The criteria for awarding certification include energy savings, water efficiency, emissions reductions and resource stewardship.
Target Field collected 36 certification points, two more than Nationals Park in Washington, D.C., received last year.
"As in many respects, Target Field has overachieved everyone's expectations," said Steve Cramer, chairman of the Minnesota Ballpark Authority. "We can be proud of the fact that the ballpark was built to this rigorous environmental standard."
Strong environmental stewardship has been the Twins' goal. Sen. Linda Higgins (DFL-Minneapolis) made sure LEED certification was a requirement in the 2006 law to fund the ballpark.
"We didn't know what that was; we're scrambling around and everyone was giving us these horror stories that it'll cost so much money, you'll have to add to your budget, blah, blah," said Jerry Bell, president of Twins Sports, Inc. "We're really, really happy that she did that."
Instead of waiting for possible grant money, the team and the the ballpark authority combined to provide $2.5 million in December 2007. The overall cost of the LEED certification was less than 0.5 percent of the ballpark's $545 million cost.
"It really isn't about money or what you can do, it's about putting imagination and effort into figuring out what we can do to make any new project more sustainable and green," Twins owner and chief executive officer Jim Pohlad said.
The process including removing and treating contaminated soil and returning some of it to the ground; having more than 70 percent of construction waste diverted or recycled; and having more than 30 percent of all installed materials made from recycled content, including the foul poles and roof canopy. Precautions were taken to control soil erosion, waterway sedimentation and airborne dust, and local materials were used to the greatest extent possible to reduce energy costs associated with shipping. For example, 60 percent of the building's exterior is regionally sourced limestone from Mankato, Minn., about a 90-minute drive from the ballpark.
Even the floor that the NBA's former Minneapolis Lakers used when playing at the Minneapolis Armory is included in the Town Ball Tavern.
The Twins encourage fans to use public transportation or pedal power when attending games. Both the Hiawatha and Northstar rail lines stop near the left-field corner, a Metro Transit bus hub is less than a block away and 827 bicycle storage locations are within 200 yards of the ballpark.
"We have great transportation to the project, which is a great thing for LEED certification; it was considered a brownfield site," said Earl Santee, a senior principal with Populous, the design firm that managed the LEED certification process for Target Field. "A lot of things about this site made it the right candidate to apply LEED guidelines and make it happen."
It is all based on the following sustainability statement:
"The Minnesota Twins organization believes our future success -- both on and off the field -- is built on a business model that embraces operational efficiency, environmental stewardship and social responsibility. We honor the power of sport by leading through example, and we will continue to use sport to inspire, build the best fan experience and cause no unnecessary harm, working with our fans, community, suppliers, partners and employees to have a positive influence in the world."
Here are some of the ways the team follows its guidelines:
A power purchase agreement is expected to offset 70 percent of energy consumption over a two-year period, saving more than 8.8 million pounds of carbon dioxide.
Captured waste energy from the adjacent Hennepin Energy Resource Center is used to heat most indoor spaces at Target Field and the playing field.
High-efficiency field lighting saves nearly $6,000 a year.
Recyclable collection points are numerous in the ballpark, expected to collect up to 400 cubic yards of material during a three-game homestand.
In the Land of 10,000 Lakes, the designers of Target Field had to be aware of water use.
A cistern system under the warning track will capture and treat rainfall runoff. That water will be filtered and reused for field irrigation and to wash down the seating area after a game.
An estimated 4.2 million gallons of water will be saved annually due to low-flow urinals, dual-flush toilets and aerated faucets. These fixtures use 30 percent less potable water than conventional fixtures. A Pentair filtration system is expected to save another 1.5 million gallons annually.