There are green buildings, and then there are green buildings. A sustainably built and operated skyscraper is currently rising over the skyline of New York City, and it has more eyes on it than any high-rise building in human history.
Upon its completion in 2013, New York’s One World Trade Center (colloquially known as the “Freedom Tower”), part of a complex currently under construction to replace and honor the World Trade Center Twin Towers and other buildings destroyed on September 11, 2001, will be the tallest building in the United States (Sorry, Chicago!) and one of the tallest buildings in the world. At the very top of the completed skyscraper, the radio antenna that will top the 400-foot spire will reach a symbolic height: precisely 1,776 feet high, in honor of the year of American independence. One World Trade Center, which will feature three million square feet of Class A office space alone (set on 71 floors dedicated for office use) will be accompanied by three other high-rise office buildings and the new National September 11 Memorial & Museum, located at the foot of One World Trade Center. The museum was opened during memorial ceremonies on September 11, 2011.
In addition to being tall and lovely, the building contains some not surprising cutting-edge safety features, including elevators that are housed in
a heavily protected central building core, pressurized stairwells that are also built wider to accommodate handicapped building occupants in an emergency, protected “tenant collection” points on each floor, a dedicated stairway for use by fire and other emergency crews, and a specially designed emergency communications systems. An on-site police command center will serve the entire World Trade Center complex of buildings. The new safety standards actually exceed the requirements of the already-stringent New York City Building Code and are expected to become standard in the development of new high-rise buildings in that city.
But here are some things you may not know: once finished, One World Trade Center will be the most environmentally sustainable building of its size in the world. (Seven World Trade Center, which was completed and opened in 2006, was hailed as New York City’s first “green” office tower, but it will be dwarfed by its new companion tower.)
Designed by architect David Childs of Skidmore, Owings and Merrill, LLP, One World Trade Center will incorporate not only new architectural and safety standards, but new environmental standards as well, “setting a new level of social responsibility in urban design,” its makers say. Once completed to the U.S. Green Building Council’s LEED (Leadership in Energy Efficient Design) Gold standards (only one removed from Platinum, the most stringent standard), One World Trade Center will set the global standard for sustainability, according to the New York Port Authority. (The completed Seven World Trade Center building has already been certified to LEED Gold.) For starters, the building’s designer intend for it to derive about 35 percent of its power from renewable energy sources. Once the building is fully operation, it’s expected to draw as much as 70 percent of its power from green energy: no small feat in a part of the world as densely populated as the New York metro area.
The building features a whole host of green elements, including:
Fuel cells. As of today, 12 United Technologies Corporation (UTC) Power PureCell Model 400 fuel cell stacks have been installed in the building. Ultimately, these fuel cells will provide 4.8 million watts per hour of clean energy when operational, and the combined systems will rank as one of the largest fuel cell installations in the world, according to UTC.
Waste steam recycling. Waste heat output from this fuel cell system will be recycled and used for hot water and heating in the podium of the building’s structure and the entrances, amounting to 70,000 BTUs of high-grade heat and 500,000 BTUs of low-grade heat. Alternatively, with the addition of an absorption chiller, the system is capable of using the waste heat to produce about 50 tons of cooling for the building, eliminating some need to draw power off the grid for air conditioning.
World-class mass transit. Workers commuting to One World Trade Center – and with millions of square feet of office space, there will be a lot of them – will have unprecedented access to mass transit service from the new complex. New climate-controlled corridors will connect the Freedom Tower to The World Trade Center Transportation Hub and the new PATH terminal, 11 NYC Transit subway lines and the new Fulton Street Transit Center, the World Financial Center and ferry terminal, underground parking and retail and dining facilities.
Exceeding code. Overall, the building’s energy performance will exceed code requirements by 20 percent, say its builders.
Recycled rainwater. Rainwater will be claimed and re-used for building cooling purposes as well as fire protection, supplemental cooling and irrigation for the complex’s extensive landscaping needs. The rain water – 60 inches annually in New York, making it one of the rainiest of American cities – will be stored in new high-efficiency evaporative cooling towers located on-site.
Functional memorial. The large, square reflecting pools which mark the “footprints” of the original World Trade Center twin towers feature 360-degree waterfalls and serve as rain collection systems themselves. The names of those who died on September 11 are inscribed on plaques around the “footprint” waterfalls. The names appear dark during the day and glow with internal light at night.
Central chiller. Air conditioning will be supplied, in part, by a highly efficient 12,500-ton Central Chiller Plant (CCP) that uses water from the Hudson River to cool the WTC Transportation Hub, National September 11 Memorial and Museum, retail space and some non-commercial areas. The plant will circulate 30,000 gallons of river water every minute.
Landscaping. The new main plaza of the World Trade Center complex will feature more than 400 trees, all of which were harvested within a 500-mile radius of the city to avoid excessive transportation and limit the amount of greenhouse gas emissions. The trees’ roots will help keep temperatures regulated within the museum that lies below.
Waste material recycling. Construction at the building site has been recycling about 80 percent of waste materials generated at the site, exceeding its own target by about 20 percent.
Recycled building materials. The new World Trade Center is already 75 percent “old,” at least in terms of materials. Everything from the facility’s gypsum boards to ceiling tiles contains a minimum of 75 percent post-industrial recycled content. This reduces the environmental footprint, not only on-site, but reduces the stress on the natural resources and energy needed to produce them, says the tower’s builders.
Taking a pass on cement. The construction of One World Trade Center used so-called “Green Concrete,” – what some believe to be more environmentally responsible than traditional cement – which will save about 12 million pounds of carbon dioxide emissions, 8 million kWh of energy and 30,000 gallons of fresh water. (It does, however, contain coal fly ash, which comes with some environmental challenges of its own.)
Renewable energy sources. The facility will make use off-site renewable wind and hydro power.
Clean diesel. During construction, contractors are being required to use only ultra-low sulfur diesel fuels, or “clean diesel” to reduces nitrogen oxide and particulate emissions in and around the construction area. In addition, all construction vehicles are equipped with extra particulate filters to further reduce their environmental impact on air quality.
No VOCs. Any use of materials that contain VOCs – volatile organic compounds, or chemicals that leach from building materials in gaseous form and cause health problems – has been banned from the entire reconstructed World Trade Center complex.
Preventing a “sick” green building. Indoor air quality will be continually monitored with a high-tech system. Carbon dioxide monitors will control ventilation and make the building healthier and improve indoor air quality. If the monitors sense more carbon dioxide than is healthy, they send a signal to the air handler software, telling it more fresh air is needed in that space. The system then automatically increases the fresh air mix in the area. The buildings contain over 3,000 points of monitoring, according to Eduardo Del Valle, Director of Design Management at One World Trade Center.
Daylighting. The buildings will use a green feature called “daylighting,” which means that on bright, sunny days when a large amount of natural daylight is coming into the windows, dimmers will automatically lower the interior lights to reduce energy consumption. Every space within 15 feet of the building’s facade will be equipped with dimming devices. In addition, the buildings’ windows are being constructed of ultra-clear glass, which will allow a maximum amount of light in while blocking excess heat from entering.
Green port-a-potties. During construction, workers are using composting toilets in place of the familiar, chemically smelly portable toilets. Essentially, their waste is being allowed to do what waste was meant to do: mix with other decaying biological products and create nutrient-rich soil. After workers make their “deposits,” the solid waste is channeled into a container half full of saw dust and worms: industrious and conscientious workers who quickly go to work turning the waste into composted soil. The water of urine is evaporated away, leaving only the faintest film of biological material. (Hope you weren’t eating lunch!) In addition to being more efficient, the toilets are smaller and easier to move than large chemical portable toilets: an important consideration when your workers need to answer nature’s call more than 1,500 feet off the ground. Once human waste – both of the liquid and solid variety – is fully processed, more than 90 percent of it is re-used, eliminating the need to constantly empty and re-plenish the water in traditional portable toilets. Workers have praised the system as far superior and less stinky to other high-rise bathroom arrangements.
Low-water bathrooms. Once completed, the building will contain high-efficiency plumbing systems designed to save thirty percent on water consumption over a typical building of its size. To achieve this, builders will install low-flow toilets and devices to limit water use for hand washing.
Save the ozone. Builders have barred the use of ozone-depleting HCFC refrigerants in the building’s mechanical systems.
Sustainable wood. Fully fifty percent of wood used in the buildings of the new World Trade Center was sourced from Forest Stewardship Council-certified (FSC) (www.fscus.org) sustainable harvested forests. FSC certification mandates that the wood used in a building project came from responsible sources and not from endangered trees or forests.
The construction of the new World Trade Center site – and in particular the One World Trade Center Tower – has not been without controversies. The building has been the topic of criticisms over delays (it had originally been slated to open this year; in 2008 the completion date was pushed to 2012 and is now scheduled for opening in April of 2013), over-budget spending (the latest figure is over $3 billion) and accusations of cronyism on the part of former New York Governor George Pataki, who was accused of using his influence to get the winning architect’s bid picked as a personal favor for a friend and campaign contributor. The design itself has been criticized, with petitions circulating that demanded the original World Trade Center Twin Towers be replaced. A media kerfuffle briefly erupted in May of this year when plans for the tower were displayed on the Web site of the New York City’s Department of Finance, with critics complaining the plans could be used by terrorists to attack the building.
The building’s designers and builders have a rather unenviable job in some ways: creating a new building that’s functional, modern, sustainable and unique while at the same honoring the memory of the buildings that stood there before and the people who perished in and around them. And while even the green components of the building have been criticized as overly expensive, these features will do more than save some water, some electricity and some emissions: they, together with the building they grace, will set an inspiring new precedent for skyscrapers for the twenty-first century.