• Electrical India
  • Sep 5, 2015

Energy Conservation   

Energy conservation is nothing but a strategic use of energy in order to reduce the energy requirements per unit output. Energy conservation in domestic sector is a good point to start as about 20 to 30% of the total energy generated is utilised for domestic purpose, which is a considerable share...   

- Vishal Kumar Gaur

& Bhavesh R Bhalja


 Better living standards, modernisation, industrialisation or development in all aspects is closely related with energy consumption. According to the International Energy Agency (IEA, 2007, p.74) projections, world primary energy demand expected to exceed half between 2005 and 2030 with an average annual rate of 1.8%. In the twenty first century, energy consumption is increasing at the fastest rate in developing nations due to rapid population growth, modernisation, urbanisation, industrialisation and economic development. According to IEA (2007, p.77) projection, developing countries expected to contribute approximately 74% of the increase in global primary energy consumption from 2005 to 2030.
India is also a very fast developing country. Like every country, India is also continuously increasing its power generation capacity. India has increased its installed capacity from 1362 MW in 1947 to 271,722 MW in 2015 with major portion (approx 70%) of thermal based generation. In spite of such growth in generation, the imbalance between demand and generation of electrical energy is increasing every year. This imbalance in power generation and demand is because of India’s vast population of more than 1.28 billion, and limited natural energy sources present in India. The developing countries like India are obliged to maintain a certain growth rate for which energy is ingredient.

  Japan and U.S.A. has lower energy intensity per unit of GDP compared to India. India has 3.7 times and 1.55 times energy per unit GDP in reference of Japan and U.S.A. respectively. This clearly indicates the inefficient use of electricity in India also responsible for imbalance between generation and demand. So there are two terms energy efficiency and energy conservation, which have their own significance in electricity sector. The reduction in gap between demand and generation needs efficient use of energy and its conservation. Efficient use and conservation has its importance in view of the fact that if we save one unit of consumption reduces the need of generation from 1.5 to 3 times of it. Generation of additional electricity is costly and needs long time in establishment, but the energy conservation activities can be implemented in short time period – and will reduce the gap between generation and demand at comparatively low investment.

  Energy conservation is nothing but a strategic use of energy in order to reduce the energy requirements per unit output.

  In India, for energy conservation and efficient use of energy, Bureau of Energy Efficiency (BEE) implements norms for appliances etc. BEE also started 'Star Rating System' for electrical appliances i.e. lamps, geysers, television etc. In star system, 5 star indicates that it gives highest efficiency in this segment.

Strategies for energy saving in industry sector

  Energy conservation options available in industrial sector are as diverse as the industries themselves. Most of the industries mainly use electric motors, compressors, boilers, furnaces etc.

  Electric motors: Half of the total energy consumption is due to motors used for processes in industry that may give sufficient options for financial savings from energy consumption. Remarkable savings can be achieved with regard to the selection and operation of electric motors by following four things: energy efficient motors, variable speed drives, correct size or rating motor, regular or routine maintenance.

  • Energy efficient motor: Most energy efficient motors use high quality materials for construction and also use latest manufacturing techniques. These motors require less input energy for same output compared to normal motors with reduced vibration, noise, and heat. In our country too, we are following global standards for manufacturing of such high efficient motors.
  • Variable speed drives: Machinery that are equipped with facility to control the speed of machinery. Many industrial processes need drives, which should be capable of operating at different speeds. Process control and energy conservation are two primary reasons for using variable speed drives.
  • Proper rating motors: In industry many motors works on partial loading. If it is much less than full rating, reduction in efficiency may be significantly large. It should be preferred to use less number of motors operating at full load, instead of more number of motors operating at partial load. However, it should also be taken care of that the motor is not significantly oversized too for the usual load. 
  • Maintenance of motors: Maintenance of motors is necessary to ensure the limit on motor temperature, noise, vibration, and other operating parameters. It increases the life cycle of motor as well as energy efficiency of motor. The saving in terms of energy consumption could range from 5 to 25% of consumption by the total motor unit.
  • Compressed air system: The process of compressed air system generates considerable amount of heat. In many applications, excess heat or waste heat from the compressed air system can be used for space heating and/or in further process. In such cases, heat recovery from compressed air can increase the overall efficiency and can make the system more effective.
  • Power factor correction device: In many industries, plants operate with low power factors, which increase the per unit generation cost. Government also implemented policies/tariff for industry customers in terms of limit at operating power factor. Use of power factor device at user end of industry customers can help in improving the power factor of the plant.

Strategies for energy saving in domestic Sector

  Energy conservation in domestic sector is a good point to start as about 20 to 30% of the total energy generated is utilised for domestic purpose, which is a considerable share.

  Lightning System: Light bills can be cut down by use of energy efficient bulbs and by using proper light fittings or arrangements. There are two main energy efficient bulbs: Compact fluorescent lamps (CFL), and Light Emitting Diode (LED).

  • CFL, LED produces visible light from electricity with efficiency more than five times compared to ordinary bulbs. In other words, it can be stated that it saves about more than 60% of energy for the equal lightning level. 
  • Use task lightning, which concentrate mainly only in the space where it is required.
  • Always use light coloured surface in workspace. Light surface reflects more light and reduce the required number of lamps for same intensity of light or illumination in space.
  • Place lamps in corners of rooms, where they can reflect light from two wall surfaces instead of one.
  • Try to use natural lightning as much as possible.

  Government has also taken initiative with energy companies to remove less efficient light bulbs from the market. Light bulb manufacturers are also changing or modifying their factories and adopting technologies to produce energy efficient bulbs.

  Air conditioners: In typical family house of our country, air conditioning uses more electricity than anything else - more than 15 to 25% of total electricity used.

  • In summer, ceiling or table fan can be used against heat. Compared to air conditioner (7-10 Rs/hour), ceiling fans costs about 1-2 Rs/hour to operate.
  • If we set temperature to above 220C, then we can save 3 to 5% energy for each degree above 220C. It is always recommendable to set the temperature of air conditioner at 250C to have the better comfort at least energy usage.
  • Generally air conditioner cool and reduce the humidity level of room in less than half an hour, so use sleep mode or timer and keep the air conditioner off for sometime. 
  • Remove dust from filter every month, it help in proper airflow. It also enables the unit to cool down quickly and use less energy.
  • West and south walls exposed to sunlight during major part of the day in summer. Therefore, it is always recommendable to place air conditioner in north and east.

  Refrigerator: Refrigeration is a common need of every house. Proper use and precautions can save considerable amount of energy.

  • Do not keep your refrigerator and freezer at very low temperature. Energy usage may go high up to 20 to 30%, if we set it to 2 to 3 degrees lower than required.
  • Never place refrigerator against west and south facing walls which are exposed to direct sunlight. 
  • Before placing food items, always letting it cool at room temperature.
  • Always lid off or cover the liquid items in the refrigerator. It is because liquids may get vaporised and can add load to compressor.
  • We can reduce the amount of time the door remains open. If we think about what we need before opening refrigerator door. 
  • Clean the condenser coils regularly to make sure that air can circulate freely. Otherwise, the motor will be more loaded to circulate the air and will consume more energy.

  Washing Machines: In this 21st century, washing machine is a common need of every house. Energy consumption for washing machines can account for as much as 20% of the electricity bill.

  • Each cycle of washing uses many liters of water. For efficient use, machine should operate on full load and should also plan periodic wash to save on water too.
  • Do not use too much detergent. It causes more time to wash and may require more energy for extra rinses.
  • Soak or pre-wash the cloths for effective cleaning and to save time of washing. It indirectly saves energy consumption.

  Geyser/Water Heater: Heating water in a geyser can be an expensive task if not done correctly. A water geyser requires a lot of energy to heat water. This high consumption of electricity shoots up the electricity bill during winters. Therefore in order to lower the monthly electricity bills, it is very important to use water geysers in a right way.

  • There are two types of geysers available in the market: One with thermostat settings outside and changeable, other where thermostat is not visible from outside and cannot be changed. Most geysers available in market have a default thermostat setting of 60 degree or high. This means that water in your geyser will be heated till it reaches a temperature of 60 degrees or high. Water heated up to this temperature becomes extremely hot and needs to be mixed with lot of cold water before use. According to many energy saving groups, water that is heated up to 40 to 45 degrees C is good to use. So, if you have a geyser with outside thermostat setting, change it from 60 degrees to 40 to 45 degrees C.
  • Do not keep water geyser ON for longer duration. Many people have a tendency of leaving the geyser 'ON' all the time. This tendency leads to lot of electricity wastage. Once the water is heated the power supply automatically cuts off. After some time hot water begins to loose the heat through the body of geyser. This way the temperature of water comes down after sometime. Once the temperature of the water is down by certain degrees, the thermostat switches on the power supply and water heating process starts all over again. This on-off process repeats all through the day and consumes electricity.
  • Select the right sized geyser as per your requirement. An over-sized geyser means heating extra water that is not required
  • Install solar water heating system.
  • Use BEE labeled product. Five Star rated geysers consume less electricity for heating water as well as have much less heat loss.

Authors are from IIT Roorkee & ADIT, Gujarat.

According to you, which is the best strategy for energy saving in industry sector? Comment your answer now!