A plan to avoid last summer’s blackouts
State’s big three energy entities have different roles, responsibilities
Last summer’s rolling blackouts in California did not last that long, relatively speaking. But the first statewide outages in nearly 20 years drew a quick and pointed response from Gov. Gavin Newsom.
“Let me make this crystal clear: We failed to predict and plan for these shortages, and that’s simply unacceptable,” Newsom said at the time, no doubt keenly aware that Gray Davis became a former governor after a string of blackouts helped to trigger a recall effort that cost Davis his job. Newsom ordered the California Energy Commission, the California Public Utilities Commission and the California Independent System Operator to deliver a report explaining what happened and why.
The final root cause analysis landed on Newsom’s desk earlier this month, and it largely underscored what a preliminary report in October found — that the pair of blackouts in the early evening hours of Aug. 14-15 were not caused by one single thing but by
The fact that the state’s electricity customers nearly experienced another round of outages just a couple of weeks later — over an extremely hot Labor Day weekend — raised an obvious question: Will California avoid a repeat this summer?
a combination of factors.
But the fact that the state’s electricity customers nearly experienced another round of outages just a couple of weeks later — over an extremely hot Labor Day weekend — raised an obvious question: Will California avoid a repeat this summer?
The state’s big three energy entities have different responsibilities when it comes to the electric grid.
The California Energy Commission’s tasks include adopting long-term demand forecasts for electricity and natural gas every two years.
Among its many jobs, the state PUC lays down requirements for “resource adequacy” — that is, directing the big utilities and state’s other so-called “loadserving entities” to line up sufficient sources of electricity so the grid runs smoothly and operates safely and reliably.
And the California Independent System Operator, known as the CAISO, manages the grid for about 80% of the state’s electric customers, plus a small portion of Nevada. An independent nonprofit, the CAISO also runs a real-time balancing market for utilities in eight states in the West.
In mid-August, a stubborn heat wave settled over California and neighboring states, leading to a sharp increase in electricity demand as millions of Californians — many working from home because of COVID-19 restrictions — turned up their air conditioners.
On Aug. 14 at 6:38 p.m., the CAISO declared a Stage 3 emergency because the surge in demand resulted in the system operator being unable to maintain the 6% minimum in contingency reserves that act as a cushion for the grid. The CAISO said running past the 6% minimum risks knocking out the greater western grid should a major
power source suddenly go offline or a transmission line bringing in power from a neighboring state suddenly fail.
In a Stage 3 emergency, the CAISO orders utilities across the state to reduce power load and rolling blackouts occur until required reserve margins are met.
In San Diego Gas & Electric’s service territory, about 59,000 customers lost power for 15-60 minutes. The outage for PG&E affected about 300,600 customers for as long as 2½ hours, and 132,000 Southern California Edison customers lost power for just over an hour. All told, the rolling blackout hit about 491,600 customers statewide.
The next day, another round of outages occurred at about the same time. The impact was a bit smaller — 321,000 customers lost power statewide, including 17,000 in SDG&E’s service territory.
For the first time since the California energy crisis of 2000 and 2001, the state had experienced rolling blackouts, also called rotating outages.
What went wrong?
Not only did the heat wave cover virtually all of California but it also lingered over neighboring states. Under normal circumstances, California can import additional sources of electricity from places like Arizona, Oregon and Washington. But with the heat affecting the entire West, energy that otherwise might be imported stayed inside those respective states.
In addition, the final report mentioned a major transmission line in the Pacific Northwest was out of service in August, reducing the capability of almost 650 megawatts of power from heading toward California.
The “heat storm” also affected the natural gas fleet, one of the workhorses of California’s grid.
Gas plants don’t run as efficiently when the weather is extremely hot.
Plus on Aug. 14, a natural gas plant in Blythe unexpectedly went offline. A day later, a miscommunication between the CAISO and a plant in Fresno County inadvertently led to a loss of 248 megawatts for a short time.
Throw in a planned outage in June that still hadn’t been remedied in August and natural gas sources came up about 1,000 megawatts short during those two days.
But one of the most significant reasons for the outages relates to when the state’s grid is under the most strain.
In the past, grid operators were most concerned about making sure they had enough resource capacity at the time the system needed the most megawatts of power — what is called peak demand. On Aug. 14, for example, peak demand came to 46,802 megawatts at 4:56 p.m.
But the outage didn’t come until nearly two hours later.
California’s energy system during the day has an abundance of renewable energy sources, especially solar. Such sources are called intermittent because the electricity solar generates during the day when the sun is out disappears after the sun sets. Similarly, wind production drops when the wind doesn’t blow.
When the sun went down Aug. 14-15 and solar production declined, it was still very hot so customers kept running their air conditioners. Demand didn’t drop fast enough to keep pace with the drop in supply, leading the CAISO to institute rotating outages around 7 p.m.
Covering this “net demand peak” has now become the most critical part of the day for grid management. A similar scenario played out over the Labor Day weekend.