Output from all renewables peaked around 8.89 GW at 5 PM, including 5.62 GW from CSP, PV, wind, hydro and biomass.

 California’s Independent System Operator (ISO) reports that the output of the state’s utility-scale solar photovoltaic (PV) and concentrating solar power (CSP) plants reached 2.57 GW at 12:44 PM on August 9th, 2013.

This translates to utility-scale solar generation peaking at 8.3% of roughly 31 GW of demand. This is a new record both in terms of total output and percentage of demand met by PV and CSP, surpassing a series of records set in the last three days of July 2013.

It is important to note that unlike German data from the EEX Transparency Exchange, California ISO data does not include “behind the meter” residential and commercial PV systems. According to the California Public Utilities Commission, 1.6 GW of rooftop PV has been installed in the state. There is currently no centralized measure of the hourly output from these systems and thus the total.

Graph of daily renewable energy output

As with previous days of record PV and CSP output, total utility-scale renewable energy output including wind, biomass, geothermal and hydro peaked later in the day at 5 PM, providing 8.89 GW. This roughly coincided with peak demand of 32.6 GW, meaning that renewables peaked at over 27% of demand.