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    Lagos State

    Rooftop solar in Badagry, Lagos: what the roofs are worth

    Badagry has 218,972 buildings with a viable rooftop and 4.3m kWp of roof capacity. 79% run a generator, and together they spend ₦224bn a year on energy.

    Viable buildings

    218,972

    Usable roof area

    19.2m m²

    4.3m kWp roof capacity

    Energy spend

    ₦224bn/yr

    193m kWh/yr burned on generators

    Median payback

    2.4 yr

    Median IRR 43% (cash saved)

    The savings bracket for Badagry

    Approach B

    Cash saved

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

    Current energy spend₦224bn/yr
    Year-one cash saved₦207bn
    Lifetime cash saved₦9.01tn
    NPV₦1.4tn
    Median IRR43%
    Median payback2.4 yr
    Unlocked energy175m kWh/yr
    Approach A

    Energy value (upper bracket)

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

    Installed capacity708k kWp
    Capex₦668bn
    Year-one energy value₦531bn
    Lifetime energy value₦24.6tn
    NPV₦4.09tn
    Median IRR77%
    Median payback1.4 yr

    Three ways to size Badagry'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
    708k kWp
    Capital cost
    ₦668bn
    Year 1 savings
    ₦531bn/yr
    NPV
    ₦4.09tn
    Median IRR
    77%
    Median payback
    1.4 yr

    How many rooftops in Badagry 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. 218,972 of 218,972 clear a positive NPV.

    Payback

    Under 3 years133,652 (61%)
    Under 5 years169,800 (78%)
    Under 7 years218,972 (100%)
    Under 10 years218,972 (100%)

    Return (IRR)

    Above 10%218,972 (100%)
    Above 15%218,972 (100%)
    Above 20%172,878 (79%)
    Above 25%161,944 (74%)
    CO₂ avoided

    389m kg/yr

    Fuel avoided

    110m L/yr

    Energy unlocked

    175m kWh/yr

    Demand that is suppressed today

    People served

    477k

    What hardware costs right now

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

    Solar panels

    250

    ₦/W

    Inverters

    127,419

    ₦/kVA

    Batteries

    177,500

    ₦/kWh

    Building mix in Badagry

    Load profile

    SegmentBuildings With generator Spend ₦/yr Cash saved yr 1 (B) Median IRR Median payback
    Residential208,302166,107₦183bn₦171bn45%2.4 yr
    Commercial General5,0743,255₦19.6bn₦19.2bn31%3.6 yr
    Commercial Retail3,6601,946₦652m₦652m25%4.1 yr
    Anchor1,213941₦18.2bn₦14.5bn47%2.1 yr
    Industrial346275₦1.57bn₦1.52bn47%2.4 yr
    Worship162116₦195m₦195m43%2.4 yr
    Filling Station11878₦161m₦161m35%3.1 yr
    Hospitality6037₦376m₦371m29%3.6 yr
    Mall Retail2811₦49.8m₦49.4m23%4.6 yr
    Automotive54₦2.21m₦2.21m29%3.9 yr
    Productive Use41₦1.51m₦1.51m23%4.6 yr

    Roof size band

    SegmentBuildings With generator Spend ₦/yr Cash saved yr 1 (B) Median IRR Median payback
    100 250m274,34860,573₦97bn₦91.6bn45%2.4 yr
    Under 30m250,53138,095₦3.71bn₦3.67bn41%2.6 yr
    50 100m245,99736,161₦18bn₦17.4bn43%2.4 yr
    30 50m231,40124,217₦4.76bn₦4.63bn43%2.4 yr
    250 1000m216,38113,465₦77.6bn₦71.9bn43%2.4 yr
    Over 1000m2314260₦23.2bn₦18.1bn47%2.1 yr

    Settlement type

    SegmentBuildings With generator Spend ₦/yr Cash saved yr 1 (B) Median IRR Median payback
    Urban Centre161,539123,771₦124bn₦120bn39%2.6 yr
    Dense Urban22,01217,751₦30.5bn₦28.6bn55%1.9 yr
    Urban20,26518,856₦40.2bn₦38.1bn63%1.6 yr
    Unclassified15,15612,393₦29.4bn₦21bn47%2.1 yr

    Lead segment

    SegmentBuildings With generator Spend ₦/yr Cash saved yr 1 (B) Median IRR Median payback
    Standard213,242168,977₦189bn₦176bn43%2.4 yr
    SME High4,1972,588₦15.8bn₦15.6bn29%3.6 yr
    Enterprise1,5331,206₦19.7bn₦16bn47%2.1 yr

    Demand tier

    SegmentBuildings With generator Spend ₦/yr Cash saved yr 1 (B) Median IRR Median payback
    4.072,44254,070₦41.4bn₦41bn
    3.065,02155,910₦144bn₦131bn
    2.037,23827,448₦21.4bn₦18.1bn
    0.033,97528,396₦3.03bn₦3.03bn
    1.07,5435,342₦2.12bn₦2.01bn
    5.02,2161,244₦5.71bn₦5.7bn
    6.0537361₦6.74bn₦6.55bn

    Nearby LGAs in Lagos

    How these numbers are produced

    Approach A — energy value (upper bracket)

    Sizes the system to the building's full latent demand and values that energy at the mixed grid/generator tariff. It answers what the energy is worth — not what anyone currently pays.

    Approach B — cash saved (lower bracket)

    Sizes the system to demand that is actually served today, values it by merit order (solar displaces generator kWh first) and caps it at current spend. It answers what a building stops paying.

    Cohort: Viable rooftops (≥0.6 kWp potential).

    • Demand is modelled latent demand, not metered consumption.
    • Fuel is priced at ₦1,800/litre (operator-set). NBS reported ₦3,277/litre for May 2026 — on that basis every naira figure here is roughly 1.8× understated.
    • Generator ownership is a model output, not a survey result: it follows from the grid-availability scale and the 25% demand-suppression assumption.
    • Approach A prices energy nobody currently buys. Its savings must never be read as cash saved.
    • Demand is MODELLED LATENT demand, not metered consumption.
    • Generator ownership is model output, not survey.
    • Medians do not combine across groups — re-derive from the histograms.
    • Per-building files are float32 with 4 significant figures; cast to float64 before summing, because polars keeps Float32 sums in Float32.
    • Null scenario fields mean the roof cannot host 0.6 kWp, not zero savings.
    • `genset` was previously named `diesel` and now uses the segment's real fuel.
    • Ordering holds by construction: grid savings < mixed < genset.