EFFICIENT MANAGEMENT OF ENERGY CONSERVATION

by – K.Sivakumar, Larsen & Toubro Limited, Switchgear Training Centre, Coonoor – 643243. T.N.

(Paper presented at the Technical Seminar on the above topic, organized by the Tamilnadu Electrical Installation Engineers’ Association (‘A’ Grade) at Coimbatore on March 17, 2007)

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(Published in the April 2007 issue of “Electrical Installation Engineer” – the monthly technical newsletter of the Tamilnadu Electrical Installation Engineers’ Association ‘A’ Grade)

Introduction:

In today’s power scenario, we are facing a major power crunch. Day by day, the gap between demand and supply of electric energy is widening. At present, the difference is about 9%, going up to about 12.8% in the peak period. Bridging this gap from the supply side is a very difficult and expensive proposition. Also, limited energy resources, scarcity of capital and high interest costs for the addition of new generation capacity is leading to the increased cost of electrical energy in India. The only viable way to handle this crisis, apart from capacity addition, is the efficient use of available energy, which is possible only by continuously monitoring and controlling the use of electric energy.

Indian Energy Scenario:

Generation capacity increased from 1, 400MW in 1947 to 1, 28, 000 MW in 2006.

Gross generation increased more than 100-fold – from 5 billion units per year to 600 billion units per year in the same period.

Still, the per capita electricity consumption is one of the lowest in the world @ 600kWh per annum.

Percentage of population with access to electricity is only 43% as against 98.6% in China and 52.9% in Pakistan.

In spite of added generation capacity, it is still inadequate – peak shortage @ 12.8% and energy shortage @ 9%.

Below Optimum Utilisation of existing generation capacity – Plant Load Factor only 72%.

High T & D Losses – 45 to 50% as against International standards of 8 to 10%.

Inefficient Utilisation of electric power by end consumer – Planning Commission estimates that over 25, 000MW equivalent capacity creation could be achieved through efficient utilization of electric energy by the end user.

Need to Conserve Energy:

Ever increasing energy tariff

Huge Demand-Supply Gap

Efficient Use of Energy

Efficient Use of Equipment

To reduce cost of Production

Why Industry?

Industry Consumes about 50% of Energy Produced in the Country

Motors consume about 72% of power consumed in the industry

Lighting consumes another 13% of energy

Hence, huge scope for energy saving

A small step in the right direction would help national economy too

Areas of Energy Conservation:

Motors

Lighting

HVAC

Reactive Power Management

Power Quality

Energy Monitoring Instruments:

To control and to conserve energy one needs to continuously measure and monitor the consumption of energy and its constituent units. There is a wide variety of energy measuring and monitoring instruments available in the market place. Some of the popular energy monitoring instruments are:

SINGLE PHASE ELECTRONIC ENERGY METER (MODEL - EM101 of L & T) – To monitor the active energy consumption of Single Phase Loads.

THREE PHASE ELECTRONIC ENERGY METER (MODEL – EM 201/ EM 301 of L & T) – To monitor the active energy consumption of Three Phase Loads – Available in 3 Phase, 3Wire (Balanced Loads) or 3 Phase, 4 Wire (Unbalanced Loads) Versions; whole current meters and CT operated meters available.

THREE PHASE ELECTRONIC ENERGY METER (MODEL – ACRUX of L & T) – To monitor the active energy consumption of Three Phase Loads – Available in 3 Phase, 3Wire (Balanced Loads) or 3 Phase, 4 Wire (Unbalanced Loads) Versions; very compact size; only 96 x 96 sq.mm

ELECTRONIC TRIVECTOR METER WITH MD CONTROLLER (Type ER300 SERIES – ER 300P/ER 300N/ER 300D of L & T) – For the measurement & recording of Active, Reactive & Apparent Energies; Can also control loads through output relays, if and when the load exceeds the sanctioned maximum demand; Also monitors other parameters like voltage, current, pf, frequency, etc.; Computer communication possible.

INTELLIGENT MULTIFUNCTION DIGITAL METER (Type QUASAR of L & T) – Compact meter for the measurement & recording of Active, Reactive & Apparent Energies; Also monitors other parameters like voltage, current, pf, frequency, etc.; Computer communication possible.

ENERGY MANAGEMENT SOFTWARE ( LnT EMS V ersion 1.0): With a suitable combination any of the above computer communicable energy meters and with computer communicable intelligent microprocessor based relays, energy measurement, monitoring, reporting, management, administration and control could be achieved from a central control station, using the energy management software. Also, complete history & trends of the parameters measured could be archived. Complete networking of entire plant electrics is possible from energy conservation point of view.

With the availability of such a wide variety of instruments for measuring and monitoring energy, one only has to be judicious in the selection and use of one or more of the above instruments, to continuously monitor the energy consumption pattern and take suitable corrective measures if, necessary, for conserving energy.

Energy Monitoring Devices:

Industries consume about 50% of the power generated in the country and electric motor consumes about 72% of the total electricity used in the industrial sector. Any inductive equipment like a motor draws, apart from the power needed for driving the equipment, a power called reactive power for magnetization of its core and to supply for the magnetic losses. This power is

totally un-warranted. But, due to the inherent nature of the induction machine, this cannot be avoided too. By suitably compensating for this reactive power, this could be minimized. And, this is called reactive power management or power factor improvement measures.

Reactive Power Management:

Low Power Factor means

Inefficient use of Electrical Energy Overloading of Transformer/Generator Overloading of Cable, Switchgear, Bus bar Higher temperature due to increased losses Imposes larger kVA demand Limits number of loads that can be connected Reduced revenue to Electrical Utilities

Benefits of Improving Power Factor

Avoid power factor penalties Reduction in current drawn Reduction in line losses Enables more loads to be connected Reduction in kVA Demand Increased life of Electrical Equipment More revenue to Utilities

Methods of Improving Power Factor

Fixed Compensation

–For Steady Loads–No load compensation of Motors–No load compensation of Transformers

Variable Compensation

–For Varying Loads

Solutions

Requires investment in capacitors, panels & switchgear Capacitors should have low watt loss (0.5W/kvaR) Payback period from 6 months to 18 months

Present realities:Present realities:

Lack of Awareness Purchase Decision Criteria

Investment in Energy Monitoring & Conserving Equipment normally assigned a low priority

Customer interested in price of the machine and not in the energy costs There are still many companies that have not implemented simple energy

efficiency initiatives Many implemented, but not maintained – savings erode over time Initiatives with investment often postponed Plant management not evaluated on energy efficiency results

Conclusion:

We need Rs. 8, 00, 000 cr. to add 1, 00, 000 MW

An unit saved = 3 units generated

Energy Conservation measures taken by individual consumers will help the national economy and benefit the environment on a global scale.

Let’s do it for the country

References:

i) The Hindu Survey of Indian Industry 2005

ii) ‘Short Circuiting Power Reforms” – By Mr.S.D.Naik, published in The Hindu Business Line, dated June 18, 2005

iii) The Complete Guide to Energy Efficient Motors – Published by the International Copper Promotional Council (India)