CASE STUDY – 21 October 2009 – The Australian Bureau of Statistics Central Offices at Belconnen in Canberra had a 4.5 star NABERS Energy base building rating. But its tenancy rating was a below average two stars.

The building was a relatively modern 34,000 square metre structure commissioned in 2002, with BMS controls.

To rectify the problem, the ABS appointed Colliers International’s Project Services team  to find ways to quantify the benefits of initiatives to improve energy efficiency and reduce carbon emissions.

David McEwen, director of consulting for Colliers International Project Services said the appointment was  to review the ABS tenancy in Canberra and identify opportunities to improve energy efficiency and reduce carbon emissions.

“Our challenge was to identify, develop and quantify cost effective solutions that would reduce energy consumption and deliver a positive payback within the existing lease term,” Mr McEwen said.

“Our team undertook a comprehensive audit of tenancy services including lighting, air conditioning, power and cooling arrangements for the ABS data centre and hot water systems.”

A key element used in the project was a unique data logging system that combines light and movement sensors.

These were placed throughout the tenancy and used to quantify energy savings opportunities that might be gained through the use of sensor controls and more efficient lamps and fittings, Mr McEwen said.

“The data logging technology assists in providing hard usage metrics to derive reliable payback and return on investment measures for efficiency initiatives such as sensor lighting, use of supplementary air conditioning, utilisation of meeting rooms and other spaces and assessment of the effectiveness of efforts to encourage energy efficient behaviours,” said Mr McEwen.

David McKewen

The loggers, a proprietary system developed by South African company PowerSense, are small battery operated units that are placed throughout a building in each type of space – open plan, offices, meeting rooms, utilities, storage areas, etc.  Each logger has a light detector (which can also distinguish between magnetic and electronic ballasts for fluorescent lighting) and a motion sensor.

“Generally we leave them in a space for a week, during which time they continuously collect lighting and occupancy data,”  McEwen said.

The sensors are then plugged straight into a computer where data is collected and turned into graphs and tables.

This allows the tenant to quickly see the actual use of space graphed against the periods of time that the space is it.

From here it is a quick step to determine the savings through implementation of efficiency measures.

Mr McEwen said the costs for each proposed initiative were researched and savings calculated (including reduced electricity costs and maintenance benefits) to derive the payback periods.

A variety of opportunities for efficiency improvements was identified covering all tenancy services, with payback periods as low as a few months and an overall potential reduction in energy consumption of 28 per cent.

In addition to lighting, further savings were identified for initiatives related to ABS’ data centre, base building services and workspace consolidation.  The implementation of selected initiatives is now underway.