sent over-the-air (OTA) notifications to drivers in asking owners to avoid charging their EVs during peak hours of energy use. The request appeared on dashboards amid a record-setting heat wave that strained the Texas power grid, and prompted its operator, ERCOT, to warn of possible blackouts.

As a response to the unprecedented power demand during the extreme heat, Tesla and ERCOT asked drivers and residents in Texas to by not charging their EVs from the afternoon through the evening and by turning up their thermostats at home.

The message from Tesla cited different peak hours than ERCOT, as shows, but it was essentially the same period of time. Tesla’s prompt said:

A heat wave is expected to impact the grid in Texas over the next few days. The grid operator recommends to avoid charging during peak hours between 3pm and 8pm, if possible, to help statewide efforts to manage demand.

ERCOT asked businesses and residents to save energy from 2-8pm, then braced for the power demand. And the power grid scraped by this time, managing to prevent major outages thanks to voluntary cutbacks in power use, according to . Industrial users were among those volunteers that helped the power grid avoid collapse; even bitcoin and other crypto miners pitched in.

Tesla in Texas the peak hour prompts, and one in Austin said that Tesla offered supercharger rates up to 50 percent off for drivers who were willing to wait until after 8pm to charge their EVs.

Tesla also asked some Powerwall owners in Texas to help boost the power grid by sending it electricity stored in these home batteries — and making some money in the process — but that’s pending rule changes at ERCOT, which doesn’t currently allow residents to participate in the state’s energy market.

This latest heat wave affected most major cities in Texas: temperatures in Austin reached 103 degrees Fahrenheit; Dallas hit 102; Houston was at 100; and the Rio Grande Valley — more of a major bloc than major city — saw 103. These triple-digit figures get even higher when taking the heat index of a given region into account. The RGV hit 103, but “felt like 109.”

This isn’t the first time the power grid has been strained by in Texas and certainly won’t be the last. Neither is it the first time Tesla has asked drivers to not charge at peak hours. At the very least, it looks like it may have helped this time. But the heat keeps coming, and ERCOT keeps underestimating demand.