Conservation Voltage Regulation: A Strategy in Search of a Technology

What Is CVR?
Conservation Voltage Regulation (CVR) is a technique for reducing voltage along the feeder lines. Utilities have been using, experimenting with or researching CVR for over 20 years. It was first introduced on a large scale in California in 1977, with good results.

But until now, widespread CVR has been a strategy in search of a technology that would allow it to reach its full potential.

CVR decreases the voltage at which electrical power is consumed and yields on average, nationwide, a 1% energy savings for each 1% in voltage reduction. And it is far less expensive to save that 1% for later use than to pay to create a 1% increase in capacity from generation to distribution.

Thus, CVR has since the late 1970s been an attractive, compelling concept.

Why CVR Is Necessary
The American National Standards Institute (ANSI) requires that voltage be made available to residential customers at 120V +/- 5% — which yields a range of 126V to 114V. On any feeder line, especially those over three miles long, voltage on the feeder line gradually decreases as the cumulative load on the feeder line increases. This is called “line drop.” Because of line drop, power must be transmitted at a high enough voltage that the last house on the line gets at least 114V. Consequently, power is often transmitted at an initial value of 126V. US homes receive an average of 122.5V. Approximately 99% receive more voltage than they need.

Line Drop Compensation
Since appliances, light bulbs and other electrical devices operate efficiently at reduced voltages, utilities can provide service at the lower end of the acceptable range with no detriment to their customers. On lines operating with CVR, voltage is regulated with a technique called Line Drop Compensation (LDC) to provide voltages within the reduced range of 120V to 114V. LDC is a form of CVR that reduces the average voltage to 117.5V, and ensures that the home at the end of the line gets the minimum 114V.

The Benefits of CVR
Customers save money on electricity with service at a lower voltage, and the life of appliances, light bulbs and other electrical devices is extended. Utilities save energy and capacity, yielding lower fixed costs. And the environment benefits as well: the by-products of the most widely used kinds of power generation are greenhouse gases.

Testing of CVR
Between 20 and 25% of US utilities have tested some form of a CVR program on parts of their systems and for widely varying lengths of time. In general they have successfully reduced the average voltage supplied to residential and some commercial customers about 4%, to about 117.5V from the average 122.5V. Yet CVR is currently applied nationwide to less than 2% of all feeders, and most of these are in California, where CVR is mandated.

Current Limitations of CVR
This appears to be the limit to which CVR can be applied by the utilities at present. Fluctuating electrical loads limit the lowest voltage setting. On any electrical distribution system, as the electrical load increases the voltage decreases. Since the load fluctuates dynamically, the utilities must keep the voltage high enough so that no customer’s voltage dips below 114V before the system-level voltage regulation reacts to the fluctuating load. Furthermore, customers with different requirements from those of residential customers are usually mixed on the same distribution feeders, interfering with implementation of CVR on those lines. The presence of particularly sensitive customers, such as hospitals and manufacturers, on a feeder line can preclude the entire feeder line from using CVR. Until now, CVR has been a thoughtful and ambitious notion that could be implemented only on short feeder lines with expensive and labor-intensive equipment upgrades. To implement CVR on the US electrical grid — even with its highly developed infrastructure — extensive modifications of utility equipment would be necessary. Here is just a partial list:

– modifying tap-changing settings and voltage regulators
– adding more LTC voltage regulators
– adding more capacitors
– reconfiguring the utility’s central control and communication systems
– constructing more substations
– shortening feeder lines and configuring them with larger conductors
– reconductoring present feeders
– converting to higher primary voltages

The greatest limitation to CVR as it is currently practiced, is what we call the gray zone. The gray zone is the voltage drop that occurs between the distribution transformer and your service entrance. Most utilities assume the average drop across the gray zone is 3 volts. In fact for the utility it is an uncontrollable variable that can be as high as 5 volts and as low as 1. This is the reason why feeder line voltage is rarely set lower than 117 volts at the distribution transformer, even using LDC techniques. A voltage drop of more than 3 volts across the gray zone would cause your voltage at the service entrance to be too low. It was impossible for the utility to set the voltage at everyone’s service entrance to 114 volts, until the HVR and EVR products became available. Our products regulate voltage beyond the point in the system where all the variables that complicate the traditional implementation of CVR occur.

The MicroPlanet Solution
Until MicroPlanet introduced its HVR™ and EVR™, there had been no way to make CVR simple enough that it could be implemented widely and intelligently, no way that it could be implemented at the micro level — that is, the service entrance to the home or office — rather than at the feeder-line level. The HVR and EVR allow Conservation Voltage Regulation to be practiced on a micro level, home by home, business by business — easily, reliably and inexpensively. It is CVR for the new millennium.

Wisconsin Environmental Research Program FAQs

1. Why study the effects of electrical generation and transmission on the environment in Wisconsin?
The more we know about how electrical generation and transmission affect the Wisconsin environment, the greater our chances are of preventing pollution in the future. As our towns and cities grow, we will need to produce more electrical power. How we accomplish this will have an impact on many things including our health, our economy, and our beautiful natural environment. We need to have more information in order to make wise decisions about new generation plants and transmission lines, and to know how we can reverse environmental damage that has already occurred.

2. What is the Environmental Research Program (ERP) and what are its goals?
The Environmental Research Program (ERP) is an important part of the Focus on Energy Program because its purpose is to further the exploration of how our energy use has an impact on Wisconsin’s natural environment. Funding for this program is designated to support research projects that study the environmental effects of electrical generation and transmission.

The primary goal of this program is to contribute practical and useful knowledge to the ongoing process of designing Wisconsin’s electrical energy future. Of specific interest are research projects that fill gaps in existing knowledge about the environmental effects of electrical energy generation and transmission in Wisconsin.

For a two-page print-optimized overview of the Environmental Research Program, download:
ERP Program Overview  ( 32KB)

For lists of projects funded by the Environmental Research Program:
Environmental Research Projects Selected in FY02  ( 71KB)

and
Environmental Research Projects Selected in FY03  ( 72KB)

3. What is the Environmental Research Forum and what is its role in the Program?
The Environmental Research Forum was appointed by the Wisconsin Department of Administration’s Division of Energy to recommend research projects for funding. The eight members of the Forum contribute a broad spectrum of viewpoints and expertise, and represent the following organizations and institutions: the University of Wisconsin, the Department of Natural Resources, the Public Service Commission, the Department of Commerce, the Department of Administration’s Division of Energy, Wisconsin Environmental Decade, and two representatives of investor-owned Wisconsin utilities.

The Forum has developed a proposal process to solicit, evaluate, and recommend research projects for funding once a year, in late autumn. Interested researchers are invited to participate. For complete information about the latest Request for Proposal, go to RFP Postings Environmental Research Program. For further information about the process, go to Grant Process FAQs.

For more information about the Environmental Research Forum, download the ERP Program Overview document listed under Question 2 above. For a print-optimized list of the members of the Environmental Research Forum, download:
ER Forum Members  ( 122KB)

4. How will the ERP results be used to improve the environment in Wisconsin?
The Environmental Research Forum wants to emphasize the importance of learning new information about the effects of electrical generation and transmission on Wisconsin’s environment. New information from research results will be made available to legislators and policy makers, the scientific community, and the general public.

Final research reports will appear at Research Reports as projects are completed. Other new data will appear on this website at Other Program Publications as they become available.

Wisconsin Research Grant Program Update

First Year of the Program: 2001-2002
The Environmental Research Forum met five times during the first year. Their work began with identification of research gap areas and development of a Request for Proposals to be distributed to the scientific community.

The Forum identified six research areas for inclusion in the Request for Proposals (RFP):

– The effect of mercury and other air pollutants on human health in Wisconsin from coal-fired power plants.

– Measurement and inventory of mercury in Wisconsin environment with regard to both sources and fate in the ecosystem.

– Deposition monitoring, modeling and fate of multiple pollutants (other than mercury) from Wisconsin power plants.

– Ecosystem impacts of electrical generation and transmission.

– Land-use issues resulting from electrical generation and transmission.

– Global climate change impacts and strategies for Wisconsin.
The Forum received twenty research proposals that met the RFP criteria, and recommended funding seven proposals, for a total of $666,788. The Department of Administration approved all seven projects for FY02 funding.

For information about the seven Environmental Research Grant Projects funded in 2002 (FY 2001), download:
Funded Environmental Research ProjectsFY02 ( 71KB)

Second Year of the Program: 2002-2003
A Request for Proposals for FY03 funding was issued in November of 2002. Research areas identified by the Forum for this year are as follows:

– Electrical Generation and Human Health:

a. Mercury: Body Burden and Levels of Exposure in Wisconsin.
b. Mercury in Wisconsin: On-site Measurement and Monitoring.
c. Fine Particulates in Wisconsin: On-site Measurement and Monitoring.
d. Hazardous Air Pollutants in Wisconsin: On-site Measurement and Monitoring-

– Carbon Sequestration/Greenhouse Gas Emissions:

a. Biotic model for Global Warming in Wisconsin.
b. Carbon and Greenhouse Gases Inventory
c. Environmental Impacts of Carbon and Greenhouse Gases Management

– The Siting of Energy Facilities:
a. Environmental Impacts of Wind Generation Siting
b. Environmental Impacts of Biomass Generation Siting
c. Transmission Lines: Ecology of Fragmentation and Transmission Line Siting; Impact of Transmission Line Construction Activity; Placement of Transmission Lines.

– Environmental Monitoring of Multiple Pollutants Including Mercury from Wisconsin Power Plants:
a. Deposition monitoring of multiple pollutants including mercury.
b. Biomonitoring of multiple pollutants including mercury.

The Forum received twenty-five research proposals that met the RFP criteria, and recommended funding ten proposals, for a total fo $965,556. The Department of Administration approved all ten projects for FY03 funding.