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Conservation of electrical energy.

Conservation of Electrical Energy

The measures for conservation of electrical energy in the domestic and commercial sectors are identified. The need for such conservation is highlighted in the perspective of a much larger rate of growth of load in the domestic and commercial sectors as compared to the industrial and agricultural sectors. Various conservation measures, alongwith their expected impact in terms of estimated saving of energy, such as promoting the use of low wattage lamps by imposing heavy excise duty on higher wattage lamp. Government subsidy on fluorescent tubes, introduction of seasonal tariffs and reduction and readjustment of television timings, have been suggested as useful conservation measures in the domestic sector. For the commercial sector, the closure of shops at sunset, introduction of daylight saving time and 5-day working week have been identified as measures which are likely to have significant impact on the overall energy situation.

The Need for Conservation

WAPDA resorts to load shedding during peak load hours in winters, as well as the months of May and June, as a result of reduced system capability, primarily on account of drop in the reservoir levels of Mangla and Tarbela which are the two main sources of power. During these times of power shortage public cooperation is sought through the information media and consumers are requested to confine their demand to essential requirements. Public response, however, has never been very positive and load management or load shedding has invariably to be resorted to and its detrimental effects on industrial and agricultural production cannot be totally eliminated.

Power shortage during January and the low water months of May and June would, as in the past, be a yearly routine and this shortage has all the portents of continuing relentlessly. No matter how adequate is the load management and how great is the public cooperation to conserve electricity, these months would always see a substantial difference between supply and demand and large scale shedding would continue to be inevitable. Nevertheless the harmful effects of the resultant shedding can, to a very large extent, be minimized by national awareness, a sense of patriotism and the desire to willingly contribute to the national development effort by reduring our wants and reconciling to the essential measures proposed for containing the demand within the capability.

Pattern of Consumption

The Table below shows year-wise consumption of electrical energy by Consumer Groups during the last 10 years in the power system of WAPDA.

In domestic group the consumption has become 4.43 times although the increase in the number of consumers has been only 2.423 times. In commercial group the increase in consumption is 2.74 times against an increase of 2.09 times in the number of consumers. This increase in domestic and commercial sectors is completely out of tune with the increase in industrial and agricultural groups.

The sharp rise in the domestic consumption is mainly attributable to Pakistanis employed abroad, especially in the Middle East, who have ushered in an era of greater utilisation of electrical power through the import of all sorts of electrical gadgets. The list is no longer restricted to such necessities as refrigerators, electric irons, toasters, etc. With the lifting of ban on VCRs the country has seen a steady lawful increase in their number. Although the electrical load of a VCR is about 50 per Watts only, it cannot work by itself and necessitates the simultaneous additional burden of the TV set, thus aggravating an already difficult situation.

Conservation Measures

Lighting: In the domestic consumer group by far the largest consumption is for lighting purposes. According to the latest statistics available, there were 5,077,901 domestic consumers on WAPDA's power system on 30th June 1989. Long term conservation of electrical energy can only be achieved if attention is focused on measures aimed at reducing the lighting load which constitutes the permanent bulk component of an average household. Two measures that immediately come to mind are the use of low wattage lamps and the greater use of fluorescent tubes.

Use of low Wattage Bulbs: The most effective and the easiest way in which considerable conservation can be achieved is the use of low wattage lamps in the houses for all purposes. Even for studying and other precision work comparatively lower wattages could suffice, provided suitable lighting fixtures are used to concentrate light over the area of activity. The use of low wattage bulbs can be made popular by (i) imposing heavy taxes on bulbs with rating of more than 60 watts; (ii) providing subsidy on bulbs with ratings of 60 watts or less; (iii) ensuring the availability of the low wattage bulbs at all times.

Use of fluorescent tubes: A 40-watt fluorescent tube emits light approximately equal to an incandescent lamp of 100 watts. Although the fluorescent lamp in itself is a high power factor circuit, the ballast used to stabilise the arc is inherently of low power factor. The resultant power factor of a single lamp reactive ballast circuit is around 50 per cent which is a drawback. The power factor, however, can be improved by means of a capacitor shunted across the line connections.

By approving a technically sound design with an acceptable power factor the Government could in the first instance direct all offices, hotels, mosques, hospitals, clinics, teaching institutions and a whole lot of other buildings to switch over exclusively to fluorescent tubes for lighting.

The switch over of the domestic consumers to fluorescent tubes would have to be spread over some years and before this is achieved two main difficulties in the way shall have to be surmounted. The first is the extremely short supply of the fluorescent tubes in the market. The second major obstacle is the initial high investment in the ballast and fixture of a fluorescent tube which is quite high and beyond the economic capacity of an average consumer. Government would therefore have to subsidise the initial cost to encourage domestic consumers to seriously consider switching over to fluorescent tubes. Also it would be necessary to arrange manufacture of tubes of all sizes and wattages, even of different designs, to suit individual requirements. To ensure that more such industries are quickly set up the Government would have to provide required incentives, especially tax holidays and exemption from excise duties for a predetermined period.

It is estimated that combined consumption of domestic consumers of WAPDA and KESC system would increase to 8600 million kwh during 1989-90. About 50 per cent of this consumption constitutes lighting load. Assuming that the proposed measure of switching over to fluorescent tubes is adopted there could be a 50 per cent reduction in the lighting load which in terms of energy would mean, an annual saving of about 2150 million kwh. Assuming average cost of energy as 53 paisa per kwh, the annual energy thus saved would be worth Rs. 1140 million on the basis of anticipated consumption figures for the current financial year.

At present the cost of one 40 watt fluorescent tube including fitting and ballast is about Rs. 103. Assuming that the cost of one tube with fixture is reduced to Rs. 50 after Government subsidy, benefit of wholesale purchase included, and further supposing that each consumer would purchase about 3 tubes the total number of tubes to be provided at subsidised rates would be 18.9 million and the Government subsidy would be Rs. 1002 million. Since the average life of a fluorescent tube is 10 times that of an incandescent lamp the subsidy constitutes long term benefits. The cost of providing 3 tubes to a consumer at the subsidised rates equals the net saving in terms of thermal generation for six months. The first year's saving would just about balance the Government Subsidy and the years that follow would all result in recurring benefits resulting from eliminating the need to install new thermal generating stations which cost Rs. 18 million per MW exclusive of the provision for system losses which would absorb 22 per cent of the additional generation.

Introduction of Seasonal Tariff: Air conditioners made in Pakistan add about 100 MW load to the system each year. Even if it is conceded that the greater use of air conditioners coincides with the increased availability of cheap hydel power, the facts still remains that during May and June a whole lot of air conditioning load comes on when the system is still in the throes of acute power storage. Since a separate tariff for the air conditioners alone cannot be imposed although it warrants very serious consideration, the only option is to introduce measures which would effectively discourage the use of power beyond a predetermined reasonable monthly consumption.

The approximately daily consumption of an urban household could be considered to generally consist of in Daily Consumption Table:

From the above table it could be summarised that reasonable electric consumption during a month should not exceed 600 units. Any use above this must be charged at progressively higher rates for different slabs to motivate the consumer to use less energy. According to the Schedule of Tariffs in force from September 1989 the domestic and commercial consumers in WAPDA's system are billed at the following rates:-

It is felt that considerable savings would accrue if seasonal tariffs were introduced to keep under control the demand during power shortages and especially to penalise wasteful use of energy. The seasonal tariff would have a normal rate for high water period when the WAPDA power system has abundance of hydel power and a higher rate for low water period when the thermal compoent of generation becomes sizeable. The existing tariff could be considered to be reasonable for the high water period from July to November. For the rest of the year the tariff could be revised upward somewhat on the lines suggested below:-

Such a tariff would have an extremely salutary effect on the campaign for conservation of electrical energy during the period when it is in short supply.

Television: Next to lighting and fans, television constitutes the largest component of domestic consumption. There were 1,627,000 registered TV sets in the country on 30th June, 1989. It is estimated that the net burden on the power system due to television sets is 200 MW for about 6 hours each day. The average daily telecast these days is about 7 houses generally from 4.00 p.m. to 11.00 p.m. If the telecast is reduced by even one hour each day for the seven months from December to June it would amount to a yearly saving of 42 million units, the equivalent of Rs. 22 million in terms of fuel. There is therefore definite need to organize the TV programmes and the duration of telecast with respect to the seasonal variation in the capability of the power system, even conceding the fact that TV is the most popular entertainment medium.

To start with, it is proposed that during the low water months of December to June, morning telecast should be totally discontinued and the duration of the telecast for the rest of the day confined to five hours on week days and seven hours on week-ends. This would result in the saving of 157 million kwh per year with increasing benefits as more TV sets get added to the system. Considering that the reduction of this much generation is a direct relief to the thermal component it would mean a saving of Rs. 38.2 million on the basis of 53 Paisa per unit. Also the telecast of cricket matches during this period when there is shortage of power is an unnecessary and avoidable burden on the power system which often results in additional costly thermal generation. It is proposed that instead of full time telecast only the highlights of the day's play should be shown late at night to avoid invoking the expensive diesel oil generation. For the rest of the year the need for conservation is less stringent as abundant hydel power would be available.

Commercial Group

Cinemas: In 1983 there were only 564 cinemas in the country out of which one third were in Karachi and Lahore. Considering the invasion of the market by VCRs and the mushrooming of video shops the popularity of cinemas has been effectively eroded. UNESCO suggests that a developing country should have at least 30 cinema seats per one thousand population. On the basis of this criterion we are way behind with only 2.3 seats per thousand. Our neighbour India has 11000 cinemas with a ratio of 7.3 seats per thousand. Our population of 110 million does not have any outdoor entertainment other than the cinema and since the number of cinema seats is in any case much lower than UNESCO's suggestion any thought of conserving energy by closure of cinemas during periods of power shortage or reduction in the number of shows does not merit serious consideration. This should also dispel the oft-expressed opinion in the press that considerable saving could be effected if cibemas were closed.

Shops: A fair amount of the commercial energy is consumed in Government and semi-Government offices including educational institutions, railway stations, bus stands and airports, etc. Other large consumers are cinemas and theatres, commercial houses and establishments; private hospitals and clinics, clubs, restaurants, hotels etc. Due to non-availability of separate consumption figures for these consumers only an assumption can be made that these account for about 60 per cent of the total commercial load; the balance 40 per cent is therefore being consumed by shops whether in the plazas, malls or in isolated areas. Assuming further that 70 per cent of this energy is consumed during four hours after sundown, the power demand on account of shops alone works out to about 249 MW, which could be considered to be a fairly accurate net relief to the power system on account of closure of shops.

The closure of shops at sunset during periods of power shortage is a step which has in the past been invoked only during periods of power shortage. But since economy in total energy is the aim, the shops should always close within half an hour of sunset, except on Fridays. This reduced demand on the power system would eliminate the need of bringing on bars some 250 MW of thermal generation and would also result in reduction in the cost of fuel on transport plying to and fro for the shoppers.

5-Day Working Week: Almost all the developed countries are on a 5-day, 40-hour week routine since long but now even a number of developing countries have found it pragmatic for energy conservation. There is no reason why this cannot be tried in a country like ours where the need to conserve energy is the greatest. If all the Government offices, semi-Government and autonomous bodies had a 5-day week it would automatically influence the timings of the commercial houses and establishments who would generally be obliged to follow the same routine. There would thus be a sizeable drop in the power requirement during the day both in summer and winter when a whole lot of lighting, air conditioning or heating load would go off the power system. Quantifying the reduction on consumption of electrical energy that would come about subsequent to the introduction of a second holiday is a rather involved exercise but there is little doubt that it would have the characteristic of suppressing the morning peak demand for one additional day in the week thus obviating the necessity of bringing on bars some thermal generation during periods of power shortage.

Daylight Saving Time: Daylight saving time provides a means of using more daylight in summer when the days are longer. There is scope for saving electrical energy by greater utilisatin of the daylight and it should be possible to introduce this practice in Pakistan with a fair degree of success. On an experimental basis the clocks could be set ahead by one hour on 15th april and set back on 31st August.

During the summer months, the sun rises as early as 5-30 a.m. and sets as late as 7.1k p.m. (Karachi excluded where the time for sunrise and sunset are half an hour later than Lahore). Most of the offices and other institutions start work at 7.30 or 8.00 a. m. Thus, in most households the morning demand of electricity starts building up at about 6.30 a.m. i.e. one hour after sunrise. Correspondingly the time of the night when most people go to sleep and major part of the lighting load is switched off is about 10.00 p.m. i.e. about two and a half hours after sunset.

If the clocks were to be advanced by one hour, this would essentially mean that the morning roudn of activity would still start at about 6.30 a.m. clock time, which would actually be 5.30 a.m. real time. Since this is after daybreak, there would be only slight, if any, increase in the electrical load on account of lighting. During evening hours shopping centres which normally close between 7.30 p.m. and 8.00 p.m. would then get closed between 6.30 and 7.00 p.m. real time providing a relief of about 249 MW for one hour. Moreover people would go to sleep at 9.00 p.m. real time (10.00 p.m. clock time) i.e. about an hour and a half after sunset. During summer the load that normally drops between 9.00 p.m. and 10.00 p.m. is about 300 MW. With the daylight saving scheme the system load occurring at 10.00 p.m. would occur at 9.00 p.m. thereby giving a relief of 300 MW with corresponding declining relief thereafter. In this way there could be a daily saving of more than 300 MW hours. If the time it could mean a minimum saving of August it could mean a minimum saving of about 32 million kwh. Since this saving would all be achieved during evening peak hours it would result in direct saving of fuel. Taking average cost of generation on gas and diesel, as 53 paisa per unit, the saving could be of the order of Rs. 17 million.


The primary responsibility for fashioning the destinies of the developing countries rests with the various planning agencies. Planning therefore has to be more broadbased and must take cognizance of the problems that are likely to arise a few years hence. Providing solution to the problems as they emerge, apart from being more expensive, suffers from the drawback that the damage is already done. It can be stated without any fear of contradiction that demand would be in excess of capability during peak hours of the critical low water period and this situation is highly unlikely to improve during the entire period of the 7th and 8th Five Year Plans. All measures aimed at reduction of the demand and conservation energy, no matter how trivial their contribution may be in the overall context, are of paramount importance to our very survival and must be allocated the highest priority.
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Title Annotation:Pakistan's energy conservation
Author:Ibrahim, A Hafeez
Publication:Economic Review
Date:Oct 1, 1990
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