Factorio solar panel to accumulator ratio (Nauvis)

On Nauvis, use about 0.84 accumulators per solar panel (21 accumulators for every 25 panels). For 1 MW of power around the clock you need about 24 panels and 20 accumulators.

Why 0.84

A solar panel peaks at 60 kW during the day but averages 42 kW over a full day and night cycle on Nauvis, because of dusk, night and dawn. The accumulators have to store the energy that carries the load through the dark part of the cycle. Working that out over the Nauvis day gives the well-known ratio of about 0.84 accumulators per panel.

Panels per megawatt

1 MW ÷ 42 kW average ≈ 23.8 panels, and 23.8 × 0.84 ≈ 20 accumulators. Round up: 24 panels and 20 accumulators per megawatt of continuous load.

Other planets

Solar power is stronger or weaker on the Space Age planets and on space platforms, and their days have different lengths, so the Nauvis ratio does not carry over. Check the solar power value shown for each planet in game before you copy a Nauvis solar field elsewhere.

Layouts

Tileable solar blocks are easiest to grow: one substation covers an 18 × 18 area, so blocks of that size snap together. See the power blueprints.