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    Sokoto State

    Rooftop solar in Illela, Sokoto: what the roofs are worth

    Illela has 191,962 buildings with a viable rooftop and 1.03m kWp of roof capacity. 66% run a generator, and together they spend ₦17.5bn a year on energy.

    Viable buildings

    191,962

    Usable roof area

    4.67m m²

    1.03m kWp roof capacity

    Energy spend

    ₦17.5bn/yr

    14.5m kWh/yr burned on generators

    Median payback

    1.9 yr

    Median IRR 59% (cash saved)

    The savings bracket for Illela

    Approach B

    Cash saved

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

    Current energy spend₦17.5bn/yr
    Year-one cash saved₦17.3bn
    Lifetime cash saved₦741bn
    NPV₦119bn
    Median IRR59%
    Median payback1.9 yr
    Unlocked energy18m kWh/yr
    Approach A

    Energy value (upper bracket)

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

    Installed capacity130k kWp
    Capex₦127bn
    Year-one energy value₦154bn
    Lifetime energy value₦7.21tn
    NPV₦1.27tn
    Median IRR141%
    Median payback0.6 yr

    Three ways to size Illela'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
    130k kWp
    Capital cost
    ₦127bn
    Year 1 savings
    ₦154bn/yr
    NPV
    ₦1.27tn
    Median IRR
    141%
    Median payback
    0.6 yr

    How many rooftops in Illela 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. 191,962 of 191,962 clear a positive NPV.

    Payback

    Under 3 years123,146 (64%)
    Under 5 years126,799 (66%)
    Under 7 years191,962 (100%)
    Under 10 years191,962 (100%)

    Return (IRR)

    Above 10%191,962 (100%)
    Above 15%191,962 (100%)
    Above 20%191,962 (100%)
    Above 25%125,932 (66%)
    CO₂ avoided

    34.2m kg/yr

    Fuel avoided

    9.24m L/yr

    Energy unlocked

    18m kWh/yr

    Demand that is suppressed today

    People served

    324k

    What hardware costs right now

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

    Solar panels

    250

    ₦/W

    Inverters

    127,419

    ₦/kVA

    Batteries

    177,500

    ₦/kWh

    Building mix in Illela

    Load profile

    SegmentBuildings With generator Spend ₦/yr Cash saved yr 1 (B) Median IRR Median payback
    Residential191,359126,669₦15.4bn₦15.3bn59%1.9 yr
    Anchor302254₦1.79bn₦1.79bn55%1.9 yr
    Commercial General182132₦254m₦254m45%2.4 yr
    Commercial Retail8015₦5.42m₦5.42m25%4.1 yr
    Worship3028₦1.74m₦1.74m49%2.1 yr
    Hospitality30₦759k₦759k25%4.1 yr
    Industrial31₦642k₦642k29%3.9 yr
    Mall Retail30₦331k₦331k25%4.1 yr

    Roof size band

    SegmentBuildings With generator Spend ₦/yr Cash saved yr 1 (B) Median IRR Median payback
    Under 30m2124,28788,525₦1.64bn₦1.64bn61%1.6 yr
    30 50m233,99321,666₦1.52bn₦1.52bn57%1.9 yr
    50 100m224,73213,570₦6.11bn₦6.05bn43%2.6 yr
    100 250m27,7942,775₦3.3bn₦3.25bn21%5.4 yr
    250 1000m21,096515₦2.8bn₦2.8bn21%5.4 yr
    Over 1000m26048₦2.09bn₦2.09bn53%2.1 yr

    Settlement type

    SegmentBuildings With generator Spend ₦/yr Cash saved yr 1 (B) Median IRR Median payback
    Unclassified70,28228,761₦4.27bn₦4.21bn21%5.4 yr
    Rural51,61251,612₦5.12bn₦5.09bn69%1.6 yr
    Urban44,68343,116₦4.99bn₦4.98bn67%1.6 yr
    Urban Centre22,2643,363₦2.96bn₦2.96bn21%5.4 yr
    Dense Urban3,121247₦105m₦104m21%5.4 yr

    Lead segment

    SegmentBuildings With generator Spend ₦/yr Cash saved yr 1 (B) Median IRR Median payback
    Standard191,617126,832₦15.5bn₦15.4bn59%1.9 yr
    Enterprise305255₦1.79bn₦1.79bn55%1.9 yr
    SME High4012₦148m₦148m25%4.1 yr

    Demand tier

    SegmentBuildings With generator Spend ₦/yr Cash saved yr 1 (B) Median IRR Median payback
    0.0134,89595,492₦1.7bn₦1.7bn
    2.025,82715,941₦4.87bn₦4.83bn
    3.015,5796,307₦8.51bn₦8.46bn
    1.011,4939,307₦2.06bn₦2.04bn
    4.04,16448₦203m₦203m
    5.044₦115m₦115m

    Nearby LGAs in Sokoto

    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.