Founders: Sonoma County engineers Raghu Belur and Martin Fornage

Employees: 2,260 total — 561 in the U.S.; 100 in Petaluma

Product: Solar energy and battery systems based on microinverters

Editor’s Note: The Press Democrat is publishing a series of stories about Sonoma County innovators who are tackling global warming. We invite readers to propose stories of those involved locally in climate change. Share your ideas by contacting our editor, rick.green@pressdemocrat.com.

Sonoma County engineers at Enphase Energy have revolutionized rooftop solar, and they’ve just released a dramatic advance.

Thanks to the engineers’ vision when they started Enphase in Petaluma in 2006, homeowners today have a range of solar energy options and Enphase has recently experienced an explosion of growth.

“Now we are truly a global company. It’s quite a remarkable achievement,” said Raghu Belur, co-founder and chief products officer of Enphase.

The original vision that still propels Enphase is a conviction that solar energy should be controlled by a high-tech system of semiconductors, cloud-based software, integrated circuits, chips and microprocessors that would let home energy systems add new features and capabilities as advances in technology permit.

With these tools Enphase is now rolling out the first rooftop solar system that lets essential appliances continue to run on sunlight during a grid outage, even without a battery. Rooftop solar is usually dead when the grid is down.

“This allows people to operate their own energy systems, completely in the background, and to be able to achieve energy independence,” said Martin Fornage, the retired co-founder of Enphase.

“Martin’s brilliant view was that it made more sense to be a distributed model, a system, He was the brains behind Enphase, and our view has not changed since we founded the company,” Belur said during an interview in April.

The Enphase vision grew directly out of the founders’ decades of experience as engineers in Sonoma County’s Telecom Valley, where more than 30 companies developed telecommunications equipment, employed thousands of workers and brought billions of dollars to Sonoma County until the dot-com recession struck in 2001.

In 2006, Fornage and Belur set out to bring their telecom network thinking to residential solar systems, starting with inverters.

All solar panels need inverters, often called the brains of a solar system. At their most basic, inverters change the direct current produced by the solar panels into the alternating current usable in homes and on the grid.

For decades, a string of panels on a roof was connected to a single inverter installed close to the home’s electricity meter. Then, in 2008, Enphase introduced microinverters that attach to each panel.

String inverters are generally cheaper than microinverters. But if one panel’s output is affected, perhaps by shade or malfunction, output for the whole system falls, while microinverters isolate problems at the affected panel so the rest of the system can continue to operate.

Over time these and other differences between the types of inverters have blurred, and competition is stiff. In the U.S., Enphase and Israel-based SolarEdge have much of the inverter market and are neck-and-neck rivals. Internationally, many companies compete.

Enphase reports installing more than 42 million microinverters on about 1.9 million homes in more than 130 countries. About 20% of its business is outside the U.S., a share it’s growing.

A feature of Enphase’s microinverters is collection and display of detailed information about system operations. Enphase claims that knowledge gleaned from its data will help a grid to stay second-by-second reliable while it incorporates the coming wave of renewables.

“Evangelical” is how PV Tech writer Andy Colthorpe in 2015 described Enphase executives and their belief in data collection and its ability to increase grid visibility and stability. “Disruptive” is how GTM Research described Enphase the same year, when it designated it as one of the top 20 companies transforming the U.S. electric market.

For Mike Pane, co-owner of Synergy Solar & Electrical Systems in Sebastopol, all of his solar panel installations since 2014 have featured Enphase microinverters.

“They’re simpler, safer and maximize the solar harvest,” Pane said.

He said he especially liked the Enphase monitoring system, including the mobile app, that lets homeowners and installers track how the system is performing and how much power the panels are making and the home is using.

The core Enphase products are the microinverter and the monitoring system. To this, for about $2,000 plus labor, customers can add the new Sunlight Backup system that lets homeowners use existing sunlight to make power during a grid outage, without a battery. They can also add Enphase or other brand batteries, or electric vehicle chargers, to store power for nighttime or other needs. Sunlight Backup can replenish these batteries when they’re depleted and the grid is down.

Enphase’s 16-year history has been a roller-coaster ride. Building the technology they envisioned was difficult and they made learning mistakes along the way, co-founder Belur said. At times they struggled through layoffs and management shake-ups.

In 2018 Enphase moved its headquarters from Petaluma to Fremont to attract more talent, though it maintains operations in Petaluma. In 2019 it reported its first profitable year. Since then revenues have doubled, from $624 million in 2019 to $1.4 billion in 2021, while profits have continued — $161 million in 2019 and $145 million in 2021. Its stock price hit a closing low of 72 cents a share in May 2017 and ended 2021 at $185 on the Nasdaq market.

Looking forward, Enphase has announced several acquisitions, ramp-up of its small commercial and industrial business and expansion of a deal with a Romanian firm to next year begin manufacturing Enphase microinverters for the European market.

Mary Fricker is a retired Press Democrat business reporter. She lives near Graton. Reach her at mfricker@sonic.net.

Founders: Sonoma County engineers Raghu Belur and Martin Fornage

Employees: 2,260 total — 561 in the U.S.; 100 in Petaluma

Product: Solar energy and battery systems based on microinverters

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