Energy Management for Industry

Transcription

1 Energy Management for Industry B usiriesses must closely manage their operations in order to be successful. But they often overlook rrianaging the use oi their energy resources as a key way to reduce operating costs. Establishing an energy management program requires cowimifment from all levels of your organization so that energy usage patterns in every department can be carefully reviewed and adjusted. This Technology Update outlines basic energy management techniques that you can apply to your business, regardless of its sizp or type. In any business, basic techniques must be applied to activities such as administration, finance, or production in order to make the enterprise successful. Energy management is the application of these techniques to the use of energy resources. Making the most effective use of energy through efficient application and reduction of waste will keep energy consumption and costs at a controlled minimum. The benefits of energy management will vary with individual circumstances. Potential annual savings in total energy costs for steam, air, water, electricity, and gas could be 10 percent or more. There is a potential savings in every plant, even in well-run plants, but it can require effort to be realized. The major benefit of a good energy management program frequently becomes apparent when there are plans to increase plant production facilities. As a result of a good program, the installation of additional equipment such as steam boilers, air compressors, and electrical services may be deferred, or at least minimized, for several years. In such cases, the interest savings on the deferred capital investment can be significant. Energy management can thus produce some immediate savings that, if continued, can reduce the investment required to meet future increased loads. Program Organization Regardless of the size or type of business organization, four basic elements are essential to any energy mctnagenient program: 1) top management commitment, (2) clearly designated program responsibility, (3) defined realistic goals, and (4) program planning and implemen tcition. Toll-free Hotlline FAX Electronic Bulletin Board Bonneviiie POWER ADMINISTRATION

2 Top Management Commitment Top management must be dedicated and committed to an energy conservation program. It must be willing to provide resources as required, both personnel and financial. Employees will apply their best efforts to the program only if their management displays a constant awareness of the program s importance. Without complete and continuing top management support, any energy management program will fail. Program Responsibility The planning and implementation of an energy management program must be the clearly defined responsibility of an energy program committee. This committee is appointed by management and headed by a coordinator, who reports to management. In most cases, the effectiveness of the program will be proportiongl to the effort and time the coordinator is allowed to spend on it. The coordinator must have the responsibility and authority for getting the job done. The committee consists of representatives from each department. Members should be prepared to make recommendations on matters affecting their areas and to conduct investigations and studies. In smaller organizations, the manager and his or her staff may conduct energy management activities as part of their management duties. Figure 1 is a typical energy management organization chart. Although individual programs will vary, the assignment of specific accountable responsibilities for energy resource management will generally produce the best results. The assistance of a qualified consultant may help the coordinator and committee to identify areas where energy management could be improved and energy saved. The consultant may also help to conduct an energy audit. The ultimate aim is to involve all levels of personnel in energy management and to maintain their interest and commitment. Individual employees can make a major contribution to the program. Program Goals Figure 1. Energy mangement organization chart (typical) I An energy saving goal should be set initially in order to provide a program target. The goal may - later be revised following a more thorough analysis of potential energy savings. - How large the initial and revised goals should be, or how they should be expressed, will depend on individual circumstances. In all cases, goals should be specific, measurable, and should offer sufficient incentive to all employees to make achievement a challenge. -~ Consul tan t Maintenance area reuresentative representative representative I 2

3 A short-term target of approximately 5 percent saving in 6 months could be generally acceptable. Too long a lead time, with a correspondingly higher target, may cause loss of enthusiasm. Realistic goals are best set by the application of standards that will indicate how much energy should be used for a particular application. Industry standards or calculation of theoretical energy requirements can provide a basic standard against which present performance can be measured. Goals and standards should always be set in familiar units (lb. of steam, therms, kwh, MMBtu). Program Planning The first technical step in an energy management program is to conduct an energy audit. An audit is made from a series of surveys that show where and how energy is being used and /or wasted. It will establish a base for measuring results and establishing energy intensity ratios. (Energy intensity ratio is the amount of energy used per unit of production.) For effective planning, it is essential to know how much energy each major area uses. Without this type of information, it may be impossible to set standards and measure performance of either an individual piece of equipment, processing line, or department. An ideal audit lists each process step, the theoretical energy required for each step, the actual energy used, and the variance between theoretical and actual use. The goal is to reduce the variance to a minimum by identi- fying wasteful practices that can be corrected by operation and maintenance actions. Goals may be shown on an energy budget using the format illustrated by Figure 2. The audit will reveal where energy flow measurement is needed and whether its installation can be justified economically. (One rule of thumb states that in-plant metering should be installed when the annual cost of energy exceeds five times the cost of the meter.) Energy can be measured in any unit compatible with the way it is purchased and should be correlated as required to an equivalent unit for all energy sources. The kilowatt-hour (kwh) or MMBtu is recommended as a common denominator. Note: 1 x 10'' Btu=293 kwh= 1 MMBtu=100,000 Btu= 1 Therm An energy audit should be organized in three phases. Phase I-Data Gathering. The logical place to begin auditing energy use is with utility bills. Data for at least a 1-year period should be obtained in order to establish a 12-month revolving base period. This base period can be used to make estimates and to compare present performance. An inventory of energy-using equipment should be prepared, showing basic energy use data (usually obtainable from nameplates) for each item. Figure 3 shows a format for the preparation of an inventory. Energy use should then be audited on a departmental basis, and finally on individual systems and equipment. The amount of detail of the survey will depend on individual circumstances. The first physical plant survey should identify obvious wastes that should be corrected immediately. A form similar to Figure 4 could be used for this purpose. This survey should be conducted department by department, and the wasteful operations should be properly documented. In commercial businesses, energy use will mostly be for housekeeping, such as space conditioning, hot water supply, and lighting. The survey for industrial processing plants will cover the normal housekeeping functions plus such items as leaking utility lines, damaged insula tion, equipment allowed to idle when it could be turned off, or other improper operation or maintenance. Phase 11-Energy Balances. Subsequent surveys should develop an energy balance for each process, department, and piece of energy-using equipment. The primary objective of an energy balance may be to determine the overall efficiency of a boiler or furnace. Its greatest value lies in indicating the way the supplied energy is utilized. By comparison with known or previous standards you can detect whether energy is being used inefficiently and, if so, to what extent. An energy balance quantifies the total energy entering a system against that leaving. Such a balance may refer to a period of time, such as 1 hour, or the time required to complete a given cycle of operations, or may be based on unit quantity of material produced. 3

4 Figure 2. Energy budget Energy use by consumption area and process steps Actual energy used Theoretical energy requirement Variance between theory and practice Amount of energy O/O Goal Change from previous month Buildings & grounds Shipping 11 Lighting I Combustion Figure 3. Energy management equipment inventory record (gas/electric) location Description Rated Input Annual use (Make, model, Quantity (Btu/hr or kw) (MMBtu 01 kwh) serial no.) Remarks 4

5 The construction of an energy balance can be simple or complicated. When a detailed analysis is required, it is best to divide the system into several main parts and make a balance for each of these units. From measurements of energy input and production records, the energy intensity ratio can be calculated. Energy used during non-working hours should also be surveyed. Figure 5 is an example of a form that can be used to monitor plant, department, and process energy use. The form can be modified as required. In addition, more sophisticated on-line monitoring systems can be installed to monitor energy use at the department or production line level. Phase 111- Analysis. An engineering analysis requires an assessment of process control by optimizing the financial return on investment. The following typical information is required: Cost of raw materials Value of products Composition of raw materials and products Current value of process variables Constraints on operation (such as safety limitations) Specifications for products All of these factors must be related to economic return by a process model, and the best operating strategy would optimize this return. Without an energy audit it is difficult to find out how to conserve energy and how to measure the success of an energy management program. With such an audit, however, it is possible to develop measures leading to prudent energy use based on sound business procedures. Program Implementation The obvious wastes found in the initial survey should have been corrected immediately, and the corrective action recorded. Most of these wastes can be eliminated by procedural changes requiring little capital investment, and can result in savings of 5 to 20 percent. An analysis of the energy audits will reveal which energy services (steam, gas, electricity) show the most potential for immediate improvement. A cost/benefit analysis (based, if possible, on future energy costs) will reveal the merit of each potential improvement project and enable priorities to be set. Selected projects should be implemented when approved. Development of Conti nu ing Energy Management Efforts Energy intensity ratios for the entire plant, every operating department, and each significant process should be calculated regularly (monthly, for instance), and compared with the optimum Values. The ratio will act as a monitor to show unfavorable trends that should be corrected as soon as possible. Designs for capital projects should be assessed for energy efficiency. The future cost and supply security of the types of energy for proposed projects should also be considered. Regular reports presented to those in charge of energy management programs are essential. An analysis of each energy-using system s performance should be made regularly and show current performance in terms of energy used, output, hours worked, variations in shop conditions, and the energy-intensity ratios. At regular intervals, the energy management coordinator should hold meetings to review progress, update project lists, and establish new goals. It is important that everybody in the organization become involved in the program. Employee interest should be maintained through a steady flow of information through channels such as employee publications and bulletin boards, and the achievements of specific individuals shou Id be publicized. The energy management coordinator should make periodic progress reports to management. This gives management an opportunity to review the program and show continuing support for it. 5

6 IIDepartment: Chemical production Surveyed by: B.A. Dawson Mackenzie I Furnaces Furnaces #1 furnace broken window Shop I I I Heat treating I I Assembly I I I Assembly I doors need xveatherstrip Shipping Receiving Receiving Laboratory Laboratory * Laboratory Utilities Chemicals Aministration reheat air Administration condition buildin Utilities I I Utilities I Chemicals I I Chemicals I

7 Plant L Electric power Natural gas Dil (or propane etc.) Energy intensity ratios + I kwh Maximum demand kw (1992) kw (1 991 ) Therms x 10 = MMBtu Gallons x - = MMBtu Total MMBtu No. of units produced kwh/unit M M Btu/un it Mar. I JdY Aug. Sept. Oct. Nov. Dec. - - Tota I Note: The above format can be modified as necessary for departmental or process energy use. Energy intensity ratios for other services such as compressed air, steam, condensate, or water can be added.

8 The Electric Ideas Clearinghouse is n cornprelieiisive iiiforinatiori soiirce for commercial arid iiidustrinl eiiergy users. It is operated by the Wasliiiigtorz State Energy Office arid is part of the Electric Ideas tecliiiology transfer program sporzsored by participatiizg utilities arid the Boiitimille Power Admiriistratior1. Technology Update CH-29 y Electric Ideas Cleariizglzowe 925 Pliiin St. S.E. P.O. Box Olyiripia, Washingtoon Toll-free Hotlirte: Fax: El ectroizic Bu 11 etirz Board: To obtain this factsheet in aiz nlterizate format contact the Clearit iglzouse. TDD (206) DOE/BP July C Adapted from B.C. Hydro. Energy Management for Industry. Guides to Energy Mangegment. GEM No December With permission from B.C. Hydro, Vancouver, British Columbia. 8