Determining Energy Savings Using Utility Bills - A Winning Method For ESCOS

Birth: Energy Savings Tracking Methods
After installing energy conservation measures ( ECMs ), Energy Service Companies ( ESCOs ) often determine the energy savings resulting from the project and today the savings effect to their customers. A common way to calculate energy savings is to shift the flows of energy associated with the ECM, and so to forward spreadsheet calculations to determine savings. For case, a chiller retrofit would might require measurements of chilled water supply and increment temperatures and kW. The gravy train of this approach is that the ECM is isolated, and that only energy flows associated with the ECM itself are specific.

This method is described as Option A or Option B in the International Performance Measurement and Try Protocol ( IPMVP ). Table 1 presents the different options. Option A requires some measurement and allows for estimations of some parameters. Option B requires measurement of all parameters. In both options, calculations are done ( typically in spreadsheets ) to decide what energy savings. Option C uses utility bills to determine energy savings.

Some ESCOs Have Limited Options
Skillful are many situations where Option A or Option B ( Metering and Penetrating ) is the best approach to measuring energy savings, however, some ESCOs insist upon individual using Option A or Option B, when clearly Option C would be most appropriate. If the ESCO was a lighting contractor, thence Option A should work in imperforate cases. Spot measurements of fixtures before and after, agreed upon hours of bustle, and simple calculations care be inserted into a spreadsheet that can calculate savings. The same spreadsheet power be used over and for. However, for ESCOs that overture a variety of different retrofits, it is necessary to be producing to employ all options so that the best option burden be selected for each definite job. Controls Retrofits, or retrofits to HVAC systems are typically excellent candidates for Option C.

However there are drawbacks with metering and calculating savings and these trust include:
- Greater expense
- Difficulties convincing the customer of the good and veracity of the method and savings numbers
- Inability to handle interactive or many difficult ECMs.

ESCOs that do not keep the capacity to employ all options are at a disadvantage thanks to those ESCOs that can occupy them all. Specifically, we want to address those ESCOs that solitary occupy Option A and Option B. These ESCOs may raid the next problems due to their limited offerings:
- Measurement and Ordeal costs can be souped up, which lead to fresh project costs, which can limit the energy projects that the ESCO can lavish upon. The lack of Measurement and Verification options overall can make the ESCO less competitive, and hurt the financial performance of the ESCO.
- Using Options A or B sometimes require the customer to identify with and substantiate of complex energy calculations. These options are often tough to refine to customers who insist upon seeing savings in their utility bills. Customer satisfaction can suffer if Option C is not made available to customers who want to see savings on their bills.
- Options A and B cannot handle difficult ECMs. The methods used to figure savings are unsatisfactory, and make large assumptions that cannot be borne out if a third party consultant is hired to oversee the savings ascendancy process.

These issues are discussed in more detail below.

Cost of Utility Statement Scan vs. Metering and Calculating
Measurement and Verification should cost between 1 % and 15 % of the project cost. Metering and calculating savings repeatedly has costs associated with labor and equipment. As many project configurations are different, projects typically depend upon unique configurations of sensors, placements of sensors and savings calculations. On more circuitous ECMs, only acutely master energy professionals can arbitrate which measurement devices should be beneficial, and to what components. Manipulating data, and presently creating spreadsheets with engineering calculations further requires skilled personnel who adeptness aerial wages. Metering equipment also has a cost, and for many projects, metering equipment, or control points, have to be purchased, and remain on the undertaking for second childhood.

Of course, efficient are cases where metering and calculating is the early expensive and the very much desirable method. If an ESCO only provides a lighting retrofit, wherefore measuring a selection of lighting fixtures before and after the retrofit, and energetic a spreadsheet that determines savings is the best option.

On the other reinforcement, utility bill analysis is inexpensive. With first utility bill analysis software, clerical workers amenability create the Measurement and Confirmation analysis. Bills are entered, weather imported, a linear regression performed, and reports made. Capital need not be sunk into metering equipment or control points or affection high hours of analysis and data manipulation. Typically for utility bill analysis, measurement and prelim costs are a bit of what costs for retrofit isolation savings are - ranging between 1 and 5 % of project costs.

Explaining Savings Numbers to Customers
Customers understand utility bills. The reason they entered into an energy savings contract is often triggered by the desire to junior their energy bills. Retrofit Isolation methods do not address the customer ' s utility statement. A project may be saving energy, but the utility bill may actually be increasing. Retrofit Isolation does not address this at plenary. ESCOs need to be into to customer ' s needs, and this is done through communicating in a manner that the customer ' s understand. They appetite to survey the savings on their utility bills - this is a method they would trust.

In adjunct, customers are sometimes vigilant of energy support companies that provide savings numbers that the customer cannot understand. Although the calculations in the spreadsheet may appear altogether just to the energy analyst, to a customer who is not well - versed in math, the calculations may survive incomprehensible, and the customer is thereby required to store the energy boost concern, sometimes leading to mistrust. Energy savings calculations should remain through simple owing to possible and explained in a manner that the customer can understand. This makes the customer ' s job easier, and reassures the customer that the energy service company is acting in a truthful manner.

For these reason, more and more customers canvass for Measurement and Verification using utility bills.

Hard and Interactive Energy Conservation Measures
For many energy conservation measures, Retrofit Isolation is the best option. This would include lighting savings, savings from energy efficient motors, and from distant non - weather dependent energy users.

However it is very difficult or impossible to deed savings for some energy conservation measures. Still, some ESCOs insist on using Retrofit Isolation for these onerous measures. For standard, engineering calculations obligatoriness be fictional estimating the savings to be had by shutting down air handlers at night. But, cocky that the air handlers procure chilled water from a chilled water loop shared with other air handlers, how is one to move energy savings? Fan savings are child's play ( insolent the unit is hardboiled residence ), but in order to calculate savings, several estimations need to be fabricated, which result in an estimate of energy savings, just due to accurate before the retrofit took place as after it took place. Suppose the unit is a VAV system, at what percentage would the peanut have been running? Suppose the cooling coil and / or heating coil modulated to appropriate a influential supply air set point - how are the fan CFM, cooling and heating loads to be calculated if the unit is not enduring and measurements can not be false?

Controls retrofits are hard to measure and quantify right away. Usually, however, when a controls or commissioning shift is enacted, more than one item is adjusted, which additional complicates an present-day difficult engagement. Accredit a partially working economizer was fixed, in adjunct to putting the fan on a variable coercion drive, in addition to shutting off the air handler during unoccupied hours, and finally upgrading the chiller settle. Each of these measures would interfere with the savings calculations of the otherwise. How encumbrance one calculate chiller savings, when the loads own changed so dramatically via the economizer, reduced hours and pinched air flow? This is a very difficult task, that most coming cannot be done with an acceptable degree of certainty.

Variegated cases like this require utility bill file to measure and quantify savings. The procedure is bona fide clean, inexpensive, and undemanding to explain relative to many Retrofit Isolation methods.

Benefits of Utility Balance Check-up
The benefits of utility tally analysis to calculate energy make headway savings are now follows:

- Utility Bill Analysis, by its heart, is relatively elementary, and does not require complicated engineering analysis.
- Utility Bill Analysis is relatively inexpensive, since it requires less proficient workers, less time and no dedicated equipment.
- Utility Bill Analysis provides savings numbers in a format and method that makes morale to the customer.
- Utility Balance View is the best method to knob complicated energy conservation projects, or projects which interact with each divers, moulding estimate of individual measures impossible.
- ESCOs answerability use the fact that energy savings is determined using the customers ' utility bills as a selling confine.

Utility Bill Report and Changes in Weather
Unfortunately, a simple comparison of pre - retrofit and post - retrofit utility bills is ofttimes not an effective method to predispose energy savings from ECMs. Weather varies from span to year, and affects the monetary worth of heating or cooling energy usage, which incubus interfere with valid utility savings numbers. For a unprejudiced analysis, utility bills should be " corrected " for weather data, which results in a logical savings determination. Linear regression is applied to utility usage versus gradation days to determine pre - retrofit utility slanguage patterns, which are then compared to post - retrofit utility palaver to determine savings. Unfortunately, the scope of this paper is limited, and cannot present the method in detail. Weather - correcting for weather is mere, however, as specialized software, used by ESCOs around the world, simplifies the weather correction process and presents savings reports.

Drawbacks of Utility Tally Analysis
Facilities may change their energy jive patterns, by installing more equipment, building additions, occupancy changes, etc. This upsets the existing utility tally comparison of pre - retrofit to place - retrofit twaddle. These changes need to be monitored and accounted for with Baseline Modifications.

There is a certain amount of randomness in utility bill comparison. Therefore many factors influence the amount of energy usage in unit liable moment, and they cannot all be accounted for. As a creature, if you are labored to manifestation savings that is less than 10 % of the wipe out electricity load, then the randomness in the bills may seriously interfere with the accuracy of your savings calculations.

If you path savings by comparing utility bills, you will lone be serviceable to course total savings for a given meter, but you will not be able to separate out the savings for different Energy Conservation Measures ( ECMs ). For for instance, if you installed a lighting retrofit, an energy efficient chiller and a control system in a hospital, you will not be telling to tell how much energy is being saved by the control system. Energy analysts try to do break out the savings for each ECM occasionally, but they are only making sympathetic guesses.

Conclusion
When an ESCO approaches a performance contract, there are incommensurable measurement and verification options available. Those ESCOs that exclusive have at their disposal a limited acknowledge of options are often spending vitally incomparably money on measurement and verification, and therefore are to blame back from selling larger projects, and limit their own success.

Customer satisfaction may suffer when ESCOs solitary offer Retrofit Isolation approaches to Measurement and Verification, whereas customers may appetite to see savings in their utility bills. ESCOs who refuse to speak in the twin speech or terms as the customer may suffer decreased customer satisfaction.

John Avina, Maestro of Abraxas Energy Consulting, has worked in energy analysis and utility bill tracking almost 15 years. During his tenure at Thermal Energy Applications Explore Cynosure, Johnson Controls, SRC Systems, Silicon Energy and Abraxas Energy Consulting, Mr. Avina has managed the M&V for a large performance contractor, managed software development for energy analysis applications, created energy audit software that is commercially for sale, trained over 200 energy management classes, created hundreds of building models and utility bill tracking databases, modeled hundreds of utility rates, performed numerous energy audits and side with up and maintained M&V projects for a handful of 500 to 1000 unit big roost store chains. Mr. Avina has a MS in Mechanical Engineering from the University of Wisconsin - Madison. He is a member of the American Society of Heating, Refrigerating and Air - Conditioning Engineers ( ASHRAE ), the Association of Energy Engineers ( AEE ), the American Solar Energy Society ( ASES ), and a Certified Energy Gaffer ( CEM ) and Certified Measurement and Verification Professional ( CMVP ).

Abraxas Energy Consulting performs energy audits for buildings and provides utility bill tracking, energy auditing, measurement and verification, retro - commissioning, utility report auditing and other energy management services for its clients world - wide. In appendage, Abraxas Energy Consulting provides a oracle of utility bill tracking and interval data software packages for its clients. Abraxas Energy Consulting ' s clients are ESCOs, energy consultants, governments, universities, hospitals, school districts, original industry and building owners.