Forward Pass for RenewablesWith the 2011 National Football League season now in full swing, savvy fans are scanning the field for the latest tactics for attacking and protecting the goal line. But above and around the stadium, another important NFL play is in motion: A move to cleaner energy.Following a trend under way at sports facilities around the world, three NFL clubs were planning to showcase new green energy installations this season. The Washington Redskins unveiled their new installation of 8,000 solar panels (and new "Solar Man" sculpture) at FedEx Field today (above), and are touting their upcoming home game this Sunday against the Arizona Cardinals as "the Solar Bowl." The next week, when the Cardinals travel to Seattle, the Seahawks will show off the new 3,750-panel array on the roof of CenturyLink Field (formerly Qwest Field) in their home opener.Perhaps the most ambitious NFL energy project that has been announced, a bid to make Philadelphia's Lincoln Financial Field energy self-sufficient, will not be completed as planned for the start of this season, said team spokesman Rob Zeiger.(Related: "Pictures: Kickoff Time for Green Stadiums")The NFL says it shouldn't be surprising that the league is on the eco-friendly bandwagon. "The NFL is in many ways a copycat league," said David Krichavsky, the league's community affairs director. "When a team has great success on the field using a particular offensive or defensive strategy, it is common for other teams to start using that strategy. The same is true off the field."Reflecting the oil-gas-coal-heavy energy mix of the United States, about 72 percent of the energy powering NFL stadiums comes from fossil fuels, according to research the environmental group, the Natural Resources Defense Council (NRDC), compiled using government data.The new projects reflect an effort to shift that ratio, although it means that the NFL teams are investing in renewable technology at a time when economic conditions and fierce global competition have roiled some segments of the industry. Seattle's solar panels were made by bankrupt manufacturer Solyndra, while the Eagles intended to buy their wind turbines from financially troubled Helix Wind.(Related: "Google's Solar Energy Gambit")With about 1 million fans turning out to NFL stadiums each weekend, and last season's opening contests watched on television by an average of 19.5 million viewers, the NRDC says it should be no surprise it is working with the NFL, Major League Baseball, and other U.S. professional leagues to minimize the environmental impact of sporting events. "What's really astounding is it's taken the modern environmental movement 40 years to affiliate with professional sports," said Allen Hershkowitz, NRDC senior scientist. "The specific ecological footprint of any stadium is not gigantic. But their cultural influence is."—Jeff Barker This story is part of a special series that explores energy issues. For more, visit The Great Energy Challenge.

Photograph by Max Taylor