Power and natural gas prices in Texas and California spiked this week to their highest levels in months, as homes and businesses cranked up the air conditioning to escape brutal heatwaves.
Power grid operators in both states warned residents to cut their electricity use as much as possible for the rest of this week to avoid blackouts.
Grids in Texas and California have imposed rotating outages over the last year to avoid widespread collapses of their power systems -- like the independent grid in Texas, where a winter storm left millions without power in February.
Parts of Texas are expected to see temperatures cross 100 degrees this week.
In California, temperatures reached the 90s in Los Angeles on Tuesday, where National Weather Service issued an Excessive Heat Warning.
And Las Vegas, Nevada, recorded 114 degrees Fahrenheit the same day, with even hotter conditions expected on Wednesday.