How to take 1 million tonnes of CO2 emissions out of the atmosphere: energy efficiency in commercial buildings

31 Mar 2010Archived News Climate Change Matters

Energetics considers the impact that energy efficiency measures can have on the emissions attributable to commercial buildings. Events, such as the global Earth Hour, continually draw attention to the significant reductions that can be achieved through switching off and powering down sources of energy within a commercial building.

Due to the National Australian Built Environment Rating System (NABERS), the commercial buildings sector in Australia has a high level of awareness of its energy efficiency improvement potential. NABERS enables the calculation and comparison of energy performance between different built environments to be made and highlights the effectiveness of their energy management programs.

Evidence of the sector's awareness of the potential savings to be gained through energy efficiency measures can also be seen in the first round of public reports that were submitted under the Federal Government's Energy Efficiency Opportunities program. The commercial sector identifies some 11% in annual energy savings. This is nearly twice the level of savings to be found across other EEO program participants.

The amount of energy usage attributable to the Australian commercial sector is signifcant. This sector uses approximately 71,500 GWh of electricity a year which equates to approximately 71.5 million tonnes of CO2 emissions a year.

In general, a typical large multi-story commercial offfice can produce up to 10,000 tonnes of CO2 per year. Therefore, approximately 100 commercial offices can cause 1 million tonnes of CO2 emissions each year. To make equivalent savings per year across the entire commercial sector, a reduction of only 1.5% of annual energy use in every commercial office is needed - surely that's not too difficult!

For a typical office, the split of energy use would be:

  • Lighting 15%
  • Heating Ventilation and Air Conditioning (HVAC) 60%
  • Office power 15%
  • Other 10%

The key steps that any commercial property manager can take to save energy and reduce emissions are:

  • Raising the air conditioning temperature set point by 1 degree. With this measure the potential saving on a building's energy use is 5%.
  • And ensuring that the heating temperature set point is lowered by 1 degree. This change should deliver a potential saving on a building's energy use of 2%.
  • Ensuring that lights are switched off in unoccupied rooms and after hours. The potential savings on a building's energy use is in the order of 1 to 2%.
  • Ensuring that all PCs and monitors are switched off after hours. The potential energy savings is between 0.5 to 1%.
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