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Measurement & Verification

The purpose of measurement and verification (M&V) is to establish the potential of a project's measures to save demand and energy and to determine the actual savings produced by those measures.

In the Large Commercial Standard Offer Program (Com SOP), project sponsors are responsible for planning and conducting all the M&V activities associated with their projects. They are required to submit, as part of the Final Application, an M&V plan that describes the specific activities, tools, and calculations the sponsor intends to use to determine the projects' actual savings.

Entergy offers two M&V approaches for project sponsors to use as guidelines when developing their M&V activities: simplified and full. Except for lighting measures to which deemed savings values apply, these guidelines adhere to the standards of the 1997 International Performance Measurement and Verification Protocol (IPMVP). Project sponsors may recommend an M&V approach not covered in these guidelines; however, any alternate approach must be approved by Entergy and adhere to IPMVP standards.


Simplified M&V

The simplified M&V approach uses stipulated values for data such as operating hours and equipment efficiencies, thereby reducing the need for certain types of field monitoring. They have been developed for common measures, which must meet certain criteria for the simplified approach to be applicable. These criteria are discussed within the guideline specific to that measure type.

Measure type (click to view)
Lighting efficiency upgrades        sim lighting.PDF (80KB)
Lighting controls sim lightcontl.PDF (88KB)
Lighting Wattage Table Wattage Table.xls (266KB)
Stipulated savings factors sim stipulated.pdf (46KB)
Cooling equipment retrofits sim cooling.PDF (68KB)
Motor efficiency upgrades sim motor.PDF (60KB)
Window Film sim film.PDF


Full M&V

The Full M&V approach uses a higher level of rigor than the simplified M&V approach; it involves the application of end-use metering, billing regression analysis, or computer simulation. Project sponsors must use a full M&V approach for measures that do not meet the criteria for a simplified M&V approach. Entergy has developed general guidelines for the full M&V approaches, and sponsors will need to adapt them to their specific projects. To view a guideline, simply click on a filename in the following table.

Measure/approach type Full M&V approach (click to view)

Measure Type (click to view)
Generic for variable load measures full varload.PDF (56KB)
Bill regression analysis full billreg.PDF (46KB)
Calibrated simulation analysis full calsim.PDF (65KB)


Site Inspections

Over the course of a project, Entergy conducts two site inspections. A baseline inspection is performed after the Standard Offer Program Contract is executed and a post-installation inspection is performed following the project sponsor's submission of the Installation Report.

Baseline Inspection

Entergy will contact the project sponsor and complete the pre-inspection within 10 days of the execution of the Standard Offer Program Contract. The purpose of this inspection is to verify the following:

  • The accuracy of the equipment survey. For most measures the accuracy of the equipment quantity and nameplate information is verified. For lighting measures, the requirement for acceptance is that the total error of the installed demand of the sample must be within +/- 5 % of the total demand submitted on the survey form.
  • The M&V plan is appropriate for the measure, and the necessary M&V activities are being performed.
  • All existing equipment listed in the final application is still in place and operational.
  • New equipment installation, or preparation for installation, has not begun.

Post-installation Inspection 

This inspection, conducted by Entergy within 30 days of its receipt of a complete Installation Report, verifies the following:

  • The equipment specified in the standard offer program contract has been installed and is operating as described in the approved final application. For most measures the accuracy of the equipment quantity and nameplate information is verified. For lighting measures, the requirement for acceptance is that the total error of the installed demand of the sample must be within +/- 5 % of the total demand submitted on the survey form.
  • The M&V plan is being followed in accordance with the approved final application.

For both inspections, the presence of at least one representative of the project sponsor familiar with the project and with the facility is required. When electrical measurements are necessary, the representative is required to perform any necessary disruptions in equipment operation, the opening of any electrical connection boxes, or the connection of current and power transducers.

If an inspection cannot be completed in a timely manner because the representative is unfamiliar with the facility or project, the project will fail the inspection. A project has two chances to pass each inspection type; after failing two inspections, the project sponsor must pay the cost incurred by Entergy for performing additional inspections of that type.


M&V Plan Requirements

The M&V plan describes the potential for the project to achieve demand and energy savings and describes the specific activities the project sponsor intends to perform to determine those savings.

In general, a project-specific M&V plan should:*

  • Describe the project site and the project; include information on how the project saves energy and what key variables affect the realization of savings.
  • Describe the M&V approach to be used.
  • Indicate who will conduct the M&V activities and prepare the M&V analyses and documentation.
  • Define the details of how calculations will be made. List analysis tools, such as DOE-2 computer simulations, and/or show the equations to be used. A complete "path" should be defined indicating how collected survey and metering/monitoring data will be used to calculate savings. All equations should be shown.
  • Specify what metering equipment will be used, who will provide the equipment, its accuracy and calibration procedures. Include a metering schedule describing metering duration and when it will occur, and how data from the metering will be validated and reported. Include data formats. Electronic, formatted data read directly from a meter or data logger is recommended for any short- or long-term metering.
  • Define what key assumptions will be made about significant variables or unknowns. For instance: "actual weather data will be used, rather than typical-year data," or "fan power will be metered for one full year for two of the six supply air systems." Describe any stipulations that will be made and the source of data for the stipulations.
  • Define how any baseline adjustments will be made.
  • Describe any sampling that will be used, why it is included, sample sizes, documentation on how sample sizes were selected, and information on how random sample points will be selected.
  • Indicate how quality assurance will be maintained and replication confirmed. For instance: "The data being collected will be checked every month," or "to ensure sufficient accuracy, results will be subjected to third-party review by the ABC company."
  • Project sponsors should work with Entergy to develop an M&V plan that is appropriate for their projects.

*1997 International Performance Measurement and Verification Protocol (IPMVP).

Sampling Guidelines

When preparing the final application, a project sponsor is required to document each fixture or piece of equipment that is part of a retrofit. Equipment with similar functional uses may be grouped together for M&V purposes. Once the equipment has been grouped, a sample of each grouping's equipment may be monitored and the results used to estimate the operating hours for all of the fixtures or equipment within that group. (For more information on specific equipment groupings, see the measure-specific M&V approaches for that equipment type.)

The table below shows how large the sample size must be to provide a reliable estimate for varying sizes of groups. The initial sample sizes represent 80% confidence/20% precision and have a coefficient of variation of 0.5; the suggested sample sizes have been increased by 10% to compensate for equipment failure or loss.

Group population Initial sample size (80/20) Suggested sample size
(80/20 plus 10%)
4 3 4
5 4 5
12 6 7
16 - 20 7 8
21 - 35 8 9
36 - 70 9 10
71 - 350 10 11
more than 350 10 11

The project sponsor may propose an alternative approach to determining sampling sizes, but it must be approved by Entergy and be based on sound statistical principles.

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