ENERGY MANAGEMENT AND AUDIT
1. Definition & Objectives of Energy Management
The fundamental goal of energy management is to produce goods and provide services with the least cost and least environmental effect. The term energy management means many things to many people. One definition of energy management is:"The judicious and effective use of energy to maximize profits (minimize costs) and enhance competitive positions" (Cape Hart, Turner and Kennedy, Guide to Energy Management Fairmont press inc. 1997).
"The strategy of adjusting and optimizing energy, using systems and procedures so as to
reduce energy requirements per unit of output while holding constant or reducing total
costs of producing the output from these systems"
The objective of Energy Management is to achieve and maintain optimum energy procurement
and utilization, throughout the organization and:
• To minimize energy costs / waste without affecting production & quality
• To minimize environmental effects.
2. Need for Energy Audit
In any industry, the three top operating expenses are often found to be energy (both electrical
and thermal), labour and materials. If one were to relate to the manageability of the cost or
potential cost savings in each of the above components, energy would invariably emerge as a
top ranker, and thus energy management function constitutes a strategic area for cost reduction.
Energy Audit will help to understand more about the ways energy and fuel are used in any
industry, and help in identifying the areas where waste can occur and where scope for improvement
exists.
The Energy Audit would give a positive orientation to the energy cost reduction, preventive
maintenance and quality control programmes which are vital for production and utility activities.
Such an audit programme will help to keep focus on variations which occur in the energy
costs, availability and reliability of supply of energy, decide on appropriate energy mix, identify
energy conservation technologies, retrofit for energy conservation equipment etc.
In general, Energy Audit is the translation of conservation ideas into realities, by lending
technically feasible solutions with economic and other organizational considerations within a
specified time frame.
The primary objective of Energy Audit is to determine ways to reduce energy consumption
per unit of product output or to lower operating costs. Energy Audit provides a " bench-mark"
(Reference point) for managing energy in the organization and also provides the basis for planning
a more effective use of energy throughout the organization.
3. Type of Energy Audit
The type of Energy Audit to be performed depends on:
- Function and type of industry
- Depth to which final audit is needed, and
- Potential and magnitude of cost reduction desired
Thus Energy Audit can be classified into the following two types.
i) Preliminary Audit
ii) Detailed Audit
3.2.3 Preliminary Energy Audit Methodology
Preliminary energy audit is a relatively quick exercise to:
• Establish energy consumption in the organization
• Estimate the scope for saving
• Identify the most likely (and the easiest areas for attention
• Identify immediate (especially no-/low-cost) improvements/ savings
• Set a 'reference point'
• Identify areas for more detailed study/measurement
• Preliminary energy audit uses existing, or easily obtained data
Detailed Energy Audit Methodology
A comprehensive audit provides a detailed energy project implementation plan for a facility, since it evaluates all major energy using systems. This type of audit offers the most accurate estimate of energy savings and cost. It considers the interactive effects of all projects, accounts for the energy use of all major equipment, and includes detailed energy cost saving calculations and project cost. In a comprehensive audit, one of the key elements is the energy balance. This is based on an inventory of energy using systems, assumptions of current operating conditions and calculations of energy use. This estimated use is then compared to utility bill charges. Detailed energy auditing is carried out in three phases: Phase I, II and III.
Phase I - Pre Audit Phase
Phase II - Audit Phase
Phase III - Post Audit Phase
3.1 Phase I -Pre Audit Phase Activities
A structured methodology to carry out an energy audit is necessary for efficient working. An initial study of the site should always be carried out, as the planning of the procedures necessary for an audit is most important.
Initial Site Visit and Preparation Required for Detailed Auditing -
An initial site visit may take one day and gives the Energy Auditor/Engineer an opportunity to meet the personnel concerned, to familiarize him with the site and to assess the procedures necessary to carry out the energy audit.
During the initial site visit the Energy Auditor/Engineer should carry out the following actions: -
• Discuss with the site's senior management the aims of the energy audit.
• Discuss economic guidelines associated with the recommendations of the audit.
• Analyse the major energy consumption data with the relevant personnel.
• Obtain site drawings where available - building layout, steam distribution, compressed air distribution, electricity distribution etc.
Tour the site accompanied by engineering/production The main aims of this visit are: -
• To finalise Energy Audit team •
To identify the main energy consuming areas/plant items to be surveyed during the audit.
• To identify any existing instrumentation/ additional metering required.
• To decide whether any meters will have to be installed prior to the audit eg. kWh, steam, oil or gas meters.
• To identify the instrumentation required for carrying out the audit.
• To plan with time frame
• To collect macro data on plant energy resources, major energy consuming centers
• To create awareness through meetings/ programme
3.2 Phase II- Detailed Energy Audit Activities
Depending on the nature and complexity of the site, a comprehensive audit can take from several
weeks to several months to complete. Detailed studies to establish, and investigate, energy
and material balances for specific plant departments or items of process equipment are carried
out. Whenever possible, checks of plant operations are carried out over extended periods of
time, at nights and at weekends as well as during normal daytime working hours, to ensure that
nothing is overlooked.
The audit report will include a description of energy inputs and product outputs by major
department or by major processing function, and will evaluate the efficiency of each step of the
manufacturing process. Means of improving these efficiencies will be listed, and at least a preliminary
assessment of the cost of the improvements will be made to indicate the expected payback
on any capital investment needed. The audit report should conclude with specific recommendations
for detailed engineering studies and feasibility analyses, which must then be performed
to justify the implementation of those conservation measures that require investments.
The information to be collected during the detailed audit includes: -
1. Energy consumption by type of energy, by department, by major items of process equip ment, by end-use
2. Material balance data (raw materials, intermediate and final products, recycled materials, use of scrap or waste products, production of by-products for re-use in other industries, etc.)
3. Energy cost and tariff data
4. Process and material flow diagrams
5. Generation and distribution of site services (eg.compressed air, steam).
6. Sources of energy supply (e.g. electricity from the grid or self-generation)
7. Potential for fuel substitution, process modifications, and the use of co-generation systems (combined heat and power generation).
8. Energy Management procedures and energy awareness training programs within the
establishment.
Existing baseline information and reports are useful to get consumption pattern, production cost
and productivity levels in terms of product per raw material inputs. The audit team should collect
the following baseline data:
- Technology, processes used and equipment details
- Capacity utilisation
- Amount & type of input materials used
- Water consumption
- Fuel Consumption
- Electrical energy consumption
- Steam consumption
-Other inputs such as compressed air, cooling water etc
- Quantity & type of wastes generated
- Percentage rejection / reprocessing
- Efficiencies / yield
4. References-
- Bureau of Energy Efficiency