If we needed a wake-up call that we require a more reliable and resilient electric grid in the US, one that’s restructured around distributed generation and robust storage, we got it last Friday.

In New York, the power failed at a single subway station in Manhattan at 7:20 in the morning, creating cascading delays that turned ordinary commutes into ordeals of two to three hours.

While that was disruptive for thousands of commuters, it was nothing compared to what happened across the continent, where 90,000 PG&E customers in San Francisco were without power for as long as seven hours.San Francisco blackout

The outage began at the very start of the workday, when a fire affected a lone distribution substation downtown. From there, much of the city’s financial district lost power, along with several other busy neighborhoods and transportation corridors. There was gridlock as traffic lights were unable to function, commuters stranded with no power for the subway or electric buses, elevators unable to bring people to their offices.

But that was just the most visible part of the failure. Plenty of other vital infrastructure failed behind the scenes. Businesses couldn’t process credit card payments, which for most retailers and restaurants meant a total loss of business for the day (even those with cash couldn’t open register drawers). ATMs didn’t work. Neither did keycards in offices or hotels, locking people out, or elevators (firefighters respond to about 30 calls for people trapped in elevators). Without computer servers, even those who got to work couldn’t do any.

“Big Lesson: backup generators,” San Francisco Mayor Ed Lee told a press conference – but some of those failed, including one in a large hotel. Even hospitals that had redundant backup generators cancelled non-emergency surgeries.

It was a beautiful, sunny day in San Francisco. Besides that making it a little more bearable for people stuck downtown, it also made it an ideal day to have had distributed solar generation to keep the trains moving, the servers up and businesses functioning. It would have been even better if the solar generation had been connected to distributed storage, especially if the outage had lasted another few hours into darkness.

Energy experts and federal regulators alike have been talking for years about the growing fragility of the US grid, and the enormous cost to the economy of the rapidly increasing instance of failures. The American Society of Civil Engineers, in its 2017 Infrastructure Report Card, gives the energy system a dismal D+ grade, and points out that “[m]ost electric transmission and distribution lines were constructed in the 1950s and 1960s with a 50-year life expectancy,” with the grid at full capacity.

So while many power failures are caused by the stresses of severe weather, system age and lack of extra capacity are major contributors to the 3,500+ power interruptions in the nation every year. It’s going to take many years, and a great deal of investment, to modernize those resources.

Fortunately, there are some cities, including Los Angeles and Portland, along with some smaller communities in Vermont, that are taking action now. Rather than large generators, they are putting distributed storage online to act as a UPS for critical public items like traffic signals and firehouse garage doors. This is a vital extension of the use of DERs, including storage, in residential and commercial buildings, and also can help relieve some of the capacity issues inherent in the aging grid.

We’re going to have more outages as utilities work to upgrade infrastructure. Distributed storage can help dramatically reduce the effects of these interruptions, both in terms of inconvenience and economic impacts.