By Lyn Drummond
22 June 2011 –
New research has shown that cutting greenhouse gas emissions from Sydney office buildings can also help reduce the pressure on electricity supply infrastructure citywide.

The findings are in a report by Jesse Steinfeld, sustainability and environment engineer at Investa Sustainability Institute, released on the Green Buildings Alive website.

Craig Roussac general manager of sustainability, safety and environment of the Investa Property Group said: “Accommodating growing peak demand is one of the major drivers in Sydney’s electricity network expansion. If energy efficiency and smart demand management can reduce electricity demand at these key times, the costs and scale of network expansion can be reduced.”

The report says growing demand for electricity at peak times has led to plans for increased spending on network infrastructure, the largest component driving up Sydney’s electricity prices.

Peak demand is important because electricity networks require spare capacity to accommodate extremely high power usage, which typically occurs only for a few hours, a few times a year, typically on hot summer days.

The research shows there is potential to reduce some of this large spending through energy efficiency and demand management.

Calculations based on 25 Sydney office buildings for 2008 show:

  • As the buildings’ yearly electricity performance improves, as tracked by the NABERS energy rating scheme, maximum electricity consumption on the hottest days also falls.
  • If a single building boosts its rating from the Sydney average of 2.5 to 5 stars then it could halve its yearly electricity consumption (56 per cent reduction), and use nearly a third less in times of peak demand (26 per cent reduction).
  • f all the buildings in the Sydney CBD boost their average NABERS rating from 2.5 to 3 stars it would be like turning off 13 large towers in the height of summer when networks are straining to supply power.
  • A typical large office tower in Sydney CBD uses nearly as much power in one workday as a typical Sydney home uses in one year, and that’s just to keep the base building services such as air conditioning, lifts and common area lighting running, says the report.
  • When tenant energy consumption is included such as office equipment and office lighting one workday’s energy consumption of a large office tower is nearly double the yearly energy consumption of a typical Sydney house.

The current Sydney average is just 2.5 stars of the available NABERS 5 stars according to the research. The study implies that for every 10 per cent reduction in buildings’ yearly electricity consumption they make a 4.5 per cent reduction in peak demand.

In Eastern Australia, electricity usage during summer afternoon peak periods has increased dramatically. More than $46 billion in spending for electricity network infrastructure is planned across Australia for the next five years and as much as $7.6 billion of this is new capital expenditure on networks in NSW is to manage growing peak demand.

The analysis also found that large electricity customers pay about 13 per cent of their bills to cover peak capacity charges each year, and a further 32 per cent to cover network energy charges – equating to approximately $150,000 per year in peak demand charges and $350,000 in network energy charges for the largest CBD buildings. This shows that any peak demand reduction also means lower energy expenditure for big business, the report says.