Exploring the Benefits of System Energy Audits
By James Piper, P.E. - September 2013 - Energy Efficiency
Energy audits have proven to be effective tools in helping maintenance and engineering managers understand and take control of the way institutional and commercial facilities use energy. They also are valuable in determining the steps to make that use more efficient.
The key to the effectiveness of an energy audit is the wealth of data it generates — in particular, how much, when, where, why, and what of facility energy use. Before managers can make strides in reducing energy use, they must have accurate answers to these and other questions related to energy use.
By themselves, the mountains of data generated by a comprehensive energy audit will do nothing to reduce the energy use in a facility. The pathway to greater energy efficiency requires managers to collect, compile, interpret, organize, analyze, and formulate the data into an action plan. This plan should identify energy-conservation opportunities, their estimated costs for implementation, and their economic benefits to the organization.
Selecting An Audit
Energy audits come in a variety of flavors, depending on the complexity, capabilities, and needs of the facility. At the low end is the Level 1 audit. This audit focuses on those conservation measures that managers and departments can implement for minimal or no cost. The audit starts with an examination of at least one year's worth of data on energy use and cost. Auditors and managers can review utility bills to identify costs related to the various elements of the rate structures that are in effect.
The auditor then walks through the facility, identifying operational and maintenance measures the department can implement in the facility without the need for a significant capital investment. Level 1 audits can be a good starting point for any institutional and commercial facility, but they are most useful in smaller facilities that generally have straightforward energy-using systems.
A Level 2 audit expands the data collected to include energy use by activities and systems within the facility. The auditor identifies the energy-using systems and quantifies their energy use. Managers can use the additional data gathered by a Level 2 audit to identify energy-conservation activities that go beyond changes to operational and maintenance practices to include modifications and upgrades to energy-using systems.
The most detailed energy audit is the Level 3 audit. In addition to the data gathered during Level 1 and Level 2 audits, a Level 3 audit dives into the details of a facility's energy use. In many cases, it involves using submetering on energy-using systems, followed by an in-depth analysis of that system's energy use.
While the Level 3 audit provides the most detailed information to managers, not all facilities can benefit equally from it. Small facilities, which tend to have relatively small energy-using systems, will get the highest rate of return by conducting a Level 1 audit. Similarly, facilities that do not have the capital budget available to invest in replacing or upgrading their energy-using systems also are likely to achieve a higher rate of return from a Level 1 or a Level 2 audit.
Level 3 audits are best suited for those facilities that are more complex, have a larger number of energy-using systems, and have a strong need — either for financial reasons or as a result of limited capacity — to reduce energy use.