California ISO: System Status They've added real-time wind power generation to the load graphs along with adding charts of previous day's renewable generation. It is highly unlikely that they are capturing much solar PV generation in the daily charts based on the shape of the generation curve - I'd guess that it's mostly recording concentrating solar generation... I tried to find out how much PV is currently installed in CA, but couldn't find any numbers...
Caiso is great but they only report what they know. I guess they don't know net-metered PV. For sure they don't know PV production by the 25,000 + off-grid homes in Calif. I guess you're right about concentrating, or they may include large-scale solar-tracking PV sources.
