What is the California ISO, and why were there no outages in Sacramento?
After two hours of rolling blackouts in El Dorado County and many parts of California, power has been restored and the juice is flowing again.
But many people, some unfamiliar with rolling blackouts that haven’t been instituted in nearly 20 years, remain in the dark about what happened and what could come next as a heat wave continues to roil California.
Here’s a primer on what Californians need to know about rolling blackouts, why they happen and why Sacramento was spared Friday night.
WHAT HAPPENED?
The California Independent Operator, citing high temperatures and heavy use of air conditioning, ordered utilities in its jurisdiction — much of California — to shut off power in a series of rolling blackouts.
Around 6:30 p.m., Pacific Gas & Electric and San Diego Gas and Electric turned off the lights. Southern California Edison said at least 132,000 of its customers were affected.
In total, about 350,000 homes and businesses were temporarily without power in the first rolling blackouts in nearly 20 years.
El Dorado County was one of the darkest areas of Northern California Friday night. More than 21,000 in El Dorado Hills, nearly 15,000 in Shingle Springs and 10,000 in Placerville were included in the outages. In all, more than 70,000 customers in the county were affected. About 2,000 were also without power in Yolo County.
By 9 p.m., the ISO lifted its orders and lights started coming back on. By 11 p.m. most customers in PG&E territory were restored.
WHY WAS SACRAMENTO SPARED AND NOT EL DORADO?
Consumers in Sacramento County were spared from the heat in air-conditioned comfort, thanks to SMUD.
That’s because the Sacramento Municipal Utility District, unlike Pacific Gas and Electric, is not controlled by the California Independent System Operator. The ISO declared a Stage 3 emergency alert Friday night, indicating a critical shortage in the state’s electrical grid as a heat wave struck.
Government-run utilities like the SMUD, Los Angeles’ city-run Department of Water and Power, and Modesto and Turlock irrigation districts aren’t part of the collective that buys power through the ISO — they generate most of their own electricity.
California hadn’t seen an electrical supply crisis on this scale for 15 years. In 2001, the ISO ordered rolling blackouts for tens of thousands of homes amid similarly scorching heat — although it was later discovered that Enron and other companies intentionally created a shortage of power to drive up prices.
WHO CONTROLS THE GRID?
The ISO manages California’s electrical grid and monitors usage, effectively controlling the supply of energy for 80% of the state. Every few seconds, the ISO takes a snapshot of demand on the grid, and accordingly makes predictions.
Utilities such as PG&E and San Diego Gas and Electric, fall within the ISO’s authority, while SMUD and Roseville Electric are part of the Balancing Authority of Northern California.
The ISO, like BANC, forecasts demand and sends power via high-voltage transmission lines in response, but another key function of the grid operator is as an energy marketplace.
Companies buy and sell energy based on ISO predictions. Enron was able to game the system in part by shutting down power plants, ostensibly for maintenance, on days of peak energy consumption to create an artificial shortage in supply.
WHAT ARE THE STAGES?
The ISO’s Stage 3 alert represents the most serious disparity between supply and demand of energy, which causes an inability of the grid to account for minimum power reserves. The ISO’s decision to turn off the lights in parts of the state did not reflect an inability to provide energy to a few thousand homes, but concern for the grid’s operating reserves, which were threatened by the surge in demand. Insufficiency in reserve energy poses a threat to the stability of the entire grid.
“If you completely run out of power, you lose control of the flow ... and the entire grid can collapse,” said Severin Borenstein, an ISO board member and energy economist at UC Berkeley.
That means blackouts have to begin before the grid runs out of power, as was the case Friday night.
A Stage 2 alert, which was declared earlier Friday evening, indicates that power cannot be provided as expected, but could be mitigated with robust ISO intervention. At the time of Friday’s Stage 2 alert, ISO officials said they were working with utilities to limit power interruptions, but demand for electricity continued to rise along with the temperature.
A Stage 1 alert simply means that power should be conserved to avert power shortfalls. The ISO asked consumers across the state the day before the blackouts to limit usage, predicting a spike in demand for Friday.
A Flex Alert was also issued by the ISO Friday in to encourage consumers to limit power usage. These alerts, meant to alert consumers for the need to conserve energy, have no affect on utilities.
Friday’s peak usage hit 46,802 megawatts just before 5 p.m., reaching historically high levels. ISO records show that California’s peak energy load for 2019 was 44,301 megawatts on August 15. California saw its highest point ever in July 2006, when the ISO grid hit 50,270 megawatts.
With an expected peak of more than 46,000 megawatts across the state on Saturday and a predicted temperature of 108 degrees Fahrenheit in the Sacramento area, it remains to be seen if or when more rolling blackouts will follow.
HOW SMUD IS DIFFERENT
After Friday’s PG&E blackouts and the company’s prior outages aimed at preventing wildfires, SMUD appears the more consistent utility.
SMUD spokesman Chris Capra said the utility’s last rolling blackout was in 2000 — back when it was still aligned with ISO and before forming its own balancing authority in 2003, now known as BANC.
Part of SMUD’s success comes from its investment in generation systems. A significant portion of its energy is derived from hydroelectric facilities along the American River. More than a fifth of SMUD’s energy demand is met with water generation, and its large natural gas facility, the Cosumnes Power Plant, can power 450,000 homes in Sacramento County.
“Generation is a big part of our picture,” Capra said.
Although SMUD cannot generate all the energy for its service area itself during periods of peak usage, which is not uncommon, it acquire longer-term contracts for power well in advance, according to Capra.
“We do that pretty consistently,” he said. “If you look at things right now, we’re doing very well.”
Beleaguered PG&E, meanwhile, has been slowly shedding generation properties. Last year, PG&E agreed to sell its only hydroelectric facility on the American River to SMUD. At the time, PG&E said generation demand on the grid had been declining. A handful of other hydroelectric facilities in Northern California in Yuba, Nevada and Merced counties have likewise been sold in recent years.
For the moment, Capra said, no rolling blackouts are expected in Sacramento County. Friday’s peak usage was 2,900 megawatts, compared with its record of 3,299 megawatts in July 2006.
Demand from industrial customers is actually down by about 10%, Capra said, due to COVID-19 shuttering many economic operations.
Although the possibility of rolling blackouts does not seem likely at the moment, if there were some sort of crisis — a fire threatening power lines or a sudden spike in demand — SMUD would not be immune from drastic action.
“Rotating outages are a last resort,” Capra said.
BOTTOM LINE: WILL IT HAPPEN AGAIN?
An ISO spokeswoman told The Sacramento Bee that more blackouts are unlikely this weekend, but all bets are off early next week.
This story was originally published August 15, 2020 at 1:10 PM.
