Energy Audit Case Study: Saraogi Paper Mills - Unlocking ₹76.7 Lakhs Annual Savings Through Strategic Energy Management
- Dr. Anubhav Gupta
- Jun 24
- 9 min read
Executive Summary
In May 2010, SARK Engineers & Consultants (formerly ANSH Energy Solutions Pvt. Ltd.) conducted a comprehensive electrical distribution network audit at Saraogi Paper Mills (P) Ltd., located in Kishanganj, Bihar[1]. This case study demonstrates how systematic energy auditing can unlock substantial cost savings and operational improvements in industrial facilities.
The paper manufacturing plant, with an installed capacity of 25 TPD (Tonnes Per Day), was operating under challenging power supply conditions - averaging only 10 hours of grid supply and 10 hours of diesel generator operation daily[1]. Through detailed technical analysis, our audit identified eight major energy-saving opportunities with a combined annual savings potential of ₹76,76,862, making this one of the most impactful energy audits in the paper industry sector[2][3].
Plant Overview and Energy Profile
Facility Details
Parameter | Value |
Client | Saraogi Paper Mills (P) Ltd. |
Location | Kishanganj, Bihar |
Production Capacity | 25 TPD |
Connected Load | 1,949 HP (1,450 KW) |
Effective Load | 500 KW |
Daily Operation | 20 hours (10 hrs grid + 10 hrs DG) |
Audit Duration | 19-21 May 2010 |
Lead Auditor | Anubhav Gupta (EA-10465) |
Energy Consumption Pattern for the Paper Mill
The facility's energy profile revealed significant dependency on expensive diesel generators due to unreliable grid supply[4]. This dual-energy scenario created unique challenges and opportunities for optimization, as energy costs varied dramatically between grid supply (₹4.50/kWh average) and DG operation (₹11.50/kWh average)[5].
Key Technical Findings
Transformer Performance Analysis
The existing 750 KVA transformer showed the following characteristics:
Parameter | Measured Value | Standard/Optimal |
Loading Percentage | 83.6% | 75-85% (Optimal) |
Efficiency | 99% | Excellent |
Power Factor | 0.92 | Good |
Voltage Unbalance | 1.57% | >1% (Concerning) |
Current Unbalance | 2.76% | >1.5% (Action Required) |
System Unbalance: A critical finding was the voltage unbalance of 1.57% and current unbalance of 2.76%[6]. System unbalance is the deviation of voltage or current values from their average across the three phases in a three-phase electrical system. Even 1% voltage unbalance can increase system losses by 5%, making this a priority area for correction[7].
Motor Loading Assessment
Our comprehensive motor survey revealed significant underloading across the facility:
Motor Application | Rated Power (HP) | Measured Power (KW) | Loading (%) | Power Factor |
Boiler FD Fan | 60 | 11.0 | 24.4% | 0.70 |
Boiler ID Fan | 60 | 11.0 | 24.4% | 0.50 |
Feed Pump | 40 | 10.0 | 33.3% | 0.56 |
17" TDR | 120 | 43.0 | 47.8% | 0.83 |
Main Motor | 150 | 66.0 | 58.7% | 0.86 |
Vacuum Pump | 50 | 36.4 | 95.8% | 0.87 |
Motor Loading Analysis: Approximately 90% of motors were operating below 50% loading, resulting in poor efficiency and low power factor[8]. Motor efficiency drops significantly at partial loads - a motor operating at 25% load typically achieves only 60% efficiency compared to 85% at full load[9].
Energy Saving Opportunities Identified
1. Transformer Optimization (₹3.51 Lakhs Annual Savings)
Recommendation: Replace the existing 750 KVA transformer with a new 1000 KVA transformer equipped with On-Load Tap Changer (OLTC), Automatic Voltage Regulator (AVR), and Remote Tap Change Control (RTCC)[5].
Technical Benefits:
OLTC Technology: Allows voltage regulation without interrupting supply, maintaining optimal voltage levels
Improved Motor Efficiency: 3-4% efficiency improvement due to regulated voltage supply
Enhanced Power Quality: Reduced voltage fluctuations and better system stability
Financial Analysis:
Investment: ₹7.5 lakhs (net after resale value)
Annual Savings: ₹3,48,633
Payback Period: 26 months
ROI: 46%
2. Star-Delta Converter Implementation (₹10.37 Lakhs Annual Savings)
Recommendation: Install automatic star-delta converters for motors operating below 55% loading[2].
Technical Principle: When a motor operates in star connection, its rating reduces by √3 times (1.732), improving efficiency at partial loads. Star-delta converters automatically switch between connections based on load conditions[4].
Implementation Scope: 12 motors totaling 399 KW
Delta mode efficiency at 25% loading: 70%
Star mode efficiency at equivalent loading: 80%
Power savings: 18 KW continuous
Financial Analysis:
Investment: ₹2.52 lakhs
Annual Savings: ₹10,36,800
Payback Period: 3 months
ROI: 411%
3. Energy Efficient Motor Replacement (₹38.59 Lakhs Annual Savings)
Recommendation: Replace 80% of old/rewound motors with new energy-efficient motors[3].
Efficiency Comparison:
Old motors: 82% average efficiency
New energy-efficient motors: 95% efficiency
Power reduction: 67 KW for 400 KW load
Financial Impact:
Investment: ₹16 lakhs
Annual Savings: ₹38,59,200
Payback Period: 5 months
ROI: 241%
4. Electrical Grounding System Overhaul (₹13.25 Lakhs Annual Savings)
Critical Finding: Grounding currents totaling 109A were identified, indicating poor earthing practices[6]. One earthing strip measured 212V to ground, essentially creating an ungrounded system condition.
Technical Impact: Poor grounding results in:
Circulating currents causing 23 KW continuous losses
Equipment overheating and reduced life
Safety hazards for personnel
Power quality issues
Solution: Install 20 independent grounding pits with proper earthing strips
Investment: ₹2 lakhs
Annual Savings: ₹13,24,800
Payback Period: 2 months
ROI: 662%
Power Quality and Distribution Improvements
Power Factor Enhancement
The facility's power factor varied significantly across different panels:
Main transformer panel: 0.95-0.98
Individual MCC panels: 0.80-0.85
Transmission & Distribution Loss Reduction: By redistributing capacitors from main panels to individual motor starters, T&D losses can be reduced by 10%[7].
Calculation:
Current T&D losses: 10% of total consumption
Annual loss reduction: 36,000 kWh
Cost savings: ₹2,88,000 annually
Implementation cost: Minimal (capacitor relocation)
Lighting System Modernization
Current Lighting Load: 63 KW comprising:
Item Type | Unit Wattage | Quantity | Total Load (W) |
Tube Lights | 55W | 150 | 8,250 |
Incandescent Lamps | 100W | 40 | 4,000 |
Fans | 60W | 50 | 3,000 |
CFLs | 14W | 100 | 1,400 |
Others | - | - | 46,250 |
Energy Efficiency Opportunity:
Replace 55W tube lights with 28W energy-efficient alternatives
Replace 100W lamps with 27W equivalents
Annual savings: 30,110 kWh (₹2,40,880)
Investment: ₹66,500
Payback: 3 months
Diesel Generator Performance Analysis
Current DG Performance
Parameter | 380 KVA Set | 250 KVA Set |
Loading | 79.47% | 87.20% |
Fuel Consumption | 70 L/hr | 50 L/hr |
Units per Liter | 3.6 kWh/L | 3.28 kWh/L |
Generation Cost | ₹11/kWh | ₹12/kWh |
Efficiency | 31% | 28% |
DG Efficiency: Diesel generator efficiency of 28-31% is typical for industrial sets[5]. The high fuel cost (₹11.50/kWh average) compared to grid supply (₹4.50/kWh) emphasizes the importance of maximizing grid utilization and minimizing DG dependency[4].
Implementation Strategy and Financial Benefits
Comprehensive Savings Summary
Energy Conservation Measure | Annual Savings (₹) | Investment (₹) | Payback Period | ROI (%) |
Transformer No-load Loss Reduction | 2,549 | 7,000 | 33 months | 36 |
New 1000 KVA Transformer | 3,48,633 | 7,50,000 | 26 months | 46 |
T&D Loss Reduction | 2,88,000 | Minimal | Immediate | - |
Star-Delta Converters | 10,36,800 | 2,52,000 | 3 months | 411 |
Energy Efficient Motors | 38,59,200 | 16,00,000 | 5 months | 241 |
Grounding System | 13,24,800 | 2,00,000 | 2 months | 662 |
Motor Maintenance | 5,76,000 | Nil | Immediate | - |
Lighting Modernization | 2,40,880 | 66,500 | 3 months | 362 |
Total | ₹76,76,862 | ₹28,75,500 | 4.5 months | 267% |
Technical Definitions and Key Terms
Energy Audit Terminology
Energy Audit: A systematic analysis of energy use and consumption to identify opportunities for energy efficiency improvements[2]. It involves detailed measurement, analysis, and recommendations for reducing energy costs while maintaining or improving operational performance.
Power Factor: The ratio of active power (kW) to apparent power (kVA), indicating how effectively electrical power is being used[7]. A power factor of 0.95 means 95% of the electricity supplied is being used productively.
System Unbalance: The deviation of voltage or current values from their average across three phases in a three-phase system[6]. Unbalance causes additional losses and reduces equipment life.
Transmission & Distribution (T&D) Losses: Electrical energy losses occurring in transformers, cables, and distribution equipment, typically 3-10% of total consumption in industrial facilities[8].
Motor Loading: The percentage of a motor's rated capacity at which it operates[9]. Optimal loading is typically 75-85% for maximum efficiency.
Conclusion and Recommendations
This comprehensive energy audit of Saraogi Paper Mills demonstrates the significant potential for energy cost reduction in industrial facilities through systematic analysis and targeted interventions[3]. The identified savings of ₹76.7 lakhs annually, with an overall payback period of just 4.5 months, represents exceptional return on investment[5].
Key Success Factors:
Comprehensive Assessment: Covering all major energy-consuming systems
Data-Driven Analysis: Using actual measurements rather than assumptions
Phased Implementation: Prioritizing high-impact, low-cost measures
Technical Expertise: Professional audit methodology and advanced diagnostic tools
The case study highlights how energy auditing serves as a critical business tool for industrial competitiveness, environmental sustainability, and operational excellence[2]. For manufacturing facilities facing similar challenges with power supply reliability and energy costs, this approach provides a proven pathway to substantial savings and improved operational efficiency.
For comprehensive energy audit services and implementation support, contact SARK Engineers & Consultants - your trusted partner in industrial energy optimization.
Citations
https://elion.co.in/case-studies-successful-energy-audits-in-indian-industries/
https://elion.co.in/case-study-of-an-energy-audit-at-a-paper-mill-in-muzaffarnagar-uttar-pradesh/
https://www.slideshare.net/slideshow/case-study-of-energy-audit/27121064
https://sdatripura.in/wp-content/uploads/2020/11/GuidelinesforpreparationofEnergyAuditReports.pdf
https://test-english.com/writing/b1-b2/writing-a-how-to-article-for-a-blog-or-magazine/3/
Frequently Asked Questions (FAQs) about Electrical Energy Audits:
What is an Electrical Energy Audit?
An electrical energy audit is a systematic process of inspecting, analyzing, and optimizing the electrical consumption within a facility or organization. It involves measuring and monitoring electrical loads, identifying areas of energy waste, and recommending solutions to improve efficiency, reduce costs, and enhance the reliability of electrical systems.
Why is an Electrical Energy Audit important?
Electrical energy audits are crucial for several reasons:
Cost Reduction: They identify opportunities to significantly lower electricity bills by optimizing usage and reducing waste.
Improved Efficiency: They lead to better utilization of electrical assets and overall operational efficiency.
Enhanced Reliability: Addressing issues like voltage unbalance or poor power factor can extend equipment lifespan and prevent breakdowns.
Sustainability: Reducing energy consumption directly lowers carbon footprint and supports environmental goals.
Compliance: In some regions or for certain industries, energy audits may be mandatory for regulatory compliance.
Safety: Identifying issues like overloaded circuits or improper grounding can enhance electrical safety.
Who can benefit from an Electrical Energy Audit?
Almost any organization with significant electrical consumption can benefit, but it's particularly valuable for:
Manufacturing Plants & Industrial Facilities
Commercial Buildings & Offices
Hotels & Hospitality Sector
Hospitals & Healthcare Facilities
Educational Institutions
Data Centers
Large retail chains
What are the key areas typically assessed in an Electrical Energy Audit?
A comprehensive electrical energy audit usually covers:
Transformers: Loading, efficiency, no-load losses, voltage regulation.
Motors: Loading levels, efficiency, power factor, age, application suitability.
Lighting Systems: Type, wattage, usage patterns, control systems.
HVAC Systems: Electrical consumption of chillers, pumps, fans (though a full HVAC audit is separate, the electrical input is crucial).
Power Quality: Power factor, voltage/current unbalance, harmonics.
Electrical Distribution Network: Cabling, switchgear, panel losses, grounding.
Diesel Generators (DGs): Loading, fuel consumption, efficiency, grid vs. DG optimization.
Metering and Monitoring Systems: Accuracy and adequacy of existing meters.
What kind of data is collected during an Electrical Energy Audit?
Auditors collect various data points using specialized instruments (e.g., power analyzers, clamp meters, thermal cameras) and historical records:
Voltage, current, power (kW, kVA, kVAr)
Power factor and harmonics
Equipment run hours and load profiles
Temperature measurements (e.g., for transformers, motors)
Electricity bills and consumption data
Equipment specifications (nameplate data for motors, transformers, etc.)
Operational schedules and maintenance logs
What are common energy-saving opportunities identified in electrical audits?
Typical recommendations include:
Power Factor Correction: Installing capacitors to improve power factor and reduce reactive power penalties.
Motor Efficiency Upgrades: Replacing old/underloaded motors with energy-efficient (IE3/IE4) motors or using Variable Frequency Drives (VFDs).
Lighting Modernization: Replacing traditional lighting with LED technology and implementing smart controls.
Transformer Optimization: Replacing old transformers, optimizing loading, or using energy-efficient amorphous core transformers.
Addressing System Unbalance: Correcting voltage and current imbalances to reduce losses and improve equipment life.
Improved Grounding: Overhauling grounding systems to eliminate stray currents and reduce losses.
Optimal DG Operation: Maximizing grid utilization and ensuring DGs operate at optimal loads.
Transmission & Distribution (T&D) Loss Reduction: Optimizing cable sizes, connections, and distribution layout.
What is Power Factor and why is it important in an Electrical Energy Audit?
Power Factor (PF) is the ratio of active power (useful power consumed by equipment, measured in kW) to apparent power (total power drawn from the grid, measured in kVA). It indicates how effectively electrical power is being utilized.
Importance: A low power factor means more current is needed to deliver the same amount of useful power, leading to:
Higher electricity bills (due to KVAH penalties or higher demand charges).
Increased losses in cables and transformers.
Reduced system capacity (less available power for useful work).
Fines from utility providers.
Audits identify opportunities to improve PF (e.g., through capacitor banks).
What is Voltage/Current Unbalance and why is it a concern?
System Unbalance refers to the deviation of voltage or current values from their average across the three phases in a three-phase electrical system.
Concern: Even small unbalances (e.g., >1% voltage unbalance) can lead to:
Significant increases in motor losses and overheating (motors are particularly sensitive).
Reduced motor lifespan and efficiency.
Increased current in the neutral conductor.
Malfunctioning of sensitive electronic equipment.
Audits measure unbalance and recommend corrective actions like load balancing or checking transformer tap settings.
How are savings calculated and what is ROI/Payback Period in an audit report?
Savings Calculation: Annual energy savings are estimated by quantifying the reduction in kWh consumption and multiplying it by the average energy cost. For industries using DGs, the savings are also calculated based on reduced fuel consumption.
Return on Investment (ROI): Measures the profitability of an investment. It's calculated as (Annual Savings / Investment Cost) * 100%.
Payback Period: The time it takes for the investment cost to be recovered through annual savings. It's calculated as (Investment Cost / Annual Savings). A shorter payback period and higher ROI indicate a more financially attractive recommendation.
Who should conduct an Electrical Energy Audit?
For reliable and actionable results, electrical energy audits should be conducted by certified energy auditors or specialized energy consulting firms with a proven track record. These professionals possess the necessary technical expertise, instrumentation, and understanding of industry best practices and regulatory requirements.
How often should an Electrical Energy Audit be conducted?
The frequency depends on the facility's energy intensity, operational changes, and regulatory mandates.
Highly energy-intensive industries or those under specific regulations (e.g., PAT scheme in India) might require audits every 1-3 years.
Other facilities may benefit from a comprehensive audit every 3-5 years.
It's also advisable to conduct an audit after significant expansion, equipment upgrades, or if there's an unexplained spike in energy consumption.
Regular internal monitoring should complement formal audits.
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