Lagos State

Rooftop solar in Eti Osa, Lagos: what the roofs are worth

Eti Osa has 231,890 buildings with a viable rooftop and 6.79 GWp of roof capacity. 40% run a generator, and together they spend ₦319bn a year on energy.

Viable buildings

231,890

Usable roof area

30.1 km²

6.79 GWp roof capacity

Energy spend

₦319bn/yr

196 GWh/yr burned on generators

Median payback

4.1 yr

Median IRR 27% (cash saved)

The savings bracket for Eti Osa

Approach B

Cash saved

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

Current energy spend₦319bn/yr

Year-one cash saved₦302bn

Lifetime cash saved₦16.2tn

NPV₦2.13tn

Median IRR27%

Median payback4.1 yr

Unlocked energy292 GWh/yr

Approach A

Energy value (upper bracket)

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

Installed capacity1.24 GWp

Capex₦1.13tn

Year-one energy value₦488bn

Lifetime energy value₦22tn

NPV₦3.16tn

Median IRR47%

Median payback2.4 yr

Three ways to size Eti Osa'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: 1.24 GWp
Capital cost: ₦1.13tn
Year 1 savings: ₦488bn/yr
NPV: ₦3.16tn
Median IRR: 47%
Median payback: 2.4 yr

The odds a rooftop in Eti Osa pays back quickly

Of the 230,599 buildings in Eti Osa with a modelled payback, 80.1% pay back inside five years and 26.6% inside three.

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How much of Eti Osa's demand actually gets met

Buildings in Eti Osa consume 944 GWh/yr but want 1.24 TWh/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 Eti Osa

Loading band economics…

How many rooftops in Eti Osa 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 230,599 buildings with a modelled result out of 231,890 in Eti Osa. 210,530 clear a positive NPV.

Payback

Under 3 years61,323 (27%)

Under 5 years184,665 (80%)

Under 7 years210,352 (91%)

Under 10 years222,517 (96%)

Return (IRR)

Above 10%221,115 (95%)

Above 15%210,529 (91%)

Above 20%193,115 (83%)

Above 25%165,030 (71%)

CO₂ avoided

629 kt/yr

Fuel avoided

84.7 million litres/yr

Energy unlocked

292 GWh/yr

Demand that is suppressed today

People served

528k

What hardware costs right now

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

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 Eti Osa

Electricity billing band

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
A	119,523	39,344	₦229bn	₦216bn	27%	4.1 yr
D	36,517	14,161	₦17.7bn	₦16.9bn	25%	4.1 yr
C	35,647	18,965	₦25.7bn	₦25.1bn	31%	3.4 yr
B	29,317	13,454	₦28.8bn	₦28.1bn	27%	4.1 yr
E	10,886	5,706	₦17.6bn	₦16.3bn	37%	2.9 yr

Load profile

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Residential	198,257	78,665	₦117bn	₦112bn	25%	4.1 yr
Commercial General	17,042	6,924	₦134bn	₦128bn	35%	3.1 yr
Commercial Retail	9,925	3,528	₦4.59bn	₦4.58bn	33%	3.1 yr
Hospitality	2,261	752	₦21.8bn	₦19.1bn	35%	3.1 yr
Anchor	2,110	912	₦35.3bn	₦31.1bn	41%	2.6 yr
Worship	1,005	417	₦1.47bn	₦1.47bn	35%	3.1 yr
Mall Retail	443	144	₦2.46bn	₦2.42bn	35%	3.1 yr
Industrial	331	125	₦2.12bn	₦2.07bn	37%	2.9 yr
Productive Use	269	74	₦434m	₦434m	35%	3.1 yr
Filling Station	131	53	₦323m	₦322m	35%	3.1 yr
Automotive	116	36	₦249m	₦249m	31%	3.6 yr

Roof size band

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Under 30m2	57,966	21,091	₦4.01bn	₦3.63bn	23%	4.9 yr
100 250m2	56,692	23,599	₦54.6bn	₦53.1bn	27%	4.1 yr
250 1000m2	45,786	18,126	₦179bn	₦172bn	27%	4.1 yr
50 100m2	37,393	15,589	₦11.7bn	₦10.8bn	27%	4.1 yr
30 50m2	32,519	12,624	₦4.27bn	₦4bn	25%	4.4 yr
Over 1000m2	1,534	601	₦65.3bn	₦59bn	33%	3.4 yr

Settlement type

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Urban Centre	214,983	83,032	₦281bn	₦268bn	27%	4.1 yr
Unclassified	12,305	5,404	₦28.4bn	₦24.8bn	27%	4.1 yr
Urban	3,984	2,865	₦7.49bn	₦7.16bn	47%	2.4 yr
Dense Urban	618	329	₦1.9bn	₦1.88bn	37%	2.9 yr

Building type

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)	Median IRR	Median payback
Residential Informal	105,325	37,772	₦59.3bn	₦56.7bn	25%	4.1 yr
Residential Formal	35,802	15,326	₦9.08bn	₦9.08bn	25%	4.1 yr
Shed	21,428	7,514	₦1.03bn	₦1.03bn	23%	4.6 yr
Residential	15,605	7,999	₦41.8bn	₦40.4bn	27%	4.1 yr
Residential Small	14,786	7,770	₦4.6bn	₦4.29bn	27%	4.1 yr
Kiosk Shop	9,685	3,388	₦2.43bn	₦2.43bn	33%	3.1 yr
Commercial Corridor	5,681	2,152	₦39bn	₦37.9bn	35%	3.1 yr
Commercial	5,050	2,433	₦55.2bn	₦52.5bn	37%	2.9 yr
Apartment	3,646	1,597	₦697m	₦697m	25%	4.1 yr
Commercial	3,132	1,084	₦22.5bn	₦21.7bn	35%	3.1 yr
Duplex	1,664	687	₦254m	₦254m	25%	4.1 yr
Unknown	1,647	633	₦10.1bn	₦9.63bn	31%	3.4 yr

Land use

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)
(Unset)	229,543	90,814	₦311bn	₦295bn
Commercial	1,059	422	₦4.31bn	₦4.24bn
Retail	862	314	₦2.63bn	₦2.57bn
Industrial	426	80	₦911m	₦873m

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	216,842	85,301	₦177bn	₦168bn	27%	4.1 yr
SME High	12,877	5,396	₦107bn	₦102bn	35%	3.1 yr
Enterprise	2,171	933	₦35.6bn	₦31.5bn	41%	2.6 yr

Demand tier

Segment	Buildings	With generator	Spend ₦/yr	Cash saved yr 1 (B)
4.0	97,672	37,247	₦144bn	₦137bn
3.0	52,460	23,329	₦63.9bn	₦59.7bn
2.0	43,117	16,479	₦7.64bn	₦6.99bn
0.0	20,895	7,394	₦1.01bn	₦1.01bn
1.0	9,146	3,370	₦656m	₦642m
5.0	5,686	2,517	₦34.7bn	₦34bn
6.0	2,914	1,294	₦67.8bn	₦63.3bn