Case study · Commercial
The bill nobody was reading
They wanted a bigger generator. The meter said the problem was somewhere else entirely.
- Client
- Distribution warehouse, Namanve
- Location
- Wakiso District
- Year
- 2024
- charge was the real cost
- Demandcharge was the real cost
- Battery sized to the peak
- 120 kWhBattery sized to the peak
- Array sized to the base
- 180 kWpArray sized to the base
- Modelled payback
- 4.1 yrsModelled payback
Figures are representative of work delivered and are rounded. Full documentation available on request.
01 — The challenge
What they asked for
A logistics operator was convinced its energy problem was outage duration. Interval metering showed the expensive line was the demand charge created by a morning start-up peak — a cost no generator would ever have touched. The fix was a battery, not a bigger engine.
The client approached us to quote a larger generator. Their reasoning was intuitive and wrong: outages were visible and irritating, so outages must be what the energy budget was going on. What they had never done was look at the shape of their consumption. The bill showed a total and a demand charge; nobody in the building could explain what drove the second number, and it was the larger of the two. Quoting the generator they asked for would have been easy, profitable, and useless.
02 — The solution
What the data told us
We logged the incoming supply at interval resolution across a full quarter before proposing anything. The data showed a pronounced peak each morning as compressors and dock equipment started together — fifteen minutes that set the demand charge for the entire billing period — sitting on top of a broad, flat daytime base load. That shape argued for two different assets doing two different jobs: an array sized to the base load, and a battery sized to the peak. We specified 180 kWp of ballasted rooftop PV and a 120 kWh BESS, with the battery discharging into the morning peak and holding ride-through capacity for grid failures. The generator they originally wanted was never quoted.
We came in asking for a generator and left with a smaller bill than the generator would have given us. Nobody had ever shown us what the demand charge actually was.
03 — The outcome
What changed
The demand charge fell materially in the first billing period — the largest single line on the bill, and the one no proposal they had received previously had even mentioned. Solar now covers the majority of daytime consumption, and the battery has absorbed every grid interruption since commissioning without a production stoppage, which quietly delivered the outage resilience they originally came for. Modelled payback is about four years and improves as tariffs rise. The lesson generalises: most operators know what they pay and very little about what they buy it for, and that gap is usually where the money is.
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