Nigeria has one of the best solar resources in the world, and that sentence has been repeated so often that it has stopped being useful. It does not tell you how much energy a roof in your compound will actually produce in July, it does not tell you whether the same system makes sense in Yola and in Warri, and it certainly does not tell you what it costs. The solar energy potential of a place is a measurable number, and the European Commission’s PVGIS database lets you measure it for your own coordinates in about a minute. We have done that for nine Nigerian cities, and the results are more interesting than the general claim.

What solar energy potential actually means

Solar energy potential is the amount of solar energy available per unit area per year, usually expressed in kilowatt-hours per square metre per year. It describes the resource, not the output of any particular system. Two places with identical potential can end up with wildly different production if one is cloudy in August and the other is not, or if one has a hazy horizon and the other is clear.

Designers usually prefer a different number, the average daily irradiation falling on the tilted plane of the array through the year, measured in kilowatt-hours per square metre per day. This is loosely called peak sun hours, and it is the number that actually multiplies out to your daily production. Potential times system efficiency gives energy. Potential on its own gives a fact about the weather.

So there are two things to keep separate. The resource, which is excellent almost everywhere in Nigeria, and the deployment, which is what has actually been built. Confusing the two is the most common exaggeration in this market, and it is worth separating them before anyone quotes you a number.

Measured solar energy potential across Nigeria

Using the PVGIS tool from the European Commission’s Joint Research Centre, modelled on the SARAH3 satellite dataset for a 1 kWp array at a 10 degree tilt facing south, with 14 per cent system losses to cover dust, heat, cable losses and mismatch, the following figures come back. They are modelled, not measured on site, but the model is satellite-derived and it is the same tool used for official European yield estimates.

Location	Annual irradiation on the array (kWh per m2 per year)	Average daily irradiation (kWh per m2 per day)	Modelled daily energy from 1 kWp (kWh)
Port Harcourt	143	4.71	3.49
Benin City	155	5.09	3.76
Ibadan	161	5.30	3.91
Lagos	163	5.37	4.05
Abuja	173	5.69	4.17
Jos	184	6.07	4.57
Kaduna	188	6.17	4.59
Maiduguri	197	6.49	4.74
Kano	197	6.49	4.77

The spread is about 38 per cent between the best and worst of these sites, and nearly 27 per cent between Port Harcourt and Lagos alone. That gap is not academic. It means a fixed array in the south is the sensible choice and a fixed array in the north is leaving something behind, which is a different design answer for the same client.

Run your own coordinates

The PVGIS tool is free, and the Global Solar Atlas from the World Bank group covers the whole of Africa on an interactive map. Enter your own latitude and longitude rather than accepting a city average, because a site ten kilometres outside Kaduna is not Kaduna. The difference matters most in the south, where rainfall and cloud cover are far more local.

Why the north has more sun than the south

Two things explain almost all of it, and both are well understood.

The first is rainfall. The southern part of the country sits under the influence of the monsoon, with a long, heavy wet season and persistent high cloud from roughly May to September. The north has a shorter, more concentrated wet season and far more months of clear sky. Look at the worst month in the table below and the effect is obvious.

The second is haze and dust. This works in the opposite direction from rainfall, and it is the reason the north is not as spectacular as the raw arithmetic suggests. Harmattan dust in the dry months scatters and absorbs light, and the aerosol loading in the Sahel reduces measured irradiance more than the cloud-free sky would imply. So the north has a higher ceiling and a slightly lower floor.

The seasonal swing is the real design constraint

Month	Port Harcourt	Lagos	Abuja	Kano
January	5.99	6.22	6.99	7.03
March	5.04	6.03	6.51	7.22
June	3.70	4.06	4.51	5.70
July	3.47	4.12	4.15	5.39
September	3.98	4.79	4.77	6.13
November	4.90	5.93	6.88	7.22

Average daily irradiation in kilowatt-hours per square metre on a south-facing array at the optimum tilt. Note that Port Harcourt falls to 3.47 in July, a drop of more than 40 per cent from its February figure, while Kano in the same month is still above 5.3. Sizing a battery bank on a dry-season figure in a southern city produces a system that sits idle most of the year, which is the most common reason people conclude that solar has not worked for them.

Potential is not deployment

This is where the popular story and the real one diverge. Nigeria’s solar energy potential is exceptional. The amount of it that has actually been converted into capacity is small, and the shape of what exists is unusual: according to the figures compiled in the energy in Nigeria overview, off-grid solar reached about 1.15 GW in 2026 and accounted for roughly 96 per cent of the country’s solar capacity, because households and businesses installed private systems rather than waiting for grid-connected projects. The same source records off-grid solar growing at around 22 per cent a year.

That is a real market, and it has grown largely because the grid has not kept up. The same overview notes that Nigeria can supply power to around half its population. So the growth in solar here is not a policy story or an environmental story. It is a reliability story, and it is driven by people who need lights, a freezer, a shop or a clinic to stay on when the supply fails.

What the potential figure cannot tell you is how much of the resource is being wasted. Nor can it tell you how much land, roof area or grid capacity is available in a particular place, all of which constrain what is genuinely buildable. A high potential number in a region with no road access, no installer within 200 kilometres and a distribution network already at its limit is a theoretical resource. Treat potential as the ceiling, not the plan.

What this means for how you design a system

Three practical consequences follow from the data above.

First, size on your own worst month, not on the annual average. A bank designed to carry the house through two evenings in February will not do it in July in Port Harcourt, and the gap is the difference between a system people are pleased with and one they distrust.

Second, tilt and orientation are worth less in Nigeria than the international literature suggests. Because the sun sits high in the sky and crosses from east to west well overhead, a near-flat south-facing array already captures most of what is available, and PVGIS puts the optimal tilt only marginally ahead of a shallow fixed mount. For Kano, the modelled annual figure is about 198 kilowatt-hours per square metre at the optimum tilt against 197 at ten degrees, which is not worth arguing about. The gains that matter come from the seasonal effect, not from the mounting angle, and you should be sceptical of anyone selling you a complicated tilting tracker frame on the strength of a percentage that PVGIS does not show.

Third, do not let anyone size your system on a nameplate figure. A 1 kWp array in Lagos produces about 4 kWh a day in an average year, and rather less in a bad July. Work through your own numbers with a solar load list, then check the production figure against the resource map. If a designer’s estimate is 20 per cent above what the resource data supports, ask them to show their working, and read how many solar panels you actually need before you accept the answer.

Frequently asked questions

Which Nigerian state has the best solar energy potential?

Among the locations modelled above, Kano and Maiduguri are the strongest, at roughly 197 kilowatt-hours per square metre per year on a shallow south-facing tilt, with Kaduna and Jos close behind. The Sahel belt generally outperforms the southern states. The difference between best and worst is meaningful but not dramatic, and it is much smaller than the difference between a well-sited array and a badly sited one.

Does the north really get that much more sun than the south?

About 38 per cent more on annual irradiation across the sites modelled, and considerably more in the worst month rather than the average. A system in Kano in July still receives more energy than a system in Port Harcourt in February, which is the comparison that matters for a battery-backed installation.

Is solar worth installing in a cloudy southern city?

Yes, with the design adjusted. Around 4 kilowatt-hours a day per kilowatt-peak in Lagos is a workable resource for the essential circuits of a home, and much of the wet-season light is diffuse, which arrays still collect. What is not workable is sizing the battery on a dry-season figure and then blaming the panels, and we cover the physics honestly in how solar performs in the rainy season.

Key Takeaways

• Solar energy potential is a measurable resource figure, and you can look it up for your own coordinates in a minute.
• Modelled annual irradiation ranges from about 143 kWh per square metre in Port Harcourt to about 197 in Kano and Maiduguri.
• The north wins on annual totals, and wins much harder on the worst month of the year.
• Peak potential says nothing about how much has been built, and nothing about your specific roof.
• Size the battery on your worst month, not on the annual average.
• Reject any design whose production estimate the resource data does not support.

Now that you have the resource figure for your location, the next step is turning it into hardware, which starts with sizing a solar system for a three-bedroom flat.

Sources: PVGIS, European Commission Joint Research Centre (SARAH3 satellite data, 1 kWp, 10 degree tilt, 14 per cent losses, and monthly optimum-tilt figures); Global Solar Atlas, World Bank Group and others; Energy in Nigeria, solar energy section (deployment figures).