19 June 2014 — A report by Flux Consultants has found carbon intensity may be a better metric than NABERS ratings for benchmarking performance and driving sustainability improvements in buildings.
Beneath the Stars: Data Empowerment for the Next Generation of Sustainable Property, authored by Flux Consultants director Ché Wall, co-founder of the Green Building Council, and sustainability consultant Siân Gibbons, takes recently released data on the Commercial Building Disclosure program and analyses it to assess how to guide best practice in low carbon policy for the buildings sector.
The data set, the report authors said, was considerably larger than any other commercial office energy efficiency data made available in Australia to date.
“Until now, only limited, and often distorted, energy and carbon efficiency data has been available,” they said, “so the release of the comprehensive CBD data set, including the underlying annual carbon footprint of buildings in our cities, provides an unprecedented basis on which to properly understand operational energy and carbon performance in Australian office buildings and to recalibrate our understanding of best practice.”
The analysis found that a building’s NABERS rating was often not a good indicator of its carbon performance.
“The use of star rating tools has driven transformation across the commercial property sector, but our analysis showed that star rating and underlying carbon intensity are not the same,” the authors said.
“Simplifying performance to a star rating metric conceals the underlying true carbon footprint of the building, which is the most useful data for investment and policy purposes.”
The report stated that true carbon intensity was a key metric for investors and financiers seeking to invest in low carbon assets, as well as for developers pursuing high performance, carbon neutral developments.
The report identified that while there was a definite market need for an asset rating tool like NABERS, there was also a growing need for “transparent carbon accounting and market benchmarking, particularly for those who seek to direct capital or policy toward low carbon outcomes that can be aggregated, pooled and verified”.
The next wave of innovation in building performance would be enabled by “simplicity and transparency and relative performance being judged against a peer group”, the report authors suggested.
“Our analysis of the CBD data set concludes that the actual underlying annual carbon intensity of buildings – the data ‘beneath the stars’ – provides a more reliable way to benchmark relative performance of an asset than the associated simplified star rating, and this data could inform city-centric common baselines that could unlock capital flows.
The data could be used to develop the next generation of performance metrics to “drive world-class energy efficient buildings as well as to attract a new audience of institutional investors”, the report stated.
Other key conclusions of the report included:
The dataset provides insight into correlations – data analysis revealed a number of correlations that appeared to contradict the current understanding of energy and carbon in buildings as assessed under star rating tools, including moderate to strong correlations found between area and greenhouse gas intensity, but little to no correlation observed between hours and greenhouse gas intensity
Boundary setting is important for fair comparison – a limitation in the CBD dataset was observed in the handling of energy boundaries and separation of landlord and tenant energy, and, as a result, buildings striving for best practice outcomes might be discouraged
Comparing well internationally, but room for improvement — the CBD program performed well against the New York City Local Law 84 program, but the comparison highlighted the need for the program to be extended to additional buildings types, to adopt annualised reporting regardless of a sale or lease trigger, for extensive year-on-year reporting of trends and observations, and the use of a common reporting period
The CBD program is scheduled for review in 2015.
Read the full report.