The New York Times has an article about utility efforts to roll back "net metering"* for solar power.
The article is pretty clearly slanted -- utilities aren't making up the free-riding problem. But it's also evident that utility companies aren't just interested in insuring grid stability but want to kneecap solar outright, because it is a threat to the monopoly utility model. In many of the states, rooftop solar is so nascent that it's almost impossible to imagine it poses any serious immediate threat to utility business models.
The fact that very liberal states like Hawaii have rolled back net metering should suggest that there's more to it than just greedy conservatives hating renewable power and protecting incumbent power producers (recall that Hawaii has actually set a 100% renewable power goal they plan to meet by 2045). But the Trump administration and allied conservative state governments are certainly sympathetic to net metering "reform" proposals which are best characterized as "greedy conservatives hating renewable power and protecting incumbent power producers."
* Net metering is the practice where households with solar panels get paid retail price for any excess power they return to the grid. If my house consumes 1,000 kWh of power, and the panels on my roof produce 1,000 kWh of power, my electricity bill nets out to zero. The reason it's a "net" is that, on a minute-to-minute basis, there will be times when my solar panels are producing more than I'm using (and the excess gets sold onto the grid) and likewise times when the panels aren't covering my usage (e.g., when it's cloudy) and I need to draw from the grid. The reason this aggravates utility companies is that my house is still hooked up to and uses the grid (to sell the excess power, to draw from non-intermittent dispatchable power at night or in the rain), but it isn't paying for any of the costs of maintaining it. As rooftop solar becomes more prominent, this becomes a genuine regulatory puzzle for utility commissions. But in most jurisdictions, we're nowhere near the point where it will make a dent.