This is from the NY Energy Alliance: https://www.facebook.com/nyenergyalliance/
Yesterday, New York’s vaunted 8 GW rooftop solar fleet met its mortal enemy: cloud cover.
This is the complete chart of how New York was powered July 21, hour by hour, accounting for every generator, the power we imported, and estimates for every rooftop panel, straight from NYISO’s public records.
New York used 493 GWh of electricity. Demand peaked at 23.8 GW at 3 PM. At that hour: gas 49%, hydro 15%, nuclear 14%, imports 10%, wind 6%, all solar (rooftop included) 6%. Over the full day: 48% fossil, 40% carbon-free, 12% imported.
About that 12% imported: NYISO doesn’t tag electrons at the border, so the card counts imports as imports — neither fossil nor carbon-free. But the day’s interface schedules show where the power actually came from. New York’s net imports on July 21 averaged about 2,460 MW, and nearly all of it arrived from the south and west: roughly 2,290 MW from PJM — the gas- and coal-heavy mid-Atlantic grid — plus 920 MW from Ontario and about 450 MW on the Connecticut ties.
And Hydro-Québec? New York was a net exporter to Quebec on July 21, sending an average of 818 MW north in nearly every interval of the day. On a hot July afternoon, the “our imports are clean Canadian hydro” assumption runs backwards: the marginal power New York bought was fossil-heavy PJM supply, and the hydro province was buying from us. If anything, counting imports as neutral makes yesterday’s 40% carbon-free figure the generous reading.
Solar’s best hour covered 9% of the state’s power and was done for the day by 8 PM. NYC wholesale prices topped out around $128/MWh (hourly average).
This is what actually ran New York yesterday.