As long as solar is a relatively small part of the mix, it actually helps
level the load curve, because
demand is so much higher
during the day than at night, and particularly if you have a lot of nuclear in the mix, solar will reduce the need for
peaking generation.
He found a consistent pattern of the battery charging overnight when wind generation was abundant and cheap, and discharging into the grid
during the late afternoon when
demand and spot market prices reached
peak levels.