The San Francisco 49ers officially broke ground on their new Santa Clara stadium site Thursday evening, bringing up the first clods of ceremonial dirt of where their future stadium will one day stand.

But project executive Jack Hill is looking to turn this plain old dirt into something more meaningful, as it is planned to be used for the the signature feature of the new venue, the 27,000-square-foot, energy-saving roof.

The roof will be the first of its kind in the NFL, using a bountiful garden of native plants to help to soak up rainwater and provide insulation for the tower of luxury suites underneath it. CEO Jed York envisions something similar to the Green Monster at Boston's Fenway Park:

"There aren't that many iconic ideas in football stadiums," York said. "It symbolizes what we're doing in that it combines energy efficiency and technology and the fan experience. And it's elegant and classy. That's the overall vision of the stadium."

Ihab Elzeyadi, an architecture professor at the University of Oregon, notes that the 49ers are moving in the right direction, but with the size of the stadium (1.85 million square feet) the roof's impact to cooling and heating will be rather minimal:

"They'll get a LEED credit for that," Elzeyadi said. "But getting LEED [Leadership in Energy and Environmental] credits doesn't mean that you're doing something important for the environment."

He would go on to mention that it's symbolic value could range much farther than it's practical value, as the idea of really going green will be perceived by the NFL and its millions of followers.

Other green initiatives of the new stadium include:

• Advanced plumbing fixtures, using non-potable water for irrigation and for flushing in the restrooms. Brightworks' Heath Blount estimated that water efficiency would be at least 45 percent better than at Candlestick Park.
• At least 20,000 square feet of solar panels, including on the roof and perhaps the parking lots. For most of the year, the stadium will actually add power to the grid.
• A ground-source heat pump, which uses the earth's surface as a heat source in the winter and as a heat sink in the summer. Most of the stadium will be open to take advantage of Santa Clara's mild weather. Enclosed areas like luxury suites will have fixtures that shut off mechanical cooling and heating when windows are opened.
• Regional and recycled materials will be used whenever possible. The woodwork in the luxury suites, for example, will be made largely from fast-growing and sustainable bamboo.
• Bicycle parking, exclusive parking for car poolers and alternative-fuel vehicles, and a charging station for electric cars will be available as well.

The 68,500-seat stadium is on track for it's grand opening for the 2014 season.

For more on the 49ers, head over to Niners Nation.