Volume 23, number 3, september 2009

IPMVP: International Performance Measuring and Verification Protocol for energy savings projects

Energy efficiency projects can only be recognized at their fair value if their impacts are measured and verified. The IPMVP defines a standardized approach to verify the savings of energy performance improvement projects. Measuring is required for a reliable determination of the actual savings generated by a given site. The IPMVP provides advice on the compromise between the measuring precision required and the associated costs. The IPMVP helps the parties involved in a performance contract to create appropriate contract terms concern-ing verification of the savings generated by a project. It supports the projects carried out by Energy Service Companies (ESCO) through international recognition of the way energy savings are verified.

The IPMVP emerges from the Efficiency Valuation Organization, an international non-profit organization run by volunteers all over the world, with an administrative -headquarters based in Sofia, Bulgaria. The Association of Energy Engineers based in the United States has adopted the IPMVP and provides training and certification to professionals who have taken the course and passed the examination to become a Certified Measurement and Verification Professional. The Association québécoise pour la maîtrise de l’énergie promotes and -organizes the training.

The IPMVP’s rigorous approach requires measuring and verification (M&V) to determine reliably the actual savings generated by implementation of energy efficiency measures (EEM). The savings are determined by comparing the consumption measured before and after implementation of the EEM, while making appropriate adjustments to account for changes in conditions.

Four IPMVP options

The IPMVP offers four options to determine the savings. The chosen option has an impact on the measuring. They offer a range of methods to evaluate the energy savings depending on the type of EEM implemented and the desired balance between precision and cost. A technique for isolating the changes is appropriate in the event that only the EEM performance must be evaluated. Options A, B or D thus may be chosen and are smaller in scale than if the entire site must be measured (options C or D). Table 1 gives an overview of the four options.

IPMVP OPTIONS HOW TO CALCULATE THE SAVINGS TYPICAL APPLICATIONS
A – EEM ISOLATION AND MEASURING OF KEY PARAMETERS
The savings are determined by measuring the main parameters, which define energy consumption of the systems affected by EEM.

The measuring frequency can be short to continuous, depending on the forecast variations of the measured parameter and the length of the monitoring period. The parameters selected for measuring are estimated, based on the historical data or the manufacturer’s features.

Calculation of energy consumption for the reference base and the monitoring period based on:

  • Continuous or short-term measuring of the main operating parameters.
  • Estimated values. Periodic and non-periodic adjustments if required.
Improvement of a system with little variation in power. The power is measured before and after the EEM and the number of hours is estimated and based on operating system of the building. Example: replacement of a lighting system.
B – EEM ISOLATION AND MEASURING OF ALL PARAMETERS
The savings are determined by measuring the energy consumption of all the parameters of the systems affected by EEM.

The measuring frequency ranges from short-term to continuous, depending on the forecast variations of the measured parameter and the length of the monitoring period.

Short-term or continuous measuring of energy consumption for the reference base and the monitoring period. Periodic and non-periodic adjustments are required. Measuring during the reference period for a representative period. Measuring throughout the monitoring period. Examples:

  • industrial heat recovery;
  • compressed air leak reduction.
C – WHOLE SITE
The savings are determined by measuring energy consumption for the entire site or a subsite.

Continuous measuring during the monitoring period.

Analysis of data for the monitoring period and the reference base for the entire system.

Periodic and non-periodic adjustments if required.

Several systems on a site. Measuring of energy with the energy providers’ meters for a 12-month reference base and during the monitoring period. Example: Several EEM in modernization of a building.
D – CALIBRATED SIMULATION
The savings are determined by simulation of energy consumption for the entire site or a subsite.

The simulation routines are shown to model the energy performance measured on the site suitably.

Install meters and gather the actual and measured energy consumption data from the modernized site.

Simulate the annual energy consumption of the site with the EEM by computer.

Compare the simulated and actual energy consumption. Adjust the simulation until the differences are minimal. The simulation is now calibrated.

Remove the EEM from the calibrated simulation and recalculate. This estimated result becomes the reference base.

Energy management program with several facts, affecting several systems on the site where no meter existed during the reference base period. Example: Modernization of a pavillion on the campus where the meters are centralized.

Calculations

The savings are determined by comparing the consumption measured before and after implementation of the EEM and by making adequate adjustments for any change
in conditions

Savings = consumption during the reference base
consumption during the monitoring period
± adjustments

Several variants of this equation are devel-oped in the IPMVP. Demand can be substituted for consumption. Adjustments can be periodic and non-periodic. The reference base can also be changed: consumption for the monitoring period and for the reference base can be adjusted from their actual conditions to the common conditions selected. Mathematical models then are required to account for the adjustments. For each of the four options described in the table, savings forms have been developed. For more details, consult the references.

Contents of the M&V plan

The preparation of an M&V plan is required to monitor a project and a budget must be provided. The reference base data, the EEM details and the assumptions must be kept for later consultation by the auditors and stakeholders. Succinctly, here are the points to include in the M&V plan:

  • Purpose of EEM: describe the EEM, the expected results and the commissioning procedures. Identify any changes fore-seen in the reference base conditions: temperature, humidity, occupancy rate, etc.
  • The IPMVP option described in the table and the measuring limits.
  • Reference base: consumption, demand, operating conditions, energy audit.
  • Monitoring period: can be as short as an instant measurement or as long as the return on investment period.
  • Adjustments: define all of the conditions to which all the energy consumption measurements will be adjusted.
  • Analysis procedures: specify the exact data analysis procedures, the algorithms and the assumptions to use for each savings monitoring report. Define the mathematical models used, their terms and the variables.
  • Energy prices: identify the prices that will be used to evaluate the monetary savings.
  • Meter features: specify the measuring points, the period, the duration, the measuring presence protocol, the calibration procedures, the data processing method, etc.
  • Responsibility for monitoring and record-ing of energy data, the variables, the static factors.
  • Expected precision related to measuring, data capture, data collection and analysis, the measurement uncertainty level.
  • Budget to define and resources required to determine the savings.
  • Report format with a model.
  • Quality warranty: indicate the quality assurance procedures for the savings monitoring reports and interim acti-vities.

Other advantages of IPMVP

For energy and atmospheric certification of LEED buildings, a credit is allocated to verify and optimize the building’s performance continuously with the IPMVP. Within the context of the carbon market, the ISO-14064 standard recognizes projects set up and monitoring according to the IPMVP to quantify the GHG reduction.

Conclusion

The IPMVP is a framework of definitions and methods to evaluate consumption savings or energy demand correctly. The IPMVP guides the users in the development of the M & V plans, while allowing the necessary flexibility to be precise, complete, conservative, consistent, relevant and trans-parent. The IPMVP gives energy saving projects the required credibility and ensures that the savings are recognized at their fair value because they will have been measured and verified.

Guy Desrosiers, Eng., CEM, CMVP
Technical Advisor
DATECH Group

References: www.evo-word.org
IPMVP, Concepts and Options for Determining Energy and Water Savings. Volume 1. CMVP Training Manual