I have a feeling the best power to weight source of night-time power for moonbases would be rectennas, with SPS at L-1 beaming down power. Rectennas are extremely lightweight, only wire mesh and schottky diodes. The cost of soft landing mass on to Luna is very high, so weight is at a premium.

The distance from L-1 to Luna is ~50,000km, slightly greater than the ~45,000km from GEO to Terra, so should be doable.

Launching an SPS to L-1 from Terra is a lot cheaper than putting one in GEO. Also would be an excellent demo for terrestrial usage.