Kendall-Jackson Wine Estates unveiled a rooftop solar cogeneration facility Thursday that is the largest of its kind in the nation.

Unlike most solar systems, which either generate electricity or heat water, the rooftop array does both. The installation sits atop the company's Kittyhawk blending and bottling facility just outside Santa Rosa.

On Thursday, guests gathered at the Kendall-Jackson Wine Center for a reception where the company announced it will install solar cogeneration arrays in two more of its facilities, making it the largest consumer of this type of solar energy in the country.

"When my father first opened Kendall-Jackson in 1982, he wanted it to be a family business and he wanted it to last for generations to come," said Katie Jackson, family spokesperson and proprietor of Jackson Family Wines. "Long-term land stewardship was always a part of his vision from the very beginning."

The company declined to divulge the cost of the project, but said it expected to recoup its investment within five years. It will generate an estimated $30,000 in annual energy savings, according to the manufacturer, Cogenra Solar.

"This project ... is a direct rebuke for those who say it can't be good for the environment and good for the bottom line. That's just nonsense," said Rep. Mike Thompson, D-St. Helena, who attended the event.

That cost-effectiveness comes in part from incentives and tax rebates that covered about three-quarters of the cost of the project, said Robert Boller, Kendall-Jackson's vice president of sustainability. Some of those incentives expired at the end of 2011, but the company purchased the equipment last year.

"The roof was not doing anything, and now it's making energy for them," said Gilad Almogy, Cogenra's CEO. "Kendall-Jackson tends to be very advanced in their energy savings."

The system will produce 1.4 million gallons of hot water annually, heated to 140 degrees Fahrenheit, and 48,000 kWh of electricity per year. It will provide about 60 percent of the water heating needs of two production buildings at the Kittyhawk facility. The electricity generated will cover only about 10 percent of one of those buildings' energy needs.

Standard solar panels alone capture about 15 percent of the sun's energy, with the remaining 85 percent of the energy converted to waste heat, according to Cogenra. A solar cogeneration system, a relatively new technology, captures 60 percent of that waste heat to heat water. The result is a reduction in greenhouse gas emissions three times greater than that achieved with traditional photovoltaic panels, the company said.

Industrial-size installations of solar cogeneration systems often cost in the hundreds of thousands of dollars, but the largest can reach into the millions, Almogy said. However, subsidies can take care of 80 percent of the cost, he noted.

To date, Cogenra has announced installations of solar cogeneration systems in nine entities, including Sonoma Wine Co. in Graton, General Hydroponics in Sebastopol, Facebook, and the U.S. Army, Navy and Marine Corps.