Solar vs Generator in Lagos: The Real Cost Comparison

Ask most people in Lagos how they actually keep the lights on and the honest answer is rarely “NEPA.” It’s a generator, and a fuel budget that climbs every year. So the real comparison isn’t solar versus the grid. It’s solar versus the generator already running in the compound. Here is what that generator costs, worked out rather than asserted.

How much does a kWh from a generator cost in Lagos?

In Lagos in September 2026, a well-maintained diesel generator produces electricity at about ₦640 per kWh in fuel alone, with diesel at ₦1,920 per litre. Across the loads most sets actually run at, fuel comes to ₦607–₦702 per kWh. Servicing, overhaul, the premium an estate charges for managed power, and diesel that walks off the site add another ₦60–₦120, which is what takes generator power past ₦700 per kWh. Even the fuel alone is three times the Band A grid tariff of ₦210 per kWh.

InfraSol derives that figure rather than estimating it. Diesel burn follows a two-part rule that any generator engineer will recognise: consumption rises with the load you draw, but there is also a fixed burn proportional to the size of the set, whether or not anything is plugged in.

Why does an oversized generator cost more per kWh?

Because the second term in that formula never goes away. A generator burns fuel in proportion to its own rating even at idle, so the fewer kilowatt-hours you draw, the more of that fixed burn each one has to carry. Most generators in Lagos are bought oversized (for a future load, for a safety margin, or on a supplier’s advice) and then spend their lives running at 40–70% of rating. InfraSol sees that band across the sites it services.

There is a counterintuitive consequence worth stating plainly. A 10 kVA generator and a 100 kVA generator cost exactly the same per kWh at the same load factor. Both terms of the formula scale with size, so size cancels out. What you pay for electricity depends on how hard you work the set, not how big it is. That makes an oversized generator a permanent tax on every kilowatt-hour it ever makes.

What does a generator cost once everything is counted?

Over ₦700 per kWh. Fuel is the largest cost, but it is not the only one. A generator needs oil, filters and belts every few hundred hours, an overhaul every few years and a replacement after that. Estates and landlords that sell managed diesel power add a premium on top of the fuel. And diesel goes missing: from the tank, from the delivery, from the jerry cans. Across the sites InfraSol works with, those costs add ₦60–₦120 to every kWh the set delivers.

Petrol sets are worse per kWh even though petrol is cheaper. A small household set at ₦1,400 per litre of petrol typically delivers 1.5–2 kWh per litre, which is ₦700–₦930 per kWh in fuel alone.

Solar removes the servicing, the overhaul and the theft along with the fuel. That is why InfraSol measures payback against the all-in cost, not the fuel alone.

How does that compare with the grid and with solar?

Band A grid power in Lagos costs ₦210 per kWh, roughly a quarter of generator electricity. The problem was never the price of grid power. It is how few hours of it arrive. A Lagos customer on a Band B or C feeder receiving around ten hours of mains daily ends up paying a blended ₦531 per kWh across grid and generator combined, on InfraSol’s September 2026 modelling. That blended number, not the grid tariff, is what solar actually has to beat.

Can a battery pay for itself without any solar?

Yes, and this is the part most buyers miss. A battery charged from Band A mains at ₦210 per kWh delivers that energy back at about ₦239 per kWh once round-trip losses are counted, against ₦640–₦675 for the fuel alone from a generator. That is roughly 63–65% cheaper, with no sunshine involved at all.

In other words the battery is an arbitrage asset in its own right: it buys your cheapest supply and sells it against your most expensive one. It earns that margin on a cloudy day, through harmattan, and overnight. This is why a battery is worth having even where the roof cannot take a large array, and why InfraSol sizes storage against a customer’s generator hours, not only against their solar.

When does solar overtake the generator in Lagos?

For a typical Lagos home, in about one and a half to two and a half years. A 7.2 kWp array with a 6 kVA hybrid inverter and a 15 kWh lithium battery is ₦5.6 million installed as of September 2026. Against the blended costs above, InfraSol’s modelling puts payback at 1.4–2.4 years for a residential site and 0.9–2.0 years for a commercial one. InfraSol quotes a 1.5-to-3.5-year payback publicly because it would rather promise less than the model shows.

What if I can’t pay ₦5.6 million upfront?

Two routes avoid the capital outlay. Lease-to-own takes 30–40% down with the balance spread over monthly payments, and you own the system at the end. Energy as a Service charges a flat monthly fee of 50–60% of your current blended energy cost, with InfraSol owning, monitoring and maintaining the system throughout, on a seven-year contract. Both redirect money already burning in a fuel tank towards power you either own or buy more cheaply.

Financing tenor matters more than most buyers expect: the same system financed over seven years at 10% produces far cheaper electricity than one financed over three at commercial Nigerian rates. It is worth reading how system size is actually determined before committing to a number.

Will I still need a generator?

Most Lagos homes keep one, and rarely start it. A correctly sized hybrid system runs the building on solar through the day, carries the night on battery, and falls back to mains automatically without a flicker or a manual changeover. Larger commercial sites sometimes retain a generator for heavy machinery or as contractual backup, but run it a small fraction as often.

The argument is not that generators are useless. It is that using one as a primary source of electricity is now, for most Lagos buyers, the most expensive option available.