Research indicates that New Zealand businesses spend more than $100 million a year on electricity to meet their compressed air requirements. With the potential to save 20-30% of that cost, compressed air systems (CAS) are proving to be a very cost-effective source of operations savings. 
To help identify and capitalise on the energy saving opportunities, the Energy Efficiency and Conservation Authority (EECA) offers fully-funded audits for compressed air systems (CAS), when performed by Accredited CAS Auditors for sites with over 75kW of operating compressor capacity.
The audits look at the whole system - they consider design and operational efficiencies of the supply and demand sides of the compressed air equation. Starting with determining the productive compressed air requirements of the operation, the audit identifies how the compressed air system can be improved to meet those needs more cost-effectively. The findings and recommendations are quantified and presented in a detailed report. 
Under EECA’s compressed air systems efficiency programme, an initial ‘Walk-thru CAS Assessment’ is offered, normally with no financial commitment required from the company. If that initial assessment identified reasonable opportunities for cost-effective savings that deserve better quantification, a more detailed ‘In-depth CAS Audit’ is offered.
Before starting the fully funded In-depth CAS Audit, EECA seeks agreement that the company concerned will action reasonable recommendations from the audit, for which the simple payback period is two years or less.
So far, 203 Walk-thru CAS Assessments have been completed through the programme. Typically, the assessments have identified electricity savings of 20-30%, with the main opportunities for cost savings coming from:
• reducing air leaks;
• removing inappropriate use of compressed air, and
• improving the controls on how the compressors operate.

Inappropriate use relates to situations where compressed air is used to deliver a service that would be more efficiently delivered by an alternative means. A common example is where unregulated compressed air is used for liquid aeration. In such cases, the amount of energy required to produce the compressed air is typically around 5 times that required if a blower was used to aerate the liquid. 

Wood processing companies lead the way
Red Stag Timber limited is just one of the success stories from the programme, with savings of $115,000 per year being obtained as a result of the follow-up actions from an In-depth CAS Audit conducted in 2009.
Environmental Administrator for Red Stag Timber, Andrew Lawes is very pleased with the results.  “The compressed air system at Red Stag Timber has improved substantially from where it was two years ago, with less wastage of air and more efficient production”.
A similar level of savings is being obtained at Nelson Pine Industries Limited, where an In-depth CAS Audit was undertaken in 2008.
Detailed information on how Red Stag Timber and Nelson Pine Industries benefited from the CAS efficiency programme is available on the EECA Business website. Visit www.eecabusiness.govt.nz/resource-centre and enter the keywords ‘Red Stag’ and ‘Nelson Pine’.

Accredited CAS Auditors
The success of the EECA programme comes from ensuring the people doing the CAS auditing are skilled in the technology they are dealing with.
To be an Accredited CAS Auditor and work with EECA on the programme, the auditor must satisfactorily complete a CAS education course through the University of Waikato as well as demonstrating practical competence in CAS auditing according to EECA audit guidelines and reporting standards.
There are now five Accredited CAS Auditors, located throughout New Zealand.
For more information and to find out if you quality for a free assessment by an Accredited CAS Auditor, visit www.eecabusiness.govt.nz/motorsystems.