California’s Independent System Operator declared a Stage 2 emergency Saturday, warning residents to expect rotating blackouts and advising them to conserve energy.

Stage 2 means, “The ISO has taken all mitigating action and is no longer able to provide its expected energy requirements.”

The declaration was due to high heat and increased demand, according to CAISO. In addition, CAISO said fires caused a generator and a solar farm to trip offline, highlighting the need for residents to reduce energy use.