The production of electricity as a primary, common emission source is recog- nised as being among the most significant contributors globally to greenhouse gas concentrations within our atmosphere. Moreover, this is primarily a result of the burning of fossil fuels in centralised electricity generation networks. As discussed in section 3.2.2, there is some debate over responsibility for these emissions. That is, should the associated emissions be attributed to the electricity generator or the end user of the electricity? For the purposes of this study, these emissions are attributed to the end user of the electricity and are thus scope 2 emissions as de- fined by the IPCC [1988]. This is because Council, and the Brighton community, have the largest influence over the associated emissions when considered from this perspective.
Since the state of Tasmania contains a reticulated electricity network known as Tasmania’s ‘electricity grid’, it is possible to determine a factor for a given period of time for the state that converts electricity usage to the amount of as- sociated scope 2 emissions, dependent on how the electricity is generated over the specified period. This is possible since the contributors of electricity to the Tasmanian electricity grid and the methods and amounts of generation over that period, are well recorded and reported by NEMMCO from which the Department of Climate Change [2008a] sources data and thus establishes an emission factor for that period.
Prior to the Basslink interconnector, commissioned in April 2006 [Basslink, n.d.], to connect Tasmania to the national electricity grid, scope 1 and 2 elec- tricity emissions were close to negligible within Tasmania. This was due to the exceptionally large proportion of renewable energy within the network, produced primarily from hydro and wind technology. Since that point, Tasmania has had an increasing reliance on fossil fuel generated electricity, imported via Basslink to the Tasmanian electricity grid. As a result, emission factors for the state of Tasmania have also been increasing. For the scoped time period of 2007, Tasma-
nia’s combined scope 1 and scope 2 emission factor is 0.13kgCO2e/kW h. There is little option within the context of the present study but to adopt this figure for electricity conversion to carbon equivalence as further analysis into the issue would go beyond the necessary extent and objective of the study.
Since we have a mechanism for the conversion of electricity usage to associ- ated carbon equivalence, it follows that we must derive a mechanism for establish- ing the electricity usage for within the scoped time period and geographical area. There are a number of methods available for achieving this.
As discussed in section 3.2.1, by definition the top-down approach to con- ducting an inventory requires an initial consideration for larger scale inventories or sets of data, followed by the disassembling of that data into smaller subsets such that the requirements of the inventory are met. This concept is directly applicable to electricity usage since we are able to obtain data both for Australia as a whole as well as for Tasmania. By the proportion of population living within the munic- ipality of Brighton we can thus disassemble this data into a subset representative of Brighton and hence equate this to associated carbon dioxide equivalence.
Electricity usage and distribution data for Australia and Tasmania is avail- able through two authorities, namely, The Australian Bureau of Agricultural and Resource Economics (ABARE) and Electricity Supply Association of Australia (ESAA). ABARE is an Australian federal government funded organisation that produces an annual publication called Australian Energy, [Syed et al., 2007], in which electricity data is presented in terms of state and industry usage. This data is obtained by ABARE via a series of surveys directed at energy users and pro- ducers. Statistical techniques are employed to extrapolate data from completed surveys in order to derive a complete data set. ESAA is the premier industry
association, grouping electricity generation and gas supply companies. ESAA
produces a publication called Energy Gas Australia [Energy Supply Association of Australia, 2008], the data for which is obtained directly from the electricity and gas distribution companies. Total electricity usage data from the ESAA is taken
to be the most applicable for this study. Whilst the Cities for Climate Protec- tion approach is to simply use the ABARE data, the present study takes data from ESAA and applies sectoral percentage breakdown information as provided by ABARE, thus providing a sectoral breakdown of energy usage within the state. Figures for electricity consumption in Tasmania for the residential sector and the business sector as a whole are available from Energy Supply Association of Australia [2008]. A fraction of the residential figure is taken based on the pro- portion of population living in the municipality of Brighton to provide electricity consumption for the residential sector. Using electricity usage data from ABARE, the percentage contribution for each of the sectors may be defined neglecting the residential contribution. Applying these percentages to the ESAA figure for the business sector, an approximation for electricity usage is derived for each other sec- tor. Application of the working population profile methodology generates values for the municipality of Brighton.
Below is a table presenting results from both the CCP methodology, as well as that derived by the present study:
Sector Derived Methodology CCP Methodology Discrepancy
TonnesCO2e TonnesCO2e
Residential 8377 8681 3%
Commercial 1580 1709 8%
Agriculture 48 - -
Industrial 6836 4799 30%
Table 5.2: Community Inventory - Derived & CCP
Note that agriculture is division A under the ANZSIC scheme and is con- sidered part of the industrial sector within the CCP methodology.
As is evident in the table, minimal discrepancy is apparent between method- ologies within the residential and commercial sectors. The agricultural sector has minimal influence despite being attributed to the industrial sector within the CCP
methodology; refer to table D.1 for a breakdown of results under the ANZSIC scheme. There is significant discrepancy evident however for the industrial sector. This is primarily a result of the varying input source data. Refer to table D.2 for the redistribution of electricity consumption within the structure of the inventory
adopted by the present study and D.3 for the calculatedCO2e.
Regardless of any discrepancy here, it is interesting to note that the order of magnitudes of the sectoral emission fluxes is similar. This reinforces the idea that the actual values are not the critical output of the model. There are a number of assumptions that are made and therefore the accuracy of the result is not necessarily great. We can however maintain a large degree of confidence in the relativity of sectors when compared to each other, thus meeting the objectives of the inventory.
5.6
Waste
Greenhouse gas emissions are generated from waste as the degradable or- ganic materials breakdown. These organic materials constitute a major component of the waste stream and include such materials as paper, timber, food products, garden material etc. Emissions associated with waste are significant in volume and since waste management is part of Council’s core business, there is a large potential for Council to make significant reductions in greenhouse gas emissions in this area. Furthermore, since all sectors of the community contribute to the waste stream, waste has been considered as a primary and common emission source as part of the present study.
As Council manages all waste within the community, actual data is available for this primary and common emission source, thus minimising any assumptions within the methodology.
There are two primary mechanisms for waste collection as managed by the Brighton Council, each of which results in final disposal of the waste at the Glenorchy landfill. Firstly, contracted kerb side collection of waste and recycling,
transported directly to the Glenorchy landfill site. Secondly, a waste transfer station within the municipality of Brighton from which waste is collected and transported to the Glenorchy landfill as required.
As all waste finds itself eventually at the Glenorchy land fill site, accurate records are available to Brighton Council detailing waste tonnages for the scoped time period of the 2007 calendar year, as recorded by the Glenorchy City Council for accounting purposes. This data is presented in table E.1.
A sectoral breakdown of waste streams in Australia is obtained from the Australian Bureau of Statistics [2006]. This however does not correspond to the ANZSIC classification scheme and thus the breakdown is redistributed accordingly
using the working population methodology. The assumption here is that the
sectoral percentage break down of waste is equivalent on the local scale to that on the national scale.
The tonnage of waste, as recorded by Glenorchy City Council is thus ac- counted for on a sector basis and then sector specific emission factors are applied according to Department of Climate Change [2008a].
A capture rate of landfill gasses is assumed to be 55% based on an Australian average [Department of Environment Water Heritage & Arts, 2006a]. Figures are thus multiplied by 45% and converted to carbon dioxide equivalence.
It should be noted here that the captured gas is converted into electricity at the landfill site. This process results in an emission flux however since this electricity is fed into the reticulated electricity grid, all associated emissions are considered within the electricity emission factor for the specified year.
Refer to tables E.2 and E.3 for the waste emission calculations.