ENERGY MANAGEMENT STRATEGIES

– Er. Roshan KC

“As a child I used to be scared of the dark, but now when I see my electricity bills I am scared of Lights.”

Energy has become the global topic of concern for all. With the energy demand trending to new heights, a greater need for operational efficiency, increasingly deregulated supply markets, and impending regulation of greenhouse gases has arisen. Suddenly energy management has been thrust to the forefront of long-term planning. Leading businesses are now looking at energy management as essential to their operations as accounting, supply management, or human resources.

Energy Management is simply defined as – “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”.

All too often, energy management occurs in the rear-view mirror. Only after bills arrive; do most businesses consider how energy use and spending might be better managed. Even then, bills contain very little information & we think on how energy was used? – What equipment or processes drove consumption? What time of day saw the most use? Was consumption as expected, or are utilities running inefficiently? Here are some of the energy management checklists applicable for the industries.

SN	Area	Objective	Requirements	Expected Benefits
1	Electrical Parameter – Power Factor (PF)	To maintain constant PF of 0.99	APFC panel with sufficient capacitor rating at appropriate locations.	Avoid penalty Get rebate in electricity bill as per the rules of local electricity board.
				KVA maximum demand is minimum. Get benefit in electricity bill.
				Optimum utilization of transformer.
2	Electrical Parameter – Maximum Demand (MD)	To keep electrical maximum demand to minimum possible and sanction demand.	Sanction contract demand has to be in line with actual maximum demand.	Required for avoiding any penalty or higher demand charges in electricity bill.
			Maximum demand controllers that will switch off the non critical load in case MD approach the contract demand.	This is an engineering control to ensure that actual MD is within contract demand.
			Avoid simultaneous operation of high HP motors.	This will help to minimize the maximum demand.
3	Electrical Parameter – TOD Billing	To reduce the average electricity rate.	Planning of maximum possible operations during minimum tariff period.	Reduce the total electricity bill based on tariff structure of local electricity board.
4	Transformer	To reduce transformer, cable losses.	Use of energy efficient transformer.	Helps to reduce the transformer losses.
			Optimum loading of transformer.	Improves the efficiency of the transformer.
			Transformer should be near to the load centers.	Reduces the LT network and hence the cable losses.
5	Power Generator	To minimize the cost of generation.	Use of cost effective fuel. (HSD, NG)	Cheaper the fuel, lesser will be the cost of generation.
			Auto synchronization and auto load sharing facility. Optimum loading of generator.	Ensures maximum Units/lit of fuel.
			Audio, visual indication of electricity board power status.	Avoids idle running of generator.
		To increase the reliability of power availability.	Auto main failure start (AMF), Auto transfer switch facility.	Starts the Generator automatically during power failure and the load transfer is also auto. Power reliability increased.
6	Electric Motors	To minimize the power consumption and to optimize the efficiency of electric motors.	While replacing rewound motors or purchasing new motors go for energy efficient motor (EFF1).	Full load efficiency of the energy efficient motors higher by 2 – 4% to standard motors.
				Considering a 75 HP motor with average load of 70% and operating for 12 hr per day, 300 days per annum and electricity rate Rs 6.00 per unit(assume); per annum saving with EFF1 motor over standard motor would be Rs 13000 approximately. -Payback period is 2 year. (Efficiency difference assumed is 1.5 %)
			If the motor is constantly underloaded, connect it in star mode.	Improves the efficiency of the motor.
			Whenever speed variation is required use VFD.	At lower speed, power consumption is less.
7	Air Compressors	To minimize power consumption and to optimize specific power consumption	Delivery pressure setting should be minimum possible.	Reduction in delivery pressure by 1 bar would reduce the power consumption by 6-10%.
			Air leakages should be minimized.	Leakage through an orifice of size 1.6 mm will result into wastage of 0.8 KW power. It’s equivalent to Rs 32000, assuming, operating hours – 8000, pressure – 7 bar and electricity rate – Rs 6 / KWh.
			Intake air temperature should be low.	Every 4°C rise in inlet air temperature results in a higher energy consumption by 1 % to achieve equivalent output.
			Location should be dust free and dry.	For every 250 mm WC pressure drop increase at the suction path due to choked filters etc, the compressor power consumption increases by about 2 % for the same output.
			Provide extra air receivers at points of high cyclic-air demand.	It permits operation without extra compressor capacity.
			A smaller dedicated compressor can be installed at load point, located far off from the central compressor house.	This avoids lengthy pipelines and hence losses.
			Usetwo separate compressed air systemsfor widely different pressure requirements.	At high pressure air compressor consumes high energy.
			A periodic assessment of the FAD (Free Air Delivery) capacity of each compressor. If the deviations > 10 %, corrective measures should be taken.	Ensuring efficient air compressor.
8	Cooling Tower	Efficient system operation.	Follow manufacturer’s recommended clearances around cooling towers	This ensures efficient operation of cooling tower.
			Consider energy efficient FRP blade adoption.	Saves fan motor energy.
			Clean the CT fills and nozzles regularly. Optimize blow down flow rate.	This ensures efficient operation of cooling tower.
9	HVAC	Minimization of power consumption and optimization of the efficiency.	Optimize the air-conditioning volumes by measures such as use of false ceiling.	Reduction in AC load.
			Set the room AC temperature optimally.	Lower temperature setting results in wastage of energy. Normally for human comfort setting is 24 deg C.
			Use evaporative cooling in dry areas.	It is less energy intensive as compared to AC.
			Go for water cooled chillers.	Better efficiency.as compared to air cooled chillers.,
			Use spare capacity of chiller for HVAC using fan coil unit.	Optimum, efficient and cost effective utilization of chiller.
			Optimum setting of chiller temperature.	A 1°C increase in evaporator temperature can help to save almost 3 % on power consumption.
			Minimize part load operations by matching loads and plant capacity on line; adopt variable speed drives for varying process load.	Efficient operation of chiller.
			Proper insulation of cold lines.	Avoids wastage of energy.
10	Lighting	Energy efficient lighting and to avoid wastage of energy	Use of energy efficient lighting – LED, CFL etc instead of incandescent lamps.	CFL saves 80% of electricity as compared to conventional incandescent lampand has more life. Certain indicating lamps are ‘ON’ continuously. Using LED lamps ensures savings in electricity.
			Use high efficiency stabilizer for lighting feeder.	Saves lighting electricity consumption upto 10-15%. Improves life of light fittings.
			Provide timers for street lights, go downs and other similar areas.	Ensures proper utilization of lighting.
			Use day light by use of translucent sheets.	Saves lighting energy.
			Use electronic ballast in place of conventional ballast.	This saves up to 35% of energy.
			Use activity sensors to switch off the lights when not required.	Avoids wastage of light.
			Use solar system for lighting.	Saves electricity.
11	Pumps	Efficient operation of pumps.	Use correct line size, minimum sharp elbows, valves having full openings, low frictional pipes.	This reduces the system resistance and hence losses.
			Replace old inefficient pumps with new efficient pumps based on cost benefit analysis.	Avoids wastage of electricity.
			Downsizing the main pump and installing a booster pump for high level users.	Power requirement reduces.
			In case of over designed pumps, provide VFD or downsize/replace/ trim impeller.	Avoids wastage of electricity.
			In pumping of liquid to multiple non-continuous users, control valves have to be installed at the users and install VFD for the pump.	Pump speed can be controlled as per load, ensuring optimum utilization of the electricity.
12	Fans and blowers	To avoid idle running.	Provide interlocks so that exhaust is operational only when intended operation is going on.	Avoids wastage of electricity.
			Provision for natural ventilation at operational area.	Avoids need for fans.
		Efficient Operation.	Provide VFD for dust collector / exhaust, in case of variable duty operation.	Fan / blower speed can be controlled as per load, ensuring optimum utilization of the electricity.
13	Process Equipment	To avoid unnecessary operation.	Provide timers to ensure unnecessary operation.	Avoids wastage of electricity.
14	Renewable energy	To reduce consumption of ‘Electricity board’ and DG set & promote to Renewable Energy	Use solar system for loads like lighting based on cost benefit analysis.	Alternate energy source.
			For heating application use solar energy based on cost benefit analysis.	Alternate energy source.

By adopting energy management strategies, businesses can regain control over their energy spending, turn costs into opportunities, reduce risk, and make smarter energy decisions. Smarter energy management has already helped thousands of commercial, institutional, and industrial customers put millions of investment back in their pockets through four key energy management strategies: reducing real-time demand for electricity, increasing energy efficiency, improving energy supply transparency, and mitigating greenhouse gas emissions. As the saying goes – “Saving is Generating” if we do so!

Roshan KC is an Industrial Engineer, and works as Assistant Project Manager at Iceland Water Park, Abu Dhabi. He can be reached at kcroshan23@gmail.com.