This document
is intended to provide guidance to those who are interested in performing
industrial assessments at manufacturing facilities. This document
is intended to be a general reference not an all encompassing guide
to industrial assessments for pollution prevention and energy conservation.
The U.S. EPA would like to thank Dr. Michael Muller and the staff
of The Office of Industrial Productivity & Energy Assessment,
Rutgers University and the Department of Energy, Office of Industrial
Technology for their efforts in producing the first version of this
document. In addition, EPA would like to acknowledge and thank those
who have performed the case study assessments.
This guide
presents an overview of industrial assessments and the general framework
for conducting an assessment. In addition, basic information about
waste generating industrial operations and energy consuming equipment
is provided. This guide can be used by both facility personnel to
conduct in-house assessments of operations and those who are interested
in providing industrial assessments to industrial and commercial
facilities since the framework for an assessment will be the same
for both.
What
is an Industrial Assessment?
An industrial assessment is an in-depth review of existing operations
to increase efficiency of the operation through pollution prevention
and energy conservation. The industrial assessment is an essential
and valuable tool used to:
- define the
specific characteristics of a whole facility that consume energy
and generate wastes,
- identify
a range of energy conservation and pollution prevention options,
- evaluate
the options based on a set of criteria, and
- select the
most promising options for implementation.
One should
find the industrial assessment instrumental to systematically identifying
opportunities to increase energy efficiency and decrease waste generation.
Assessments can be divided into three types: energy, waste (hazardous
and non-hazardous) or a combination of the two. Energy conservation
and pollution prevention are complementary activities. That is,
generally actions that conserve energy reduce the quantity of wastes
produced by energy-generating processes and actions that reduce
production wastes lower the expenditure of energy for waste handling
and treatment. It is a well used and proven approach to identifying
cost saving energy conservation and pollution prevention technologies
that enhance a facility's performance.
Energy conservation
and pollution prevention opportunities provide many benefits. An
industrial assessment is intended to increase the efficient use
of energy and materials. The process of performing an assessment
provides useful information for facility personnel to evaluate a
particular operation or the entire facility. Benefits resulting
from industrial assessments include decreased costs, reduced liability,
reduced energy consumption, increased worker health and safety,
improved public relations and compliance with regulations.
Any facility
that wishes to find opportunities to increase the efficiency of
their operations should conduct an industrial assessment. Businesses
have strong incentives to increase operation efficiency as this
increases competitive edge. Operations that are more efficient can
operate with lower expenses and decrease their cost per unit production.
An industrial assessment is not something that is performed only
once and options are implemented. Industrial assessments should
be used as a tool to periodically examine operation efficiency and
re-evaluate current opportunities. As new technologies become available,
an opportunity that was not economically or perhaps technically
feasible when the last industrial assessment was performed can become
a viable opportunity.
Pollution prevention
means "source reduction" as defined under the Pollution
Prevention Act and other practices that reduce or eliminate the
creation of pollutants through:
- increased
efficiency in the use of raw materials, energy, water or other
resources, or
- protection
of natural resources by conservation.
A pollution
prevention program provides the mechanism to a facility for continuous
self-evaluation and improvement. Assessments are key components
of a facility's pollution prevention program. A pollution prevention
program provides the framework for a facility to develop goals,
establish a working group, provide reports on energy use and waste
generation and mechanisms to track results of implemented projects.
The most important
element of a pollution prevention program is management support.
Top management must demonstrate support for the program because
employees who believe that the program is not supported by management
get the attitude of "They don't care, why should we."
Management's support should be demonstrated through several mechanisms:
- circulating
a written policy,
- establishing
goals for reducing waste generation and energy consumption,
- establishing
a working group,
- providing
training on conservation techniques, and
- publicizing
and rewarding successes.
After a facility
has established its goals and objectives for its pollution prevention
program it is ready to conduct industrial assessments.
Conducting
an Industrial Assessment
The assessment process begins with the recognition of the need for
pollution prevention and energy conservation. An industrial assessment
consists of four general phases:
1. Planning
and Organization
2. Assessment
3. Feasibility Analysis, and
4. Implementation
This document
will focus on phases one through 3 and will briefly discuss phase
four.
The first step
in an assessment is to establish the assessment team. The team should
be composed of personnel from many areas of the facility. Core team
members will include those that are involved with the operation
or process, both supervisors and staff, as well as energy management
and environmental staff. Other areas that may be included are health
and safety, facility or civil engineering, quality control, accounting
and finance, purchasing and contracting and legal.
Once the assessment team is established, the team will need to determine:
- What
processes will be assessed,
- Who
will be involved with the assessment,
- When
will the assessment take place, and
- How
will the team approach the assessment.
Planning
and Organization. The planning and organization of an industrial
assessment is important to obtain the desired results. The assessment
team should decide on a data collection format for the assessment.
The team may use standard worksheets provided in EPA's "Facility
Pollution Prevention Guide" or may develop their own assessment
worksheets, questionnaires or checklists. The team should prepare
an assessment agenda and schedule the assessment in advance to coincide
with a particular operation of interest.
Assessment.
The second phase is the assessment phase. This phase can be broken
down into two parts: the pre-assessment and the actual assessment.
Prior to the
assessment it is a good idea to collect information, allowing the
assessment team to review and prepare additional questions. Information
that should be collected includes: a facility description, a process
description, a process flow diagram, major energy consuming equipment,
raw material use and energy and waste data. The team should collect
information for a 12-month period and all information should be
for the same 12-month period. The energy information should be converted
to a standard unit of measure and graphed to view energy use trends.
Waste data can be summarized in a table format for review and reference.
Collection of this data prior to the assessment will also give the
assessment team an idea of where its attention should be focused
during the actual assessment.
During the
actual assessment, the team should begin with a review of operations
and data collected prior to the assessment with persons who work
in the area on a day-to-day basis. After the team has discussed
the operations, the team should take a walk through the facility
to observe actual operations. During the walk-through team members
should talk with personnel to confirm operation procedures and information
collected prior to the assessment. After the walk-through, the team
members should brain storm ideas for energy conservation and pollution
prevention. This is the point where the team will generate a list
of ideas without regard to cost or feasibility. Once the list of
ideas has been generated, the team can collect information that
it needs to complete a feasibility analysis.
Feasibility
Analysis. The third phase of the assessment is the feasibility
analysis. This portion of the assessment is usually completed over
several days after the assessment and will include both a technical
feasibility analysis and an economic feasibility analysis.
The feasibility
analysis should begin with a prioritization of the identified opportunities.
Because of time and resource constraints many facilities will have
to chose among opportunities for implementation. The team can develop
a relative ranking of opportunities using a tool known as a decision
matrix. The decision matrix tool can be used to rank the identified
opportunities using a list of critical factors that are important
to the facility allowing an apples-to-apples comparison of the options.
The feasibility
analysis should be documented for presentation to other facility
personnel or to management. This documentation should include a
clear description of current operations and practices, a description
of the opportunity, the benefits that would result from implementation
of the opportunity as well as technical and economic evaluation
of the opportunity. The detail of the technical and economic evaluations
will vary depending on facility requirements and the complexity
of the opportunity.
The technical feasibility analysis can include:
- Calculation
of energy consumption and waste generation reductions,
- Determination
of how much labor will be involved with the changes in operations
or equipment,
- Evaluations
of space constraints,
- Evaluation
of safety and health aspects for employees,
- Compatibility
with current operations and materials, and
- Changes
in annual operating and maintenance costs.
There are many
factors that can be included in a technical evaluation. All of the
factors listed above may not apply to every opportunity. The team
should determine what criteria are applicable to a specific opportunity
based on the complexity and applicability of implementation and
impact on operations.
An economic
feasibility analysis is a process in which financial costs, revenues
and savings are evaluated for a particular project. This analysis
is necessary to evaluate the economic advantages of competing projects
and is used to determine how to allocate limited resources. There
are several methods of comparison currently in widespread use: payback
period; net present value; and internal rate of return. The method
of economic evaluation is often determined by internal company requirements.
In addition, life cycle costing and total cost accounting tools
are used to establish economic criteria to justify energy conservation
and pollution prevention. Total cost accounting is used to describe
internal costs and savings, including environmental criteria. Life
cycle costing includes all internal costs plus external costs incurred
throughout the entire life cycle of a product, process or activity.
Implementation.
Management support is the most important element in successfully
implementing energy conservation and pollution opportunities. Actions
taken to implement energy conservation and pollution prevention
projects vary greatly from project to project and company to company.
One facility may decide to use in-house expertise to implement projects
while another may find it beneficial to contract the work to an
outside organization. After successful implementation of the project,
it is beneficial to track and advertise the resulting cost savings
and impacts to give feedback to facility personnel. This allows
personnel to see the results of changes in procedures or installation
of new equipment and to participate in the energy conservation and
pollution prevention program.
Sources
of Energy and Pollution
Sources of energy and pollution come in a great variety. Energy
is generated from many sources, including:
- Nuclear,
- Wind,
- Coal-fired
electric generation plants,
- Solid waste
incinerators,
- Fossil fuels,
- Geothermal,
- Solar,
- Biomass
fuels (including wood, peat, and wood charcoal), and
- Hydroelectric.
These sources
are used to generate energy mainly in the form of electricity because
it is more easily transmitted over long distances and can be used
for more tasks. These sources are also used to generate steam and
compressed air for use in industrial operations.
Energy generation,
as well as many industrial operations, create pollution. Energy
generation operations impact the environment either through air
emissions from the burning of fossil fuels, wastes from the maintenance
of equipment and other operations, flooding of areas by hydroelectric
dams and mining or drilling of fossil fuels. Industrial operations
also impact the environment in a similar manner.
Over the past
three decades, the generation of wastes that are released to the
environment through any media has become more stringently regulated.
The regulations that have been enacted require much record keeping,
documenting a facility's status for permitting discharges to the
air and water and for disposal. Regulations such as the Clean Air
Act (CAA) and the National Pollutant Discharge Elimination System
(NPDES) require facilities to apply for and obtain permits to discharge
pollutants from its operations. The limits placed on a facility
as a result of their discharge permits may impact a facility's production
capabilities and the types of equipment that will be required to
treat and monitor discharges.
Industrial
Operations
There are many common applications that are applied in a variety
of ways throughout industry. Pollution prevention opportunities
exist for a variety of industrial operations. Even though these
operations are applied in a variety of ways there are many common
opportunities for pollution prevention. The following ten areas
have widespread application in today's industrial operations:
- Office operations,
- Plating
operations,
- Materials
management/housekeeping,
- Paint application,
- Facility
maintenance,
- Paint removal,
- Metalworking,
- Cleaning
and degreasing,
- Chemical
etching, and
- Wastewater
treatment.
These operations
generate similar types of wastes without regard to the specific
industry. As such, there are many common opportunities for pollution
prevention that can be applied to many industrial operations. There
are many sector guides that focus on these areas available from
EPA (see Appendix A of the report).
For example,
every facility has some type of office operations to manage the
purchase of materials, personnel and other administrative tasks.
Opportunities that can be implemented in any office include:
- Reducing
lighting levels in certain areas,
- Using energy
efficient bulbs and fixtures,
- Retrofitting
plumbing with water saving devices,
- Using electronic
documents and mail, and
- Making double-sided
copies.
While these
opportunities will be common to many industries there will always
be opportunities that are specific to a particular facility and
its operations. The assessment team should explore other opportunities
that fit a facility's unique needs. This chapter of the document
gives a description of each operation area, the types of wastes
generated from each operation and potential pollution prevention
opportunities.
Energy
Consuming Equipment
Industrial operations are very energy intensive. Equipment can be
combined into a multitude of applications. There are common types
of equipment used across industries such as boilers, air compressors
and lighting. There are many energy conservation opportunities that
can be implemented for these types of equipment independent of application.
Following are brief descriptions of common types of equipment used
in industry and applicable energy conservation opportunities. Several
energy conservation case studies are given in the appendices of
the report.
Electric
Equipment. Motors represent the largest single use of electricity
in most facilities. The function of an electric motor is to convert
electrical energy into mechanical energy. Motors are designed to
perform this function efficiently; the opportunity for energy savings
with motors rests primarily in selection and use. The most direct
power savings can be obtained by shutting off idling motors, eliminating
no-load losses.
Often motors
have a greater rating than required, operating at partial load.
Reasons for oversized motors include:
- Personnel
may not know the actual load; and to be conservative, select a
motor larger than necessary.
- The designer
or supplier wants to ensure that the unit will have ample power.
- The correct
motor rating is not available when a replacement is needed.
Newer technologies
have made motors more efficient and allow flexibility in motor loads
such as reduce speed/variable drives and variable frequency AC motors.
Many lighting
systems that represented good practice in the past are inefficient
in view of today's higher electrical costs. A lighting conservation
program not only saves energy but is a highly visible indication
of management's interest in conserving energy in general. The importance
of lighting conservation should be considered not only for its dollar
savings but also for its psychological effect on the facility's
entire conservation program. Opportunities for conservation include:
- Using task
specific lighting levels,
- Turning
off unneeded lighting,
- Using lighting
specifically designed for high ceiling areas, and
- Using energy
efficient lamps.
Heat.
Boilers are common throughout industry to provide steam for applications
as well as heat. A boiler system is comprised of four main parts:
a boiler, a steam distribution system, steam traps and a condensate
return system. There are several factors that can impact a boiler's
efficiency. These include adjustment of air/fuel ratio for fuel
combustion, make-up water pre-heat, frequency and amount of blowdown
to clean the system of excess solids, percentage of condensate return
and maintenance of the system for leaks and proper operation. Many
opportunities for increasing efficiency can be realized through
simple maintenance of the system through cleaning, repairing leaks
and periodically adjusting the air/fuel ratio for combustion.
Heating systems
are an integral part of industry today. They are used for process
heating, drying and comfort/space heating. The main purpose of industrial
space heating is to provide a comfortable work environment for its
employees. De stratification fans are used to push warm air that
has risen to the ceiling back down to personnel level. This allows
the air to mix and reduces the heating requirements for the facility.
Stratification is a result of an increasing air temperature gradient
between the floor and the ceiling in an enclosed area. Destratification
fans can also be used to increase air circulation and cooling during
the summer months.
Electric heating
equipment is often inexpensive and convenient to install. While
electrical heating is efficient, the cost of electricity is significantly
higher than other sources of energy such as steam or natural gas.
Opportunities for increased energy efficiency can be realized by
applying the correct type of heating for the application. For example,
radiant heating systems are ideal for comfort heating since the
infrared radiation elevates body temperature without heating the
air through which it travels.
Furnaces are
used to generate heat for application directly to a product for
tempering, curing coatings or drying. Furnaces can use electricity
or a fossil fuel to generate heat. Opportunities for conservation
in furnace operations include adjustment of combustion efficiency,
installation of better insulation, improved product cycling, preheating
of combustion air and installation of furnace covers.
Cogeneration
is the simultaneous production of electric power and use of thermal
energy from a common fuel source. Interest in cogeneration derives
from its inherent thermodynamic efficiency. Fossil fuel-fired central
stations convert only about one-third of their energy input to electricity
and reject two-thirds in the form of thermal discharges to the atmosphere.
Industrial plants with cogeneration facilities can use the rejected
steam in their plant process and thereby achieve a thermal efficiency
as high as 80%.
Thermoenergy
storage systems are used to take advantage of lower cost electrical
rates with nighttime operation to provide daytime thermal needs.
There must be a significant difference between night and daytime
electrical costs, and the daytime refrigeration load must result
in high daytime costs in order for this system to be economically
feasible.
Prime Movers
of Energy. Pumps are widely used for the transfer of liquids
from one place to another. Pumps are usually driven by electrical
motors but can also be driven by compressed air or hydraulics. There
are many types of pumps in use in industry and will vary depending
on the application. A few types include:
- Centrifugal
pumps used for transfer of large volumes;
- Metering
pumps used for precise delivery of liquids to a point of application
and ensuring the constant discharge regardless of back-pressure
in the lines; and
- Progressive
cavity pumps or peristaltic pumps used for delivery of very viscous
materials.
Opportunities
for energy savings in pump operation are overlooked because pump
inefficiency is not readily apparent. These measures can improve
pump efficiency:
- Shut down
of unnecessary pumps,
- Restore
internal clearances if performance has changed significantly,
- Trim or
change impellers if head is larger than necessary,
- Control
by throttle instead of running wide open or bypassing the flow,
- Replace
oversized pumps,
- Use multiple
pumps instead of one large pump, and
- Use a small
booster pump.
Fans provide
the necessary energy input to pump air from one location to another
while they overcome the resistance created by equipment and the
duct distribution system. Factors that can reduce fan efficiency
are: excessive static-pressure losses through poor duct configuration
or plugging, duct leakage, improperly installed inlet cone causing
excessive air recirculation, oversized fan and buildup of negative
pressure. Reductions in exhaust airflows are usually obtained by
adjustment of dampers in the duct. More efficient methods of volume
control that can be used are to install inlet damper control, reduce
the speed of the fan, and provide variable speed control for the
fan.
Air compressors
are often large consumers of electricity. There are two types of
air compressors: reciprocating and screw compressors. Reciprocating
compressors operate in a manner similar to that of an automobile
engine, using a piston to compress the air. Screw compressors work
by entraining the air between two rotating augers. The space between
the augers becomes smaller as the air moves toward the outlet, thereby
compressing the air. Screw type compressors, especially older models,
use more energy than reciprocating compressors. This is especially
true if the compressor is over sized because the screw compressor
continues to rotate, whereas a reciprocating compressor requires
no power during the unloaded state. There are many opportunities
to reduce the amount of energy used by air compressors including:
- Repairing
air leaks,
- Reducing
the operating pressure,
- Recovering
heat from compressor exhaust or cooling water,
- Using outside
air, and
- Installing
low-pressure blowers where applicable.
Thermal
Applications. The most common types of cooling towers dissipate
heat by evaporation of water that is trickling from different levels
of the tower. Cooling towers conserve water, prevent discharge of
heated water into natural streams and avoid treating large amounts
of make-up water. Opportunities for energy reduction in cooling
tower operations include adjustment of condenser water temperature,
adjustment of chilled water supply temperature, installation of
variable speed motors for cooling tower fans and use of hot gas
defrost for air cooler coils.
Absorption
and mechanical chillers are used to produce chilled liquid for air
conditioning and industrial refrigeration processes. These chillers
are usually powered by low-pressure steam or hot water, which can
be supplied by the plant boiler or by waste heat from a process.
When prime energy is needed, mechanical refrigeration is usually
preferable. Air leakage can be a serious operating problem for absorption
chillers. Every effort must be made to keep the system airtight,
as even very small leaks can cause problems and are difficult to
detect. Air entering the machine causes the lithium bromide solution
to become highly corrosive to metals, crystallize and cause the
chilled water temperature to increase.
For mechanical
chillers, greater energy efficiency can be achieved through the
following steps:
- Use refrigeration
efficiently,
- Operate
at the lowest possible condenser temperature/pressure,
- Operate
at the highest possible evaporator temperature/pressure,
- Operate
multiple compressors economically,
- Recover
heat rejected in the condenser, and
- Use a hot
gas bypass only when necessary.
Insulation
is an important component in thermal applications to increase the
efficient use of conditioned fluids and gases. Proper insulation
allows the conditioned fluid or gas to retain its temperature or
pressure longer and reduce losses in transportation to the point
of use. For example, insulation of steam and hot water pipes reduces
the heat loss prior to its intended use. Insulation is also an important
consideration for other items such as heated tanks, refrigeration
units and general building insulation.
HVAC. Employee
comfort as well as a healthful working environment is an important
consideration for facility managers. A controlled working environment
is also important for equipment or processes that are sensitive
to temperature and humidity. Air conditioning is the process of
treating air to control its temperature, humidity, cleanliness,
and distribution to meet the given requirements. The basic components
include a fan to move air; coils to heat an/or cool the air; filters
to clean the air; humidifiers to add moisture; controls to maintain
the specified conditions automatically; and a distribution system.
Potential energy conservation can be realized from air conditioning
operations by operating the system only when needed; eliminating
over cooling and over heating;, eliminating reheat; minimizing amounts
of makeup and exhaust air; minimizing the amount of air delivered
to conditioned spaces; recovering energy, and maintaining equipment.
HVAC systems
are typically used for conditioning of space for human comfort.
Employee comfort has a great influence on productivity. However,
all the comfort should be provided at the minimum expense. Factors
that should be considered when controlling the HVAC settings include
activities to be performed within the space and the types of clothing
typically worn. There are several types of HVAC systems available
today. The assessment team should base any recommended opportunities
on the type of system installed at the facility.
Many operations
require ventilation to control the level of dust, gases, fumes or
vapors. Excess ventilation for this purpose can significantly add
to the heating and/or cooling load. Areas that require significant
amounts of ventilation are not always cooled but will in most cases
be heated. A common problem during the heating season is negative
building pressure resulting from attempting to exhaust more air
than can be supplied. A facility can minimize the impact of ventilation
during winter months by balancing airflow and recovering heat for
reuse.
References
and Resources
This guide is intended to be a starting point for those interested
in increasing a facility's efficient use of materials and energy.
References used in compilation of this document are listed for more
in-depth information. Industry specific guides available from EPA
and other sources are also listed. There are many agencies and organizations
that are available to provide assistance to industrial and commercial
facilities in the areas of energy conservation and pollution prevention.
The agencies and organizations are presented by type (i.e. federal,
state, university, or non-profit). Information for web sites and
e-mail addresses are given when available.
