Lean Six-Sigma Approach to Industrial Energy Assessment

Abiodun Babalola*

Department of Mechanical Engineering, University of Louisiana at Lafayette, USA

*Corresponding author: University of Louisiana at Lafayette , P.O. Box 44170, Lafayette,

LA 70504. Tel.: (01) 337-326-0075. E-mail address: ababalola2001@yahoo.com.

Abstract

With recent hikes in prices of energy and electricity, companies are seeking avenues to

reduce the cost of goods and services in order to remain competitive. Energy assessment is an

important tool for companies to uncover the areas energy cost could be saved. This paper

outlines lean six-sigma approach to conducting an industrial energy assessment in a facility.

This approach is based on the internal energy assessment within an industry. This paper

focus on five major steps: define measure, analyze, improve and control. It is worthy to note

that for a company to conduct internal energy assessment, it must have an energy

management team in place. The energy management team is to comprise of top management,

energy management champion, energy management team.

This paper provides a lean six-sigma approach to conduct energy assessment in order to

identify areas to reduce waste in energy, productivity and also a reduction in carbon

footprint. This guideline can be used as part of the procedure for developing an energy

management plan.

Keywords: Energy assessment, lean six-sigma, energy efficiency, energy management

1 Introduction

Increasing energy demand and cost has necessitated research into ways of reducing

energy consumption and waste. Industries are faced with an increasing cost of energy and

this has been transmitted to the cost of operation. In the past, companies do consider energy

cost as a normal operating cost which is been considered as normal cost of doing business.

Now everyone is being sensitive to energy cost and ways of reducing it.

In the recent past, companies and organizations have all been under great operational and

environmental pressure. Being economically competitive in the global market and meeting

increasing environmental standards to reduce air and water pollution have been the major

driving factor in most of the recent operational cost and capital cost investment decision for

organizations [1]. Most companies and organization depend on energy for their operation and

this can be a major operational cost to the company, whichever line of business they may be

engaged in. Environmental cost can also be attributed to energy by the emission of

greenhouse gases which deplete the ozone layer, cause acid rain and invariably cause climate

change.

In order to improve organization profitability and environmental sustainability, it is

essential to improve energy conservation and efficiency. This is the simplest way to

minimize emission of greenhouse gas and other air pollutant that causes acid rain [2]. Rising

energy prices and increasing awareness of the environmental problems coincident with

energy use have highlighted the importance of research that investigates the economic

efficiency of energy production and consumption.

Energy management is a tool that helps companies to meet these objectives. Energy

management is described as a standardized way of managing energy [3]. Energy

management has been identified as business management which possesses a framework for

encouraging companies, suppliers and customers to control their energy in a better way, and

thus they can promote energy efficiency through supply chain. For successful

implementation of energy management systems (EMS) there is the need of top

management’s involvement and leadership. An effective energy management commences

with an assessment of the energy systems in the facility [4]. This results in cost savings and

protection of the environment as proposed in the recommendation of the energy assessment

report.

Energy efficiency activities are those sets of activities embarked upon by a company or

industry in order to reduce energy waste. Asides from the reduction in energy waste, energy

efficiency reduces greenhouse gas emission by decreasing energy consumption and peak

demand, thereby delaying or avoiding capacity upgrades [5]. Energy efficiency is enhanced

when an economizer is installed in a boiler in order to reduce the energy required to convert

water into steam. Energy efficiency is improved when a photo sensor or occupancy sensor is

installed to control the switching on and off of the lighting when it is daylight or night and

when there is no occupant in a room

Six-sigma is a well-established approach that seeks to identify and eliminate defects,

mistakes or failures in processes or systems by focusing on those process performance

characteristics that are of critical importance to customers [12]. The main focus of six-sigma

is to reduce potential variability from processes and products by using a continuous

improvement methodology [13]. This methodology employs define, measure, analyze,

improve and control phases. This is known as DMAIC (‘Duh-MAY-ick’) methodology and

is employed in existing processes or products.

Lean manufacturing is the elimination of waste which forms the core of the Toyota

Production System [14]. Waste elimination is one of the most effective ways to increase the

profitability of any business [15]. During operation in a facility, process is either value added

or non-value added. There are seven wastes identified by lean, which are: (1) overproduction,

(2) large inventory, (3) excess motion, (4) waiting, (5) transportation, (6) over-processing,

and (7) defects. All the identified wastes contribute to an increase in the consumption of

energy in a facility. By overproducing products and having large inventory, energy is used up

in production and in some instance used to prevent the excess inventory from perishing (if

perishable). Excessive motion and transportation increases the fuel consumed by the forklift

or leaving the machine on to get the product to another product line. Energy that can be used

to produce one product will be used for rework and over processing. All these are energy

waste and result in an increased energy cost.

Lean six-sigma is the integration of lean manufacturing and six-sigma in a process. The

integration of lean and six-sigma is important because lean alone cannot bring process under

control and six-sigma alone cannot eliminate waste from a process [16]. Lean six-sigma

drives the elimination of defects and waste from a systematic analysis of processes based on

facts [17].

This paper focuses on the use of lean six-sigma approach to conduct industrial energy

assessment. It focuses on the use of internal energy management team to conduct energy

assessment as the employees assigned to the team know that it is part of their job

responsibilities. The flow chart for the lean six-sigma approach is shown in Figure 1 Energy

Assessment Flow Chartand the major steps discussed in the following sections are: (1) Define

team and level of assessment, (2) Measure the facility energy use, (3) Analyze energy data,

(4) Improve and recommend, and (5) Control.

Figure 1 Energy Assessment Flow Chart

2 Define Team and Level of Assessment

In conducting an effective and efficient industrial energy assessment, the first thing is to

define the team and the level of assessment. This is the planning stage of the energy

assessment and lots of hours should be spent at this level to ensure an effective and efficient

assessment. This is important as this will form the yardstick for measuring the success or

failure of the energy assessment. The flowchart for the define stage is shown inError!

Reference source not found.. The energy assessment team should consist of five to seven

people. This team can further be subdivided into the basic energy consuming equipment in

the facility. Examples include; lighting team, motor driven system team, HVAC team, infra-

red survey team and air compressed system team.

2.1 Create Energy Assessment Team

The energy assessment team is needed in performing all the activities involved in the

energy assessment. These activities include energy data collection, analyzing of energy data,

Define team and

level of assessment

Control

Improve and

recommend

Measure facility

energy use

Analyze energy

data

plant survey. The size of the team is dependent on the level and scope of the energy

assessment. The size of the company to be assessed could also be a determining factor. The

energy assessment team can be drawn from a cross functional group. The production and

maintenance staffs that are familiar with the facility [4] can also be part of the team. This will

allow for varying skills and experience. An effective energy assessment team may take many

forms [18]:

A stand-alone group, or be distributed among existing job functions

Many people, just a few, or a single individual

Entirely internal, or make extensive use of consultants and contractors.

Figure 2 Define Team and Level of Assessment Flowchart

The team should be subdivided according to the various energy systems to be assessed.

Examples are lighting team, HVAC team, air compressor team, motor driven system team

and infra-red survey team. The responsibilities of the energy management assessment team

are; (1) Conduct energy assessment audit, (2) Identify the sources of energy procurement, (3)

Identify activities, equipment and human activity which affect the energy consumption and

contribute to CO2 emission and (4) Identify and prioritize for opportunities for improvement.

Create Energy

Assessment Team

Lighting

Team

Motor Driven

System Team

Infra-red

Survey Team

HVAC

Team

Air Compressed

System Team

Train Team

Pre-Assessment

Data Collection

Define Level and

Scope of Assessment

Start-up Meeting

Facility Survey

Team member roles and responsibilities should be documented using the assignment matrix.

This gives the team members a clear understanding of their responsibilities in conducting the

energy assessment. In assigning responsibilities to the team members, it is essential to assign

the right person to the right task.

It is important to have the commitment of the higher management. The higher

management should have a representative in the energy management team. This

representative is called an energy management champion whose responsibilities are; (1)

Direct activities of the energy management team as well as the organization as a whole, (2)

Report to top management for the energy management system improvement, (3) Assign

responsibility for energy management systems in organization and cooperate within

organization, and (4) Monitor implementation and make sure for continuous improvement.

The top management serves as a source of the voice of customer (VOC). A one on one

interview should be conducted with the energy champion to figure out the level of

management’s commitment to energy efficiency. A summary of the energy management

team responsibilities are summarized in Table 1.

Table 1 Energy Management Team Responsibilities

Energy Management Team Responsibilities

Top Management

Allocating Resources.

Defining and creating the energy policy.

Energy Management Champion Directing activities of the team.

Assign responsibilities to the energy management team.

Monitor implementation of recommendations.

Reporting improvement to top management.

Energy Manager Performs training for the energy management team.

Oversees the activities of the energy management team.

Energy Management Team Conduct energy assessment.

Identify sources of energy consumption

2.2 Train Team

The energy assessment team should be trained on how to assess the various forms of

energy systems within the facilities. This is where the role of the energy manager comes in.

As it is expected, the energy manager must be knowledgeable of what energy assessment

entails, must be fully informed of the technicality involved, and must understand the impact

of a successful assessment to the goals, growth and development of his company. These

trainings should include safety procedure while conducting the assessment, how to conduct

leak test, how to measure with basic assessment tools like the lux meter, ammeter, infra-red

cameras etc. Some simple tools needed for a successful energy assessment are listed below:

Lux-meter: The lux-meter is a simple hand held tool used to measure light

illumination levels during energy assessment. This instrument measures in foot-

candles and the value is compared with the illumination levels specified by the

Illuminating Engineering Society (IES). This comparison allows the team to make

recommendation like reducing the number of lighting, replacing lamps with efficient

ones.

Thermometer: This tool is used to determine the temperature of offices, working

areas and other equipment within the facility. In measuring temperature, the auditor is

able to determine the quantity of energy and lost in different ways. More often, air,

gas and surface temperature are measurement carried out in energy audit. Different

types of temperature tools can be used, the common being thermocouple is used

because of its efficiency in providing a more adequate range of 392 degrees

Fahrenheit to 272 degree Fahrenheit and a high reading accuracy.

Wattmeter: This tool measures voltage and current using a clip-on current

transformer. A typical wattmeter is capable of measuring 600volts systems up to a

maximum of current of 200 amps. This tool is often most effective in performing

measurement on a balance 3-phase power system even though it is primarily intended

for measuring in a single phase power systems. It captures the maximum current

values and its best utilized by measuring values using shorter intervals.

Combustion analyzer: This is an electronic instrument used in measuring the

combustion efficiency of furnace, boiler and other equipment with a fuel combustion

system. Its major aim is to ensure that the optimum air to fuel ratio is used. The

efficiency of’ the combustion analysis is derived by different analysis which includes

stack temperature and the composition of stack gas. Its use cuts across many

industries using combustion equipment. Its main function in ensuring efficiency is

dependent on its level of air ratio of optimization to fuel.

Tape measure: Tape measure is used to measure the dimension of ceilings, walls,

windows and generally the distance between two points on equipment. For example,

it can be used to measure the length of the hot water outlet pipe on a steam boiler in

order to know the quantity of lagging material it would require.

2.3 Pre-Assessment Data Collection

Information of the facility should be collected and analyzed before survey of the facility.

This information is to give the team the current state of energy health of the facility. Sources

of data include electricity bill, water bill, and natural gas bill, number of lighting fixtures,

number of HVAC units, Chillers, cooling towers, compressors, and productivity data. Pre-

assessment forms as shown in Table 2 can be used to collect basic information about the

facility to be assessed. The utility bills should be between 12 months to 36 months.

The utility bills should be analyzed using a statistical tool like run-chart or performance

metrics to get a visual understanding of the energy consumption profile of the company as

shown in Figure 3. The figure shows a twelve months energy consumption pattern, in July,

2010, the energy use was the highest. July can serve as a for cost reduction by analyzing all

the energy consuming equipment used. The Pareto chart is another important six-sigma tool

which provides information on the few energy systems consuming the highest energy as

illustrated in Figure 4. From the figure, it can be observed that the boiler and compressed air

system energy cost is about 80% of the total energy cost. This shows a high potential for

energy savings from the assessment of these equipment. The analyzed bill should also be

verified to ensure that the company is billed at the approved commercial or industrial rate. It

is also important to compare current company’s utility rate with other utility companies to

determine the cheapest rate.

Table 2 Pre-Assessment Data Sheet

Assessment Date: 10/01/2013

Company Name: ABC Chemical Company

Company Address: 3217 US 90,Broussard, LA70518

PPE for Assessment Steel toe, hard hat, safety glasses

Contact Name:

Name: Smith Jack

Contact Title:

Plant Manager

Email:sjack@abcchem.com

Phone:

337-326-0137

SIC: 3225 No of Employees: 320 Plant Area: 650,000 sq.ft.

Gross Annual Sales:

$ 120 million

Annual Production:

900,000 Tons

Principle Product:

Chemicals

Total HP

Capacity: 1700

Largest Motor HP: 450 Power Factor: 2.0

Operation Hours Days/Week Weeks/Year

Shift 1 8 5 50

Shift 2 8 5 50

Production Lighting Hours 24 7 52

Office Hours 10 5 50

Office Lighting Hours 10 5 50

Figure 3 Energy Consumption Performance Metrics

Figure 4 Pareto Chart of Energy Cost by Energy System

Utility bills have three basic charges and these are:

Customer Charge: this is a flat fee charged to the customer irrespective of the energy

use. This charge ranges from zero to $25 for residential customers to thousands of

dollars for commercial and industrial customers. The energy assessment team should

explore different utility providers to determine the cost effective charge as this char

varies from one utility provider to the other.

Energy Charge: energy charge measured in dollars per kilowatt-hour ($/kWh) of

electricity or dollars per cubic foot ($/ft3) is the charge for energy use. This is

dependent on the amount of electricity or the quantity of gas used for the month. The

charge varies with seasons and the cost of generating electricity or the price of gas.

500

600

700

800

900

1,000

Oct-09 Jan-10 May-10 Aug-10 Nov-10

Ele

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cal E

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rgy

Usa

age

(kW

h)

Tho

usa

nd

s

Energy Use UCL LCL Mean

0

20

40

60

80

100

120

$-

$20.00

$40.00

$60.00

$80.00

$100.00

$120.00

Pe

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nta

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Ene

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$/y

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Energy System

Demand Charge: This charge is measured with the demand meter and usually applied

to commercial and industrial customers. The demand meter measures the minimum

demand and maximum demand in any 15, 30, or 60 minutes time increment in the

billing period.

Some basic six-sigma tools like performance metrics, histogram, pie-chart, and run chart

can aid in the analysis of these data. Abnormal spikes in the chart should raise concern to the

team on the possibility of abnormal energy charge or usage. The plant energy profiler (PEP)

an online software tool provided by DOE can be used by the energy management team to

profile the facility’s energy use and consumption [8]. The data gathered are input into the

software and a report is generated to show the details of purchased energy, consumed energy

and possible areas of energy cost savings. This will provide the current state of the facility

and aid the team to know where to focus their attention during the facility assessment and

also the extent or level of the assessment.

2.4 Facility Survey

During the facility survey, the energy management team walks the entire facility to list

the building envelope (roof, windows, etc.), the heating, ventilation, and air conditioning

equipment (HVAC), the lighting equipment, boiler, conveyors other facility specific

equipment. A plant survey identifies:

Areas of energy waste,

Areas that require repair or maintenance work, and

Areas that require capital investment to improve energy efficiency.

With a facility survey, the energy management team would have better understanding of

how each facility is used, operated and the level of deterioration. This survey will identify

activities that require kaizen, 5S projects that can be carried out in order to reduce energy

consumption thereby reducing cost. For example on a facility survey of one of the sites

visited, the condenser (Figure 5) was discovered to be covered with dust. In recommending

this type of observation, the energy management team can recommend a 5S project for the

condensers in the facility. 5S is a lean tool which is the foundation for continuous

improvement and cost reduction through employee involvement [19]

The facility survey also enables the team to collect voice of employee (VOE). Collecting

VOE enable the team to identify the likely areas of energy cost savings since the employees

are the ones using the energy system. The VOC can be collected by face to face interviews

and surveys.

Figure 5 Example of finding from a facility survey

2.5 Define the Level of Assessment

After all the steps listed above have been completed, then the team would be able to

define the level of assessment. There is no agreed definition for the types of energy

assessment in an industry. Different bodies classify energy assessment based on different

factors such as; size, function and operations in the industry, level of detail needed and scope

of the energy assessment. CIPEC [6] identifies two types of energy assessment based on the

level of details needed. These are:

1. Macro Energy Assessment: with this type of energy assessment, the entire facility is

assessed in an effort to identify energy saving opportunities. It involves a broad

physical scope and less detail.

2. Micro Energy Assessment: this type of energy assessment is energy system specific,

it usually start with the macro energy assessment. For example, a boiler identified for

possible energy saving opportunity in the macro audit is further analyzed. This type

of energy assessment is of less scope and broad details.

2.5.1 Create an Energy Assessment Plan

The energy manager is responsible for creating the energy assessment plan with input

from the team. This is a document which outlines the approach and strategy for carrying out

the energy assessment. The energy assessment plan ensures that the energy assessment is in

consistent with what it was intended to achieve and serves a guide for the energy

management team to ensure consistency, effectiveness and completeness in use of allocated

resources. The energy assessment plan should provide the following [6]:

The energy assessment charter and scope,

Where, when and duration of the energy assessment,

High priority activities of the energy assessment and timeline to completion,

Names of the energy management team conducting the energy audit, and

Energy audit report format, contents, deadline for completion and circulation

2.5.2 Develop Energy Assessment Charter and Scope

The energy assessment charter is the most important output of the define phase. It

summarizes the main focus of the assessment and the time frame for the completion of

assessment. In developing the scope of the assessment, the persons involved are considered.

In most cases, it should be decided early if carrying out the assessment will involve working

with in-house expertise alongside the external energy auditor. The internal auditor needs to

be part of the process from the beginning even though the bulk of the assessment procedure

is coordinated by the energy manager who should be independent of any bias in order to

achieve a credible result. Also of consideration is the content of the assessment which will in

most case refer to the energy systems to be assessed, as well as the reporting, format of

findings reporting, circulation of reports. In all of these, the time frame for completion is

highly crucial and must be stated. In summary, the details involved in the assessment define

the scope.

In order to effectively define the energy assessment scope, Plant Energy Profiler (PEP)

can be used. The PEP is an online or offline software provided by DOE that can be used by

the energy manager to quantify energy purchase and use in a facility. It also helps to identify

energy cost savings potentials. Energy managers can download the software from the DOE

website.

2.6 Start-up Meeting

Once the scope of assessment has been established, the next step is the start-up meeting.

This meeting informs all stakeholders involved in energy assessment of the procedure

involved in in terms of manpower, technicality which will include instrumentation and the

expected outcome of the assessment. It will also allow for specific role identification and

equally give room to obtaining other needed information on the assessment. In most cases,

the start-up meeting gives information such as: (1) the need for the energy assessment, (2)

Those involved in the assessment, (3) resources available for the assessment, (4) duration of

the assessment, and (5) expected results and their effect on the energy system or plant. The

meeting can also be an avenue to gather useful existing information and identify loop-holes

or areas of interest to be considered in achieving overall success of the assessment

3 Measure the Facility Energy Use

A basic understanding of energy measurement techniques and equipment is needed for a

successful energy assessment. Both correct tools and its use are fundamental in obtaining

useful measured data. Knowledge of energy measurement makes it easy to measure the

energy in terms of how much energy is consumed by each energy system, and how all the

units add up to equal the energy use of a facility. In measuring energy use in a facility, you

might want to consider answering the following questions: (1) which energy systems

consume energy? (2) how much of energy is consumed and at what rate? And (3) what

activities are carried out with the energy systems or within the facility?

Giving specific answers to the questions will invariably help to locate where energy is

overused or underuse making it easier to identify areas in which energy saving opportunities

abound. Figure 6 is a flowchart of the activities involved in measure the facility energy use

and this include (1) Measure the baseline, (2) Conduct energy assessment of facility, (3)

Gather data, and (4) conduct analytical assessment.

3.1 Measure the Energy Baseline

The energy baseline of the company should be measured. This can be done by analyzing

the energy sources used by the facility. These sources include electricity, propane, and

natural gas. This baseline is important in order to compare the facility to other facilities of

the same capacity thereby evaluating the facility’s energy consumption. Examples of energy

baseline parameters are energy use index, energy productivity index and the energy cost

index.

3.2 Conduct Energy Assessment of Facility

Having gathered information and data needed by measuring the energy use of the facility

and the energy baseline as well as other information deem useful from equipment and facility

operation, the next step is to be considered is conducting the energy assessment of the facility

as planned. An energy assessment should be carried out during normal operation period as

this affords the team the opportunity to speak with plant supervisor and some other facility

employee who are in a technical position. As already suggested, facility operation period is

the best time for assessment since it is the time the equipment are in use even though some

other equipment might be used after normal operation hours.

Figure 6 Measure the Facility Energy Use

To ensure a successful assessment, further information of the facility and energy systems

should be gathered while engaging in this assessment. In most cases, specific information

pertaining to different energy system of the facility will be made available by the employee

(VOE) operating the energy system. Most likely, a maintenance supervisor will provide

information on the performance and the problem areas of energy systems such as lighting

system, motor driven system, HVAC system, air compressors. The data gathered from the

interview with the employee can lead to the identification of energy savings opportunities. In

gathering the data, the team should look at the areas in which energy savings opportunities

appropriate for the facility can be achieved. Below are some energy systems to consider:

Measure Energy

Baseline

Conduct Energy

Assessment of Facility

Compressed

Air Systems

Lighting

Systems HVAC

Systems

Motor Driven

Systems

Infra-red

Survey

3.2.1 Lighting System

In order to conduct an effective lighting assessment, the lighting team needs to have a

lighting inventory data sheet in place for taking data readings as shown in Table 3 and lux

meter for measuring the light illumination. Inventory on the number of each type of light,

light wattage and the hours of operation of each type should be recorded. Readings of the

light intensity of each area putting into consideration of the activities carried out in each area

should be noted. The team should be able to identify areas of potential energy saving

opportunities by considering where light is in excess, looking at such factors as: the type of

light being used, the number of each type used, the size and wattage of lighting used, hours

of operation of each type and the area light is used in terms of activity carried out.

In order to control lighting inefficiency, these recommendations should be considered:

Offices and areas which are less frequently used should be checked for availability of

occupancy sensor control, where not available installation of such should be

recommended.

Offices and common areas where daylight can serve as an alternative source of light

will require less energy consuming light type.

Table 3 Lightening Inventory Sheet

COMPANY NAME ABC Chemical company

Lighting Summary

No Room Name Type Size Units Wattage

(TX)

Recommendation Lux

Reading

1 Rm202 F 4X2 18 T8 R.O 450

2 Rm203 F 4X4 8 T8 O 330

3 Rm204 F 4X2 14 T8 P,R 450

4 Rm205 F 8X2 6 T8 O 247

5 Rm206 F 4X2 24 T8 P,R 436

Legend

Type Size Recommendation

Incandescent (I) 4 foot 2 bulbs (4x2) (R) Reduce lighting

Fluorescent (F) 4 foot 4 bulbs (4x4) (O) Occupancy Sensor

Metal Halide (MH) Bright

white

8 foot 2 bulbs (8x2) (P) Photo Sensor

Operation floor with more than the recommended light intensity should be checked

with the lux meter and compared with the recommended illumination levels specified

by the Illuminating Engineering Society (IES). Recommendation should be made for

the reduction of the excessive light.

It is important to have a photo sensor lighting control installation control in place

especially in operation areas where daylight serves as an alternative source of light

during the day since the sensor is capable of measuring a drop in the intensity of light

and automatically turns on the light at night when daylight is not available.

Operation floors with the recommended light during hours of operation should be

checked after hours of operation and the light possibly turned off or switched to a

lighting type adequate enough for an off operation period.

3.2.2 Motor Driven Systems

An inventory of all motor should be taken with data sheet providing information on

motor size, hours of operation, usage, age and model. Recordings on motors that are less

frequently used measurement of voltage, current and other power related factors of motors

should also be considered.

Some of the most commonly used motor driven systems in facilities include fans, pumps,

compressors, blowers, and conveyors among others. Electric motors account for over 60% of

electrical energy used in facility [20], as a result of this; great potential energy savings can be

identified in energy efficient motors. The energy assessment team should consider paying

attention to pumps and fans as they account for the highest number of energy system using

motors in most facilities for potential energy saving opportunities. The team should be able

to identify areas of possible energy savings by checking the output level of the machines and

taking note of the speed of the motors. In most cases, a variable speed drive (VSD)

installation should be done. The VSD reduces the output of the machine by controlling the

motor speed. Often times, oversize motors capable of handling maximum load demand which

are hardly reached at demand, in this case, the VSD controls the speed of the motor to that

needed.

In order to achieve motor driven system efficiency, the following should be

recommended:

Old motors with high usage time should be replaced with new high efficiency ones.

A VSD installation should be checked and installed in motors in which they are

unavailable. This is to reduce machine output by controlling the speed of the motor.

Oversized motors should be replaced with optimum sized motors.

3.2.3 HVAC

The HVAC system comprises of the heating equipment, cooling equipment and

ventilating equipment. Heaters and air conditioning systems inefficiency are sources of

waste heat as a result much attention needs to be given to it since the wasted heat can be

recovered and used as part of the heat needed for efficiency. The temperature of these

sources of waste heat should be taken, also the air velocity should be measured as this will

enable for discovery of air leaks.

Most facility do not condition or heat operation areas, the most conditioned and heated

areas are offices and common areas. In identifying possible areas of energy savings the

condition of the evaporators, air filters, condensers and insulation should be examined. The

structural and architectural features of the facility such as the walls, ceiling and ceiling

heights should be considered. Most non-air conditioned operation floors with large number

of ventilating fans are usually left running all year round especially in facilities with high

heats and in location experiencing mild weather making them areas of possible energy saving

opportunities

Inventory of heating, air conditioning and ventilating equipment should be recorded in a

data sheet. Information like the model number, size, type of equipment, age, operating hours,

should be recorded on a data sheet. The team should consider the following when conducting

assessment on the HVAC system:

1. Office and rooms that are not occupied should be checked to confirm that the rooms

are not being conditioned. When such is discovered, recommendation should be made

for the discontinue condition of the room or space.

2. The team should compare the space cooling or heating rate during operational hours

to non-operational hours to ensure energy is not being wasted via cooling during non-

operational hours.

3. Installation of programmable thermostat should be checked on the HVAC system,

where this is not installed, it should be recommended.

4. The team should check the HVAC system and ensure that dirty or hot air is not being

introduced into the system as this would reduce the efficiency of the system.

5. The team should check the maintenance record of the system to ensure proper

maintenance is done on the system which includes changing of the air filters and

some 5s operations on the condensers.

6. The distribution piping of the HVAC system should be checked for insulation. Where

insulation is not effective, replacing of the insulating material should be

recommended.

3.2.4 Compressed Air Systems

Compressed air is an indispensable tool [21]; it is considered as the fourth most used

utility after electricity, natural gas and water in manufacturing companies. It is use ranges

from simple hand tools, HVAC control systems, to pneumatic robots in car assembly.

Compressed air is one of the most expensive utilities in manufacturing facilities [22]. Most

energy use in the air compressor ends up as heat which is wasted and also causes an

increased load for the HVAC system. Air leaks in compressed air system are the significant

source of waste and it results in 20% - 30% of the air compressor’s output [23].

Compressed air leaks is also associated with problems resulting in the operation of the

system which include; (1) increased in compressor pressure which results in increased cost of

operation, (2) fluctuation in system pressure which results in inefficient and ineffective

operation of air tools and other air operated equipment, (3) increased in maintenance cost of

the system and a reduced service life. Common areas of air leakage are hoses, couplings,

fittings, tubes, pipe joints, valves, flanges to mention a few.

Ultrasonic detector is the best tool to detect compressed air leakage. Other method

includes the use of soapy water to the suspected areas but this can take some considerable

amount of time and energy. The energy management team must be knowledgeable in the use

of both methods to detect air leakages and should use it to detect air leakages. The team

should also check the air compressor’s pressure to be sure it is at a minimum set pressure of

100 psig (114 psia) as leakage accounts for pressure drop in the system.

3.4.5 Infra-red Survey

The electrical system in the facility should be scanned for heat emission which is as a

result of loose connection. This can be achieved by using an infrared camera to detect the

heat emitted from the system. The benefits of an Infrared survey [24]:

Help prevent emergency, unscheduled maintenance

Fewer interruptions to production – Greater uptime

More efficient energy usage

Reduction in potential damage to equipment and the facility from fire

4 Analyze Energy Assessment Data

Energy data gathered from the measure stage are analyzed by the team to identify energy

savings opportunities abound in the facility. The energy savings opportunities are converted

to equivalent dollar amount understandable by the management. At this stage, economic

analysis is performed to estimate the energy cost savings, implementation cost and the

payback period. Figure 7 is a flow chart of the analyze stage. The result of this is used in

formulating the recommendations needed to be taken by the facility in order to reduce energy

waste and cost.

Figure 7 Analyse Energy Data

4.1 Analyze Energy Data

With the completion of the facility or system survey assessment as per plan, the next step

is the analysis of all collected data. These data should be organized, examined and reviewed

to ensure that all data needed for significant assessment is collected. Often times even before

the assessment is conducted, a good knowledge of different energy efficiency measures that

can bring about energy savings must have been identified as it enables the team to determine

areas of potential energy savings from analyzing the data got from the actual assessment

conducted on the systems and facilities. For example, old motors or motors with high time

usage are potential energy saving opportunity for high efficiency ones. Over lighting in an

area signifies potential energy savings in light change or removal. A cause and effect

diagram can aid in analyzing the cause of the energy waste.

In performing an assessment analysis, the team aims at determining the cost and benefits

of the potential energy savings opportunities that is cost effectiveness. There are three

Analyze Energy

Data

Compute Energy

Savings

Energy Cost

Savings

Implementation

Cost

Pay Back

Period

commonly used medium for measuring cost-effectiveness: payback-period, discounted

benefit- cost ratio, and life cycle cost (LCC) approach. Most facilities look for a payback-

period of two years or less [10], this is derived by dividing the initial cost by the annual

savings. Another method of measuring is the discounted benefit-cost ratio which is derived

by adding up the future discounted annual savings to find the present value of annual savings

over a period of time and then dividing it by the initial cost, a ratio more than one signifies

great savings. The third relevant medium is the life cycle cost approach which focuses on the

savings accumulation and its relevance on the present savings to future savings and costs,

this approach gives a better evaluation of long term effects on energy savings. Another focus

of the analysis is in giving a valid and assured judgment on the cost-effectiveness of a

potential energy savings opportunity by computing cost savings and implementation savings.

5 Improve and Recommend

At this stage in the energy assessment process, the recommendations are developed and

evaluated; the initial draft of the assessment report is written and reviewed with the energy

management champion. Once all the recommendations are agreed on, the report should be

signed, distributed and a copy achieved with the energy management team for future

reference. Figure 8 is a process flow chart for improve and recommend stage.

Figure 8 Improve and Recommend

5.1 Develop and Evaluate Recommendations

The recommendations are developed from the analyzed data gathered for the assessment.

Table 4 is a summary of the recommended savings based on the assessment carried out in a

sugar mill by the IAC, Louisiana [25]. The recommendations are further evaluated to by the

energy manager to identify alternative method of energy cost reduction.

Develop and Evaluate

Recommendations

Draft Initial

Assessment Report

Review Draft

Assessment

Report

End of Improve

phase

Table 4 Recommendation Description, Resource Savings, Energy Cost Savings,

Implementation Cost and Payback Period

s/n Recommendation

Description

Resource

Savings

(/yr)

Energy Cost

Savings

($/yr)

Implementation

Cost

($)

Payback

Period

(month)

1 Install back pressure

turbine

8,600,000 kWh

electricity $ 573,937.00 $ 2,150,000.00 45

2 Repair steam leaks 120,454 MMBtu gas $ 69,765.00 $ 12,567.00 2

3 Install economizer 63,000 MMBtu gas $ 31,500.00 $ 21,500.00 8

4 Improve power

factor

$8,829.67 Power

factor $ 8,829.67 $ 4,602.34 6

5 Install photo sensor 38,753 kWh

electricity $ 37,535.46 $ 270.00 0

6 Repair pump seal 12,347 kWh

electricity $ 1,912.00 $ 756.00 5

7 Reduce number of

lights

$117.84 service

charge $ 117.84 $ - 0

8 Insulate surface of

pipes 66 MMBtu gas $ 304.50 $ 442.08 17

Total $ 723,901.47 $ 2,190,137.42 36

5.2 Draft Initial Assessment Report

A draft assessment report should be written to summarize the findings of the industrial

energy assessment. The facility assessed, level and type of assessment will determine the

length and content of this report. This report will have a summary of the energy sources and

use in the facility, the cost of the energy, the major energy consuming equipment,

recommended energy savings, implementation cost and the payback period on the

investment. An outline of an energy assessment report is shown Table 5 [26].

Table 5 Assessment Report Outline

Executive Summary

A brief summary of the recommendations and cost savings

Table of Contents

Introduction

Purpose of the energy assessment

Need for a continuing energy cost control program

Facility Description

Product or service, and materials flow

Size, construction, facility layout, and hours of operation

Equipment list, with specifications

Energy Bill Analysis

Utility rate structures

Tables and graphs of energy consumptions and costs

Discussion of energy costs and energy bills

Energy Conservation Opportunities

Listing of potential ECOs

Cost and savings analysis

Economic evaluation

Action Plan

Recommended ECOs and an implementation schedule

Designation of an energy monitor and ongoing program

Conclusion

Additional comments not otherwise covered

5.3 Review Draft Assessment Report

The drafted assessment report should be reviewed with the energy management

champion to obtain his reviews on the energy assessment conducted in the facility and the

recommendations made. His observations should be noted and incorporated into the energy

assessment report. Once all stakeholders involved with the assessment are satisfied with the

report, the report should be signed and distributed to the top management for their further

action. A copy of the assessment report should be archived by the energy management team

for future reference. This is important for future assessment as the report would serve as a

reference material for the energy management team.

6 Control

The control phase is outside the scope of the energy assessment as this is particular to the

top management. This includes procedure that can be taken to ensure implementation of the

recommendations from the energy assessment report in the industry in order to reduce energy

cost. The energy management team should also include actions that can be taken by top

management in order to implement the recommendations. Such actions include the

development of an energy management plan (EMP), and energy policy. EMP is an approach

of reducing energy consumption and operating cost simultaneously. Energy assessment is a

continuous improvement tool and should also be included in the EMP. Further research on

EMP was conducted by Lee, Yuvarmitra, Guiberteau and Kozman [27] and Osho [28].

7 Conclusion

This paper developed a lean six-sigma approach to conduct an industrial energy

assessment in a facility. The procedure is developed based on an internal energy assessment.

The following information was provided by this paper:

1. The procedure is based on internal energy assessment which is an employee based

type of energy assessment.

2. The procedure involves developing a procedure for conducting industrial energy

assessment based on the DMAIC approach.

3. This approach was implemented in a manufacturing industry and has yielded a 19.7%

reduction in energy savings.

4. This approach provides employee participation in energy assessment of the facility.

5. Developing an energy management plan and energy policy, which is the control

phase of this approach, would ensure continuous improvement in energy waste and

reduction.

It is not intended to claim the insignificance of the IAC but to show how the integration

of the internal energy team and lean six- sigma can bring about energy cost savings

opportunities. This approach also ensures continuous energy savings through implementation

of energy management plan and energy policy.

The lean six-sigma approach discussed in this paper can be employed in other manufacturing

industries for conducting industrial energy assessment. Further research should be done on

investigating the energy saved from the energy assessment conducted by an external auditor.

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