Dongtan: The world’s first large-scale eco-city?
The eco-city of Dongtan, construction of which is planned for the island of Chongming off Shanghai, is an ambitious vision of sustainable design and urban planning, including an entirely self-sufficient energy system. Energy consumption will be minimised using zero-energy buildings, while energy will be generated by solar panels, wind turbines and bio-fuels. The visions are grand, but the project has been delayed and the only indication on Chongming today of the city to be is a solitary wind turbine farm.
Illustration af den planlagte økoby Dongtan, venligst udlånt af Arup
In 2005, the Shanghai Industrial Investment Corporation (SIIC) hired the consultancy Arup to design a city which would exclusively use sustainable energy, be self-sufficient and reduce energy consumption by 66% in relation to its neighbour Shanghai. The plan is for Dongtan to house 500,000 people from rural areas.
China faces pressing energy problems. Migration from the land to the cities means it will be necessary to build some 400 cities by 2020 to house 300 million people from rural areas. In order to meet their increasing energy consumption they will have to focus more sharply on energy-efficient design and technology, on the quality of urban planning strategies and to increase the degree of sustainable development.
Solar panels, wind turbines and biomass-based fuels will produce all the energy Dongtan will need. Most buildings will have photovoltaic cell arrays on their roofs. A minimum of 20% of Dongtan's energy requirements will be covered by wind power. A lot of the energy will be produced by a large wind turbine farm outside the city and micro wind turbines adapted to buildings and roads will produce electricity for the individual blocks of flats.
Up to 80% of the city's refuse will be recycled, and some of the organic waste, including rice husks, will be used to make energy to power a combined heat and power plant. Rice husks and other organic waste will be loaded into large bioreactors which will gasify the waste to produce electricity and heat.
All the buildings in Dongtan will be zero-energy or passive structures. Establishing gardens or other green vegetation on the rooftops will provide insulation and filter rainwater, thus helping to reduce energy consumption. Natural ventilation will be provided by adapting to the local microclimate and positioning individual buildings accordingly. Windows, especially those facing north, will have thermal glass to minimise the need for heating and therefore the consumption of energy.
The intention is to reduce the ecological footprint of Dongtan to 2.2 ha per person by means of a combination of behaviour change and energy efficiency. According to the World Wide Fund for Nature, WWF, 1.9 ha is the limit for sustainability. By way of comparison, Shanghai has an eco-footprint three times the size.
A critical look at Dongtan
Although Arup has drawn up a master plan for Dongtan along with sustainability guidelines, the dream of the world's first eco-city has, in the eyes of some experts, ended as a nightmare.
Dongtan consists today of 10 wind turbines - no buildings, water taxis, water cleansing plant or energy centres. Construction was to have started in 2006 but nothing has happened yet. The project's project coordinator in the Communist Party has been jailed, charged with corruption, and consultants Arup have since been criticised for participating in numerous dodgy sustainable construction projects. The Dongtan project seems to have lost its momentum, and because of the delay it has been given a mixed reception.
Although the project involves construction of a sustainable city, further doubts have arisen as to whether it can be defined as sustainable, taking into consideration the fact that it would sit on a disappearing green area outside Shanghai. The most sustainable use for this vital area, which constitutes one of China's largest bird reserves, would be for it to remain undeveloped.
Dongtan would not have much influence on or much to inspire existing Chinese cities, which will still house the majority of the Chinese population.
When it comes to sustainable city development, developments in efficiency in existing local urban areas have proven more efficient and more viable than high-profile, prestigious projects like Dongtan.
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Last updated Tuesday, May 27, 2014