Carbon neutral mine site villages: Myth or reality?
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This paper focuses on the calculation of the carbon footprint of a typical West Australian mine site village and the ways by which it can be reduced to a point where the village can be legitimately described as 'carbon neutral'. The study contributes to a broader ARC joint research program by Murdoch and Curtin Universities entitled 'Decarbonising Cities and Regions'.
The term carbon neutral has a far from uniform definition. For the purpose of the carbon accounting that follows carbon neutrality is achieved when there is a net zero carbon footprint across the full life cycle or when total emissions are balanced by total offsets. As much of the full life cycle of the village as is practical is included in the process and acknowledges any omissions made. The paper will show how the carbon footprint of a mine site village in Western Australia's mid-west has been measured, calculated and reduced effectively to a point where carbon neutrality can be claimed. This will commence with calculation of the embodied and operational energy in constructing and operating the village, followed by methods towards achieving carbon neutrality. The latter includes energy efficiency opportunities; an environmental and economic sustainability assessment of renewable energy and construction materials; design modification of the infrastructure; and assessment of accredited biomass offset mechanisms. The whole process has been termed LEVI©, Low Energy Village Infrastructure.
An economic assessment of the carbon neutral strategy is the key to implementation. Mining companies are particularly drawn to the 'bottom line' when making investment decisions and only sound financial analysis will facilitate substantial carbon neutral expenditure. LEVI© significantly includes a net present cost (NPC) analysis of all such investment and belies the myth that carbon neutral mine site accommodation cannot be achieved. The paper then presents a carbon accounting methodology of the case study mine site village and set out the results and overall carbon emissions the village is responsible for. This life cycle analysis (LCA) is done from cradle to gate in terms of LCA terminology and represents the manufacture, construction, installation and operation. Energy efficiencies and behavioural changes are then applied and estimated as to their carbon reductive effect on the total carbon, followed by verifiable renewable energy offsets. These offsets are substantiated by a vigorous renewable energy analysis and selection supported by an NPC analysis. An optimum renewable energy system (RE) is then selected (best value for money) and its carbon reducing effect over the current power system calculated. This amount, together with that produced by energy efficiencies and behavioural changes, makes a total carbon reduction and is annualised.
The paper clearly shows that the projected life of the mine, and therefore the village, is a critical factor in the overall carbon analysis and that the optimum time period within which carbon neutrality of such a mine site village can be claimed lays somewhere between 7 and 10 years. Another key finding was that the capital expenditure (CAPEX) savings by developing such a village as a standalone facility produces clear advantages over connection to a mine power generation system as is the case study example. The optimum standalone RE system for introduction from 2014 was found to be 110kW fixed amorphous photovoltaic array and two 100kW wind turbines with one 150kW and one 100kW low-cycle diesel generators as a backup. The projected cost was approximately $2 million.
It is contended that the metrics produced from the results can provide a pro-rata basis with which to model future carbon neutral villages of similar construction. The model accommodates dependencies such as life of mine, size of village, number of workers and location. The paper will describe some innovative solutions and outcomes from this research that may be applied to the built environment on a broader scale.
|Publication Type:||Journal Article|
|Murdoch Affiliation:||School of Engineering and Information Technology|
|Copyright:||© 2013 Published by Elsevier Ltd.|
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