That is not exactly true when the plants need to be kept in standby mode so they can supply power immediately when renewables drop off. More importantly, if regulation did not force the fossil fuel plants to curtail production it would often be more cost effective to dump the solar/wind rather than to curtail fossil fuel production. This means the % of renewables is a fiction created by regulation rather than an emergent property of a sustainable power market.
geezaz! Is operating reserve just for (supply/demand) contingencies relative to renewables... just renewables?
a short few posts back you were asked for a cite in regards your statement, "force these fossil fuel plants to curtail production when renewable production is high (at great cost)"... and now, again, in this latest post you're beaking off about regulation forcing production curtailment. Citation request.