Energy Efficient HousingSolarCity, on the outskirts of Linz in Austria, is a shining example of sustainable development for the 21st century, writes Frank McDonald, Environment Editor

Living on the sunny side - that's the slogan for SolarCity outside Linz, capital of Upper Austria. And though this new suburb was designed by some of the world's leading architects, it's not an exclusive enclave, but rather a social and affordable housing scheme promoted by the municipality.

Linz had a housing problem in the early 1990s, with up to 12,000 people on low-to-average incomes looking for homes in the city. But there wasn't any room in the existing built-up area, so a decision was made to develop a greenfield site on the outskirts, south of the city's heavy industrial zone.

At the time, people were becoming more aware that the high consumption of fossil fuels by buildings is a major contributor to the greenhouse effect blamed for causing climate change. This was one of the decisive arguments in favour of developing the 78-acre site as an "ecological urban district".

In 1992, the municipality commissioned award-winning Austrian urban planner Roland Rainer to draw up a masterplan for Linz-Pichling, 7km from the city centre, with the aim of creating something special in terms of architecture, energy use, social life and other elements of "sustainable development".

A first phase of 1,300 new homes was planned, ranging from two-storey terraced houses to four-storey apartment blocks, as well as shops, schools, a tramline to the city centre, a network of pedestrian and cycle paths, green spaces for recreation and underground parking to keep cars separate from living areas.

With support from the European Commission, Pichling was turned into a demonstration project to show the benefits of energy-efficient construction, passive solar heating and solar-generated electricity - not least for its residents, whose annual heating bills are just over half of the Austrian average.

Highly insulated façades, natural ventilation and daylight, winter gardens, sun-shading and optimum retention of heat are the characteristics of this solar construction; the sun is used passively, to improve individual comfort - all of the housing is south-facing - as well as actively, as a source of energy.

The task of putting architectural flesh on the masterplan was given to the READ (Renewable Energy in Architecture and Design) consortium formed by leading Austrian architect Thomas Herzog, Norman Foster and Partners and the Richard Rogers Partnership, along with environmental engineer Norbert Kaiser.

The project also benefited from the consulting services of Renzo Piano's studio. Another plus was the involvement of 12 different construction companies, each of which undertook to build sections of the scheme to exacting standards laid down by a central planning office and supervised by five project groups.

Sustainability parameters included achieving a relatively modest density of 16 homes per acre, a good mix of units from 40-110sq m (430-1,184sq ft), and a requirement that no building would cast a shadow on any other; even in midwinter, every home in SolarCity gets a minimum of two hours sunshine per day.

The new town was also to have a balanced mix of tenure (rental, purchase, rental-purchase), and its design was to take into account new family structures, bringing together related generations in close proximity, planning mixed-use neighbourhoods in manageable sizes, and involving residents in future decisions.

Solar panels provide a minimum of 34 per cent of hot water needs, with the rest supplied by a district heating system.

But the long-term aim is that it will co-generate its own energy with solar installations, so that SolarCity becomes completely independent of the Linz electricity grid - other than to dispose of its surplus.

All ventilation systems have heat exchangers to ensure comfortable indoor temperatures - the air taken in is warmed up while the air taken out is cooled. But the kindergarten, with its huge solar bank, is so well-insulated that it uses only 10 kilowatt hours per square metre, a fraction of the usual level of energy consumption.

As part of a "no waste water" project, 106 homes and the local school have separators in the toilets to collect nutrients for composting. Grey water from showers, dishwashers and washing machines is filtered through a sand bed, purified and channelled into a nearby watercourse. All surface parking is also naturally drained.

Only visitor parking is provided at street level ; the rest (1.2 spaces per unit) is underground.

Throughout SolarCity, maximum priority is given to pedestrians and cyclists, with the network of roads and paths planned accordingly. There is even provision for indoor communal storage of bicycles in each housing block.

The town centre includes not just a basic range of shops, such as Spar (yes, it's all over Austria too), but also a medical centre and other community facilities. There are large or small rooms available for meetings, at a modest rent, and next door they're building a church which will also function for other purposes.

A landscape design competition for Solar City was held by the City of Linz in 1997 and won by a German practice, Atelier Dreiseitl.

The aim was to control high-pressure use of sensitive forests along the river Traun, while at the same time creating attractive open spaces with a high leisure and recreational value.

Altogether, the development has cost €200 million so far - €125 million for the residential component and €75 million for the other facilities. The 1,300 new homes were subsidised by the provincial government of Upper Austria, which provides financial incentives to people buying energy-efficient homes.

As for public transport, there are plans in the medium term to extend Linz's DART-style S-bahn to Solar City. At present, the nearest S-bahn station is seven minutes away by tram, and residents can change there for a faster service to the city centre.

But even the tramline would get its users there in 35 minutes.

Under the masterplan, it is envisaged that the new town will expand to 6,000 homes. The next phase is being designed by Viennese architect Martin Treberspurg, a specialist in solar construction, following another architectural competition. When complete, it is intended that SolarCity will be a model for the 21st century.

Can the same be said of our own new-look suburbs, such as Adamstown or Pelletstown? Certainly, they are improvements on what was built previously.

But it is a remarkable fact that energy efficiency is completely overlooked in their masterplans, which are blind to any ambition to trap the boundless power of the sun.