A few decades ago, zero to low carbon cities that are sustainable and energy efficient were something of a pipe dream, but now they are becoming reality. And they need to be because as the world population expands, so do our cities and their carbon emissions.

The United Nations estimates that the World’s city living populations will increase by 66 per cent by 2050, up 12 per cent from today’s figures.  This will add another 2.5 billion people to urban populations, with 90 per cent of these being concentrated in Asia and Africa.

In Australia, infrastructure changes in our built environment – resulting from an expected 60 per cent growth in our population by 2050 – will significantly influence and entrench the way we consume energy and our resulting carbon signature.

These are huge numbers so the use of innovative new building and energy technologies plus clever design are paramount. Thankfully, such innovation is being embraced around the world and it will snowball, but there are many challenges, particularly in old, established cities where you need to work around current structures and utilities.

Two overseas projects worth mentioning are the UK’s Peterborough Carbon Challenge and Sweden’s Hammarby Sjostad. Both are public-private partnership projects with ambitions to demonstrate that zero/low-carbon housing is possible (see A Review of International Low Carbon Precincts to Identify Pathways for Mainstreaming Sustainable Urbanism in Australia for more information).

The Peterborough project – which will consist of 295 dwellings, a centrally located office and community space within a seven-hectare brownfield site – became a ‘Carbon Challenge’ and zero-carbon housing pilot project because no existing housing development could satisfy the UK Government’s Code for Sustainable Homes, developed in response to pressure to take action on climate change. According to Peterborough City Council, once completed it will be the UK’s largest zero-carbon mixed-use development.

Hammarby Sjostad is a larger project with around 10,000 dwellings and office, retail and community space in a 200-hectare medium to high density neighbourhood in central Stockholm. Soon to be completed, it aims to reduce emissions and waste by 50 per cent by increasing system efficiency through low energy buildings, public transport, and district heating, plus swapping fossil fuels for renewable energy or waste eco-cycles systems – for example, incinerating combustible waste to produce both electricity and district heating.

As both projects are young, there is still much to learn from their progress but importantly, they are examples of a world rising to the carbon emissions reduction challenge.

In Australia, we are also taking great strides to develop low-carbon precincts and energy efficient homes and a new 10-part video series produced by Dr Josh Byrne, a Research Fellow at the CRC for Low Carbon Living, will reveal the progress and impact of some leading low carbon Australian city projects that are really making a difference.

The projects featured are taking place in the cities of Adelaide, Melbourne, Sydney and Fremantle.

Christie Walk, which was completed in Adelaide in 2006, is home to around 40 people in 27 energy efficient, community-focussed homes. It has five environmental criteria: energy, water, land, health and pollution reduction. Much has been learned from this project, including how important it is to work as a community when the aim is to encourage low carbon lifestyles.

Also in Adelaide is Bowden – a 16-hectare urban renewal project on former industrial land just two kilometres from the city. The project has strict design controls to ensure best environmental practice whilst also remaining flexible in its planning guidelines to encourage innovation and design excellence by proponents.

In Melbourne, The Commons is a project that is challenging conventional development models by limiting investor profits in order to deliver more affordable housing options. Sustainability features include climate responsive design, use of low energy materials, no cars, instead relying on the proximity to train lines, car share schemes and bikes. Shared rooftop solar production and rainwater harvesting has also been incorporated into the building.

Sydney’s Central Park – a more recent development – is considered a showcase on inner city urban renewal at a precinct scale. Here, there has been a huge investment in the buildings’ eco design and the precinct has its own tri-generation plant to supply electricity, heating and cooling, as well as an on-site wastewater treatment and reuse scheme to reduce the strain on surrounding infrastructure. It is an ambitious project that will continue to develop and have a huge impact to on how future precincts can be built and adapted.

Last but not least, Fremantle’s White Gum Valley  – called the WGV Project – will be of national importance by mainstreaming high performance, low carbon, medium density housing at a precinct scale. It will help to change the way we live by using the latest in water and energy saving technologies and initiatives plus the best in urban design for its scale. Perhaps most importantly, it will act as a ‘Living Laboratory’ where performance data will be collected and shared to inform industry and encourage further update of the successful initiatives.

Although many of these projects have their differences, they are all of great importance to how sustainable cities can be achieved, precinct by precinct throughout the world.

We may not have zero carbon precincts yet but this will happen over time, especially as technology booms, building guidelines are updated to embrace low carbon living, and current power systems are adapted to embrace the renewable energy revolution. We have made great progress, but much more still needs to be done.