Assuring Success in Energy Efficiency

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International Performance Measurement and Verification Protocol

How are you going to measure it?

Most energy efficiency projects are embarked upon with no consideration of how the results will be measured. This may be due to the additional cost of measurement & verification (M&V), the complexities involved, or simply that M&V falls between the cracks and is forgotten about until the project is completed. The upshot is that a great many projects have an ambiguous outcome, and sound energy efficiency measures are rejected or neglected because they remain ‘unproven’. Often, if the energy bill does not come down, an efficiency project is considered a failure, when in reality other factors (the weather, for example) may have masked the savings by causing energy use to increase.

IPMVP helps to tackle this problem. It provides a framework for ‘good M&V’ without being too prescriptive, so M&V solutions do not have to be expensive or overly complex. Developed in the mid-1990s by the US Department of Energy, IPMVP is now the most widely used and recognised M&V protocol in the world. Having been developed with ESCO contracts in mind, it defines a common sense approach to M&V, and is perfectly placed to help improve the credibility and attractiveness of energy efficiency projects. IPMVP is managed worldwide by EVO (Efficiency Valuation Organisation), and much more information is available on their website.

Good and Bad M&V

The most common approach to determining energy savings is to compare two periods before and after implementation of the ECM (Energy Conservation Measure). This generates a saving number, but this is only valid if the two periods happen to be directly comparable. In many cases they may not be, so the savings figure is meaningless.

We believe this practice is giving energy efficiency (EE) in general a bad name. EE should be recognised as a source of clean energy in its own right, but while there is a question mark over the validity of the savings assessment, this will not be achieved.

IPMVP tells us that:

However:

This analysis is crucial. A simple comparison of averages may tell you the cost reduction over the period you are looking at, but an energy saving is actually the avoided energy use. So the saving tells you how much less you have used than you would have without implementing the ECM. Consequently, IPMVP’s governing equation is:

Savings reported for any period = baseline period energy - reporting period energy ± adjustments

Example Good M&V

The ‘adjustments’ part is where the analysis comes in. To give a fair evaluation, we need to consider the factors that drive energy use on the site we are analysing. For example, a common factor is the weather, which governs how hard heating or cooling equipment must work to provide a comfortable indoor temperature. Accounting for these ‘externalities’ using a regression analysis is often a key part of an IPMVP-adherent savings analysis, or alternatively we may ‘zoom in’ and look closely at the ECM itself rather than the whole site. We also have to build an understanding of how the site uses energy, so we can account for any sudden changes in energy use and ensure these do not affect our evaluation.

This kind of analysis allows us to isolate the effect of your ECM and quantify how much it is saving. Importantly, the analysis and modelling should be done before the ECM is implemented, making M&V part of the project from the outset. So an IPMVP analysis comes in two parts:

  1. The M&V Plan. The site is analysed in detail, and the plan commits to a methodology for determining the savings from the proposed ECM.
  2. The savings report. A final analysis quantifies the avoided energy use, in line with IPMVP’s governing equation.

Any M&V strategy that does not have these two ingredients could be open to ambiguity, or worse, abuse, as the savings analysis will simply be thrown together after ECM implementation.

Large scale ESCO programmes are increasingly specifying IPMVP as the required M&V protocol.

We are experienced in producing M&V Plans and savings reports, and have been using the principles of IPMVP for several years. We have seven of only a handful of CMVPs (qualified IPMVP practitioners) in the UK, along with a team of professional Energy Analysts dedicated to IPMVP-guided M&V analysis.