Several days of intense heat and a spike in power demand has stressed the California power grid, with the California Independent System Operator issuing calls for conservation and the Secretary of Energy issuing an emergency order to help preserve the reliability of the state’s grid.
Despite temperatures of 100 degrees or more over the weekend and the increase in power demand in the state, CAISO was able to avert the need for implementing rotating outages, which it had to turn to last month.
On Saturday, Sept. 5, CAISO reported that consumer conservation helped avoid rotating power outages that day. The grid operator had declared a Stage 2 Emergency, when wildfires took 1,600 megawatts of resources off the grid, but conservation helped avoid further emergencies, including rolling outages.
The ISO issued a Flex Alert to urge consumers to conserve energy during the statewide heatwave that drove up energy consumption.
On Sunday, Sept. 6, CAISO issued a statewide Flex Alert and later in the day declared a statewide Stage 2 emergency due to excessive heat driving up electricity use and putting strain on the grid.
The ISO called the emergency after a transmission line carrying power from Oregon to California reduced its capacity by 900 MW due to the heat and an generation totaling 260 MW tripped offline unexpectedly. The cause of the outages was not immediately known.
The emergency declaration allows the grid operator to use reserve power and to tap into emergency assistance from neighboring balancing authorities.
Ultimately, CAISO said it was able to avoid rotating power outages on Sept. 6 thanks to consumer conservation.
On Labor Day, Sept. 7, CAISO again issued a statewide Flex Alert, noting that temperatures were expected to be above normal statewide for the third consecutive day, driving up electricity demand, primarily from air conditioning use.
The ISO also said that day that it was monitoring several serious wildfires throughout the state threatening power lines. “Weather forecasts show wind will pick up beginning late tonight through Wednesday, increasing fire danger. Wildfires can trip or destroy power lines, reducing transmission and shrinking energy supplies,” CAISO said in a news release.
California governor signed emergency proclamation
California Gov. Gavin Newsom on Sept. 3 signed an emergency proclamation to free up additional energy capacity amid extreme temperatures across California.
The proclamation permits power plants to generate more power by suspending certain permitting requirements, helping to alleviate the heat-induced demands on the state’s energy grid.
Facilities are required to report any violations of these suspended permitting requirements to relevant local and state regulatory bodies. The proclamation also contains provisions related to the use of generators and auxiliary ship engines.
DOE emergency order
On the evening of Sept. 6, the Department of Energy issued an emergency order under section 202(c) of the Federal Power Act to preserve the reliability of the bulk electric power system. The order was issued in response to a request from the CAISO for authorization for “specific electric generating units located within the CAISO balancing authority area to operate at their maximum generation output levels when directed to do so by the CAISO, notwithstanding air quality or other permit limitations.” These generating units, totaling up to 100 megawatts, are referred to as “specified resources.”
Secretary of Energy Dan Brouillette “concurs with the California Independent System Operator Corporation that a grid reliability emergency exists which demands immediate federal intervention,” said DOE spokeswoman Shaylyn Hynes.
CAISO anticipates that the DOE order may result in exceedance of National Ambient Air Quality Standards under the Clean Air Act and notes that specified resources are located in different communities within California and should not result in any disproportionate impact on a single community, Bruce Walker, the DOE’s Assistant Secretary for Electricity, said in the order.
“To minimize adverse environmental impacts, this order limits operation of dispatched units to the times and within the parameters determined by the CAISO for reliability purposes.”
From September 6 to September 13, “in the event that the CAISO determines that generation from the Specified Resources is necessary to meet the exceptional levels of electricity demand that the CAISO anticipates in California, I direct the CAISO to dispatch such unit or units and to order their operation only as needed to maintain the reliability of the power grid in California between the hours of 14:00 Pacific Daylight Time and 22:00 Pacific Daylight Time on days when the demand on the CAISO system exceeds expected energy and reserve requirements,” wrote Walker.
The order also said that CAISO should select the combination of units that meets the reliability emergency and minimizes environmental impact. “Consistent with good utility practice, the CAISO shall exhaust all reasonably and practically available resources, including demand response and identified behind-the-meter generation resources to the extent that such resources provide support to maintain grid reliability, prior to dispatching the Specified Resources.”
The petition that CAISO sent to the DOE and the emergency order are available here.
Public Power Safety Shutoffs
Meanwhile, investor-owned Pacific Gas and Electric Company (PG&E) on Sept. 8 confirmed that customers in the Sierra Foothills, Northern Sierra and elevated North Bay terrain who were notified of an impending Public Safety Power Shutoff (PSPS) were without power.
The PSPS event was affecting approximately 172,000 customers in 22 counties: Alpine, Amador, Butte, Calaveras, El Dorado, Humboldt, Lake, Lassen, Mariposa, Napa, Nevada, Placer, Plumas, Shasta, Sierra, Siskiyou, Sonoma, Tehama, Trinity, Tuolumne and Yuba, PG&E reported.
The process to turn off power to these counties was completed between approximately 9 p.m. Monday evening and 6 a.m. Tuesday morning. Power was scheduled to be shut off in Kern County at approximately 2 p.m. Tuesday.
“PG&E only undertakes a PSPS as a last resort, when it is necessary to do so to protect public safety from extreme wildfire threat,” it said.
The PSPS decision was based on forecasts of dry, hot weather with strong winds that pose significant fire risk. The National Weather Service has placed most of Northern and Southern California, including 1.5 million PG&E customers, under Red Flag Warnings for fire danger.
Forecasts indicate that the peak period of winds should end Wednesday morning, the utility said.
LADWP experienced power outages over the weekend
The Los Angeles Department of Water and Power reported experiencing power outages over the weekend.
On the evening of Monday, Sept. 7, LADWP reported that crews continued to make progress throughout the day, restoring power to over 22,000 customers since that morning. As of 9 p.m., 23,000 customers remained without power as crews continued working 16-hour shifts around the clock, it reported in a news release.
CMUA details how public power utilities helped CAISO respond to heat wave, stress on grid
In a recent letter to a California state lawmaker, the California Municipal Utilities Association (CMUA) details how public power utilities in the state took a number of actions on the supply and demand side to help CAISO manage stress placed on the California power grid last month due to soaring temperatures.
California last month experienced a record setting heat wave that caused CAISO to initiate at least two Stage 3 emergencies that led to load shedding events, commonly referred to as rolling blackouts.
WAPA, U.S. Bureau of Reclamation tapped hydro to help response to Calif. energy emergency
The Western Area Power Administration and the U.S. Bureau of Reclamation joined forces between Aug. 14 and 19 to generate and transmit roughly 5,400 megawatt-hours in response to California’s energy emergency, the two federal agencies reported in late August.