PureWatts AI

    Solar energy assistant

    📍 Home

    Hi there! 👋

    I'm your PureWatts AI assistant. Ask me anything about solar energy, system sizing, or how to use the platform.

    Skip to content

    Lagos State

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

    Ojo has 185,539 buildings with a viable rooftop and 4.23m kWp of roof capacity. 58% run a generator, and together they spend ₦361bn a year on energy.

    Viable buildings

    185,539

    Usable roof area

    18.8m m²

    4.23m kWp roof capacity

    Energy spend

    ₦361bn/yr

    278m kWh/yr burned on generators

    Median payback

    4.9 yr

    Median IRR 23% (cash saved)

    The savings bracket for Ojo

    Approach B

    Cash saved

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

    Current energy spend₦361bn/yr
    Year-one cash saved₦290bn
    Lifetime cash saved₦12.3tn
    NPV₦1.8tn
    Median IRR23%
    Median payback4.9 yr
    Unlocked energy295m kWh/yr
    Approach A

    Energy value (upper bracket)

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

    Installed capacity1.25m kWp
    Capex₦1.22tn
    Year-one energy value₦783bn
    Lifetime energy value₦36tn
    NPV₦5.74tn
    Median IRR65%
    Median payback1.6 yr

    Three ways to size Ojo'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
    1.25m kWp
    Capital cost
    ₦1.22tn
    Year 1 savings
    ₦783bn/yr
    NPV
    ₦5.74tn
    Median IRR
    65%
    Median payback
    1.6 yr

    How many rooftops in Ojo 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. 185,539 of 185,539 clear a positive NPV.

    Payback

    Under 3 years54,739 (30%)
    Under 5 years95,087 (51%)
    Under 7 years185,539 (100%)
    Under 10 years185,539 (100%)

    Return (IRR)

    Above 10%185,539 (100%)
    Above 15%185,539 (100%)
    Above 20%102,050 (55%)
    Above 25%85,669 (46%)
    CO₂ avoided

    585m kg/yr

    Fuel avoided

    141m L/yr

    Energy unlocked

    295m kWh/yr

    Demand that is suppressed today

    People served

    1.11m

    What hardware costs right now

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

    Solar panels

    250

    ₦/W

    Inverters

    127,419

    ₦/kVA

    Batteries

    177,500

    ₦/kWh

    Building mix in Ojo

    Load profile

    SegmentBuildings With generator Spend ₦/yr Cash saved yr 1 (B) Median IRR Median payback
    Residential178,901103,164₦314bn₦247bn23%4.9 yr
    Commercial General2,6961,345₦13.4bn₦12.9bn23%4.6 yr
    Anchor1,7671,045₦28.6bn₦26.7bn31%3.4 yr
    Commercial Retail958462₦948m₦948m23%4.6 yr
    Worship663420₦622m₦621m27%3.9 yr
    Industrial256131₦1.75bn₦1.7bn29%3.9 yr
    Hospitality13364₦547m₦537m23%4.6 yr
    Filling Station8530₦102m₦102m23%4.6 yr
    Mall Retail5333₦261m₦260m29%3.9 yr
    Productive Use2012₦41.2m₦41.2m23%4.1 yr
    Automotive73₦12.1m₦12.1m21%5.4 yr

    Roof size band

    SegmentBuildings With generator Spend ₦/yr Cash saved yr 1 (B) Median IRR Median payback
    100 250m258,25834,374₦149bn₦116bn23%4.6 yr
    Under 30m245,96925,569₦7.44bn₦3.67bn21%5.1 yr
    50 100m235,19620,102₦26.4bn₦22.5bn23%4.9 yr
    30 50m223,31113,096₦5.55bn₦4.93bn21%5.1 yr
    250 1000m222,40213,302₦138bn₦112bn23%4.6 yr
    Over 1000m2403266₦34.1bn₦31.3bn29%3.6 yr

    Settlement type

    SegmentBuildings With generator Spend ₦/yr Cash saved yr 1 (B) Median IRR Median payback
    Urban Centre175,45398,834₦251bn₦230bn21%5.1 yr
    Unclassified7,2825,100₦54.7bn₦34.8bn35%3.1 yr
    Urban2,8042,775₦55bn₦25.3bn69%1.6 yr

    Lead segment

    SegmentBuildings With generator Spend ₦/yr Cash saved yr 1 (B) Median IRR Median payback
    Standard182,199104,838₦323bn₦255bn23%4.9 yr
    Enterprise1,9591,134₦29.9bn₦28bn31%3.6 yr
    SME High1,381737₦8.01bn₦7.61bn27%3.9 yr

    Demand tier

    SegmentBuildings With generator Spend ₦/yr Cash saved yr 1 (B) Median IRR Median payback
    4.096,53050,304₦141bn₦138bn
    3.044,11828,444₦186bn₦128bn
    2.027,09915,604₦19.2bn₦14.2bn
    0.09,5337,752₦912m₦912m
    1.07,6134,230₦5.86bn₦1.6bn
    5.0509268₦4.12bn₦3.93bn
    6.0137107₦3.56bn₦3.3bn

    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.