This particular proposal is trying to end the mandate for the utility to purchase electricity from rooftop solar owners at times when there is no demand for it and no existing infrastructure for storing it.

To cover the expense of having purchased goods they can't sell, the utility needs to increase their rates, and that cost increase hits people who don't own solar panels harder than it hits those who do. That makes installing solar panels more financially appealing to people who can afford them, but it also increases costs for the people least able to pay.

And it seems like the utilities are pretty attached to the idea of keeping maintenance fees proportional to actual usage. If I'm reading the article correctly, there was an earlier proposal to require rooftop solar owners to sell 100% of what they produce, and buy 100% of what they use, presumably with a % surcharge for maintenance attached to the purchase. Assuming the utility would pay the current market rate for solar power at the time it was produced, it could be a fair system that would adjust itself automatically based on market forces so the government would not need to update pricing regulations every time a new gas or nuke plant is added to the grid.

Circling back around to the initial point though, we wouldn't have this problem if more storage infrastructure were built, allowing the utilities to sell the solar power they're currently mandated to buy. I suspect that energy storage via home appliance usage patterns will only cover part of our storage needs.