Most businesses know their monthly diesel bill. Very few know their cost per kilowatt-hour, which is the only number that lets you compare diesel with solar, grid or a service contract. The calculation takes five minutes.
Key facts
- A generator burns roughly 0.28 litres of diesel per kWh at a healthy load; more when it idles at 30% load overnight.
- At US$1.00 per litre that is US$0.28/kWh for fuel alone — before oil, filters, injectors and the engine's shortened life.
- All-in, diesel power in most African markets lands between US$0.35 and US$0.60 per kWh.
- Solar plus battery under Energy-as-a-Service is priced 20–30% below your diesel-plus-grid blend.
The five-minute calculation
Take last month's diesel litres and multiply by the price per litre. Add servicing (oil changes, filters, the mechanic's visits), a share of the generator's purchase price spread over its life, and the cost of the hours you lost when it failed. Divide by the kWh you actually used — your meter, or the generator's hour-meter times its average load.
Most owners are surprised twice: first by how much they spend on servicing, and second by how little of the generator's rated capacity they use overnight, when it burns fuel to keep a few cold rooms and lights alive.
Why night-time diesel is the worst diesel
A 500 kVA generator running a 100 kW overnight load is working at 20% capacity. Fuel efficiency collapses, the engine glazes, and you pay close to double the daytime cost per kWh. This is exactly the load a battery is designed to carry — charged for free by the day's solar.
That is why our systems pre-cool cold rooms in the afternoon: the battery only has to carry 60–70% of daytime demand through the night.
The comparison that matters
Put your all-in diesel cost per kWh beside a fixed monthly fee for a solar plus battery plant. For most sites burning 1,000 litres a day, the fee is 20–30% lower and the diesel deliveries stop. Our savings calculator turns litres per day into a yearly figure.
Turn your litres per day into a yearly saving.
Talk to Frontières BayFrequently asked
What if diesel is cheaper in my country?
Even subsidised diesel rarely beats solar over an 8-year contract once servicing, downtime and delivery are counted. Run your own numbers in the calculator.
Do you replace the generator?
Solar and battery carry the normal load; your generator stays as backup. New backup at off-grid sites is gas, never diesel.