NAPA -- Nova Group, a general engineering contracting company that has built large-scale fueling, utilities and waterfront military and private projects worldwide for three decades, on Monday said it has been sold to a Houston-based Fortune 400 company specializing in designing and building energy infrastructure projects.

The name, staffing and management will stay the same, but Nova Group (707-265-1100, will have the capital backing of Quanta Services, Inc. (NYSE: PWR), which builds electricity, natural-gas and pipeline projects in North America and certain other countries, according to Ron Fedrick, Nova Group chief executive officer and founder.

Quanta Services first approached Nova Group in November 2012 about an acquisition then acquired total ownership of Nova Group on Jan. 31. The acquisition price wasn't disclosed.

"Nova's market opportunity has grown with projects increasing in number and magnitude, primarily due to environmental compliance requirements and growing energy needs," Mr. Fedrick said. "Many of the projects we perform are capital intensive and significant in scope and size with sizable bonding and capital requirements. Joining Quanta, a company with a strong balance sheet and significant financial resources, will allow Nova to grow further and afford more opportunities for its people, both personally and professionally. Nova's continued growth will also benefit the local economies and communities of the areas where we work."

As a medium-sized construction company, Nova Group had been limited in taking on the jobs that were within reach because of the company's bonding and banking limits, he added.

Quanta Services reported $6.52 billion in revenues last year, up 10.1 percent from 2012. Quanta acquired six companies in 2013. As of its latest earnings report, released Feb. 20, Quanta had spent $116.5 million in the first quarter of this year buying four Canadian electrical-power infrastructure companies and Nova Group.

Nova Group was the 18th largest private employer in Napa County last year, with 148 employees reported for the Aug. 28 Business Journal list. Seventy-five of those employees work in Napa.

"But that will probably double in the next three to six month due to the new work we have acquired," Mr. Fedrick told the Business Journal on Tuesday.

It specializes in hydrant fueling, waterfront and utility construction for U.S. Department of Defense military bases and civilian facilities. Mr. Fedrick started the company in 1976. Government work started with steam lines at Mare Island Naval Shipyard in Vallejo. By the end of the 1970s, Nova Group's government jobs expanded to other bases.

In the mid-1980s the company expanded to Hawaii with government projects based out of Oahu. In the 1990s Nova Group started installing aircraft fueling hydrants at bases and airports from the Bay Area to the East Coast.