What One Hour of Grid Outage Actually Costs a Ugandan Business

An outage hour has three cost layers

A grid outage rarely costs you only the power you didn’t use. For most Ugandan businesses, the real cost has three parts: output you couldn’t produce or sell, labour you still paid, and the premium you paid for backup energy, usually diesel. The first two are business-specific, but the third can be estimated from current tariff and fuel figures.

Diesel backup: the visible cost per kWh

Diesel generators typically consume around 0.25–0.30 litres per kVA per hour at roughly 75% load. For quick planning, 0.28 litres per kWh is a defensible mid-range figure. At a diesel pump price of about UGX 5,200 per litre, the fuel-only cost of backup power is approximately UGX 1,456 per kWh. Once you add maintenance and the gradual depreciation of the generator itself, a realistic all-in cost falls between about UGX 1,500 and UGX 1,900 per kWh.

That gap matters. At indicative 2026 grid tariffs, diesel all-in backup typically runs about 2.5 to 3 times a commercial grid tariff, and more against lower industrial tariffs. It is a costly way to buy certainty for hours at a time.

The hidden costs: idle labour, lost output, spoiled stock

Labour is usually fixed in the short term. If your team cannot work or serve customers for one hour, most of that wage cost continues. Output or gross margin that would have been earned in that hour is gone, it cannot be recovered later unless you have true spare capacity. Cold-chain and food businesses face a further line item: the value of stock at risk if outages run long enough.

Why the cheapest mitigation is usually smaller than a full building generator

The instinct is to size a generator for the entire building, but that is often the least economical first step. A 6–8 kVA genset may cost UGX 3.5–5.5 million, while a 20–30 kVA silent unit can run UGX 12–22 million, and the larger machine burns more fuel even during a short outage. In many retail, office and small food-service settings, the critical loads are much smaller: tills, card machines, routers, security, and a fridge or two. A battery or UPS sized for those loads can ride through short outages without burning diesel at all. For help calculating that capacity, see our battery sizing Uganda guide.

How to calculate your own outage number

Start with the loads that truly must stay on, not every socket in the building. Then estimate the cost over your worst plausible outage, not the best case.

1. List critical equipment and note its watts from the nameplate or a plug-in energy meter.
2. Estimate the longest outage you are likely to protect against, in hours.
3. Calculate backup energy: total watts × hours ÷ 1,000 = kWh.
4. Price that energy at the grid tariff you normally pay, then at the diesel all-in range above.
5. Add lost contribution margin, idle direct labour and spoilage to get a full per-hour figure.

Where solar-plus-storage changes the arithmetic

Solar-plus-storage can reduce the diesel premium, but the financial case depends heavily on how often you actually lose power and how much energy you must cover. The useful comparison is not the upfront price of solar versus a generator; it is the all-in cost per kWh over your actual outage hours. We break down that comparison in solar vs diesel in Uganda: the real cost per kWh.

The defensible decision

There is no single national figure for an outage hour, because your lost margin and stock exposure differ from another company’s. But the calculation is simple enough to do on one page. The businesses that avoid expensive mistakes usually do the arithmetic before they invite vendors to quote. That independent, vendor-neutral calculation is exactly what we do with Ugandan businesses before they commit capital.