Shanghai developers plan to build what they say will be the world's first sustainable "eco-city" on a plot three-fourths the size of Manhattan.

Called Dongtan, or East Beach, the project attempts to channel China's voracious demand for housing and energy into a radical new model: a city that eventually supports half a million residents, recycles almost all of its waste, produces its electricity from wind turbines, solar panels and biofuel, and ferries people around in hydrogen fuel-cell buses and solar-powered water taxis. Construction is set to start this year, and city planners hope to complete the first phase by 2010, when visitors flock to Shanghai for the World Expo.

If it succeeds, Dongtan could be a model not only for China but for the rest of the world. Or it could be another grand idea that failed in practice, an example of how China's relentless drive for economic growth can torpedo even a high-profile environmental project.

China's environmental problems and massive energy needs affect everything from global warming and oil prices to the air quality in Western Washington. But they also open the door to innovative solutions.

At Dongtan, China has a rare chance to create a green city from scratch and plot a new way forward. The ultimate planned community, it's designed to show how growing crops, disposing waste, producing energy and providing transit can be integrated to work like an ecosystem and be as close to carbon neutral as possible, Lawrence said.

The energy will come from wind turbines, agricultural waste and solar panels. Dongtan's power plant will burn a material found here in abundance: rice husks and plans are to recycle and reuse 90% of its waste.

The three-phase development combines homes, offices and shops in small clusters to encourage walking or public transit. Most of the 33-square-mile space will remain organic farms and parks, buffering the wetlands that inspired the original plan.

Architects from around the world have toured the site, and the mayor of London has hailed the project, raising expectations even before the first shovel hits the dirt.

"Dongtan will be an international example, so the scrutiny will be very high, which both thrills us and terrifies us,"