Energy Audits Energy Usage | NaturalGasEfficiency.org

Energy Usage

Where is Energy Used in the Facility?

This is the most important TECHNICAL step in the Energy Management Program. If major mistakes are made here, the entire focus of the Program will be wrong. However, don’t worry about getting caught-up in the small details at this point. Refinements and adjustments will be made as more knowledge is gained from working the Program. The main idea here is, for example ….don’t expect to save 50% of the facility’s electric load by making changes to the lighting system if it only represents 10% of the total electric cost.

Water Usage?

Water cost has become as, and in some cases, more important than electric and natural gas. The same Team that is assigned to manage energy is often also assigned water management responsibility. Energy TechPro does not currently contain information on water management. However, the same general procedures below can be easily adapted for water management.

How to Get Started

The Steps

Gather Energy Bills
Identify Major Energy Users (walk-thru)
Determine Load Factors for Equipment (energy usage)
Create Equipment Spreadsheets/Databases
Perform Analysis to Identify Users and Benchmark to actual utility bills
Determine What Can Be Done (Options)
Create the Action Plan and Implement Measures

Some Details

Energy Bills

Start by collecting at least 12 months of energy bills; 24 months or more is better if the facility has been growing or changing usage patterns. It is important to have the actual bills, NOT just dollars, as the units/volumes are needed. This information must be collected and organized for EVERY meter in the facility.

Create a spreadsheet and graph as much detail as is available on the bills. For natural gas bills, the minimum information should be CCF or MCF of usage, unit cost and monthly service charge. For electricity, the minimum information should be kWh, kW Demand, unit cost for kWh and KW Demand, monthly service charge, Power Factor or other penalties, kWh On-Peak and kWh Off-Peak (assuming a time-of-day tariff). Fine details, such as 15 minute electrical usage data is generally available from the electric utility in spreadsheet format for larger electric meters that have that capability. Although this level of detail may be needed later, it’s generally not needed to get started.

This may also be a good time to get to know your utility reps, if you don’t already know them. Many utilities have specific people assigned to accounts (end-users), but the account may not know who they are unless they take the effort to find out. If you find that you have a rep, that person could be a valuable asset to your Energy Management Team.

After the data is graphed in the spreadsheet, look for patterns. Facilities that are greatly affected by the weather should show clear seasonal changes. Facilities that use most of their energy in processes should see patterns that reflect production schedules. This information becomes your base-line for measuring future success.

Identify Major Energy Using Equipment

Many maintenance departments keep very good records about equipment and capacities. However, in other facilities, gathering this detail could be an extremely time consuming, but necessary, part of the Program.

For natural gas equipment, gather BTU INPUT per Hour Ratings. In the case of variable-fire equipment, determine the range of operation (such as minimum firing rate in BTUs per hour). If you must estimate, seeEstimating BTU Ratings for assistance.

For electric equipment, gather the Horse Power and/or Amp and Voltage Rating. If the equipment includes multiple stages or a variable speed drive, note this information. If for some reason a tag cannot be located, use an amp meter to take a reading while the equipment is running at typical conditions. (Note: Be sure to follow proper electrical safety and union regulations for doing this kind of work.)

Determine Load Factor

Determine the hours of operation for each kind of equipment. This is primarily applicable to process equipment that may not run during all production hours and major HVAC equipment that may not run a typical usage pattern – such as a large make-up-air unit that only runs during a certain process that requires heavy ventilation.

Equipment Spreadsheet

Create another spreadsheet for equipment, or use the a separate tab on the same spreadsheet used to log energy usage. If you cannot get all the data about every piece of equipment, log what you have and fill in the rest later. It may not be critical to have every number for large facilities. If good, complete information can be gathered for 70 – 80% of the equipment, that’s a very good start.

Create a separate spreadsheet or tab for electric equipment, gas process equipment, and gas space heating equipment. Organize the information according to building and then meter. The spreadsheet should include the following columns:

Electric:

Equipment Name/Description
Location
Amps
Voltage
Calculated kW (Amps x Volts /1,000)
Hours per Month On
Estimated Load Factor (if applicable for equipment that shuts off or uses less energy under certain conditions during parts of the ‘On Hours’)
Calculated Estimated Monthly Energy Usage = kW x Hours per Month x Load Factor
Sum the totals and compare to the actual monthly electric bill; the kW connected should be higher than the actual Demand Charge, but if the kWh total is substantially different, than adjust the Hours or Load Factor until estimates are reasonably close to actuals (be sure to include lighting and consider seasonal variations from cooling equipment)

Natural Gas Process Equipment:

Equipment Name/Description
Location
BTUs per Hour name plate (total including ALL burners)
Hours per Month On
Estimated Load Factor (if applicable for equipment that shuts off or uses less energy under certain conditions during parts of the ‘On Hours’)
Calculated Estimated Monthly Energy Usage = BTUs/1,000,000 x Hours per Month x Load Factor = MCF (use 100,000 for CCF)
Sum the totals and compare to the SUMMER gas bills (ie: the summer should include process gas usage only)

Natural Gas Space Heating Equipment: (Grouped according to equipment that serves a common space and/or similar operating/temperature pattern)

Equipment Name/Description
Location
BTUs per Hour name plate
Estimated Load Factor (ie: 100% for equipment always on, and 33% for equipment that only is one for one shift – like door heaters)
Sum the totals (See Energy Calculations for information about how to use these totals)

Data Analysis to Identify Major Users

With all of the above information gathered as completely as it can be reasonably assembled, sort the data, or otherwise evaluate what appears to be the biggest non-HVAC users. For HVAC information see Space Heating

What Can Be Done?

Create a matrix that includes each major energy user, the options that should be considered for each user and probable cost and benefits. Equipment may be grouped according to site, building, department, profit center, production line, or whatever categorization makes sense for the corporation.

At first, do this roughly based on your knowledge, content within Energy TechPro and other resources. ESTIMATE a priority and assign to each user. In some cases, the major users won’t have many opportunities for savings, or the options may be very expensive. Smaller users may have more options that can be accomplished for less cost, but the savings may not be worth the effort.

Starting with the ESTIMATED priorities, do the real investigative work and refine the matrix. This process should be expected to take several months for large facilities. Identify options, costs, savings potentials and payback periods. Impact on production, environmental and safety issues. Future growth/needs, corporate priorities and other factors that can be measured in terms of relative value. Build all of these factors into the Matrix.

Top priority in the Matrix may go to Measures with the lowest cost, the quickest payback or meet other corporate goals such as equipment upgrades, safety or environmental improvement, or other non-energy benefits.

After the Matrix is refined and the Energy Management Team agrees the most reasonable priorities have been established, its time to write the Action Plan.

The Action Plan

The Energy Management Action Plan can be as simple or complex as is required to obtain the financial approvals to spend the money and do the work. If the ‘right’ people are on the Energy Management Team, the Action Plan may be the same as the completed Matrix. Simply start at the top of the Matrix and work down the list as far as the available funding will go. Then next year, re-evaluate the Matrix to make sure it’s still correct, and take the next Measures on the list; repeat each year.

Source: Text Bob Fegan 1/2009