SALIENT ASPECTS OF ENERGY AUDIT SANJAY GHOSHAL BE (Gold Medalist), MBA CEA ,PROFESSIONAL ENGINEER K.RAMESH BE, CEACEM,FIE,FMSESI,CHARTERED ENGINEER (India)

What is Energy Audit ??? AN ENERGY AUDIT IS A PRELIMINARY ACTIVITY TOWARDS INSTITUTING ENERGY EFFICIENCY PROGRAMS IN AN ESTABLISHMENT. IT CONSISTS OF ACTIVITIES THAT SEEK TO IDENTIFY ENERGY CONSERVATION OPPORTUNITIES PRELIMINARY TO THE DEVELOPMENT OF AN ENERGY SAVINGS PROGRAM.

NEED FOR ENERGY AUDIT AN ENERGY AUDIT WILL: HELP TO UNDERSTAND HOW ENERGY AND FUEL ARE USED IN INDUSTRY IDETIFY AREAS WHERE WASTE OCCURS AND WHERE THERE IS SCOPE FOR IMPROVEMENT GIVE A POSITIVE ORIENTATION TO ENERGY COST REDUCTION TRANSLATE CONSRVATION IDEAS INTO REALITY

Energy Audit Definition As per Energy Conservation Act 2001, Energy Audit is defined as: “ The Verification, Monitoring & Analysis of use of energy, including submission of technical report containing recommendations for improving energy efficiency with cost benefit analysis and an action plan to reduce energy consumption”.

Types of Energy Audit Preliminary energy audit Detailed energy audit Type of Energy Audit   The type of Energy Audit to be performed depends on. -         the function and type of industry -         the depth to which final audit is needed, and -         the potential and magnitude of cost reduction desired Thus Energy Audit can be classified into the following two types. i)        Preliminary Audit ii)       Detailed Audit

Preliminary Energy Audit Also called simple audit or walk through audit It involves: i) minimal interview with site personnel ii) brief review of operating data iii) walk through of plant to --- Identify glaring areas of wastage & inefficiency Estimate the scope for saving Identify the most likely areas for attention Identify immediate ( no-/low-cost) improvements Set a ‘reference point’ Identify areas for more detailed study/measurement   2.      Collect the existing data e.g., a energy bills(volume/cost)      Collect the Production output/records plant layouts using checklists 3. Analyse data:      Find unit cost of energy (Rs./ kWh for all types)      Find fixed and variable energy element      Derive ‘energy Index’: energy cost/unit output ,energy cost/floor area 4.      Formulate plan: Formulate Immediate energy-saving actions: Where? How ? How much?          Areas to investigate further          Resources required for more detailed study 5.      Actions and monitoring Next steps (e.g. detailed audits), where needed

Detailed Energy Audit This Expands on the Preliminary Energy Audit by :- Collecting more detailed information of plant operations Identifying all energy conservation measures appropriate for the unit Performing more detailed evaluation of energy conservation measures identified Performing detailed financial analysis of each measure to justify implementation.

Energy Audit Methodology Comprehensive TEN Step Methodology involves: Interview with key Plant Personnel with focus on:- i) Audit objectives & scope of work ii) Plant rules and regulations iii) Roles and responsibilities of Audit Team Members iv) Description of scheduled project activities

Plant Tour:- After the initial meeting, a tour of the Plant is undertaken to:- i) Observe the various operations first hand ii) Focus on major Energy consuming systems identified during the interview including Lighting & Power, Mechanical and Process energy systems. Documentation Review:- Review plant documentation including – i) All available engineering plans ii) All service Utilities system diagram iii) Plant operation & maintenance procedures and logs iv) Annual Energy bills and consumption pattern

Plant Inspection :- i) For further investigation of major energy consuming processes ii) Taking field measurements to substantiate operating parameters iii) Conducting detailed trials and surveys such as Motor survey, insulation and lighting survey etc. Staff Interview:- Meet again with the department staff to – i) review the preliminary findings and recommendations being considered ii) Management input at this stage will help to establish the priorities that form the foundation of the Energy Audit

Plant Analysis Carry out an analysis of energy usage in the plant through:- i) Detailed review of “energy bills” of all purchased energy for the previous 12 to 36 months ii) Energy and material balance & energy loss/waste analysis This data is also used as a baseline to compute projected energy savings for the ‘Energy Conservation Measures’ (ECM)

Identify and Evaluate Suitable ECM’s An energy audit will uncover:- i) Major plant modifications requiring economic analysis ii) Minor operation modifications offering simple/quick pay backs A list of Major ECM’s is developed for each of the energy consuming systems (process, power, lighting) Based upon a final review and reaction of Plant personnel, a finalized list of ECM’s is developed and reviewed with the Plant Manager

Economic Analysis The data collected during the Audit is :- i) Processed and analyzed for technical and economic viability ii) Models are built and simulations done to reproduce field observations iii) Baseline is developed, against which to measure the energy savings potential of the identified ECM’s The implementation cost, energy savings and simple pay back period for each of the investigated ECM’s is calculated iv) Select the most promising projects and prioritise the ECM’s

Preparation of Final report The results are summarized in a Final Report This report includes:- i) Description of Plant and Operations ii) Discussion of all major energy consuming systems iii) Description of all recommended ECM’s with their specific energy impact iv) Implementation Costs v) Benefits & Pay back

Presentation to Top Management, Implementation and Follow Up The Final Recommendations are presented to the Top Management, to make a decision on which ECM’s are to be implemented Assist in implementation of Recommended ECM’s and monitoring of Performance Follow Up and periodically review the progress

Identification of Energy Conservation Opportunities Energy generation  Energy distribution: Energy usage by processes: Fuel substitution:

Benchmarking for energy performance Internal Benchmarking Historical and trend analysis External Benchmarking Across similar industries Scale of operation, vintage of technology, raw material specification and quality and product specification and quality

Benchmarking parameters Gross production related e.g. kWh/MT clinker or cement produced (cement plant) e.g. kWh/MT, kCal/kg, paper produced (Paper plant) e.g. kCal/kWh Power produced (Heat rate of a power plant) e.g. Million kilocals/MT Urea or Ammonia (Fertilizer plant) Equipment / utility related e.g. kWh/ton of refrigeration (on Air conditioning plant) e.g. % thermal efficiency of a boiler plant e.g. kWh/NM3 of compressed air generated e.g. kWh /litre in a diesel power generation plant. 

Optimizing Input Energy Requirement Shuffling of compressors to match needs. Periodic review of insulation thickness Identify potential for heat exchanger networking and process integration. Optimization of transformer operation with respect to load

Fuel and Energy Substitution Fuel substitution Natural gas is increasingly the fuel of choice as fuel and feedstock in the fertilizer, petrochemicals, power and sponge iron industries. Replacement of coal by coconut shells, rice husk,etc Replacement of LDO by LSHS Energy substitution Replacement of electric heaters by steam heaters Replacement of steam based hot water by solar systems

Energy Audit Instruments

Energy Audit Instruments

Energy Audit Instruments

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