Abstract

Sydney and Auckland have similar climates, cultures and urban form. However, methods for reducing carbon emissions and energy use are completely different. Auckland has low carbon buildings due to the large proportion of renewable energy in the electricity supply. However, it is a car dependent city and lacks resilience in transport energy. Sydney has high carbon buildings due to the large proportion of coal used to generate electricity. However, its public transport system is more resilient than Auckland.

In the case of Sydney, the energy use and carbon emissions of buildings and precincts is measured and mapped onto a 'carbon map'. This informs policy on the appropriate technologies and distribution systems for infrastructure in the city. A precinct based tri-generation system is shown to be the most effective means of reducing energy demand and carbon emissions in Sydney's central business district.

In Auckland, a sprawling city with poor public transport systems, the most effective means of reducing energy demand and carbon emissions is by tackling the suburbs. This is established by mapping the 'net-metering' potential of the City. Distributed renewable energy by photovoltaics located on suburban roofs will not only power all the transport energy needs of the City but also produce an excess for reducing peak cooling demands in buildings.

This presentation argues that each city should be evaluated on its own individual merits. The emerging technologies of tri-generation, photovoltaics, smart metering and electric vehicles offer different solutions for different cities. It is argued that the energy culture of each city should be taken into account and that commonly held beliefs of the relationship between urban form and resilience, such as the compact city, are not always appropriate.

For all their similarities, Auckland and Sydney are almost opposites where methods for carbon reduction are concerned. The most effective way to tackle Sydney is improving its buildings in the CBD. The most effective way of tackling Auckland is improving its transport system in the suburbs. For, many other cities, the effective means of increasing resilience, in terms of energy and carbon, may lie somewhere between.

Both electricity and carbon emissions are generally invisible. The metrics that this paper uses to evaluate cities and the different mapping techniques that are presented make energy and carbon visible so that they are readily understood for policy purposes. While this research focuses on Sydney and Auckland the mapping techniques would be appropriate for other cities.