OXNARD, Calif. — Two energy-efficient produce companies had dueling ribbon-cutting ceremonies to unveil their latest green energy technologies.

Duda, Gills unveil energy-saving technologyOn July 11, Gills Onions LLC debuted what is billed as the world’s largest vanadium flow battery, and Duda Farm Fresh Foods Inc. introduced 37,000 square feet of photovoltaic solar panels.

Karen Ross, secretary of California’s Department of Food and Agriculture; Gordon Burns, undersecretary of the California Environmental Protection Agency; and several local government officials were on hand for the event.

Gills’ vanadium flow battery, which is as big as a tennis court, stores electricity at night, when energy rates are lowest. During peak daytime hours, the battery provides 600 kilowatts of power for as long as six hours.

“We’re using low-cost energy to offset high-cost energy,” said Steve Gill, managing partner.

The battery builds on the company’s award-winning Advanced Energy Recovery System, which it installed nearly four years ago, he said.

The system was developed by Washington, D.C.-based Prudent Energy.

Duda says the solar panels will generate 688,000 kilowatt hours annually and provide 40% of the power for its fresh-cut celery and cooling facility.

The panels also enable the company to reduce carbon dioxide emissions by 478 metric tons each year, which is the equivalent of emissions from nearly 54,000 gallons of gasoline, said Sam Duda, vice president of Western operations.

The system was engineered by Cenergy Power, Merced, Calif.

Ross said the systems go far beyond the immediate borders of the two companies.

“It truly is an example of how we will be able to feed people and feed people better for decades to come,” she said.

California is the home of innovators and dreamers, she said, “and nowhere is that more evident than in the agricultural sector.”

The efforts are in line with California Gov. Jerry Brown’s goal of having one-third of the state’s energy come from renewable energy by 2020, Gordon said.

Jeff Pierson, senior vice president of Prudent Energy, called Gill’s battery “one big electricity warehouse” and said the project will help the company reduce its utility bill and keep the firm growing and adding jobs.

Nader Yarpezeshkan, director of corporate development for Cenergy Power, pointed out that solar panels can be subsidized to a large degree by tax credits and other incentives, and that the system can pay for itself in less than five years.

Gill said he started looking into new technology many years ago when he realized that, “When we peel onions, we lose about 35% of the onion.”

The $11 million Advanced Energy Recovery System previously installed provides 600 kilowatts of electricity, enough to power 460 homes, he said. Power comes from methane gas produced by onion waste.

Duda said it’s important that sustainable technology make economic sense.

“In our mind, ‘sustainable’ has to have a green impact but also be financially sound, otherwise it’s not sustainable — you’re just spending money to feel good,” he said.

The new solar panel project will offset 40% of the company’s energy costs year-round, he said.