22-0722 Interior building typology Energy Baseline for Australia and New Zealand
The LBC Core Imperative 07 Energy + Carbon Reduction has an energy use reduction requirement for interior projects of 35% reduction from an equivalent building baseline. Projects must demonstrate a reduction in total net annual energy consumption as compared to a project-specific baseline. The Imperative criteria states project teams must use approved tools to calculate energy baselines.
We are proposing to use the National Australian Built Environment Rating System (NABERS) historical rating data to establish the project specific baseline energy usage for office interiors projects in Australia and New Zealand.
There is an established precedent for using NABERS for Australian projects; Dialogue 1064-21-1222 Alternate Baseline ZC. This confirms the previous use of energy intensity based on historic building performance using the NABERS database. In this instance 2011 was used as the first date NABERS ratings became mandatory in Australia (therefore a dataset showing many buildings with a full range of performance, not as positively skewed).
The proposed dataset for reference data is the more recent NABERS data that is published. In recent years office tenancy data has continued to be rated but Covid-19 has made this data not fit for purpose. NABERS 2019 (pre-Covid) rating data filtered for office tenancies shows a national average star rating of 5 stars. Breaking this down per state is not considered suitable as not all states have significant numbers of NABERS tenant ratings. Using the NABERS rating system reverse calculator version 15.0 Jul-21 - Office Tenancy Energy gave a national average NABERS 5-star benchmarking target of 386 MJ/m2.a. This assumes 1 computer per person and 10m2 NLA per person.
To confirm the use of the recent NABERS average data two other Australian datasets were referenced:
- Baseline Energy Consumption and Greenhouse Gas Emissions - 2012. This is a large study by the Australian Federal government and indicates an average energy intensity in office tenancies of ~415 MJ/m2.a in 2001.
- NABERS Annual Report 2013/14 (oldest on record publicly). At this stage NABERS wasn't mandatory (and still isn't) for tenancies so potentially represents a skewed dataset with only better than average offices being represented. The average energy intensity of 336 MJ/m2.a was recorded nationally.
Applying this to Auckland, NABERSNZ is adapted from NABERS, to rate the energy performance of office buildings in New Zealand however the rating scale is slightly different. For NABERSNZ a 3-star rating target is indicative of "good performance" giving a target of 600 MJ/m2.a for office tenancy, which could be considered average or typical. A 5-star rating indicative of "market leading performance" gives a target of 300 MJ/m2.a. The tenancy energy coverage in New Zealand is consistent with Australia however and includes only lighting, equipment and tenant supplementary HVAC for meeting rooms etc. so should not vary between the two countries in theory. We had an extensive look for other NZ benchmarks and found very little, ultimately NABERS has been brought across from Australia to fulfill this role.
For this reason, we propose to use the NABERS 5-star average benchmarking target of 386 MJ/m2.a as a baseline for both Australia and New Zealand interior, office building typologies. The use of the same target across both is sensible and shouldn't be different from the first principles of what we are measuring which should not differ with the location as they are not climate sensitive.
The project team has clarified the energy scope of what is considered an office fitout is the same across all of Australia and New Zealand - lighting, equipment and tenant supplementary HVAC for meeting rooms etc, and that the same metering protocols and delineation between base building and fitout are used. The team has also clarified that between the two rating systems, while 5-star represents the average in Australia, the average in New Zealand is represented by 3-star.
The proposed baseline is derived from a nationally recognized dataset appropriate to the proposed building type, project typology, and use scenarios. The dataset is collected and managed by an established organization that has expertise in tracking and encouraging efficiency, and is part of a program structured to move buildings towards electrification/net zero.
The Institute agrees with the methodology used to derive the proposed baseline of 386 MJ/m2/yr: using consumption data from 2019 (substantially more recent than that used in the ZeroTool), and taking the national average of the most commonly achieved performance level across the nation (5-star). The Institute also agrees that given that the parameters and protocols used to delineate Interior project energy consumption are the same in New Zealand and Australia and that the proposed baseline is lower than what would have been derived by applying the same methodology to the New Zealand NABERSNZ dataset, applying the baseline to both Australia and New Zealand is appropriate.
Per the Interiors guidance under Energy Baseline Clarifications in the Energy and Carbon Reduction section of the LBC 4.0 and Core Petal Handbooks, the baseline scope must align with what is under the tenant's space and control. Where the end uses for the NABERS 2019 Interior building dataset match what is within the tenant's space and control, the proposed baseline of 386 MJ/m2/yr, resulting in a 35% reduction energy target of 251 MJ/m2.a (69.6 kWh/m2.a), may be used for purposes of the LBC 4.0/Core I07/C4 Energy + Carbon Reduction Imperative, operational energy reduction target.