The California Energy Commission explains its decision by saying the typical $10k extra building cost would be earned back and more by energy savings.
Given that solar costs have plunged so much in recent years, this decision is a contender for the “no brainer” maxim. As such there will be no rational reason for other states not to follow, and I predict they will. Even cloudy states / nations like the UK can justify this policy move on economic grounds today ….never mind the climate rationale of emissions reductions commitments under the Paris Agreement.
Image: Ibex News 24