Investors in African solar increasingly refuse to fund any site that keeps burning diesel. That leaves a practical question for off-grid sites: what runs on the fifth cloudy day? The answer is gas — sized small and used rarely.
Key facts
- Frontières Bay's investors require 100% diesel replacement at every new site.
- Backup at off-grid sites is a gas generator sized for the critical load only, not the whole site.
- A well-sized solar plus battery plant should call the backup a handful of times a year.
- Where grid exists, grid is the backup and no generator is needed.
Why diesel is out
Development finance institutions fund solar to displace diesel; a site that keeps a diesel generator in the design undermines the case and the emissions reporting. A gas generator running a few days a year is a different proposition — lower emissions, cleaner and quieter — and it is acceptable to lenders.
Sizing the backup
The backup covers the critical load — cold rooms and essential motors — not peak demand. That keeps it small and cheap. Solar and battery are sized so that the backup is a last resort: 10–15% extra battery for cloudy runs at sites without grid, monitored so an engineer sees the trend before it becomes an outage.
What about my existing diesel generator?
At transition it stays as a fallback while the new plant proves itself. Most customers stop buying fuel in the first month and retire or sell the generator within the year.
Off-grid site? Ask how we size the backup.
Talk to Frontières BayFrequently asked
Is LPG available where I am?
LPG and CNG supply is expanding across Nigeria and Ghana; we confirm supply during the audit.
Can I keep diesel as backup if I buy outright?
On a direct purchase the choice is yours, though we still recommend gas for cost and noise.