Centrelink – Detailed Feasibility Study

Date: 2000-2001
Client:  AGL
 
Centrelink is the Australian Government’s social security interface, operating from approximately 420 properties across Australia.  Exergy were engaged by AGL to lead the assessment of guaranteeable energy savings across this portfolio as part of a detailed feasibility study for an energy performance contract.  To achieve this, we designed a sampling process, as it was clearly not going to be practical to visit all 420 sites.  The overall methodology was:

• Initial audits.  We audited an initial sample of sites, identified key issues and developed a standard audit form.
• Audit roll-out.  The standard audit form was applied to audit 60 sites.  We inspected 15 of these sites while AGL staff did the remainder, using the forms we developed. 
• Survey.  Additional data on a larger number of sites was gathered using survey forms sent out to each office.
• Collation of results.  Results were collated into a standard format and a series of key measures were identified, bearing in mind the need for measures to be simple and repeatable.  The main measures identified were reduction of lighting power density, improved control of lighting switch-off at the end of the day, and improved matching of HVAC hours to occupancy periods.
• Energy database development.  Centrelink operates a dynamic portfolio with frequent changes in the location, size and energy provider of many sites.  However, energy data and property data were stored on separate databases with no mechanism for linkage.  Exergy developed a common database and reporting structure to enable tables from the separate databases to be combined to produce performance indices such as kWh/m2.  This task was further complicated by the fact that the coverage of the energy bills varied from site to site – being either tenant light and power only or whole building – with no record available as to what the coverage of any particular site was.
• Savings extrapolation.  We used statistical analysis methods to develop an estimate of the impact of the savings measures extrapolated across the portfolio.  Detailed, probability based risk assessment were performed to provide AGL with information on the statistical uncertainty of figures.

The key success of the project was the assessment of savings across a broad portfolio based on a sampling process.  Furthermore, we consider that our manipulation of the often quite problematic base data to produce a successful and credible outcome was also a significant achievement.

Above, A typical Centrelink office – a small freestanding office of 1500-2500m² floor area.