A carbon assessment and design tool to assist in planning low carbon development

To avert runaway climate change the agreed international aim is to keep greenhouse gas emissions to a maximum of 450ppm of CO2-e (carbon dioxide equivalents) in the atmosphere. Those countries that have ratified the Kyoto protocol have agreed on specific targets in terms of percentages, generally but not always, against a baseline, of CO2-e levels produced in 1990. Having agreed in principal to specific individual figures for each country, and a consensus on which processes and activities should be included in the accounting, then it is simply a case of doing the arithmetic and in 2012, when the reporting period ends, it will be clear where the successes and failures lie. 2010 was the year when the majority of the planet's population moved to cities, a trend that is likely to continue, and with cities being responsible for possibly as much as 70% of the world's emissions, it is clear that the built environment needs some close scrutiny now and in the future. Buildings are, and have been for the last two decades, the focus of assessment programs and there is a vast array of tools that have been developed in the form of checklists or rating measures, but those that provide clearly defined metrics are not common. In an atmosphere where there is, arguably, an understanding of the importance of energy use and how it relates to greenhouse gas emissions (at a commercial level if not domestic) there is an increasing interest in how our buildings perform in this regard. This is acknowledged by policies like the mandatory disclosure of building performance, now being rolled out across Australia. There also seems to be an understanding that considering precincts or neighbourhoods is as important, if not more important than individual buildings, because it integrates how people move between and around the city. This is extremely important considering the impact of various modes of transport on the production of greenhouse gasses. Recently, the availability of assessment tools for sustainable development such as BREEAM (Building Research Establishment Environmental Assessment Method) Communities and the LEED (Leadership in Energy and Environmental Design) Neighbourhood Development tool, seem to have grown exponentially. These tools take on a range of forms from simple checklists to detailed rating tools, but few focus on actual metrics, without which it is difficult to understand the true impact of what is being assessed. Climate change as an environmental issue is proving to be extremely difficult to address, particularly in Australia where, should we choose to believe the media, the science is still being questioned. However if we consider that what the science is telling us is true, we are faced with a challenge of numbers. Decarbonising Cities and Regions (DCR) is an Australian Research Council linkage project that proposes to examine the greenhouse gas emissions (GHGe) of four land redevelopment case studies. The proposal includes a framework that outlines the sources of GHGe that will be examined for all of the case studies. The framework proposed covers: raw materials and building assemblies, construction emissions, operational emissions, private transport, the full water cycle and emissions from municipal waste. This framework is featured in a study of carbon assessment tools which identified the C CAP Precinct tool as the most comprehensive for urban development and redevelopment in accordance with the DCR framework C CAP Precinct has been developed to provide a number of sustainability metrics for developments at all scales, the focus of this paper will be the GHGe that a development proposal is responsible for from operational energy consumption, GHGe associated with water (pumping) and direct emissions from transport options available. The tool also calculates affordability based on annual operating costs and capital costs for technology options applied to a development to reduce GHGe. This paper contains a detailed review of the