Engineering giant CH2M Hill Cos. Ltd., an employee-owned firm with about $5 billion in annual revenue, has received a “small-but-noteworthy” contract of $6 million under the U.S. Solar America Initiative to provide raw data on solar-power potential, MarketWatch.com reported. The contract will pay the expansion of the city of San Francisco’s recently posted solar energy map. It will use advanced 3-D modeling and aerial imagery and will be available for public access through a special Web portal.

Punching an address into the city’s search engine pulls up data on the estimated amount of solar photovoltaic energy that could be installed on a specific roof. Additional available data includes the potential electricity-cost reduction and the potential reduction in dioxide/greenhouse gases, the company said.

The Web site also provides information on installing a photovoltaic system, including contact information for local solar installers.

David Herrmann, CH2M Hill’s director of client solutions, said the mapping program could potentially replace the current method of assessing solar energy potential.

“Right now, to get a solar assessment on a roof, you have to call up the solar installer, they bring their ladder, a guy wanders around on your roof, and two or three weeks later you get a report,” Herrmann told MarketWatch. “With this technology, you could do it accurately and quickly without having to roll a truck.”

Herrmann said the company’s solar maps use a format from Google Inc.’s (GOOG) Google Maps to display the data, but that CH2M Hill collects the images through its own proprietary process with Esri Inc. – A Redlands, Calif.-based company that’s recognized as a leader in geographic information systems (GIS) also supplying technology for the effort.

The solar map is also compatible with the Microsoft Corp.