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72 PROPOSAL TO REVISE ENERGY EFFICIENCY REQUIREMENTS OF THE BUILDING CODE OF AUSTRALIA FOR COMMERCIAL BUILDINGS
That said, the relative cost effectiveness of GHG abatement via the
proposed amendments, and the total quantum of abated GHG emissions
are nonetheless important measures when assessing the appropriateness
of the amendments.
Accounting for the CPRS’s likely impact on the emissions intensity of
electricity, it is estimated that the amendments could reduce the sector’s
emissions by some 1.2 MtCO2-e by the year 2020. Cumulatively to 2020,
the amendments could reduce GHG emissions by 7.5 Mt CO2-e.
Notably, these estimates have been calculated assuming a building life of
only 40 years. And as indicated previously, there may be a case to
suggest that this estimate is rather conservative. If a building’s ‘life’
continued beyond the assumed 40 years, the total GHG abatement
achieved by the policy would increase. 28
Chart 6.7 plots the annual abatement achieved by the proposed
amendments to 2020 (separated by Class 1 and 2 buildings). It is useful to
consider the chart with respect to four key phases.
• Over the period 2010-2020, the number of ‘post 2010 BCA buildings’ is
rapidly increasing, and so too then does abatement.
• At the end of the policy’s life (2020), the size of the ‘affected’ stock
remains constant. However, over this period the emissions intensity of
electricity declines more rapidly, reducing the annual abatement
achieved both per building and overall.
• From 2050, cohorts of buildings built under the 2010 BCA begin to
retire. As they do so, the stock of post 2010 BCA dwellings reduces (as
does their contribution to GHG abatement).
• Eventually in 2060 (some 40 years after the last cohort of buildings are
added to the stock), all buildings built during the 2010-2020 period are
assumed to have retired, and therefore no longer contribute to GHG
abatement.
28 That said, it should also noted that the emissions intensity of electricity by 2050 is
expected to be well below current levels. Therefore, while GHG abatement will
increase with a building life, the increase will not be of an equivalent proportion.
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