China’s Shanghai Tower claims to be the world’s greenest skyscraper, but can the buildings that dominate city skylines around the globe ever really be green?
The Shanghai Tower, which is due for completion in the coming months, is the tallest structure of any kind in China, and at 632m is the second tallest building in the world after the 828m-tall Burj Khalifa in Dubai.
Those behind the £1.5 billion project designed the structure to be a sign of Shanghai’s future, demonstrating not just China’s increasing economic might, but also their aspiration to transform Shanghai into a futuristic and green global financial hub to rival and eventually replace London and New York.
The Shanghai Tower was designed to meet the US Green Building Council’s LEED (Leadership in Energy and Environmental Design) “gold” standard, its second highest ranking of sustainability. Gensler, the architecture firm behind the project, say that in total the building will use 43 different sustainable technologies to reduce energy consumption by 21 per cent compared with a conventionally built skyscraper, bringing down its carbon footprint by 34,000 tonnes per year.
“It’s the greenest super high-rise building on earth at this point in time” said Dan Winey, Asia managing principal for Gensler.
The structure is designed as nine cylindrical buildings stacked on top of each other, offering 121 storeys of office, retail and hotel space. Each of the cylinders or “neighbourhoods” of the building offer an atrium with planted gardens irrigated by a drop system.
A double glass façade works like a Thermos flask for insulation, and the 120-degree twist minimises wind loads on the structure by 24%, say Gensler. The reduction in wind affecting the structure has also meant that the building is lighter and uses £37 million in expensive materials than a traditionally shaped block skyscraper.
The spiraling parapet also collects rainwater to be used for the tower’s internal heating and air conditioning systems, and wind turbines situated below the parapet generate on-site power.
Chairman of Gensler, Art Gensler, commented:
“We hope Shanghai Tower inspires new ideas about what sustainable tall buildings can be… We’ve lined the perimeter of the tower, top to bottom, with public spaces, and we’ve integrated strategic environmental thinking into every move. The tower is a stage that comes to life through the presence of people.”
Despite all the efforts to make the building more sustainable, the use of glass curtain walls remains an issue for some commentators, as Alex Wilson points out in Rethinking the All-Glass Building:
“Some of the world’s most prominent “green” skyscrapers, including New York City’s One Bryant Park (the LEED Platinum Bank of America skyscraper) and the New York Times Tower, wear the mantle of green with transparent façades. But there is a high environmental cost to all that glitter: increased energy consumption. Until new glazing technologies make technical solutions more affordable, many experts suggest that we should collectively end our infatuation with heavily glazed, all-glass buildings”
The construction of skyscrapers also has a major environmental impact, and the durability, resistance, and length of time the building is expected to stand in a rapidly changing city should also be taken into account. Archetects cannot plan for every accident, but by using impact and fire-resistant materials such as Durasteel, and ultra-durable concrete mixes like Superhydrophobic Engineered Cementitious Composite (SECC) recently developed by researchers at University of Wisconsin-Milwaukee, buildings can last longer and have a reduced impact on the environment.
