There has been so much talk, much of it no more than guff, about sustainable development that one might almost imagine we have already taken it on board. Yet there is not a single building in Ireland that the public can visit to see the concept turned into practical reality.

To fill this yawning information gap, the Energy Research Group at UCD together with ROUND (Regeneration of Urban North Dublin) and the youth environmental organisation, ECO-UNESCO Clubs, have come up with Earthlab, an "Irish centre of excellence for sustainable solutions".

The £4 million project, earmarked for an island site in the Tolka valley next to the planned urban quarter of Pelletstown, has won the backing of Dublin Corporation. However, if it is to get off the ground, it will clearly need a national sponsor, such as the Department of the Environment.

Dick Gleeson, deputy city planning officer, sees Earthlab as an exciting project that would meet a real need to propagate the idea of sustainable building in Ireland. Developed in an enjoyable way, it would add greatly to a cluster of attractions in the area, including the National Botanic Gardens and Dunsink Observatory.

With a gross floor area of 1,500 sq m (16,146 sq ft), the riverside building would be an environmental education centre for school and youth groups and the general public as well as a clearing house for professional advice on sustainable development techniques - not least because it has been designed as a working model.

Earthlab's design has been developed over the past 18 months, including consultation with local community groups, by a team involving architects from the Energy Research Group and Solearth Ecological Architecture, structural engineers John Moylan and Associates and sustainable services engineers Buro Happold.

As designed by Brian O'Brien and Vivienne Brophy, it is divided into several elements, amounting to an exercise in deconstruction. They describe it as a series of "boxes in a box". The larger box is sunny, light-filled and full of plants, like a conservatory; the smaller boxes, "little pavilions", are solid objects inside the outer shell.

Each of these "pavilions" will house a different activity and demonstrate various types of sustainable building. One will contain a pair of demonstration "green" apartments, stacked over offices, while another will house an energy centre showing how the building's wind turbines and solar panels perform.

One of the apartments would be occupied by a permanent warden, to ensure a continuous presence on the site for security reasons. During the day, Earthlab would provide an appropriately "green" headquarters for ECO-UNESCO clubs, as well as for a core organisation dedicated to promoting sustainable construction.

The role of this institute or expert group would be to fill the information gaps on how to build sustainably for professionals, local authorities and Government agencies as well as the general public. Its function will be to translate proven "green" technological developments abroad into useable practices and standards in the Irish context.

Visitors would cross a series of timber bridges over a reed-bed wetland system to enter the building through its "hard", almost windowless, north-facing wall. By contrast, the south front - facing the sun - is fully glazed, offering views from various levels over landscaped gardens contained within a bend on the Tolka. Given that one of its principal aims is to show how buildings can be built more sustainably, the emphasis is on breath-ability, air-tightness and heat retention. Though now quite commonplace in other countries, Brian O'Brien says this technology is not yet accepted here "because of our conservative building and financing culture".

Building materials would be drawn from natural products, such as timber from certified sustainably managed forests as well as materials salvaged from the waste stream. The roof, made entirely from solar panels to provide electricity and hot water, would "harvest" all rainwater for use in flushing toilets and irrigating plants.

As cement production worldwide accounts for a significant percentage of global carbon dioxide emissions generation, Earthlab will make use of other cementatious materials such as lime, flyash and calcium carbonates. It will also demonstrate alternatives to harmful plastics such as PVC, industrial glues and oil-based compounds.

The pavilions within the building would "showcase" such sustainable construction materials as earth bricks, lime renders, strawbale, structural cardboard, recycled newsprint (cellulose) and sheepswool insulation. Its south-facing front would also incorporate different types of solar glazing and screens for seasonal shading.

According to its design team, Earthlab will meet all its own energy needs - an exciting challenge that they believe is "easily achievable" because it has been designed to avoid heat loss. Its electrical power as well as heating and cooling needs would be met by external wind turbines, solar panels and heat-pump technology.

Water wastage is also minimised. As Brian O'Brien points out, only 12 per cent of treated drinking water in Ireland is actually drunk; the rest of it is used to flush toilets, wash dishes and so on. Apart from harvesting rainwater from the roof, Earthlab will have demonstration composting toilets that use no water, as well as low-flow and dual-flush units.

Sewage will be treated naturally in the reed-beds outside, providing nutrients for Earthlab's constructed wetland system which will complete its island site, while "composting balconies" adjacent to its restaurant kitchen and larger displays in the gardens will show how to turn organic wastes into new soil for a permaculture project.

There will also be something in it for the business sector - a circular "think tank" separate from the main building, but linked to it. This is intended to meet a demand within this sector for "special" uplifting conference facilities for brainstorming sessions, as an alternative to stuffy, artificially-lit hotel meeting rooms.

The building is also flexible enough to change over time and, as green technologies develop further, new components can be installed for display.

Ultimately, when a sustainable demonstration building is no longer required, it could be turned over to civic, commercial or other uses, thereby ensuring its own durability.

In Denmark, for example, there would be no need for an Earthlab-style project because so much of the green agenda has already been taken on board by the building industry there. "The Danes would see what we're doing as boring. But in the context of the Kyoto Protocol, we have to start somewhere", says Brian O'Brien.

The Minister for the Environment, Mr Dempsey, spent a full week at the failed Hague summit on climate change last November and understands what is at stake. If he really wants to make progress, he should seriously consider sponsoring Earthlab; after all, the price-tag is quite modest compared to its long-term value.