For today's building owners and managers, awareness of their energy consumption through constant monitoring can produce real results

Sophisticated tracking of your energy consumption on a monthly or at least a quarterly basis will enable you to recognize problem areas, or building changes, as they happen, before they affect your bottom line.

Professionals who manage multiple buildings and who are not monitoring energy consumption should be aware of the savings they may be leaving on the table. Tracking your buildings' costs per square foot or consumption per square foot allows you to compare your buildings' efficiencies to similar buildings. By being aware of where your energy is going, your chances of initiating a successful energy program are significantly enhanced.

Energy monitoring can become onerous. Maintaining your system's maximum efficiency is the goal, and if you are falling short, get outside help. An energy analyst can help you to determine where your efficiency should be. Analysts utilize software to enable easy monitoring of multiple buildings and produce relevant results for your review.

ESCO's (energy service companies) have known the value of energy monitoring for years. The introduction of performance contracting has focused attention on the verification of cost savings through the monitoring of energy consumption.

Normally, ESCO's will monitor the energy savings achieved due to their energy retrofit programs, and all costs are include in the performance contract. Some ESCO's deal with independent contractors to analyze savings and present these reports to their clients.

Building owners should be aware that they can request that savings be monitored directly by a third party and not through the ESCO. This can be stated in the Request for Proposal and costs to the owner can be incorporated into the performance contract.

An independent contractor should have various energy analysis programs for use and be able to recommend one to fit your needs. The information should be presented in an easy to read format with plenty of graphical representations. The end user of the reports should always be the focus of the report's presentation.

Costs for analysis should be based on the number of meters to be monitored in a facility. Be aware that costs to monitor a large office building with two energy meters will be less than a small school with many additional meters due to portables, additions, etc. Costs will also vary with the length of the monitoring period and the complexity of the report.

Some clients prefer a monthly update with a full report at year end, while others require a full report on a quarterly basis. This will depend on your building's dynamics and the energy retrofit installed.

Analysis of utility bills is one of the major methods of monitoring energy savings. Some retrofits are monitored directly through metering equipment. This method reveals how the retrofit is affecting a specific area, while the utility bill method gives an overall indication of how the energy efficiency program is affecting total building use.

For example, a reduction in lighting may be monitored through direct metering of kW and kWhr for that area. However, an increase in gas consumption may have occurred in the building to compensate for the loss of heating load in that area. This increase would be considered when savings calculations are made using the utility bill method.

Direct monitoring of systems can give more detailed information when monitoring energy use, and is often performed through the Energy Management Control system. Remember that for energy comparison, it must also have been in place during the base, or pre-retrofit year.

Any analysis of energy savings always involves a method of estimation. As technical people, we like to pin down the results exactly, but due to building dynamics this becomes highly improbable.

Any analysis will depend largely on the data you have available from the base year. I cannot stress enough how important good base year documentation is. This includes such things as equipment runtimes, occupancy, and building envelope. Once an energy savings program is in place, there is usually a lot of system data available, but nothing to compare it to from the pre-retrofit period.

Once commissioning and fine tuning has been completed, the objective of energy monitoring is to ensure the savings achieved are maintained as these should not vary greatly from year to year. This, of course, will depend on your maintenance schedule, equipment upkeep and other building changes.

Understand your performance contract. Some savings are based on rate schedules in effect during the base year and/or on planned increases (%/year) in utility costs. If utlity cost increases are less than planned, the savings will be somewhat inflated. Either method is acceptable; just be aware of what it signifies.

Most methods of monitoring savings through utility bill analysis deal with development of a base year (pre-retrofit year) building model.

To develop a model of how your building reacts to weather, the weather severity (in heating or cooling degree days) is plotted vs. each month's energy consumption. Take, for example, the model of a typical Canadian building's gas consumption.

This model shows how the building reacts to the weather. We can therefore predict the energy consumption given any weather severity.

For example, at 500 HDD/month, this building would consume approximately 600 GJ of gas. This model can also be adapted to electrical consumption and Cooling degree days, and a variation can be used to plot maximum monthly demand and weather severity.

More sophisticated modeling can also take into account other factors that may have an impact on building consumption, such as occupancy (for hotels) or production (for manufacturers).

This model of the pre-retrofit building can then be carried forward to produce predicted consumption for each month in the current year. These calculated values are often referred to as the "adjusted baseline" or predicted or target usage.

We can now compare the current monthly usage to the predicted usage to determine consumption savings. By applying the complete rate schedule to each usage, we can compare costs and thereby determine cost savings.

Of course, not all energy meters are related to weather severity or building occupancy. In these cases, the usage is predicted by taking the montly base year energy consumption and adjusting it to reflect the current billing period length.

Say, for example, our building consumed 300,000 kWhr in 30 days in the base year. In the current year, our billing period is now 28 days and we would expect to use 280,000 kWhr. We can compare this value to the actual use to determine the savings achieved.

The long-term success of energy management projects has been limited by the ability of project players to agree upon a method of calculating energy savings. Building owners/operators are generally less experienced in negotiating performance contracts than Energy Service Companies (ESCO's), and thus susceptible to onerous clauses. Building owners/operators need to become more aware of the issues and obtain tools to provide them with the knowledge needed to enter into a contract that represents their interests.

The North American Energy Measurement and Verification Protocol

An International Protocol has now been developed to provide guidance in establishing monitoring and verification procedures for performance contracts. The North American Energy Measurement and Verification protocol (NEMVP) - (soon to be changed to Building Measurement and Verification (M&V) Protocol to reflect it¹s new international use). The Protocol provides an overview of current techniques available for verifying aspects of third-party financed energy projects. It may also be used by building owners/operators to assess and improve facility performance.

This Protocol should be of great interest to Canadian building owners, manager, operators and ESCO's involved with performance contracts. The establishment of a standard consensus on measurement and verification will provide greater and more reliable savings. It is believed that the financial markets will respond by developing new methods and lower costs of financing for energy efficiency projects.

The participating organizations in the NEMVP cover from Canada (CAESCO) to Mexico and include federal energy departments, ESCO's, energy associations, utilities, and financial institutions. It has been closely coordinated with the efforts of the ASHRAE Guideline GPC 14 (Measurement of Energy and Demand Savings). This parallel ASHRAE document is currently under construction, but will contain more technical details on how to instrument, measure, and analyze energy savings.

This 100 page document (Protocol) describes the best practical methodology for the sequence of steps that should be followed to ensure reliable energy efficiency installations. In general, it provides guidance in establishing M&V procedures for performance contracts. The following represents some of the material covered in the Protocol:
i) types of performance contracts
ii) procuring performance contracts
iii) various options for M&V based on the type of retrofit completed - provides actual examples.
iv) defining the appropriate level of M&V
v) M&V professionals - third party monitoring

It is likely that Natural Resources Canada (NRCAN) - Federal Building Initiative (FBI) program will be referencing the Protocol in their model contract documents. These model documents are available to government departments (and the public) who are interested in performance contracting. British Columbia also appears likely to use the Protocol in 900 provincial and public buildings.

The Building Measurement and Verification Protocol home page (http://www.ipmvp.org/) is a great place for building owners/operators to get more information. You can also download a copy of the NEMVP from here. The site is in the early stages of development, so keep checking back.

References:
North American Energy Measurement & Verification Protocol, Version 1.0, March 1996

Main Menu | REA Information | Energy Analysis | Contact Us