Cal-ISO issues Flex Alert to reduce stress on grid, avoid power outages

The California Independent System Operator has issued a statewide Flex Alert to encourage electricity conservation as extreme heat blasts the region, driving up cooling demand along with power prices.

The Flex Alert, a voluntary call to conserve electricity during anticipated energy supply shortages, is in effect 5-10 pm PT June 17 to reduce stress on the grid and avoid power outages.

The alert was called "in a preponderance of caution" because demand and supply forecasts for June 17 show a shortfall of about 300 MW of electricity available to the grid, ISO President and CEO Elliot Mainzer said in a statement.

"The public's help is essential when extreme weather or other factors beyond our control put undue stress on the electric grid," ISO president and CEO Elliot Mainzer said in a June 16 statement. "We have seen the huge impact that occurs when consumers pitch in and limit their energy use. Their cooperation can really make a difference."

During past Flex Alerts, consumers cut back electricity use and helped California avoid or limit power outages that can, if conditions persist or worsen, become necessary when demand for electricity outstrips capacity, according to the ISO statement. Last August and September, consumers reduced electricity by 1 GW to 3 GW during flex alerts.

"The statewide call for conservation is critical because when temperatures hit triple digits across a wide geographic area, no state has enough energy available to meet all the heightened demand, primarily due to air conditioning use," according to the ISO statement.

The ISO already declared restricted maintenance operations from noon to 10 pm daily until June 18, which requires generators and transmission operators to postpone any planned outages for routine equipment maintenance, ensuring all grid assets are available for use.

"If demand still outstrips supply after Flex Alerts and other measures are taken, the ISO could again order utilities to begin rotating power outages," according to the statement. "That would extend available power supplies and guard against longer and more extensive disruptions while protecting high-voltage transmission lines from damage."

The ISO forecast peakload around 43.323 GW June 17, up 11% day on day, and around 42.168 GW June 18. The all-time peakload record is 50.27 GW reached July 24, 2006.

The Aug. 14-15, 2000, rotating outages were the first since 2001.

Climbing prices

Wholesale power prices spiked in response to the situation.

SP15 on-peak day-ahead locational marginal prices rose 28% day on day at $129.59/MWh for June 17 delivery, the highest level since the nationwide February winter storm, according to ISO data. NP15 on-peak day-ahead LMP jumped 34% day on day at $134.26/MWh for June 17.

Likewise, Palo Verde on-peak day-ahead climbed 336% at $1,575/MWh, the highest since hitting $1,643.25/MWh Aug. 19, 2020, according to S&P Global Platts pricing data.

The SP15 on-peak day-ahead LMP record high is $697.91/MWh reached Aug. 18, 2020, while the NP15 on-peak day-ahead LMP record high is $487/MWh reached Aug. 19, 2020.

Weather outlook

Widespread excessive heat warnings and heat advisories are in effect for the southwestern quadrant of the country, according to the US National Weather Service. The persistent and extreme heatwave is set to expand over the next couple of days.

A strong upper-level ridge over the Southwest will remain in place through the end of the week, according to NWS. High temperatures 10 to 25 degrees above average will spread into central and northern California June 17 and reach portions of the Northern Great Basin by June 18.

Dangerous and potentially deadly heat will continue throughout the Southwest and Intermountain West with highs into the 110s and even 120s likely, according to NWS. Widespread triple digits will be felt throughout California and lower elevations of the Central Great Basin and Central Rockies.

Many of these regions could see dozens of daily record high temperatures set. A few monthly and all-time records have already been tied or broken associated with the current stretch of heat.

"Under such conditions, evening is the most difficult time of day for grid operations, especially in persistent hot weather when evening temperatures stay warm, because demand for electricity remains high as solar energy diminishes," according to the ISO statement.

As California's ability to store solar and wind energy with batteries or other technology continues to increase, the crucial evening hours will be less challenging. But for now, concerted action to conserve is our most effective way of keeping the grid working for everyone, ISO said.