What is required, they add, is for developers to understand that it is in their own interest to pursue 'clean and green' building codes, and an example they cite is China Solar Valley, a development from Himin Solar Energy Group.

The project is planned to cover a site of 3 square kilometres in Dezhou economic development zone in Shandong province and will consist of residential buildings, hotels, convention facilities and a solar energy theme park.

It is billed as a model project to demonstrate how solar energy can be harnessed in every household. The residential component of the development - Utopia Garden - is to be built with environmentally friendly materials. Houses will be fitted with technologies to offer a sustainable and green lifestyle.

Solar water heaters will be installed to provide for the estimated daily needs of 300 litres of hot water for every household.

Geothermal heat and solar photovoltaic systems will be used to generate electricity for common areas and household appliances, and heat insulating construction materials together with energy-saving glass will be used in the buildings which will help to reduce energy consumption by air-conditioning systems.

The developer estimates that with these measures in place energy consumption can be reduced by more than 65 per cent.

'We want to show the public that an environmentally friendly living style does not mean one has to sacrifice comfort,' said Huang Ming, the chairman of Himin Solar Energy. 'Installation of these systems might be costly now but that will come down when they become more popular.'

Since owners will enjoy the benefits of reduced energy bills such projects are likely to attract higher prices and more secure lines of credit from financial backers, supporters said.

The first phase of the 1,900-unit project should be completed next year and sales will start later this year. Prices have not been set but the developer said they would be the highest in the city.

While Utopia Garden is pitched as a role model for future living space, Shanghai Industrial Investment Corp's Dongtan Eco-city also has a lofty ambition.

The ecologically friendly residential project on Chongming Island at the mouth of the Yangtze River aims to be the world's first carbon-neutral city.

About an hour by ferry from the outskirts of Shanghai, the city will produce its own energy from wind, solar cells, bio-fuels and recycled city waste while hydrogen fuel cells will power public transport.

A network of cycle and footpaths is also aimed at helping achieve close to zero vehicle emissions and human sewage will be processed for irrigation and composting to reduce the need for landfill waste sites.

Phase one is scheduled for completion next year, and 80,000 people are expected to occupy the project by 2020.

'Over-reliance on a single source of energy will have a great impact on the environment and our living and large-scale electricity black-outs after heavy snowstorms around the world are reminders,' said Gao Hui, a professor at the school of architecture in Tianjin University specialising in construction technology and science.

Professor Gao believes the introduction of alternative energy such as solar energy can help solve the problem.

However, critics have voiced concerns that the Dongtan project will be aimed exclusively at an elite market, rather than become a model for future eco-friendly living standards. Frequent delays have also prompted some to conclude that the idea of an eco-city is proving too costly to be feasible.

The Sunday Telegraph, a British newspaper, has described Dongtan as a 'pipe dream'.

'The greenfield site, a lush area three-quarters the size of Manhattan, remains untouched - and planning permission won by the Shanghai Industrial Investment Corp, the property developer which commissioned Arup to design and build the city, has now lapsed,' according to the report.

However, others say the attractions of eco-friendly building will grow and in October last year, Beijing introduced a Civil Energy Act intended to promote energy savings and increase energy efficiency in buildings and to encourage the development of solar, geothermal and alternative power sources.

Tax incentives and tariff reductions aim to encourage energy saving while penalties will be imposed for violations.

As buyers become more conscious of environmental issues and savings to be achieved in projects built on low-energy guidelines, developers will become more willing to introduce green components into their projects, some believe.