A tale of two cities

As oil-rich Abu Dhabi builds the 'world's greenest' city, carbon-heavy China has designs on an eco-friendly metropolis. E&T takes a look.

Exactly when the world decided eco-villages just weren't big enough is difficult to gauge, but for today's environmentally friendly developments, size is everything. Forget any ideals of holistic living and group-hugs; the present-day eco-city is big, bold, sophisticated and requires a lot of cash.

Roger Wood, an associate director of Arup, the global engineering consultancy that designed Chinese eco-city, Dongtan, is only too aware of this fact. In 2005, Dongtan was destined to be built on Chongming, at the mouth of China's Yangtze River. While the alluvial island had looked like the ideal site to build yet another sprawl of commuter towns, its city planners, backed by the Chinese government and funded by Shanghai Industrial Investment Corporation, decided to build an eco-city, ready for 5,000 residents by 2010, instead. However, spool forward to 2009 and the outlook is somewhat different.

First, government backing is now less certain, with media reports saying Dongtan's key political supporter is now under house arrest for fraud. Second, the worldwide recession means funds are no longer flowing. Put simply, the project has stalled with construction yet to start.

As Wood explains: "The issue we have with all of this is over whether there is enough government policy. We were hoping to get all the permissions in place to build the first phase by 2010, but the permissions have dragged on and, given the current economic situation, we are not sure when this phase will be delivered."

This is a pity as Dongtan not only makes a stunning template for future projects but, when built, will exhibit a myriad of innovative designs and technologies. The 30km2 site, eventually housing 50,000 residents, will consist of three villages linked to Shanghai by a new rail and road link.

Dongtan details

From the start, Wood says his designers wanted to reduce the amount of any resource used in the city, be it in construction or the daily use of electricity. As a result, the city will require 66 per cent less power than a conventional development, with energy coming from wind turbines, solar panels and biological sources such as human sewage and municipal waste. Indeed a combined heat and power plant is expected to burn waste rice husks.

"We want to produce energy from a reliable renewable source, so biomass is one solution," adds Wood. "We asked ourselves, where can we find a waste product that's already done what it's done so we're not adding to the carbon footprint by [growing] it. We came up with rice husks and sewage."

Wood also looked to minimise energy use in transport, but rather than specifying Dongtan a car-free zone, he's decided the city will have zero-emissions transport, running on either electricity or hydrogen. Electricity will come from renewable sources while plans are in place to build a renewable energy plant to create the electricity needed to produce hydrogen.

When dealing with waste the designers hope to implement an automated vacuum collection system. Here, waste is transported at high speeds through underground tunnels to a building where it is collected.

"You put your waste in a bin and it gets sucked along to a particular place," explains Wood. "This means you only need one place where vehicles come to collect refuse from, instead of driving to every single house, and so saving energy."

And, because Dongtan will be built on what is currently farm land, Wood felt the agriculture production of the city should equal that of the the present land. Not easy, although factories that produce organic food under artificial light have been designed into the plans.

Clearly achieving 'zero-carbon' status is no mean feat, and, technology aside, Wood believes urban planning is crucial. "You need to plan a city to encourage these things to work, and once you do this the situation will snowball," asserts Wood. "It has to be easy to walk, cycle or catch a bus to go to the shops or go to work, so you have to make the employment, facilities and housing all close together."

Indeed, Dongtan is designed so every single resident will be no more than a seven-minute walk from public transport. And, while cars are allowed into the eco-city, its three villages are planned so this isn't necessary.

Wood also worked hard to design a city where people would actually want to work, rest and play. Looking carefully at optimum dwelling density, he decided that low-rise but high-density living would achieve this while still being economical.

"Shanghai has 250 to 300 dwellings per hectare packed into tall towers, but we felt this wouldn't work in Dongtan," he says. "So we are thinking of five-to eight-storey dwellings, with 75 per hectare. This is equivalent to say west Kensington in London."

Buildings will be constructed predominantly with timber, with stringent criteria set out regarding the use of renewable or reclaimed sources. "We hope there will an element of pre-fabrication to minimise waste, but we don't want the dwellings to look like the same little box, we want freedom of design as well," adds Wood.

Masdar City

The opposite holds true for Masdar City, where construction is in full swing some 17km east of Abu Dhabi in the United Arab Emirates. Spearheaded by the Government of Abu Dhabi, the "world's first zero-carbon, zero-waste city" will cost an incredible US$22bn, span 6.5km2, house 40,000 residents and support 1,500 businesses. A recently completed 10MW solar plant - the largest of its kind in the Middle East - will power construction, which should come to an end by 2015.

The city's figures may impress, but its credentials deliver real clout. The project was designed by British architects Foster and Partners, famed for high-profile glass and steel buildings including the London Gherkin and Beijing Capital International Airport.

It has support from global conservation charity the World Wide Fund for Nature, while organisations around the world, including BP, Rolls-Royce and GE, are clamouring to get on board. Cooperation with the Massachusetts Institute of Technology has paved the way to the Masdar Institute of Science and Technology, which will open in September of this year, welcoming in 38 postgraduates and staff, the city's first residents.

As Norman Foster of Foster and Partners put it: "The environmental ambitions of the Masdar Initiative are a world first... Masdar promises to set new benchmarks for the sustainable city of the future."

So what exactly are these benchmarks? Once built, the city will consume only 20 per cent as much energy as a similar-sized conventional city and will be completely powered by solar energy. Roofs, canopies and land on the city's edge will support photovoltaics while a concentrating solar power plant will provide the city with the electricity it needs to keep cool under the blistering Abu Dhabi sun.

Keeping cool is crucial. In July and August, Abu Dhabi temperatures top 50°C, so a first design step was to orient the city north east to south west. This helps to minimise the amount of direct sunlight on buildings while still providing enough natural sunlight.

According to Foster and Partners architect Gerard Evenden, building designs incorporate heavily insulated walls with thin layers of copper foil on the outside to keep heat out and hopefully prevent residents reaching for the air-conditioning. Evenden has also made Masdar City a car-free zone, so the entire development is being built with narrow, shaded passage-ways, instead of roads, which will funnel breezes and help to keep the city cool. Pillars will also raise the city off the ground, making space for a personal rapid transport network of compact, driverless 'podcars'.

Water conservation

Unlike heat, water is an increasingly sparse resource in and around Abu Dhabi and while Masdar City will have a solar-powered desalination plant, around 80 per cent of water will be recycled. Dew catchers, rainwater harvesting and electronic sensors to detect cracked pipes will all be used and dedicated green spaces will be planted with drought-resistant plants,not lawns. And as part of the zero-waste strategy, biological waste will be processed into fuel or used to create nutrient-rich soil and fertiliser while everyday waste will be sorted and recycled.

But, as breathtaking and bold as Masdar City undoubtedly is, one fact is clear, its designers and engineers are not bound by the usual set of rules and constraints. Strong political leadership twinned with generous funds means the new eco-city can showcase unorthodox innovations that the rest of the cash-strapped world would probably write off as 'pie-in-the-sky'.

So while Dongtan, and indeed Masdar City, sound like the kind of places you might like to live, could you afford it? Planned eco-cities have already been pessimistically labelled mere playgrounds for the rich. Not so, says Wood.

Pointing to the Palm in Dubai, three palm-shaped man-made islands currently under construction in the Persian Gulf, he asserts: "The emphasis here has been to create housing for those who can afford it - the wealthy basically. This doesn't give you a city, it gives you a development of a specific resident that can afford to live there. [Eco-cities] want a mixed community, that's how cities evolve."

And, as Wood points out ironically, this requires governance and policies, the very things Dongtan desperately needs to get started.

So as Dongtan waits for its permits, and Masdar breaks ground, architects worldwide are already designing the next wave of eco-cities. Inspired by new renewable technologies and driven by the threat of climate change, the designs include floating lilypad-style cities to house climate change refugees, urban life in houses grown from trees and a metropolis comprising high rise, algae-growing apartments (see 'San Francisco with a difference', right).

In late 2007, when plans for Masdar City emerged, chief executive, Sultan Al Jaber said: "One day all cities will be like this." Roger Wood, architects and engineers worldwide would probably beg to differ.

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