One Way California Can Avoid More Blackouts? Make Power Lines Smarter

After millions of Californians lost electricity last week, state officials are demanding that utilities find ways to reduce the impact of future disruptions. To prevent wildfires and reduce liability, power companies are almost certain to impose blackouts again.

New technology for power lines that make the electric grid “smarter” could help keep the lights on for more customers. Utilities are testing devices that can communicate in real time or can cut power in downed lines before they cause problems. Those investments could ultimately cost billions of dollars.

“We are seeing impacts of climate change,” said UC Berkeley electrical engineering professor Sascha von Meier. She lost power at her Oakland Hills home for about 24 hours during the recent blackout. “But I think there are a lot of technical things we could do more intelligently to minimize the need for this.”

Electrical equipment started 6 of the 10 most destructive fires in California’s history. But power outages hit vulnerable populations the hardest. People who rely on medical devices had to scramble for backup power or find places to stay. Others on tight budgets struggled to replace food that spoiled in their fridge.

Burying Power Lines 

Many customers are demanding that PG&E put its power lines underground. Other California utilities and cities are slowly doing that. San Diego Gas & Electric has buried 60 percent of its lines.

In Oakland, the power lines a few blocks from von Meier’s house are also underground. In 1991, a massive fire tore through the hills and burned almost 3,000 homes. PG&E had to rebuild the power grid there from scratch.

“They were going to spend a lot of money anyway, and realizing that this was a particularly hazardous fire area, it was put underground,” von Meier said. The utility has pledged to bury power lines in Paradise, where last year’s record-breaking Camp Fire caused widespread destruction.

PG&E estimates that putting power lines underground costs around $3 million per mile. The utility has 81,000 miles of overhead lines, not to mention 18,000 miles of transmission lines. It costs more to maintain underground lines than those aboveground.

“If and when something does go wrong,” von Meier said, “it’s a lot harder to find where the problem is and go fix it.”

Smart Grid Sensors

Because the existing grid is still pretty analog, utilities can make safety improvements in overhead power lines, too. “A lot of this isn’t even 20th century technology,” von Meier said. “It’s kind of 19th century.”

Utilities are starting to install networks of sensors, known as synchrophasors, which can communicate when problems occur and help restore power faster. San Diego Gas & Electric is also using them to prevent fires.

“The sensors can detect if a line is broken and then within a split fraction of a second, shut the power off to that line before it hits the ground,” von Meier said.

PG&E says it’s testing a similar technology, called a Rapid Earth Fault Current Limiter, which Australian power companies use.

Turning Off Auto-Restart

If a power line is broken, utilities are also starting to ensure that the power stays off. Typically, a device called a recloser automatically attempts to restore electricity when a power line is broken, sending current back down the line sometimes up to three times to determine whether the problem has cleared.

“That’s standard operation,” von Meier said. “Without it, your power would be out a lot more often.”

But reclosers have been implicated in sparking previous wildfires. So some utilities, like SDG&E, turn off automatic restarting in high risk areas. PG&E says it’s now made its reclosers remotely controlled, so they can be reprogrammed to shut off during fire season.

“Having these high-speed devices that are intelligent and smart is the only way that I believe that we can effectively manage the grid in the future,” said Caroline Winn, chief operating officer at SDG&E.

Utilities will have to convince regulators that these technologies are worth the cost and that Californians should pick up the tab through higher electricity rates. Networks of real-time devices also require new investments in data and information management.

“It really does need high-speed communication,” Winn said. “We’re installing our own private LTE communications network.”

Even if these technologies reduce the risk of fire, they won’t prevent all wildfires, so precautionary power outages will happen again. SDG&E is working on segmenting its grid so it can independently turn off smaller sections and affect fewer people.

“They’re still building homes in these high fire-threat districts,” Winn said. “In my opinion, there should be some policies on the types of homes you can build and [the power lines] should be undergrounded. Because undergrounding is really the only opportunity to eliminate the risk completely.”

Still, one of the most effective ways to prevent wildfires is low-tech: trimming trees around power lines. California’s major utilities have pledged to spend more on managing vegetation, but as of September, PG&E was falling far short of its tree-clearing goal.

“I think the difficulty is always how much can we afford to pay and who is going to pay it,” von Meier said. “That really is the prickly question.”