Early one December morning in 2010, the inflatable roof on the Minnesota Vikings’ old stadium in Minneapolis ruptured and collapsed under the weight of 17 inches of wet snow. No one was hurt, but the incident was a wake-up call for the Vikings’ front office. The team needed a new facility that could withstand the rigors of a Minnesota winter.
On Sunday, the stadium will be on full display as Minneapolis hosts Super Bowl LII between the New England Patriots and the Philadelphia Eagles. The US Bank Stadium, which replaced the old Metrodome in 2014, is built to endure the fiercest storms. And, because bitter cold outside makes it costly to keep the stadium warm inside, the venue also deploys an array of energy-saving features.
“We knew that the roof had to be strong enough to weather significant 100-year snow loads,” said John Hutchings, who led the team at HKS Architects that designed the building. “No storm will collapse this roof.”
In addition to winning awards for its near-indestructible roof, the US Bank Stadium earned a LEED Gold certification from the US Green Building Council for conserving energy.
US Bank Stadium’s roof is treated with a special glaze that deflects sunlight, and helps to melt snow quickly. Its pitch is very sharp, which helps snow slide into large snow gutter — 50 feet wide at its largest. The roof allows natural sunlight in, which helps the venue save money on lighting.
“The roof creates an ideal outdoor atmosphere inside the stadium,” Hutchings said. “So much sunlight pours into the bowl that it’s not unusual to see fans wearing sunglasses inside.” The roof is the one of the stadium’s most popular features.
“I think the daylight quality of the game really makes you feel like you’re outside and creates a pretty good fan experience,” said Richard Strong, an architect with the University of Minnesota’s Center for Sustainable Building Research, which made sure the stadium followed state sustainability guidelines. “The balance between energy efficiency and the ability to have a lot of light is one of the things that stadium really achieved.”
Most Vikings games are played when it is cold — usually below 45 degrees Fahrenheit — with temperatures that can plummet to less than -10. Heating typically makes up 50% of building energy use in this region, so stadium designers decided to use solar heating and capture heat in the facility as it rises, then recirculate it to the fans below. The system redistributes warm air in the winter and pumps in cold air during the summer.
US Bank Stadium is one of just 80 LEED-certified sports venues in the United States, according to the American Council for an Energy Efficient Economy (ACEEE). It is also the first NFL stadium to be built with LED lighting, which uses 75% less electricity than metal halide lighting typically deployed in stadiums.
Furthermore, the stadium offsets all of its energy with renewable energy credits. It deploys low-flow faucets to save water. It was built with a single steel truss, instead of two, which reduced the amount of steel needed for construction. And, it has committed to becoming a zero waste facility where almost all waste is recyclable or compostable.
Minnesota was ranked 9th in ACEEE’s 2016 State Energy Efficiency Scorecard because of its energy efficiency policies. The state’s building standards call for structures built after 2010 to consume 60% less energy than the average building, with the goal of reaching net zero by 2030. The US Bank Stadium is working to adhere to these standards.
“I think the stadium sends a message to the people of Minnesota about being environmentally responsible,” Strong said. “It comes very close to meeting all the state’s sustainability guidelines.”
One issue yet to be resolved is whether the building’s glass windows pose a danger to birds. Many birds migrate to or through Minnesota in large numbers, according to the Audubon Minnesota, which raised the issue of potential bird collisions before the stadium opened. Since then, Audubon, the Minnesota Sports Facility Authority, the University of Minnesota and Oklahoma State University announced they would collaborate on a two-year study to evaluate the threat.
The US Bank Stadium is one example of a larger trend among college and professional sports teams to conserve energy, both to save money and to limit carbon pollution that contributes to climate change. This effort assumes a higher profile during the Super Bowl.
“Given the bewildering retreat from essential, science-based climate policy being enacted by the worst environmental administration in our nation’s history, a counter message by the NFL promoting progress on climate could not be more important,” said Allen Hershkowitz, chairman of Sport and Sustainability International.“As one of the most visible sporting events in the world, the Super Bowl has a unique opportunity to promote environmental literacy and reduce cultural polarization related to climate change.”
He added: “The US Bank venue’s commitment to 100% renewable energy credits, combined with its ambitious zero waste goals, and the region’s intelligent mass transit infrastructure, position this event to be among the most carbon intelligent Super Bowls ever.”
While locals are happy to see Minnesota represented in Super Bowl LII, game day will be bittersweet. Strong, a lifelong Minnesotan, regrets the fact that the Vikings won’t be in it. They suffered a crushing loss to the Eagles in the NFC championship game two weeks ago, and they won’t get to play at home in the biggest football event of the year.
“We would have loved for them to be playing in the Super Bowl, in their home stadium, and in front of a national audience,” Strong said. “We really wanted to be able to root for the hometown team.”