|Fig. 1: The LEED Gold certified Levi's Stadium (Source: Wikimedia Commons)|
The U.S. professional sports industry hauls in tens of billions of dollars each year and has become an integral part of American culture. Traditionally, American sports have represented the excess and wasteful ways of our country. While sports stadiums have usually failed to make sustainability a focal point, this trend is changing, as the sports industry is starting to make environmental efficiency a focal point. Stadiums place a sizable strain on water systems and create a massive demand for energy and electricity. They can emit huge amounts of greenhouse gases (GHG) and produce thousands of tons of waste each year. Adding to the problem, owners are constantly looking for ways to enhance the fan experience at the stadium with features such as high-speed internet and improved video displays. These features may make the gameday experience more entertaining, but it puts an even larger strain on the environment. Fan transportation to and from the stadium can also generate thousands of tons of GHG emissions each year.  But teams are starting to focus more on reducing energy emissions through the use of solar panels and other low carbon alternatives. The San Francisco 49ers and their new $1.3 billion Levi's Stadium is at the forefront of this new movement with a wide variety of environmentally-friendly features that make it one of the greenest stadiums ever.
The brand new Levi's Stadium is the first stadium in the U.S. to achieve LEED gold certification. It boasts a number of innovative features, beginning with a "green roof" - a canopy of green plants spanning 27,000 square feet along the top of the luxury suites. With 2,000 tons of dirt, this green roof helps reduce the stadium's energy usage and provides other environmental benefits by soaking up rainwater and insulating the luxury suites.  These green roofs, sometimes referred to as living roofs, are a relatively new concept thanks in large part to advances in technology. Waterproof membranes now make it easier to "capture water for irrigation, allow drainage, support the growing medium, and resist the invasion of roots." The soil and vegetation act as a natural insulation barrier that can reduce heating and cooling costs by up to 20 percent. When it rains, green roofs absorb the water, filter it, and store it for later use.  Stadium officials are also considering using this green roof to grow herbs and other vegetation that could be used in stadium concessions. This would help to cut down on transportation of food from the east coast.  Also situated above the luxury suites is the NRG Solar Terrace. This solar canopy, along with photovoltaic solar systems located on three pedestrian bridges between the stadium and the parking lot, will help supply a portion of the stadium's electricity. The 1,150 solar panels have a peak output of 375 kilowatts; this means that over the course of the course of a year, Levi's Stadium will generate as much electricity as it consumes during its 10 home games. 
Stadium designers also initially installed Bandera Bermuda turf grass, which requires up to 50% less water than the average turf used in the Bay Area. Although this turf needed to be replaced because players complained of poor traction, the irrigation system used for the turf is one of the more sustainable features of the stadium.  Instead of fresh water being wasted, recycled water is used in toilets and irrigating the green roof and field turf. In addition, the low-flow plumbing fixtures are 40% more efficient than building codes require.  Recycled building materials were also used as much as possible throughout the construction of the stadium. For example, the wood used in the luxury suites was recycled from a nearby airfield hangar. The stadium seats were also made in Fremont rather than overseas, which has helped save energy from shipping. Another sustainable transportation feature of the stadium is electric vehicle charging stations in one of the parking lots. 
75% of the construction materials are being recycled and the 49ers have used sustainable bamboo wood in the luxury suites. The 49ers have also installed high-efficiency LED bulbs in 40% of the stadium lighting. Officials initially planned to put LED bulbs in the stadium lights but decided not to because of concerns about it altering the color of players' jerseys.  At the end of the day, when more than 65,000 fans flock to Levi's stadium on Sundays, they see how much of an effort the organization is making to be environmentally-friendly. So the 49ers are doing more than just making the stadium sustainable - they are raising the awareness of fans and people around the Bay Area, making them more conscious of energy efficient practices.
© Henry Anderson. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
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