Because consumers want it. Consumers used to pay 50 cents for a cup of coffee. Now they pay $5. That didn't happen because of government nudging. It happened because a different demand was created.
A fancy $5 coffee drink looks, tastes, and smells different from a 50 cent cup of coffee.
A kilowatt hour of electricity that came from the dirtiest coal plant in the universe and a kilowatt hour of electricity that came from whatever the cleanest source is are completely indistinguishable when they come out of my sockets and go into my appliances.
True. But people are very aware of green branding in any form that it presents itself. Idaho's population growth was 2.1% in 2018, tying with Nevada for the highest in the country. I assume this is largely driven by similar population growth in Boise in the same period which was the highest in the top 100 cities in the US by population. I don't have data on this, but given what Moody's says is the demographic driving this (tech workers from the Bay Area and Seattle), I would think that all else being equal, this green image is a huge draw for the state.
A kilowatt hour of electricity that came from the dirtiest coal plant in the universe and a kilowatt hour of electricity that came from whatever the cleanest source is are completely indistinguishable when they come out of my sockets and go into my appliances.