3.41bn	37%	2.9 yr
Enterprise	641	481	₦1.17bn	₦1.17bn	55%	1.9 yr

Demand tier

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)
0.0	164,075	7,602	₦648m	₦648m
2.0	25,746	3,253	₦2.21bn	₦2.21bn
1.0	16,197	2,329	₦1.02bn	₦1.01bn
3.0	15,703	2,290	₦5.09bn	₦4.88bn
4.0	7,295	101	₦1.29bn	₦1.28bn
5.0	427	7	₦1.08bn	₦1.04bn
6.0	17	0	₦37.1m	₦37.1m