Starting today, Mark Mariani will begin powering the packing lines of one of the world's largest dried fruit plants with the same energy source his grandfather tapped at the start of the century-old family business.

"What better resource can you use but the sun that dries our fruit?" said Mariani, 56, chairman and chief executive officer of Mariani Packing Co. in Vacaville.

More than 5,800 skyward-tilted solar panels aligned like orchard trees next to the Mariani plant in Vacaville will generate up to 1.1 megawatts of electricity a year for the next 20 years.

That's nearly one-fourth of the power Pacific Gas and Electric Co. currently supplies the company to process more than 100 million pounds of dried fruit a year.

The Mariani installation stands out as an exception even in California's fast-growing solar energy market. While open-sun drying of fruits, vegetables and meats has been practiced for eons, the modern application of solar power to run the machinery on major farms has lagged, renewable energy experts said.

California's $50 billion food processing industry is the third-largest electricity user in the state, following oil refining and high-tech manufacturing.

Energy accounts for up to 60 percent of the cost of producing dried fruit in the Central Valley, with most of the power going to operate the 3,000 driers and dehydrators in the region, according to a 2006 state Energy Commission study by University of California, Davis, researchers. Yet, the report said, "the hydration process is often inefficient, employing outdated technologies."

The Marianis, however, have a history of being pioneers of conservation and efficiency.

In the 1960s, while irrigated farming mushroomed in the Central Valley, Mariani's father, Paul, installed the first micro-irrigation system in the state, cutting water use 70 percent in the company's Santa Clara Valley orchards, Mariani said.

More recently, Mariani family members and senior managers switched to driving hybrid vehicles.

"It speaks to commitment across the board to reduce carbon dioxide and global warming," Mariani said. "It sends a message to my whole company that this is the way we will be doing things in the future."

By relying on solar panels for about one-quarter of its energy needs, the company expects to reduce global-warming emissions of carbon dioxide by about 30 million pounds in the next 20 years – the equivalent of taking 3,000 cars off the road for one year.

The move to solar energy is in keeping with the company's decades-old core values, listed on the backs of their business cards: "We embrace change."

The food processor won't see much change in its electric bills in the near future.

Under its solar purchase agreement, SunEdison of Beltsville, Md., will charge no more than current retail price for the electricity supplied by the 7 acres of photovoltaic panels it financed and installed at the plant. Mariani, however, is lured by a provision that locks those rates for the life of the contract.

The venture into solar is a hedge against what company officials believe will be volatility and price inflation in the energy market, as they experienced in the California energy crisis of 2001.

Much of the prospective savings would accrue in the heat of the summer days. In those high-demand hours, as PG&E's peak rates kick in, Mariani will be drawing heavily from its lower-priced solar energy supply.

Also, on weekends when the plant is usually closed, Mariani can sell electricity from the solar farm to PG&E's power grid.

"On Day One, we won't save any money," Mariani said. "But years from now we will look back and say that was a good decision. Our sights are decade by decade rather than quarter by quarter."

SunEdison is hedging its bets that more companies will see the same light.

"Rates are going to go up, and the cost of sunshine is pretty predictable," said Mark Culpepper, the firm's chief technology officer in San Francisco.

Since its start in 2004, SunEdison has installed 170 similar solar power generators around the country, most of them in California. The sites include the roofs of Kohl's department stores and the grounds of the sun-drenched Chuckawalla Valley and Ironwood state prisons on the outskirts of the Riverside County desert town of Blythe.

In October, SunEdison signed a 20-year agreement with the state to deliver 8 megawatts of electricity to 15 California State University campuses, including the Sacramento campus. The solar panels will be installed on roofs, atop parking garages and on campus grounds.

Call The Bee's Chris Bowman, (916) 321-1069.