When Wim Coekaerts bought a hillside lot to build his California dream house, there was an old horse barn, a grove of olive trees and lovely views of Silicon Valley. But there was no electricity, and the nearest utility pole to his bucolic acre was 550 feet away.
The town of Woodside requires new homes without utility service to pay for wires to be buried underground. Coekaerts faced a choice: pay PG&E Corp. roughly $100,000 for engineering work and foot the enormous additional cost of the trenching, or engineer a more personal fix.
Coekaerts, who grew up in Belgium, is a man who highly values reliable, stable electricity—something PG&E has not always provided in recent years amid increasingly ferocious wildfires. And it's not just California: this week, a winter storm has paralyzed the grid in much of Texas, highlighting just how fragile the legacy system is. Coekaerts is senior vice president of software development at Oracle Corp., a legend in the open source community and is the longest serving board member of the Linux Foundation. We all want the lights to stay on; he needs to be able to run his servers and charge his electric Tesla Model S.
His house is the exact opposite of a small cabin: it was designed by an architect and spans 2,800 square feet. Coekaerts started puzzling through the engineering challenges: What if he cut ties with PG&E? What would it take to build his own self sufficient energy system, with the electricity produced and stored on site? He started researching microgrids, a small energy grid with control capability, which typically means it can disconnect from the traditional grid. Coekaerts wanted to be autonomous from the beginning. He started looking at Tesla’s energy products: the home battery known as the Powerwall and larger systems called Powerpacks.
“This is not a tiny home,” says Coekaerts, as contractors put the finishing touches on the three-bedroom limestone house. “A lot of people say they are off grid, but they have a tiny house where they only need two solar panels. I didn’t want to have a lifestyle where I’m just getting by. This is a normal house with normal energy consumption, and I can charge my car if needed.”
In the developing world, microgrids may leap frog traditional utilities, much in the way that mobile phones made the need for landlines obsolete. In the U.S., military bases, universities, prisons, and hospitals are turning to microgrids as a way to operate independently from the grid. The Santa Rita Jail in Alameda County, about a half-hour’s drive east of Oakland, has a microgrid that allows it to operate as an island for extended periods.
Individuals are also pursuing them. Larry Ellison, who serves on the board of directors of Tesla Inc. and is the chairman and chief technology officer of Oracle, has expressed interest in a microgrid for Lanai, the island in Hawaii that he bought in 2012. Tesla disclosed in a regulatory filing that director James Murdoch purchased a Powerpack system from the company for $600,000 in 2019 and that in 2020, a company affiliated with Ellison “entered into an agreement to obtain preliminary design services from us for an estimated $400,000, relating to the potential future implementation of a Tesla Energy system.”
PG&E has more than half a million residential solar customers, and at least 18,000 have installed battery energy storage systems. You hear a lot in California about “solar plus storage”: solar panels to harvest sunlight into electricity, paired with a home battery that can store the electricity for later use, like after the sun goes down. Tesla markets the Powerwall as a backup for when the grid goes down. The Powerpack is mostly sold to businesses and utilities.
Coekaerts didn’t want his system to function as a backup to the grid: he wanted to be independent of the grid. So through Luminalt, the San Francisco company that installed his solar system, he was able to get a Powerpack, which is about 17 times what a single Powerwall provides. Tesla representatives have told him it is the first residential Powerpack installation that they know of, though others are in the pipeline. The total cost, including permitting, labor for the installation and a federal tax credit for the solar system, was roughly $300,000.
His system, which was activated in November, combines 27 kw of photovoltaic solar panels with a 232kWh Tesla Powerpack. There are five ground-mounted arrays of 15 solar panels each, or 75 solar panels total, stretching across the yard. The Tesla Powerpack, which on the outside just looks like a massive white box with Tesla’s logo, emits a low hum and is protected and surrounded by a tasteful wooden fence. During long summer days, the system will probably generate far more electricity than he needs, and neighbors have joked that they’ll get out their extension cords.