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    Imo State

    Rooftop solar in Ehime-Mbano, Imo: what the roofs are worth

    Ehime-Mbano has 59,753 buildings with a viable rooftop and 1.34m kWp of roof capacity. 96% run a generator, and together they spend ₦36.8bn a year on energy.

    Viable buildings

    59,753

    Usable roof area

    5.97m m²

    1.34m kWp roof capacity

    Energy spend

    ₦36.8bn/yr

    34.8m kWh/yr burned on generators

    Median payback

    1.6 yr

    Median IRR 65% (cash saved)

    The savings bracket for Ehime-Mbano

    Approach B

    Cash saved

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

    Current energy spend₦36.8bn/yr
    Year-one cash saved₦36.8bn
    Lifetime cash saved₦1.55tn
    NPV₦248bn
    Median IRR65%
    Median payback1.6 yr
    Unlocked energy32.8m kWh/yr
    Approach A

    Energy value (upper bracket)

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

    Installed capacity213k kWp
    Capex₦202bn
    Year-one energy value₦197bn
    Lifetime energy value₦9.3tn
    NPV₦1.59tn
    Median IRR111%
    Median payback0.9 yr

    Three ways to size Ehime-Mbano'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
    213k kWp
    Capital cost
    ₦202bn
    Year 1 savings
    ₦197bn/yr
    NPV
    ₦1.59tn
    Median IRR
    111%
    Median payback
    0.9 yr

    How many rooftops in Ehime-Mbano 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. 59,753 of 59,753 clear a positive NPV.

    Payback

    Under 3 years55,155 (92%)
    Under 5 years57,147 (96%)
    Under 7 years59,753 (100%)
    Under 10 years59,753 (100%)

    Return (IRR)

    Above 10%59,753 (100%)
    Above 15%59,753 (100%)
    Above 20%57,221 (96%)
    Above 25%56,980 (95%)
    CO₂ avoided

    67.8m kg/yr

    Fuel avoided

    20.7m L/yr

    Energy unlocked

    32.8m kWh/yr

    Demand that is suppressed today

    People served

    251k

    What hardware costs right now

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

    Solar panels

    250

    ₦/W

    Inverters

    127,419

    ₦/kVA

    Batteries

    177,500

    ₦/kWh

    Building mix in Ehime-Mbano

    Load profile

    SegmentBuildings With generator Spend ₦/yr Cash saved yr 1 (B) Median IRR Median payback
    Residential58,13455,666₦29.6bn₦29.6bn65%1.6 yr
    Commercial General736724₦3.33bn₦3.33bn53%2.1 yr
    Anchor440433₦3.27bn₦3.24bn73%1.4 yr
    Worship208193₦427m₦427m55%1.9 yr
    Commercial Retail181178₦30.9m₦30.9m39%2.6 yr
    Industrial4545₦157m₦157m65%1.6 yr
    Filling Station77₦10.6m₦10.6m55%1.9 yr
    Hospitality22₦13.9m₦13.9m43%1.9 yr

    Roof size band

    SegmentBuildings With generator Spend ₦/yr Cash saved yr 1 (B) Median IRR Median payback
    100 250m222,39721,498₦16.6bn₦16.6bn65%1.6 yr
    50 100m213,75313,197₦2.74bn₦2.74bn65%1.6 yr
    Under 30m210,1979,718₦514m₦514m65%1.6 yr
    30 50m27,4957,177₦634m₦634m63%1.6 yr
    250 1000m25,8595,609₦14.3bn₦14.3bn65%1.6 yr
    Over 1000m25249₦2.06bn₦2.04bn67%1.6 yr

    Settlement type

    SegmentBuildings With generator Spend ₦/yr Cash saved yr 1 (B) Median IRR Median payback
    Urban Centre44,71242,264₦23.4bn₦23.4bn63%1.6 yr
    Urban13,03613,021₦12.2bn₦12.2bn65%1.6 yr
    Unclassified1,9711,929₦1.22bn₦1.22bn63%1.6 yr
    Rural3434₦29m₦29m65%1.6 yr

    Lead segment

    SegmentBuildings With generator Spend ₦/yr Cash saved yr 1 (B) Median IRR Median payback
    Standard58,83056,334₦31.3bn₦31.3bn65%1.6 yr
    Enterprise485478₦3.43bn₦3.4bn71%1.4 yr
    SME High438436₦2.07bn₦2.07bn57%1.9 yr

    Demand tier

    SegmentBuildings With generator Spend ₦/yr Cash saved yr 1 (B) Median IRR Median payback
    3.034,73434,511₦31.9bn₦31.9bn
    0.012,48712,446₦648m₦648m
    2.08,7048,657₦2.08bn₦2.08bn
    4.02,953762₦1.57bn₦1.57bn
    1.0729728₦106m₦106m
    5.0120119₦298m₦298m
    6.02625₦211m₦211m

    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.