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After millions of Californians endured a power shutdown earlier this month, state officials are demanding that utilities find ways to reduce the impact of outages. Blackouts are almost certain to happen again to prevent devastating wildfires. In fact, power company Pacific Gas & Electric now says customers can expect outages for at least a decade as it upgrades its systems.
New technology for power lines, making the electric grid “smarter,” could help keep the lights on for more residents. Utilities are testing devices that can communicate in real time or turn off power to broken lines before they cause problems, an investment that could ultimately cost billions.
“We are seeing impacts of climate change,” said Sascha von Meier, professor of electrical engineering at University of California, Berkeley, who also lost power at her Oakland Hills home for about 24 hours. “But I think there are a lot of technical things we could do more intelligently to minimize the need for this.”
Six of the 10 most destructive fires in California’s history were started by electrical equipment. But power outages hit vulnerable populations the hardest. People with medical devices had to scramble for back-up power or find places to stay. Others on tight budgets struggled to replace food that spoiled in their fridge.
Many residents are demanding that PG&E bury power lines underground, something other California utilities and cities are slowly doing. San Diego Gas & Electric has buried 60% 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, burning almost 3,000 homes. PG&E had to rebuild the power grid 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,” she said. The utility has said it will bury power lines in Paradise, which was largely destroyed in the record-breaking Camp Fire last year.
Still, putting power lines underground costs about $3 million per mile, according to PG&E estimates. The utility has 81,000 miles of overhead lines, not to mention 18,000 miles of transmission lines. Maintaining underground lines is also more expensive.
“If and when something does go wrong, it’s a lot harder to find where the problem is and go fix it,” said von Meier.
Overhead power lines can be made safer too, since today, the grid is still pretty analog.
“A lot of this isn’t even 20th century technology,” von Meier said. “It’s kind of 19th century.”
Smarter power grids
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 that has been used by utilities in Australia, known as Rapid Earth Fault Current Limiter, but it’s not currently deployed on their grid.
If a power line is broken, utilities are also starting to ensure the power stays off. While it seems as if that would naturally happen, utilities routinely attempt to turn the power back on with a device called a recloser. It sends current back down the line, sometimes up to three times, to see whether the problem has cleared and power can be restored.
“That’s standard operation,” said von Meier. “Without it, your power would be out a lot more often.”
But reclosers have been implicated in starting previous wildfires. So some utilities, like SDG&E, turn off automatic restarting in high-risk areas. PG&E says it has made its reclosers remotely operated in fire zones, so they can be reprogrammed 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,” she 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 smaller sections of the grid can be turned off independently, affecting fewer people.
“They’re still building homes in these high fire-threat districts,” said Winn. “In my opinion, there should be some policies on the types of homes you can build and it 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,” said von Meier. “That’s really is the prickly question.”