Maybe just force grid-connected solar installations that want credit (any size) and even those that just want to be grid-tied (beyond some small size like maybe 5 panels/2kW worth of MPPT) to use a registering meter that meters net energy for each like 15 min interval (that's the granularity we use in central Europe; I assume the US would have come to a similar choice of granularity), and bills energy according to market rate and appropriately handles connection capacity/transformer capex by like taking a histogram of those individual measurements or otherwise letting a few isolated bursts through while ensuring transformer capacity is paid for by those responsible for the (hypothetical, until it's not) transformer upgrade.
Maybe just force grid-connected solar installations that want credit (any size) and even those that just want to be grid-tied (beyond some small size like maybe 5 panels/2kW worth of MPPT) to use a registering meter that meters net energy for each like 15 min interval (that's the granularity we use in central Europe; I assume the US would have come to a similar choice of granularity), and bills energy according to market rate and appropriately handles connection capacity/transformer capex by like taking a histogram of those individual measurements or otherwise letting a few isolated bursts through while ensuring transformer capacity is paid for by those responsible for the (hypothetical, until it's not) transformer upgrade.