Build costSolar farm is at least half cost of coal plant.Running costsSolar 5c Coal 25c / kWhUpkeepEach 25 years replace solar panels.At that time cost should be half.BatteriesGrid controller can assess when and wherethey are needed.Likely to be little need 6 am to 6 pm.VPPs with batteries in homes can help.Next gen solid state battery will betwice density, so half cost.Due 2025-2030