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    Taraba State

    Rooftop solar in Lau, Taraba: what the roofs are worth

    Lau has 74,559 buildings with a viable rooftop and 297k kWp of roof capacity. 93% run a generator, and together they spend ₦10.4bn a year on energy.

    Viable buildings

    74,559

    Usable roof area

    1.36m m²

    297k kWp roof capacity

    Energy spend

    ₦10.4bn/yr

    9.04m kWh/yr burned on generators

    Median payback

    1.6 yr

    Median IRR 63% (cash saved)

    The savings bracket for Lau

    Approach B

    Cash saved

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

    Current energy spend₦10.4bn/yr
    Year-one cash saved₦10.1bn
    Lifetime cash saved₦428bn
    NPV₦69.6bn
    Median IRR63%
    Median payback1.6 yr
    Unlocked energy9.78m kWh/yr
    Approach A

    Energy value (upper bracket)

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

    Installed capacity63.4k kWp
    Capex₦60.4bn
    Year-one energy value₦70.6bn
    Lifetime energy value₦3.29tn
    NPV₦577bn
    Median IRR133%
    Median payback0.9 yr

    Three ways to size Lau'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
    63.4k kWp
    Capital cost
    ₦60.4bn
    Year 1 savings
    ₦70.6bn/yr
    NPV
    ₦577bn
    Median IRR
    133%
    Median payback
    0.9 yr

    How many rooftops in Lau 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. 74,559 of 74,559 clear a positive NPV.

    Payback

    Under 3 years66,651 (89%)
    Under 5 years70,360 (94%)
    Under 7 years74,559 (100%)
    Under 10 years74,559 (100%)

    Return (IRR)

    Above 10%74,559 (100%)
    Above 15%74,559 (100%)
    Above 20%70,426 (94%)
    Above 25%70,282 (94%)
    CO₂ avoided

    19.4m kg/yr

    Fuel avoided

    5.58m L/yr

    Energy unlocked

    9.78m kWh/yr

    Demand that is suppressed today

    People served

    126k

    What hardware costs right now

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

    Solar panels

    250

    ₦/W

    Inverters

    127,419

    ₦/kVA

    Batteries

    177,500

    ₦/kWh

    Building mix in Lau

    Load profile

    SegmentBuildings With generator Spend ₦/yr Cash saved yr 1 (B) Median IRR Median payback
    Residential71,63467,511₦8.99bn₦8.74bn63%1.6 yr
    Commercial Retail2,038862₦78.9m₦78.9m25%4.4 yr
    Commercial General423256₦486m₦486m37%2.9 yr
    Anchor295274₦764m₦764m69%1.6 yr
    Worship152138₦50m₦50m55%1.9 yr
    Industrial1612₦3.57m₦3.57m57%1.9 yr
    Filling Station10₦65.6k₦65.6k25%4.4 yr

    Roof size band

    SegmentBuildings With generator Spend ₦/yr Cash saved yr 1 (B) Median IRR Median payback
    Under 30m260,57856,958₦1.3bn₦1.28bn63%1.6 yr
    30 50m26,0855,454₦646m₦645m65%1.6 yr
    50 100m25,2854,411₦2.71bn₦2.61bn63%1.6 yr
    100 250m22,2241,883₦2.85bn₦2.85bn63%1.6 yr
    250 1000m2382342₦2.65bn₦2.53bn71%1.4 yr
    Over 1000m255₦208m₦208m49%2.1 yr

    Settlement type

    SegmentBuildings With generator Spend ₦/yr Cash saved yr 1 (B) Median IRR Median payback
    Unclassified34,26033,972₦4.85bn₦4.6bn63%1.6 yr
    Rural20,99220,992₦2.83bn₦2.83bn71%1.4 yr
    Urban16,26012,287₦1.97bn₦1.97bn57%1.9 yr
    Dense Urban3,0471,802₦714m₦714m33%3.4 yr

    Lead segment

    SegmentBuildings With generator Spend ₦/yr Cash saved yr 1 (B) Median IRR Median payback
    Standard74,00768,676₦9.45bn₦9.19bn63%1.6 yr
    Enterprise307284₦767m₦767m67%1.6 yr
    SME High24593₦161m₦161m25%4.4 yr

    Demand tier

    SegmentBuildings With generator Spend ₦/yr Cash saved yr 1 (B) Median IRR Median payback
    0.056,06353,743₦928m₦928m
    2.08,6946,904₦2.84bn₦2.84bn
    3.05,2654,347₦5.33bn₦5.21bn
    1.04,3343,992₦1.12bn₦996m
    5.013335₦50m₦50m
    4.05626₦55.3m₦55.3m
    6.0146₦44.6m₦44.6m

    Nearby LGAs in Taraba

    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.