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July 29, 2004

Utilities to study energy coming into homes

  • By regulating incoming voltage, it is estimated 20,000 homes could be powered for a year on the energy savings.
    • By STACEY HOBART
    Northwest Energy Efficiency Alliance

    voltage regulator
    Photo courtesy Northwest Energy Efficiency Alliance
    About 500 local homes will be outfitted with a voltage regulator as part of a study to determine how much energy could be saved by lowering the voltage of electricity entering the homes.

    Most people don't ever think about the voltage used to operate their refrigerator. Instead they depend on their local utility to deliver the electricity in whatever form necessary to keep the milk cold.

    What most utility engineers know is that while many appliances are optimized at 115 volts, delivering electricity at that exact voltage can be tricky business.

    The American National Standards Institute's service voltage standard is 120 volts with a margin of supply of plus or minus 5 percent. In other words, voltage coming into your home may range anywhere from 114 to 126 volts.

    The reason? Voltage is essentially the pressure at which power comes into the home, said Bob Fletcher, principal engineer at the Snohomish Public Utility District in Everett. As electricity is transported across distribution lines from one home to the next, the amount of "pressure" available decreases the further the house is away from the utility substation.

    To deal with this issue, electric utilities send power at a voltage higher than needed so that by the time it gets to your refrigerator — no matter where you sit on the distribution line — you can be sure that you won't be getting less than the needed 114 volts.

    The Northwest Energy Efficiency Alliance recently funded an initiative to look into how much electricity could be saved if utilities used technologies that better regulated voltage to keep it at the lower edge of the range. Snohomish PUD has been doing this for about 15 years now with considerable success, said Fletcher.

    "We estimate the net savings over the time we've employed conservation voltage regulation practices to be about $25 million," he said.

    That's money Snohomish Public Utility District customers haven't had to pay in monthly electricity bills.

    The $2.58 million Distribution Efficiency Initiative (DEI) launched by the alliance this year will build on Snohomish PUD's work and attempt to replicate the practice of conservation voltage regulation (CVR) on up to 10 other utility distribution systems. The effort is intended to verify the amount of energy savings that utilities could achieve by making efficiency improvements on their systems and confirm the actual cost of implementing CVR.

    The Northwest Energy Efficiency Alliance is a nonprofit corporation supported by electric utilities, system benefits administrators, state governments, consumer interest groups and efficiency industry representatives. These entities work together to make affordable, energy-efficient products and services available in the marketplace.

    Under the multi-year study, 600 Northwest homes are being recruited and will be used to test CVR practices to determine what techniques would yield the greatest energy savings on what type of distribution systems. "We estimate that for every percent drop in voltage, we can save seven tenths of a percent of electricity," said Bob Helm, manager of DEI at the alliance.

    If successful, the alliance believes the energy savings from the Distribution Efficiency Initiative could total 28.2 average megawatts of electricity by 2010 — enough to power about 20,000 homes for a year. That is expected to save consumers $9.8 million. In addition, the energy savings — power utilities will not have to generate — would keep over 100,000 tons of carbon dioxide emissions out of the air.

    The reduction in electricity demand will also help utilities keep pace with the growing energy demand in the region. "Consumers' demands for power are continuing to increase," Helm said. "By optimizing the distribution system and reducing the loads the systems must carry, utilities can put off capital improvements for many years," he said.

    Fletcher said Snohomish engineers have learned a lot about their system by practicing conservation voltage regulation. "In order to effectively manage the system voltage, you have to have better information and in the process of gathering that you get a better system," he said.

    The utility has developed a process of decision models that helps it maintain the voltage; and has added more regulators to its lines and improved controls.

    Five hundred of the homes participating in DEI will receive an extensive audit of energy-using equipment such as appliances, air conditioning and space heating, and computers.

    In addition, homes in the study will be outfitted with a Home Voltage Regulator, a device made by a company called MicroPlanet. The regulator will maintain the level of voltage coming into the home and make sure it never drops below the required 114 volts.

    Utilities participating in the effort will apply voltage conservation techniques and monitor the voltage of the system on an hourly basis using controls already available on the distribution lines. This methodology will aid in the development of engineering models and software simulations to help utility engineers raise or lower voltage based on the demands of the distribution system at any given point in time.

    One Northwest utility has installed a distribution automation technology called AdaptiVolt, made by PCS Utilidata, at its substation that will receive a radio signal from a voltage monitor at the end of the distribution line. The signal will let the automation technology know when and by how much to raise or lower the voltage depending on the distribution system needs at the time. This utility plus two other participating utilities will provide data for the study that will help assess energy savings.

    The Distribution Efficiency Initiative is a three-phase project that is expected to finish in 2007. Phase one of the effort, which involves load research and the pilot demonstration projects, will end sometime in 2006.

    According to Helm, the Bonneville Power Administration took a close look at voltage regulation in the late 1980s. At that time, regulating voltage was determined to be a cost-effective means of reducing energy consumption. "DEI will build on the work of BPA and others to determine the available savings," he said.

    "After gathering and analyzing usage data, we will then develop guidelines and toolkits that will assist Northwest electric utility partners in the design of their distribution systems to achieve energy savings," Helm said.

    Long-term, the alliance hopes CVR will become standard practice among Northwest utilities.

    R.W. Beck of Seattle, teamed with Auriga Corp. and RLW Analytics, has been selected by the alliance to implement the DEI study.

    Stacey Hobart is manager of marketing and communications at the Northwest Energy Efficiency Alliance.


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