An Energy Audit for commercial and industrial facilities includes the study of electric and natural gas usage and billing. Usage covers lighting, HVAC, motors, boilers, other energy using equipment, and building envelope. A typical audit usually takes two to ten hours at the facility, depending on size. It is helpful to have the assistance of a facility's person to locate the energy using equipment and to answer questions about plant operation. Also, twelve months of electric and gas bills are necessary for an effective energy study. After gathering the data, it is analyzed and a detailed report is prepared. The report addresses specific energy and cost reduction recommendations for the facility as well as their environmental reduction impacts.
Predominant Use Study:
A Predominant Use study entails the analysis of all the energy load usage in the facility. Each piece of energy using equipment must have its power consumption recorded and a determination made as to how much of it's energy is used for manufacturing. A list of all the equipment and their power consumption is recorded. This results is then analyzed to determine what percentage of energy is being used for manufacturing and if it is over 50%. If this criteria is met, then a certificate of exemption is written and sent to the utility which then places the company on their exempt sales tax list and no further sales taxes are added to future billings. Along with this certificate, the Predominant Use Report also shows a year of energy demand, consumption, and billing. As a bonus, taxes may be refunded for up to four years.
Power Factor Analysis and Correction:
Power Factor (PF) is the ratio of working power to effective power. PF = kW/kVA. It measures the effectiveness of the electric power being used. 100% effectiveness is a PF of 1.0 and kVA = kW. Most electric loads today, such as motors and fluorescent lighting ballasts, are inductive and need a magnetic field to operate. The magnetic field works against the electron flow from the power company causing a heavier drain on the source and distribution system. Inductive loads require working power (kW), which drives the machines and lights, and reactive power (kVAR) to sustain the magnetic field,performs no useful "work", but only cycles between the generator and the load. These two loads, kW and kVAR, make up the apparent or effective power (kVA), the true total electric load needed by the power company to operate an inductive load. To improve PF and avoid a PF penalty, facilities may install power factor correction capacitors. Most power companies require a 0.95 PF to avoid penalty payments. A 70% PF requires 142 kVAs to produce 100 kWs, while a 95% PF requires only 105 kVAs to produce the same 100 kWs. It takes 35% more power at 70% PF than at 95% PF to provide the same power to the equipment. The utility must supply this excess reactive current plus the working current and they have various ways to pass along the expenses of the larger generators, transformers, cables, switches, etc. required.
Energy Star Certification:
An ENERGY STAR qualified facility meets strict energy performance standards set by EPA and uses less energy, is less expensive to operate, and creates fewer greenhouse gas emissions than its peers. Commercial and industrial facilities are responsible for nearly half of U.S. greenhouse gas emissions which contribute to global warming. To qualify for the ENERGY STAR certification, a building or manufacturing plant must score in the top 25 percent based on EPA's National Energy Performance Rating System. To determine the performance of a facility, EPA compares energy use among other, similar types of facilities on a scale of 1-100. Buildings that achieve a score of 75 or higher and are verified by a professional engineer are eligible for the ENERGY STAR certification.
Utility Bill Analysis:
Errors on utility (electric and gas) bills can be expensive oversights which continue for long periods of time if not caught. Errors may include demand and power factor penalties, taxing errors, meter reading or recording errors, wrong meter listings, or any number of other errors. Most bills are just paid as a matter of habit. It takes experience when looking at a bill to locate these type errors. Besides errors, analyzing a year of billings may identify equipment or operational problems by the effect on the demand or energy usage changes.
Distributed Generation/CHP Analysis:
“Distributive Generation” or “Decentralized Generation” is the use of small electricity generating equipment located close to the load being served. It expands energy options by improving reliability and security in energy supply and produces a cleaner environment by reducing emissions. A number of factors are driving interest in Distributed Generation solutions, including the restructuring of the U.S. energy industry and the introduction of new technologies. Electric utilities, commercial and industrial companies, prisons, hospitals, and school districts are evaluating where DG should fit into their business planning process. “Combined Heat and Power” is the combined production of electricity and thermal (heat) energy. The use of the thermal energy adds value to Decentralized Generation. Overall efficiency of a CHP system is about 80% while the separate usage of electric power for electricity and natural gas for hot water is about 57% efficient, which means that overall operation costs are reduced with CHP.