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Opinion Op-Ed

Published: May 16, 2012 00:53 IST | Updated: May 16, 2012 00:53 IST

Advance Indian Standard Time by half an hour

D. P. SenGuptaDilip R. Ahuja

THIRTY MINUTES: The energy benefits of advancing IST accrue for the entire year throughout the country.

It would help to reduce the evening peak energy deficit more effectively and without the difficulties of dividing the countryinto two time zones

Most Indians are not particularly worried about Indian Standard Time (IST), except for those who live in the

Northeast where the sun rises around 4 a.m. in summer, and gets dark well before 4 p.m. in winter. Those of us whohave to make overseas long distance calls and get into trouble with fractions are not even aware that we belong to aminority (three per cent) of regions whose standard times are fractional hours off from GMT.

India spans longitudes of 68 at the western end and 98 at the eastern boundary and as there is a difference of onehour for every 15 of longitude, the two extremes differ by two hours. Thus, when the sun sets at 4 p.m. in Kohima, itsets at 6 p.m. in Porbunder. IST was fixed in 1906 midway at 82.5, or 5/ hours ahead of Greenwich Mean Time(GMT). Periodically, there are demands from the Northeast region for a separate time zone so that the clocks theremay be advanced by an hour.

There is a general misconception among those who worry about saving energy such as the Planning Commission that dividing the country into time zones will save a lot of energy. The savings are almost always described byadjectives, for very few have estimated correctly the amount of savings that may accrue by altering IST or creatingtwo time zones. There is also the practice in several countries, of Daylight Saving Time (DST), wherein the time in

summer is advanced (or the clocks put forward) by one hour and retracted during winter. This enables people toenjoy sunlight longer in summer and avoid the inconveniences of late sunrises and early sunsets during winter.

Load demand data

Our proposal for India is to introduce neither time zones nor DST, but to advance IST by half an hour to being sixhours ahead of GMT, once and permanently. Such a suggestion has been made before, but until now no one hascomputed the energy savings that would accrue as a result using a correct model and dependable data. Our fairlyrigorous method has been vetted by national and international experts and is based on data on load demand everyminute for two years at five electrical zones of India provided by the Power Grid Corporation of India. The Bureau ofEnergy Efficiency provided financial support for the study.

Problems of time zones

India has a huge population; if the country were divided into two time zones, there would be chaos at the border

between the two zones. It would mean resetting clocks with each crossing of the time zone. There is scope for moredangerous kinds of confusion. Railway signals are not fully automated and many routes have single tracks. Trainsmay meet with major accidents owing to human errors. Just one such accident would wipe out any benefits resultingfrom different time zones in the country.

Partitioning the already divided country further into time zones may also have undesirable political consequences.

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Moreover, our research shows that the energy saving from creating two time zones is not particularly large.

Problems of DST

As is known, the sun always rises at 6 a.m. on the Equator and sets at 6 p.m. irrespective of the season. It is the tiltof the axis round which the earth rotates by 23.5, that causes the length of days and nights to change as we gofurther away from the equator towards the north or the south. At the poles the sun does not set for six months anddoes not rise for six months. In tropical countries, the duration of light and darkness over the seasons does not vary

widely. If we were to introduce DST in India, the inconvenience of time adjustment during summer and wintermonths would involve the whole country, happening twice a year, with marginal benefits. The possibilities of rail

accidents would still be high. Even in the U.S. and Canada, road accidents increase discernibly in the daysimmediately following the change.

Advance IST by half an hour.

Our proposal of advancing IST by half an hour avoids the problems apprehended in the other two proposals (of timezones and DST) but provides maximum energy saving during evening hours when the utilities fail to supplycontinuous power. Load shedding is common all over the country and power and energy shortages amount to 11 percent and 12 per cent respectively.

How is energy saved?

Energy is saved by longer use of sunlight and consequently less use of energy for lighting. The demand for electricitygoes up in the morning for water heating and increases again in the evening for five to six hours, mainly for lighting,declining as people turn off lights and go to bed. The advancement of IST by half an hour only is unlikely to alter

their habits and a person waking at 7 a.m. and going to bed at 11 p.m. will continue to do so, but advanced 7 a.m. isunaltered 6.30 a.m. when the sun is already up in most parts of the country, and 11 p.m. is the same as unaltered10.30 p.m. In other words, people all over India will go to bed and wake up half an hour before they presently do andthus their waking hours will be more aligned to the daily cycle of sunshine. One assumption of course is that officetimes and factory times remain unaltered. It needs to be understood that people switch on lights not by looking atthe watch but by the descending darkness after sunset. If on a particular day it got dark at 6 p.m., in say Mumbai, it

will still get dark at the same time but the watch would show 6.30, since it has been put forward by half an hour.

Assuming lights kept turned on for five hours from 6 to 11 (bedtime) now will be kept on from 6.30 to 11 (bedtime),that is for 4/ hours, the half-hour saving on lighting leads to an energy saving of 2.3 billion units of energy per yearfor the country. This saving amounts to almost 18 per cent of evening peaking energy use, and would partly reducethe deficit that we presently suffer. The savings from time zones and DST are significantly less the saving due totime zones comes from the eastern zone only, and for DST from half the year. The half-hour advancement of IST

provides benefits for the whole country for the whole year. Besides saving energy, a longer sunlit evening wouldreduce street crimes. Traffic accidents may also come down to some extent.

By advancing IST by half an hour we meet the legitimate demands of the Northeast halfway without any of theinconveniences of time zones or DST. So why not advance it by an hour? It would cause complaints from thenorthwest about the inconvenience of later winter sunrises.

(D.P. SenGupta was formerly a professor at the Indian Institute of Science and is currently a visiting professor ofthe National Institute of Advanced Studies in Bangalore. Dilip R. Ahuja is ISRO Professor at NIAS. The Bureau of

Energy Efficiency commissioned a study by them on quantifying energy savings through advancing IST, basedon a paper published by them in Current Science in 2007. Their final report was submitted to the BEE in

September 2011.)

Keywords: energy saving, advancing IST, Daylight Saving Time, time zones

Printable version | May 23, 2012 10:26:57 PM | http://www.thehindu.com/opinion/op-ed/article3422881.ece The Hindu

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