Every solar panel has a power rating, such as 550 watts. That number is measured under standard test conditions, including a cell temperature of 25°C. Real conditions in Nigeria are rarely that kind.
Loss 1: heat
Solar panels get less efficient as they get hotter. Typical panel datasheets list a loss of roughly 0.3–0.5% of output for every 1°C the cells run above 25°C. On a sunny afternoon, panel cells can run far hotter than the air around them, so heat alone can take a noticeable bite out of output.
Loss 2: Harmattan dust
From roughly November to March, the Harmattan wind carries fine Saharan dust across West Africa. Dust settles on panels and blocks sunlight. The losses can be large:
- A 2023 study in Applied Energy estimated that during the Harmattan season, soiling losses can exceed 50% in the most affected parts of West Africa, varying a lot from year to year.
- A field study in Ede, southwest Nigeria, found a dusty panel produced more than 18% less power than a cleaned one over the test period.
Losses depend heavily on location. Northern sites are usually hit hardest.
How good design plans for it
- Realistic modelling: output estimates should include heat and dust losses, not just the panel's label rating.
- Regular cleaning: a simple cleaning schedule, more often during Harmattan, is one of the cheapest ways to recover lost power.
- Mounting for airflow: panels with space behind them run cooler.
- Panels with lower heat losses: some panel types lose less output as they warm up. Check the temperature figures on the datasheet.
- Backup for the dusty season: a hybrid design with batteries and a small generator keeps power on when output drops.
The takeaway: if a plan assumes panels will always produce their label rating, it will overpromise. Plan for heat and dust from day one.
Sources and notes
- Isaacs et al., Dust soiling effects on decentralized solar in West Africa, Applied Energy (2023).
- Redeemer's University repository: Harmattan aerosol effects on PV modules in Ede, Nigeria.
- University of Exeter: mapping of soiling losses across Nigeria.
- Temperature losses vary by panel. Check the manufacturer's datasheet.