People fret about loss of spinning mass in generation systems, hence loss of automagical side-effect frequency control.
Here's some good news in that dept.
"This research investigates the economic viability of photovoltaic (PV) systems operating with an active power reserve to provide frequency containment reserve (FCR) services in the Netherlands. For that reason, the potential revenue of a PV system on the day-ahead (DA) market is compared to the FCR market using market price data from the period of January 1st to October 31st, 2024. Results show that there are 71 out of 304 days in which it is profitable for the considered 49.5 MWp PV system to provide FCR during the selected interval of 12:00–16:00 h. The PV system increased its revenue by €53 661 or 11.34% during these 71 days, which corresponds to a 2.87% increase compared to the total revenue earned on the DA market over the 10-month interval. Furthermore, aggregating the production of three PV plants reduces variability and increases minimum power output during the same 4-hour window. The minimum aggregated PV output power is higher than 10% of the nominal value for 85% of considered days, as opposed to 44%–53% for individual sites, while a delta power analysis shows a 22.9%–31.6% reduction in short-term variability through aggregation, demonstrating its potential to improve FCR provision viability."
https://advanced.onlinelibrary.wiley.com/doi/10.1002/aesr.202500295?af=R
