Does a remote solar power system need a diesel generator?

No. A well-sized ModX2 solar and battery system can operate standalone indefinitely without one.

The case for including a generator comes down to three situations. First, where the load cannot be interrupted—a communications tower that must stay online, a pumping station that cannot stop mid-cycle. Second, where geography genuinely limits solar yield in winter, and the asset owner won’t accept manual load-shedding or seasonal downtime. Third, where you need a reliability number to defend to a regulator and want that margin baked in.

The case against is practical: a generator adds fuel logistics, service intervals, noise, and emissions to a site chosen partly because nobody wants to visit it.

If you do include one, size the array and battery for the reliability you need in a normal year, then treat the generator as an exception handler, not the daily workhorse. ModX2 can auto-start at 20% state of charge and auto-stop at 80%, with both thresholds adjustable. If the generator is running weekly, the system is undersized, and that’s worth revisiting.