Public Power Magazine

Austin Energy Showcases New Software to Raise Power Factor, Improve Efficiency


From the May 2013 issue (Vol. 71, No. 3) of Public Power

Originally published May 1, 2013

DEED
By Laurel Lundstrom
May 1, 2013

Forced to raise rates to meet the ascending cost of energy, Austin Energy is optimistic that a new software program will help commercial and industrial customers save on their bills, conserve energy, and minimize recently instituted power-factor correction penalties.

Power-factor penalties, levied for a low power factor, signal inefficient power use. While low power factor has many causes, it occurs chiefly due to inefficient inductive loads from transformers, induction motors, generators and certain lighting ballasts.

The new software program and user’s manual, developed by Austin Energy and GDS Associates, Inc. with a $55,000 grant from the American Public Power Association’s  Demonstration of Energy & Efficiency Developments program, is designed to help commercial and industrial customers review their equipment and evaluate potential upgrades that will reduce power-factor penalties while increasing energy efficiency.

Avoiding sticker shock

“Recently, Austin Energy started to charge a power-factor penalty to customers,” said Karen Poff, an engineer with Austin Energy. “In anticipation of sticker shock, we wanted to come to the table to say we have this tool that can help you identify energy efficiency measures that will ease the financial burden.”

Austin Energy took advantage of the fact that power factor, traditionally corrected with capacitors—a simple device used to store excess electrical energy—could also be improved by making certain upgrades. The utility found that by installing equipment, such as variable frequency drives to water pumps, efficient motors to industrial refrigerators, or high-efficiency lighting, customers could slim down their power bills by correcting power factor and limiting power use. Those improvements would also help Austin Energy cut demand.

“Capacitors will get you what you need, but they don’t do anything to address energy efficiency,” said Poff.  “Once we realized there were energy-efficiency improvements that would improve power factor, we started the push to develop the tool.”

The software, developed as a Microsoft Excel spreadsheet, includes default values for each piece of equipment that customers can input if they are unable to generate their own numbers. To fully realize the benefits of the software and make the most effective upgrades, however, customers are required to take accurate power factor readings from their equipment.

The software is “only as good as data that you input,” said Poff. Austin Energy employs energy conservation representatives who can help customers measure power factor and assess equipment loading.

Understanding where power factor matters most

Before creating the software, Austin Energy hired GDS to gauge which customer classes had the highest incidences of low power factor. The research revealed that the raw material processing and oil and gas extraction industries were particularly susceptible to power-factor penalties, while energy efficiency measures at restaurants could potentially help the greatest number of customers.

GDS identified energy efficiency strategies applied by Austin Energy that could also improve power factor and examined equipment used at customer sites. GDS found that upgrades to the following types of equipment would most effectively address low power factor and energy efficiency among Austin Energy’s commercial and industrial customers: lighting, office equipment, variable-speed drives and electronically commutated motors for air conditioning and refrigeration equipment, and high-efficiency motors for industrial applications.

Based on those findings and a study of existing software tools that address either energy efficiency or power factor (none address both), GDS and Austin Energy developed the software.

As a final step, Austin Energy identified three individual customers with low power factor—a small grocery store, an office building and a cold storage distribution facility—to test and evaluate the effectiveness of the tool. With the addition of variable frequency drives to chilled water pumps at the office building, and a cold storage compressor at the distribution facility, for example, the software calculated that each could save around $4,300 and $12,000 each year, respectively.

Rebates offered as incentives
To make use of the software doubly enticing, Austin Energy manages a robust rebate program for many of the equipment types recommended by the software, including: efficient motors for industrial manufacturing, electronically commutated motors for commercial refrigeration, variable frequency drives, and energy-efficient lighting installations.

Although the utility has not started to promote use of the software among the larger public power community, Poff insisted it would be particularly useful to any utilities instituting power factor correction penalties.

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