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    Imo State

    Rooftop solar in Ngor-Okpala, Imo: what the roofs are worth

    Ngor-Okpala has 61,667 buildings with a viable rooftop and 1.33m kWp of roof capacity. 99% run a generator, and together they spend ₦58.5bn a year on energy.

    Viable buildings

    61,667

    Usable roof area

    5.92m m²

    1.33m kWp roof capacity

    Energy spend

    ₦58.5bn/yr

    54.7m kWh/yr burned on generators

    Median payback

    1.6 yr

    Median IRR 65% (cash saved)

    The savings bracket for Ngor-Okpala

    Approach B

    Cash saved

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

    Current energy spend₦58.5bn/yr
    Year-one cash saved₦57.8bn
    Lifetime cash saved₦2.45tn
    NPV₦389bn
    Median IRR65%
    Median payback1.6 yr
    Unlocked energy52.2m kWh/yr
    Approach A

    Energy value (upper bracket)

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

    Installed capacity294k kWp
    Capex₦275bn
    Year-one energy value₦258bn
    Lifetime energy value₦12.1tn
    NPV₦2.05tn
    Median IRR109%
    Median payback0.9 yr

    Three ways to size Ngor-Okpala'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
    294k kWp
    Capital cost
    ₦275bn
    Year 1 savings
    ₦258bn/yr
    NPV
    ₦2.05tn
    Median IRR
    109%
    Median payback
    0.9 yr

    How many rooftops in Ngor-Okpala 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. 61,667 of 61,667 clear a positive NPV.

    Payback

    Under 3 years59,496 (96%)
    Under 5 years61,451 (100%)
    Under 7 years61,667 (100%)
    Under 10 years61,667 (100%)

    Return (IRR)

    Above 10%61,667 (100%)
    Above 15%61,667 (100%)
    Above 20%61,478 (100%)
    Above 25%60,698 (98%)
    CO₂ avoided

    107m kg/yr

    Fuel avoided

    32.3m L/yr

    Energy unlocked

    52.2m kWh/yr

    Demand that is suppressed today

    People served

    265k

    What hardware costs right now

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

    Solar panels

    250

    ₦/W

    Inverters

    127,419

    ₦/kVA

    Batteries

    177,500

    ₦/kWh

    Building mix in Ngor-Okpala

    Load profile

    SegmentBuildings With generator Spend ₦/yr Cash saved yr 1 (B) Median IRR Median payback
    Residential57,99957,890₦46.2bn₦45.6bn65%1.6 yr
    Commercial General1,7961,419₦6.29bn₦6.28bn41%2.6 yr
    Commercial Retail894591₦147m₦147m35%3.1 yr
    Worship474471₦853m₦853m55%1.9 yr
    Anchor413406₦4.65bn₦4.55bn69%1.6 yr
    Industrial8685₦388m₦388m63%1.6 yr
    Filling Station44₦4.06m₦4.06m35%1.9 yr
    Hospitality11₦498k₦498k29%3.9 yr

    Roof size band

    SegmentBuildings With generator Spend ₦/yr Cash saved yr 1 (B) Median IRR Median payback
    100 250m222,26122,027₦25.7bn₦25.5bn65%1.6 yr
    50 100m215,33715,160₦4.87bn₦4.67bn65%1.6 yr
    Under 30m29,7249,552₦690m₦657m65%1.6 yr
    30 50m29,0938,966₦1.13bn₦1.1bn65%1.6 yr
    250 1000m25,1555,069₦22.7bn₦22.5bn65%1.6 yr
    Over 1000m29793₦3.42bn₦3.42bn65%1.6 yr

    Settlement type

    SegmentBuildings With generator Spend ₦/yr Cash saved yr 1 (B) Median IRR Median payback
    Urban45,27744,578₦40.9bn₦40.7bn65%1.6 yr
    Unclassified6,7676,691₦8.69bn₦8.45bn65%1.6 yr
    Dense Urban5,5435,518₦6.44bn₦6.23bn65%1.6 yr
    Rural3,8163,816₦2.31bn₦2.31bn65%1.6 yr
    Urban Centre264264₦122m₦122m65%1.6 yr

    Lead segment

    SegmentBuildings With generator Spend ₦/yr Cash saved yr 1 (B) Median IRR Median payback
    Standard59,74059,309₦48.8bn₦48.3bn65%1.6 yr
    SME High1,4371,076₦4.67bn₦4.67bn39%2.6 yr
    Enterprise490482₦4.98bn₦4.89bn65%1.6 yr

    Demand tier

    SegmentBuildings With generator Spend ₦/yr Cash saved yr 1 (B) Median IRR Median payback
    3.035,60635,390₦48.9bn₦48.3bn
    0.013,49913,464₦918m₦918m
    2.09,0968,921₦3.16bn₦3.15bn
    1.01,6141,507₦297m₦297m
    4.01,0891,018₦2.79bn₦2.76bn
    5.0607447₦1.37bn₦1.37bn
    6.0156120₦1.05bn₦1.05bn

    Nearby LGAs in Imo

    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.