Industrial Assessments for Pollution Prevention and Energy Efficiency

Article From: Products Finishing, ,

Posted on: 3/1/2002

Is it going to cost your company money to become more environmentally friendly and energy efficient? Some think it will. This executive summary and the associated report show that pollution prevention and energy efficient operations may actually save you money. A link to the full report is provided…

 

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.

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