Think medium.

That's the general idea among architects and urban designers who envision a future of energy-efficient and sustainable neighborhoods and public squares. Bigger than individual homes or buildings, but smaller than ambitious green-city initiatives, these projects aim to land somewhere in the middle. Three new European projects, currently in various stages of development, illustrate the concept nicely.

Meanwhile, over in the Netherlands, architects are planning a similar eco-village on a somewhat larger scale. The Regen Villages project envisions self-sustaining communities that can exist entirely off-grid, generating their own energy and even food by way of biogas facilities and aquaponic farming.

According to an intriguing write-up over at Off-Grid.net, the proposed design calls for radical recycling systems, in which compost from each home is used as food for livestock - and flies, which are fed to fish. The animals, in turn, would provide fertilizer for gardens and vegetables. Rainwater is automatically collected and stored, while solar panels and an on-site biogas facility generate electricity. What's more, each house is built inside a greenhouse "envelope" to maintain a consistent climate.

This is no far-off concept design, either. The first ReGen Village is already being built in the city of Almere, outside Amsterdam.

From the sci-fi end of the spectrum, we have the Icelandic project known as BioDome Reykjavík, which is precisely as futuristic as it sounds. If all goes according to plan, the massive public initiative will create a cluster of domed public plazas and urban farms right in the heart of the Capital region.

Each domed area would maintain a balmy climate warmed by Iceland's famous geothermal energy systems. The largest of the domes will create a subtropical environment in the middle of the city, with exotic plant and animal species. Rather than cover an entire residential village, the biodome structures would provide something more akin to a collective village square, with restaurants, cafes, public meeting spaces and farmer's markets.

For Reykjavikians looking to duck out of the cold for a bit, it should be a nice option - current plans call for temperatures under the domes to hover at a comfortable 25 degrees Celsius (77 degrees Fahrenheit) year-round. Average Reykjavik temperatures in February? Anywhere from -2 to 3 degrees Celsius. You can do the math from there.

Source: www.seeker.com