When Does Solar Make Financial Sense in Nigeria?

Solar is having a moment in Nigeria. Door-to-door salespeople pitch systems. Social media is full of installation videos. Friends recommend it to friends. Some of this is good. Solar is genuinely useful in many Nigerian contexts. Some of it is not. Solar is also being sold to people for whom it doesn't make financial sense.

This post tries to be honest about when solar pays back, when it doesn't, and how to decide for your specific situation.

The basic question: what are you actually paying for now?

Before considering solar, calculate your current cost of electricity. For most Nigerian homes that means:

Your monthly grid electricity bill (if you have a connection that actually works)
Plus your monthly generator running cost (fuel + maintenance + replacement amortisation)

The generator part is what most people underestimate. A 5kVA generator running 6 hours daily on petrol burns roughly 1.2 litres per hour, or 7.2 litres per day, or 216 litres per month. At current petrol prices, that's somewhere around N210,000-260,000 per month in fuel alone. Add servicing every few months (around N30,000) and the generator wearing out after a few years (N300,000+ to replace), and the total monthly cost is N250,000-300,000+.

For a smaller 3kVA generator running fewer hours, it might be N80,000-150,000 per month.

For a household with no generator and only intermittent grid power, the "cost" is largely the inconvenience of frequent outages.

The solar option: what does it cost?

A solar system that genuinely covers essential loads (lights, fans, fridge, TV, phone charging. Roughly 3-5 kWh per day) currently costs in the range of N1.5m-3m installed, depending on:

Battery technology (lead-acid cheaper but shorter life; lithium more expensive but lasts 3-5x longer)
Panel quality (cheap Chinese panels vs reputable brands)
Inverter quality (no-name vs reputable like Sukam, Microtek, Growatt, etc.)
Installation quality (proper sizing, proper wiring, proper mounting vs corner-cutting)

A system that runs more loads (including a small inverter AC for a few hours daily) might be N4m-7m.

A whole-home off-grid system covering everything including heavy loads is N10m+.

The maths: payback period

Payback period is how long the savings take to repay the upfront investment.

For a household currently spending N250,000/month on generator fuel and maintenance, who installs a N3m solar system that eliminates most of that running cost:

Monthly saving: ~N220,000 (allowing for some occasional generator use)
Payback: 14 months

For a household currently spending N100,000/month on a smaller generator, who installs a N2m system:

Monthly saving: ~N80,000
Payback: 25 months

For a household with reliable grid power and minimal generator use, where solar is being installed primarily for environmental reasons or marginal bill reduction:

Monthly saving: maybe N20,000-50,000
Payback: 5+ years

The payback math gets dramatically better the more you're currently spending on diesel or petrol generation.

When solar makes clear sense

You currently run a generator daily for several hours
You have a roof or ground space appropriate for panel installation
You can afford the upfront cost or have access to credit at reasonable rates
You plan to stay in the property for at least 3-5 years (otherwise you lose the payback)
You can find a reputable installer who'll do the job properly (this is the single biggest variable)

When solar doesn't make clear sense

You have reliable grid power and minimal generator use
You're renting and can't take the system with you
The total system cost is more than 3-4 years of your current generator running cost
You can't afford the upfront cost without taking on expensive credit
You can't find a reputable installer in your area

The hidden variable: installer quality

The single biggest determinant of whether a solar installation works out financially is whether the installer did it properly.

Common installer mistakes that destroy the payback math:

Under-sizing the system. The system you bought can't actually run what you need. You still run the generator constantly.
Wrong batteries. Cheap or wrong-spec batteries fail in 12-18 months. You're back to N200,000+ to replace them, and the payback math collapses.
Bad inverter. Cheap inverter fails in 2 years. Replacement adds significantly to total cost.
Bad installation. Connections corrode, wiring degrades, output drops, system underperforms.
Wrong mounting. Panels not optimally oriented or shaded by trees the installer didn't notice.

A well-installed system from a reputable installer pays back in the timeframes above. A badly-installed system might never pay back. You spend more on the system and then more again on repairs and replacements.

Practical advice

Calculate your actual current spending on grid + generator. Be honest with yourself about how often you run the generator.
Get quotes from at least three installers and ask them to break down their system: panel brand, inverter brand, battery brand and capacity, expected daily generation, warranty terms.
Ask to see existing installations. Visit one if possible. Talk to the customer.
Don't trust round-figure quotes. A reputable installer can break down exactly what goes into the cost.
Beware of "free maintenance for life" or other promises. Maintenance over the system's life is real work; nobody does it for free indefinitely.
Plan for battery replacement. Even good lithium batteries last 5-7 years. Include this in your total cost of ownership thinking.
Start with the right size. If you're sure you'll need a bigger system later, sometimes it makes sense to size now for future expansion. Other times it makes sense to start with essentials and expand later.

The wider picture

Solar in Nigeria is part of a larger trend: distributed power generation as a response to centralised grid unreliability. As the cost of panels and batteries continues to fall (it has fallen roughly 90% in the last decade), the math improves. What's a marginal investment today is probably a clear winner in five years.

But the math only works if the installation is done properly. The single best thing a prospective solar customer can do is invest time in choosing the right installer. Even more than in choosing the right hardware. A great installation with average hardware outperforms a poor installation with premium hardware every time.