Energy Audits: Analyze Energy Use, Review Utility Rate Structure
By Gregory Hughel September 2010 - Energy Efficiency
The next step is to implement a game plan that spells out key tasks that properly focus the auditors' efforts. Managers need to make sure auditors performing these tasks look for ways to optimize systems and reduce energy where possible:
Understanding the building and building systems. Performing a walk-through survey of the building provides a better understanding of the facility's construction, equipment, and energy-consuming systems. Managers need to identify opportunities for equipment replacement and upgrades, as well as identify system modifications that might improve the overall performance of a major building system, such as the chilled-water system.
Examples of equipment replacement or upgrade projects include replacing existing motors with premium-efficiency motors and installing variable-frequency drives to control cooling-tower motors.
Understanding operation and maintenance. Talk with the engineering and operations staff regarding the operation and maintenance of a building's energy-consuming systems. Identify maintenance problems and practices that affect energy efficiency. Use the building-automation system (BAS) or energy-management system (EMS) to better understand the facility's operation.
Most of the effort to optimize the operation of building systems should focus on using the BAS and EMS to locate problems within these systems, such as faulty sensors and controllers, improper operation, and components that are failing or might have failed.
Analyzing building energy use. Start with a review of utility bills. Managers can use these bills to understand a building's current energy use and, if possible, the trend of energy consumption in years past. Understanding the facility's past and current performance in terms of energy use will help in setting performance goals.
Reviewing utility rate options. Review current utility rates, including monthly demand and consumption charges. Managers also should identify on-, mid-, and off-peak charges. Armed with a proper understanding of the rate structure, managers can research other rate structures available through the current utility provider, as well as those available through other providers.
These tasks are guidelines. Managers need to keep in mind that all facilities are unique, so an energy audit might need to include additional tasks specific to a particular facility. For example, in a facility with a large kitchen and cafeteria, a manager might want to include additional tasks to focus the audit scope on improving the equipment efficiency in these areas.
The next step is to compile a list of identified energy-conservation measures. Typically, energy-conservation measures fall into two categories: low- or no-cost measures and capital-improvement measures.
Low- or no-cost measures typically address issues and identify opportunities for savings by making recommendations on operation, maintenance, and general best practices. These measures normally do not require a capital investment, while bigger-ticket measures focus on equipment replacement and upgrades that require capital investment.