Heat Stretches Power Network to the Limit
Southern California was struck with a new round of power outages Monday as demand for electricity stretched the state’s supply and the aging system of local lines and transformers continued to fail in the face of a record heat wave.
The demand for electricity was so great that California’s power regulators asked some businesses to cut back their power usage. The state narrowly avoiding rolling blackouts as temperatures moderated slightly -- a cooling trend expected to continue today.
For the record:
12:00 a.m. July 27, 2006 For The Record
Los Angeles Times Thursday July 27, 2006 Home Edition Main News Part A Page 2 National Desk 1 inches; 63 words Type of Material: Correction
Power transmission: A graphic in Tuesday’s Section A about the role of transformers in distributing power to homes referred to current being stepped up to hundreds of thousands of volts on its way from the generating plant to a receiving station. The voltage is stepped up in that process. Current is measured in amperes, not volts, and it is reduced in that process.
Officials were more immediately concerned about the nearly 1,000 transformers atop power poles and in underground vaults that have been overwhelmed in recent days, leaving thousands without electricity.
Both the Los Angeles Department of Water and Power and Southern California Edison acknowledged Monday that their systems -- parts of which were built in the 1920s and 1930s -- were not designed to handle anywhere near the power demand produced during the heat wave.
Many older transformers are too small to carry the loads put on them by modern households, said DWP General Manager Ron Deaton.
“When these transformers were installed, you had neighborhoods that weren’t air-conditioned, homes without two computers and five television sets,” he said.
City officials said they have been trying to replace the older transformers for years but have made only modest progress because of limited funding.
Los Angeles has about 126,000 pole-top and underground transformers. About 150 have been replaced and 274 repaired during the heat wave.
Councilman Greig Smith estimated that most of the city’s transformers are already at or near capacity. It’s unclear how many need to be replaced, a question Smith hopes the DWP can answer at today’s City Council meeting.
One concern now is a shortage of new pole transformers statewide because so many have overheated over the last few weeks. But in the wake of the blackouts, several City Council members said they would push to replace the aging transformers more quickly.
“We have a situation of urgency,” said Councilwoman Jan Perry. “Clearly, the population has outweighed the city’s infrastructure.”
As of Monday afternoon, there were still 10,000 customers in the San Fernando Valley and 5,600 customers in the rest of Los Angeles without power. An additional 17,000 customers in territories covered by Edison -- including the South Bay, the San Gabriel Valley and Orange County -- were without electricity.
The DWP had 91 crews in the field Monday replacing transformers and overhead and underground power lines, including repair crews brought in from the Owens Valley and Utah. Some neighborhoods have been without power for more than a day.
Henry Martinez, the head of the DWP’s power system, said the utility was hoping to restore all power within the next 24 hours.
“We’ve got crews out there, and they are running from site to site,” he said.
While many families continued to go without power on Monday, the ordeal ended for some.
The power came back on at Desiree Causey’s Westminster house at 2 a.m. Monday, after nearly two days.
Causey said she had to throw out $400 worth of food in her refrigerator.
“It’s been pretty miserable,” she said. “I’ve got a husband, two kids, and two hot dogs. We’ve spent a lot of time in our pool.”
Since July 13, when the high heat began, 765,000 Edison customers have lost power due to heat, wind or lightning strikes, the utility said.
Officials said the hot weather has underscored the age and vulnerability of the region’s electricity transmission system.
Since the heat wave began, Edison has had to replace more than 715 transformers, spokesman Steven Conroy said. Transformers are crucial equipment that reduce the flow of electricity so that it is safe for use in homes and businesses.
Some were overwhelmed because of their age, Conroy said. Many of the company’s poles, wires, transformers and other equipment are more than 40 years old.
But others shut down because they were simply not built to carry the electricity demanded by customers during the heat wave, Conroy said. In June and thus far through July, Edison customers have used 18% more power than during the same period last year, he said.
Edison officials said they hope to make fixes as part of a $9-billion infrastructure upgrade over the next five years.
The DWP increased its budget for infrastructure maintenance and upgrades by more than $75 million this year, including $3.5 million to replace pole-top transformers.
“Obviously, we are continuing to maintain our system,” Mayor Antonio Villaraigosa said. “We may have to more aggressively do so.”
The DWP has about 200 new transformers in its warehouses and is expecting 150 more in September, city officials said. The transformers cost $1,500 or more, depending on their size. Most pole-top transformers are gray or black cylindrical metal structures that are 3 or 4 feet high and weigh about 300 pounds.
But the DWP’s Martinez noted that with transformers going out all over the West, the supply of replacements is running thin.
“We have gone through the stock,” he said. “We have ordered more
If the heat continues, more equipment is likely to fail, he said.
The question of capacity goes to the heart of why the system was overwhelmed in some areas but not in others.
For example, Edison routinely supplies more power to homes and businesses in areas that typically have the highest summer temperatures, such as the high desert and Palm Springs. By way of example, Conroy compared underground transformers used in Palm Springs and Santa Monica. Although both carry the same amount of electricity, the Palm Springs transformers are wired to serve just six households each, while those in Santa Monica serve 11 apiece.
The situation is similar in non-desert areas throughout the region -- even hot climates like the Inland Empire and the San Gabriel Valley, where many of the week’s outages took place. Conroy said it would be too expensive to use additional transformers or larger ones.
Though temperatures are dipping slightly, the heat continues to cause numerous problems.
Statewide, power usage neared maximum capacity Monday, and Gov. Arnold Schwarzenegger directed state agencies to reduce electricity use by 25% and turn off unnecessary equipment. He urged local and municipal governments and universities to do the same.
The heat wave is the worst since 1998 statewide and has been so intense that the demand for electricity is up 40% compared with the state’s energy crisis of 2001, Cal-ISO Chief Executive Yakout Mansour said.
Heat is at levels expected only once every 50 years in some parts of the state and once every 100 years in others, said Joseph Desmond, deputy secretary for energy at the California Resources Agency.
Four deaths in Southern California over the weekend were linked to the heat, mostly in outlying portions of San Bernardino and Riverside counties. In the Central Valley, 13 deaths have been blamed on the heat, including two men who died on a front lawn in Fresno.
Meanwhile, officials were investigating a Stockton nursing home after a patient died when the air conditioner gave out in the 115-degree weather. They also were looking into the death of a gardener who collapsed on the job in Bakersfield.
No deaths were reported in Los Angeles County. But the heat appears to have caused an increase in ambulance calls, said L.A. Fire Chief William Bamattre. On an average day, crews respond to about 1,000 medical and fire calls, but Bamattre said his agency received about 1,500 calls on Saturday and more than 1,200 on Sunday.
Times staff writers Susannah Rosenblatt, Andrew Blankstein, Dave McKibben, Ashley Powers, Ashley Surdin and Hector Becerra contributed to this report.
(BEGIN TEXT OF INFOBOX)
Power to the home
Old transformers that weren’t designed to handle the demands of modern homes during a heat wave are a weak link in the power distribution system.
How transformers work
- Transformer drums on power poles (or green transformer boxes attached to underground lines) reduce high voltage running through power lines to lower levels for household use.
- In Southern California, parts of the power distribution system date to the 1920s and 1930s.
- Inside the transformer, higher voltage electricity in a tightly wound set of coils is transferred to output wires with fewer coils. Fewer coils means less voltage.
How we get electricity
- Generating plants are powered by fossil fuels, water, nuclear power, wind and solar energy.
- The current from the plant is stepped up to between 220,000 and 500,000 volts on its way to a receiving station, to reduce energy loss on its journey over long distances.
- Voltage is reduced as it passes through distribution stations, substations and transformers on the way to homes and businesses.
Sources: HowStuffWorks. Graphics reporting by Cheryl Brownstein Santiago