Many lodges that advertise solar power still start a generator after dark. The reason is the shape of the demand curve rather than any shortfall in the panels themselves.
Generation and demand peak at different hours
Solar output follows the sun, peaking in the middle of the day when guests are out and rooms are empty.
Lodge demand peaks in the evening: lighting, hot water for showers, kitchen equipment for dinner service and pumps refilling tanks. Almost none of that overlaps with generation.
The gap has to be bridged by storage, and storage is the component that determines whether the generator stays off.
Batteries are sized against the worst case
A battery bank must cover the evening peak plus a run of cloudy days, not an average night. Sizing for the average leaves the lodge dark in bad weather.
Doubling autonomy roughly doubles the bank, and batteries are the shortest-lived part of the system. They are replaced several times over the life of the panels.
A diesel generator, by contrast, is cheap to buy and only costs money when it runs. For a handful of hours a week that arithmetic favours the generator.
Some loads resist electrification
Heating water, running commercial laundry and driving deep borehole pumps draw heavy current for sustained periods. Those are the loads that empty a battery bank fastest.
Lodges usually attack them individually. Solar thermal panels heat water directly, pumps are scheduled for midday when generation is highest, and laundry moves to daylight hours.
Each load shifted out of the evening reduces the battery required, which is often cheaper than adding storage to serve it.
Fuel logistics carry their own footprint
Diesel reaching a remote lodge has usually travelled by road, boat or air, and the emissions of that journey belong to the lodge as much as the fuel burned on site.
Delivery frequency also dictates road use, and roads are the intrusion that operators most want to limit.
That is why generator hours are tracked closely on well-run properties. Fewer hours means fewer deliveries, which means less traffic through habitat.
Hybrid systems are the practical answer
The common arrangement is solar for daytime and shoulder hours, batteries for the evening peak, and a generator that starts only when the bank falls below a set level.
Controllers automate the handover, and the generator runs at full load when it does start, which is where it is most efficient.
A lodge claiming to be fully solar is either very small, in a reliably sunny place, or accepting outages that most guests would not tolerate.