R3-2011

D. P. Sen Gupta
Dilip R. Ahuja

Options for Adjusting
Indian Standard Time
for Saving Energy

NATIONAL INSTITUTE OF ADVANCED STUDIESWith support fromBUREAU OF ENERGY EFFICIENCYOptions for Adjusting Indian Standard Time
for Saving Energy

D. P. Sen Gupta and Dilip R. Ahuja

Final Report submitted to
BUREAU OF ENERGY EFFICIENCY(Government of India, Ministry of Power)
by

NATIONAL INSTITUTE OF ADVANCED STUDIES
Bengaluru, India

September 2011i© National Institute of Advanced Studies 2011

Published by
National Institute of Advanced Studies
Indian Institute of Science Campus
Bengaluru - 560 012
Tel: 2218 5000, Fax: 2218 5028
E-mail: admin@nias.iisc.ernet.in

NIAS Report: R3-2011

ISBN: 978-81-87663-51-5

Typeset & Printed byAditi Enterprises
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Ph.: 080-2310 7302
E-mail: aditiprints@gmail.com
ii

Contents
Acronyms ----------------------------------------------------------------------------------------------------------------------- iv
Acknowledgements ----------------------------------------------------------------------------------------------------------- v
Foreword ---------------------------------------------------------------------------------------------------------------------- vii
Summary for Policy Makers ----------------------------------------------------------------------------------------------- 01
Introduction ------------------------------------------------------------------------------------------------------------------- 03
Method Developed for Estimating Energy Changes --------------------------------------------------------------- 09
Resulting Changes in Electricity Consumption ---------------------------------------------------------------------- 19
Discussion of Confidence in Results ----------------------------------------------------------------------------------- 23
Non-Energy Implications --------------------------------------------------------------------------------------------------- 29
The Optimal Option for India --------------------------------------------------------------------------------------------- 33
References -------------------------------------------------------------------------------------------------------------------- 39
Appendix 1: Correspondence between Luminance and Evening Peaking Load --------------------------- 41
Appendix 2: Evening Peaking Power is Largely Residential and small Commercial Loads ------------- 45
Appendix 3: Evening Peaking Load is Primarily Lighting Load ------------------------------------------------- 49
Appendix 4: Choice of Appropriate Level of Spatial Aggregation ----------------------------------------------- 51
Appendix 5: Expert Advisory Committee ------------------------------------------------------------------------------ 55
Appendix 6: Interministerial Group -------------------------------------------------------------------------------------- 59
Appendix 7: Energy Savings for Half Hour Advancement for 2008 -------------------------------------------- 61iii

Acronyms

a.m.

ante meridiem

AC

Air Conditioners

AI

All India

BESCOM

Bangalore Electric Supply Company

CFL

Compact Fluorescent Lamp

DST

Daylight Saving Time

GMT

Greenwich Mean Time

GW

Giga Watts

IST

Indian Standard TimekWhs

kilo Watt hours

LAT

Local Apparent Time

LED

Light Emitting DiodeMU/dMillion Units per Day

MW

Mega Watts

MWhs

Mega Watt hours

NE

North East

NW

North Westp.m.

post meridiem

STStandard TimeTV

Television Sets

UK

United Kingdom

US

United States of America

UTC

Coordinated Universal Time (Universal temps coordonne)

YRDSTYear Round Daylight Saving Timeiv

Acknowledgements

We have many debts of gratitude to acknowledge:R

To Dr. Arcot Ramachandran for acting as asounding board for our ideas, and for his

Radvice.

First and foremost to Dr. Ajay Mathur,
Director-General of the Bureau of Energy
Efficiency for awarding the study to theR

To Mr. Toine van Megen for his enthusiasm

National Institute of Advanced Studies (NIAS)

and persistent championing of the concept

and for so ably chairing the deliberations ofof advancing IST;the Expert Advisory Committee.
R
R

To Mr. P Varshney, Senior Vice President,

The comments and suggestions made by the

PTC India Ltd for providing data on the pricemembers of the Expert Advisory Committeeof electricity traded in the evenings;

are gratefully acknowledged.
R
R

Similarly

comments

madeby

To Prof. G Gururaj, Head of the Departmentof Epidemiology, NIMHANS for the data on

theaccidents in Bengaluru;

Interministerial Group both at the meetingon December 15, 2010, and in writing are
gratefully acknowledged.

R

To Mr. K K Chakarvarti and Mr. Neeraj
Dhingra of BEE for useful interactions.

R

To Mr. V K Agrawal, General Manager in thePower Grid Corporation of India and MemberRof the Expert Advisory Committee for

To Mr. M Muniswamy, former Technical
Director, BESCOM for fruitful discussions.

providing the data on load curves which
formed the basis for the analyses in thisR

study. We are also thankful to him for several

To Mr. M M Babunarayanan, Additional
Director-DSD, CPRI for useful discussions;discussions on a number of technical details.
Without his assistance, the study could notRhave produced the results it did.
R

To Prof. Lalitha Sundaresan of NIAS foradvice on calculating confidence intervals.

To Prof. V S Ramamurthy, Director, NIAS forR

To Prof. Narendar Pani, NIAS for reading an

his support and encouragement at various

earlier draft of this report and providing

stages of the project.

comments;v

R

To Ms. Soumya Mangalagiri and Mr. N V N

R

Jagadish for their technical support;

To Ms. Kala Sunder for editorial help with thesummary for policy makers.

Ms. Mangalagiri was meticulous in her
analysis of data.

Responsibility rests with us for the errors that may
have remained in the report, despite all thisR

assistance so willingly proffered.

To Mr. P. Srinivasa Aithal and Ms. Gayathri
Lokhande of NIAS for their able administrative
support.

D. P. Sen Gupta and Dilip R Ahuja
Principal InvestigatorsviForewordii.

As the east-west span of India is large enough to

Adopting daylight saving time during thesummer months; andjustify two time zones, demands have been madeiii.

several times to have two time zones in the

Advancing Indian Standard Time.

country. Upon consideration, it has always beenfound that the costs that will be imposed by having

Using a robust methodology vetted by a

two time zones exceed the benefits that would

30-member Expert Advisory Committee comprisedensue.

of various stakeholders, the project concluded
that the energy savings obtained by advancing

As then the Secretary, Department of Science and

IST substantially exceed those to be obtained fromTechnology, Government of India, I Chaired a Higheither dividing the country into two time zones orLevel Committee (HLC) constituted to consider

introducing daylight saving time during summer

Two Time Zones for India. The HLC considered

months. Moreover, the one-time advancement

the option of two time zones for India and rejectedof IST by half an hour does not entail theit in favour of changing office timings in the

disadvantages of the other two options.

eastern part of the country. The HLC alsosuggested the adoption of daylight saving time

Had the analysis presented in this Report been

be considered for the entire country during

available to the High Level Committee in 2002,

summer months. It submitted its Report in 2002.

I am sure the Committee would have come to thesame conclusion.

The project undertaken by NIAS last year byProfessors D. P. Sen Gupta and Dilip R. Ahuja at

NIAS will continue to strive to conduct policy-

the request of BEE, Ministry of Power had therelevant research for the country.

objective to consider energy savings to be
V. S. Ramamurthy

obtained from:

Directori.

Dividing the country into two time zones;

National Institute of Advanced Studies, Bengaluru

vii

viii

Summary for Policy Makers

Researchers from the National Institute ofhome in daylight throughout the year. This is of

Advanced Studies, Bengaluru, with support fromcourse based on the assumption that working

the Bureau of Energy Efficiency, developed ahours will remain unchanged. It would address

robust method of estimating energy savings to

the persistent complaints from the north-eastern

be obtained from the three major ways ofpart of our country, which is most adversely

adjusting standard time:

affected by the current standard time.

a)Advancing Indian Standard Time (IST),

Non-energy benefits of better alignment of activitiesb)

Introducing Daylight Saving Time (DST), andwith available daylight include reduction in trafficc)Introducing two time zones.

accidents and street crime, fewer flight
postponements due to winter morning fog, fewer

It was found that advancing IST yields the largest

postponements of sporting events, increase inenergy savings. If IST is advanced by half an

outdoor activities like sports and shopping, increase

hour, making it six hours ahead of UTC or GMT

in evening playtime for children, and a possible

instead of the current five and a half, the country

increase in office productivity. Quantification of thesewould save more than 2 billion units (worth

additional benefits, which may be substantial, wasapproximately Rs. 1300-1400 crores) on abeyond the scope of this study.

recurring basis year after year, all of them during
the evening hours when the utilities find it difficult

Proposals have been made from time to time toto supply electricity. It would also align the country

divide India into time zones because the timewith 96% of the regions of the world whose

difference between sunrises or sunsets at thestandard times differ from UTC by integral (noteastern and western edges is almost two hours.

fractional) hours.

However, the benefits accruing from two timezones are limited to the lower energy consuming

The principal reason for adjusting standard timeeastern part of the country. Introducing timein a country is to make more use of daylight inzones would imply that watches would have to be

the evenings and thus reduce the amount ofreset every time one crosses from one zone toelectricity required for lighting, the major

the other. This could increase the chances of train

contributor to the evening peaking energy.

accidents owing to human errors in manual control

Advancing IST would allow most Indians to return

still widely used in the country.

1Summary for Policy Makers

The suggestion to governments in the East andin the meeting is appended to this report along

North East States to advance their working hours

with the list of the ministries from where comments

without changing IST has not met with widespreadon the draft report have been subsequently

acceptance. Moreover, this would not contributereceived in writing. The comments received during

to energy saving in the rest of the country.

the meeting and later in writing have beenaddressed in this final report.

The benefits of introducing DST are confined tohalf the year (summer months) whereas advancing

The investigators suggest that the country

IST yields energy savings throughout the year.

seriously consider advancing Indian Standard

Resetting the time twice a year could have theTime by half an hour to being six hours aheadsame disadvantages as introducing time zones.

of GMT. It is assumed that a change of half
an hour, by and large, will not change people's

A one-time advancement of IST avoids thesedaily habits. While all residents of the country

complications. It would lead to better use ofwould be affected by the change, thesunlight than is done now and would provide theinvestigators identify several stakeholders wholargest energy savings.

will be especially affected and who will need to
be brought on board. Should the country decide

The work described in this report was presented

to implement the recommendation, close to two

to an Interministerial Group under theyears will be required to plan for a smooth

Chairmanship of Shri G. B. Pradhan, Additionaltransition. The cost associated with the one-time

Secretary, Ministry of Power, on 15 December

switch-over has not been estimated as it was also

2010. The list of members of the group present

beyond the scope of the study.

2

1. Introduction

1.1 Historical Introduction

1784 first proposed aligning human activities withthe available daylight as a candle saving

For millenia, in any given place on earth noonmeasure. Daylight saving time (DST) was firstwas when the sun was highest in the sky. Up until

proposed by the New Zealand entomologist

the middle ages time was essentially a local

George Hudson in 1895 in a paper to thephenomenon; shadows of obelisks and later

Wellington Philosophical Society proposing asundials tracked the passage of time. Both travelsummer-timeand communications were slow. With increasing

advancement. Independently, the English

accuracy of mechanical clocks, a need arose toarchitect William Willett began championing DST

equalize the length of the day which varies during

in 1907. He advocated clocks be advanced in thea year because of the eccentricity of the earth’s

summer and retracted in the fall. Germany wasorbit and the tilt of its axis (Prerau, 2005, p. 30).

the first country to adopt DST as a war-timeThus Geneva became the first city to introduce

energy saving measure, followed soon by otherthe first adjustment to local time by adopting mean

countries. This was the third major adjustment insolar time in 1780. As east-west travel by railways

time keeping.

two-hourdaylight-saving

and communication by telegraph became moreprevalent, the use of a single mean time over a

During World War II, year-round DST (YRDST)

large region was the second adjustment to natural

was instituted, but later the countries went backsun time starting in Britain in 1840. At first it wasto summer DST. The UK experimented withcalled railroad time, later it came to be calledYRDST during a three year period from 1968 to

standard time. At the International Prime Meridian

1971. As a response to the oil embargo in 1973,

Conference held in Washington in 1884, thethe US conducted another trial of YRDST in

system of international standard time according

1974-75. After these trials, both countries returned

to established time zones was adopted. Thisto summer DST, although the US has sporadicallysystem is still in use today.

increased its duration. Countries have retained
DST because a majority of their citizens likes

Except on the equator, the duration of light andhaving “more light in the evenings”. People’s

darkness varies from day to day as a result of

dislike of waking up in the dark or sending

the tilt in earth’s axis. This makes days longer inchildren to school in the dark during wintersummer than in winter, and nights longer in wintermornings is what generally prevents the adoption

than in summer. It was Benjamin Franklin who inof YRDST. There are calls again in the USA

3

Introduction(Calandrillo and Buehler, 2008) and UK (Hill etsunrises in winter months. Normally one time zoneal, 2010) to adopt YRDST because of the multiple

spans 15 degrees of longitude corresponding tobenefits it would offer.

a difference of one hour.

For the most part of nineteenth century, each

India extends from 68°07’E to 97°25’E (Figure

large city in India observed its own local time as1.1). Although this east-west spread of 29° is just

was the practice elsewhere in the world. In 1884

about wide to justify two time zones, India since

two time zones were established in India, theits Independence has chosen a single time zone

Bombay Time (4 hours and 51 minutes ahead ofbased on the longitude passing through 82.5°,

GMT) and the Calcutta Time. Railways usedalmost the exact east-west centre of the country—

Madras Time (where an observatory was built infive and half hour ahead of Universal Coordinated1792) because it was between Bombay andTime (UTC). This in essence provides the benefit

Calcutta Times. On 1 January 1906, British Indiaof daylight saving only to the part of the country

adopted Indian Standard Time (IST) as five andthat lies to the west of 82.5°. If they are on

half hours ahead of GMT. Between 1 September

de-facto daylight saving time, the people to the1942 and 14 October 1945, India had YRDST oreast of 82.5° are in fact on what may be termed

War Time, which was ahead of IST by one hour.

as daylight wasting time. This explains the

Since independence, IST has been the official

complaints from people in the north-eastern parttime for the whole country. Provisions in labourof the country about the inconvenience thelaws, such as the Plantations Labour Act, 1951

current IST entails for them and to calls for aallow the Central and State Governments toseparate time zone for them (see for example,

define and set a local time for a particular area.

Barua, 2010).

In Assam, tea gardens follow a Tea Garden Time
or Bagan-time that is one hour ahead of IST.

The second impetus for changing IST comes fromthe possibility that it offers for energy saving. The

1.2 Rationale for the Study

Planning Commission (2006, p. 85) recommended
the introduction of two time zones in the country,

One set of consequences of having the same timeasserting it would save “a lot of energy”. One

over a time zone is that the sun rises earlier andprevious analysis had concluded (Natarajan etsets earlier at the eastern boundary than at theal, 1988) that energy savings from dividing thewestern boundary of the zone. The bigger thecountry into two time zones, or from introducing

east-west spread of the time zone, the more

DST, were not large enough to warrant the

pronounced will be the differences. If the east-changes.

west spread of the zone is large, people at theeastern boundary will complain about earlier

It is well-known that the country has both a powersunsets during winter months and people at the(capacity) shortage (inability to meet peakwestern boundary will complain about later

demand) and energy shortage. In the last three4

Options for Adjusting Indian Standard Time for Saving Energy

years these have averaged 14% and 10%

3.

Identify states and sectors which are likely
to be affected; andrespectively. This is shown in Table 1.1. Ahuja,
Sen Gupta and Agrawal (2007) have proposed
the adoption of YRDST in India by advancing IST

4.

Suggest the optimal option for India.

by half-hour and estimated the electricity savings.
In August 2009, the Bureau of Energy Efficiency,

It became apparent to the investigators that in

Ministry of Power, Government of India, entrusted

each of these three options (i.e., DST, the second

the National Institute of Advanced Studies,

option of one zone, and YRDST, and third option

Bengaluru, to undertake a study to assess theof two time zones) are embedded other possible

scope of potential energy savings through various

options that should also be studied. In fact thechanges in Indian Standard Time.

status quo belongs to the option of one time zone
for the country and one time for the entire year.
This is labelled Option 1. It is the no-change option.

1.3 Objectives of the Study

All savings or changes in electricity consumption
The relevant terms of reference for the study

would be estimated in relation to this option.

undertaken by the National Institute of Advanced

Besides this, there are 8 other plausible options.

Studies were the following:

As shown in Table 1.2, there are three options for
DST (Options 4, 5, and 6) and three for two time1.

Estimate the scope of electricity savings forzones (Options 7, 8, and 9). India is divided intoa.

introducing daylight saving time in thefive electrical regions as shown in Figure 1.1. For

country;

studying time zones, the regions comprising theadvancing IST by half-hour (akin towestern, northern and southern grids in the country

year-round DST or YRDST)

were considered to constitute the western zone

introducing two time zones in theand the eastern and the north-eastern regions

country;

formed the eastern zone as shown in Figure 1.1.

b.
c.

In addition, there are two options for keeping one
2.

Compare advantages and disadvantages oftime zone without DST in the country, i.e.,each of these options;advancing it either by 30 minutes (Option 2) or by

Table 1.1: Electricity Deficit in India 2007-2010
Power (GW)

Energy (billion Units)

Year

Peak Demand

Availability% Deficit

Requirement

Availability% Deficit

2007-08

108.9

90.8

16.6

739.3

666.0

9.9

2008-09

109.8

96.8

11.9

777.0

691.0

11.1

2009-10

119.2

104.0

12.7

830.6

746.6

10.1

Source: Ministry of Power (2010)5

Introduction

one hour (Option 3). Options 2 and 3 are referredadvance IST by an hour for the entire country andto in the scientific literature as year-round daylightnot have any zones. Similarly all the other options

saving time (YRDST).

can be understood from Table 1.2. Options 5 and6 are corresponding (to 2 and 3) options for DST;

The three basic options are in the three major

and Options 8 and 9 are corresponding options

columns. Entries in each row in column 1 (onefor two time zones. By the terms of references thatstandard time, no zones) are the means of thewere agreed upon, the investigators were notentries in columns 2 and 3 (winter time andrequired to study options that were combinations

summer time of DST) or also in column 4 and 5of the three fundamental options, such as an(western time and eastern time of two time zones).

option where the country was divided into time

Winter time and summer time differ by one hourzones and also had bi-annually cycling DST.

as do eastern time and western time. The present
IST, which is 5:30 hours ahead of UTC, in principle,

In Chapter 2 are presented certain methodologicalcould be replaced by DST when summer time forpreliminaries

the whole country is 6:00 hours ahead and winterunderstanding of the results that follow in Chapter

time is 5:00 hours ahead. This gives rise to

3. Detailed methodological questions are treated

Option 4. Similarly, it could be replaced by twoin the four Appendices at the end. Confidence intime zones, wherein eastern time is 6:00 hours

the results is discussed in Chapter 4. Non-energy

ahead of UTC and western time is 5:00 hours

considerations are presented in Chapter 5.

ahead. This gives rise to Option 7.

Advantages and disadvantages of various options

that

are

essentialtoanare discussed in Chapter 6 (this pertains to
Entry in succeeding row in Table 1.2 differs fromobjective 2 on page 5), where stakeholders andthe entry in the previous row by half-hour. Thus,

sectors which are likely to be affected are identified

Option 2 retains the present structure of no(objective 3, also on page 5). Conclusions andbi-annual changes in time and one zone for therecommendation of the optimal option for India

entire country but is UTC + 6:00. Option 3 would(objective 4) are also dealt with in Chapter 6.

Table 1.2: Possible Options for Adjusting ISTYear-round Standard Time;No Time Zones

Daylight Saving Time Options(One Zone, Two Times)
Winter Time

Option 1+5:30 (Status Quo)

+5:00

6

+6:00

+5:30

+5:00

+6:00
Option 8

+6:30

+5:30

Option 6+6:00

Eastern Time
Option 7

Option 5

Option 3 (YRDST)+6:30

Western Time

Option 4

Option 2 (YRDST)+6:00

Summer Time

Two Time Zones Options(Two Zones, no DST)

+6:30
Option 9

+7:00

+6:00

+7:00

Options for Adjusting Indian Standard Time for Saving Energy

68°E

Western Zone

Eastern Zone

98°E

REGIONALGRIDSNORTHERNREGIONNORTHEASTERNREGIONEASTERNREGIONWESTERNREGION

SOUTHERNREGION

Figure 1.1: Regional Grids in India. For Studying time zones the Eastern and the North-eastern regions constitute theEastern Zone. The Northern, Western and Southern regions constitute the Western Zone.

78

2. Method Developed for Estimating
Energy Changes
Many attempts have been made in the recent past

Behavioral models for light switching andto estimate energy savings due to implementation

thermostat setting should be included whereof Daylight Saving Time, (Aries and Newsham,appropriate. Interactions between building

2008, provides an extensive review). Twotypes should be addressed; for example,

techniques have been primarily followed:

lower occupancy homes on lighter evenings
might mean higher occupancy in shopping1)

Trying to estimate how much energy was

malls. All assumptions should be supported

saved or lost by re-scheduling the standard

by empirical data. Further, simulations should

time based on past data

include not only existing descriptions ofbuilding occupancy patterns, insulation

2)

Makingeconometricmodelsusing

values, equipment efficiency and controls, but

parameters that are likely to influencealso a variety of future scenarios...”energy consumption such as luminance,wind velocity, population, etc.

The investigators of this study did not attempt tomake use of any of the above two standard

Aries and Newsham (2008) in their concluding

techniques using past data or simulation for theremarks about the effect of daylight saving time

following reasons:(DST) state that: “The existing knowledge about
how DST affects energy use is limited, incompletea)No organized attempt has been made sinceor contradictory……” and that “effects of DST on

independence to make zonal or seasonal

lighting energy use are mainly noticeable inchanges in IST and therefore no data

residential buildings”. Further,consequent to such changes are available.
Data from smaller neighboring countries“Given the difficulties of separating DST

where changes in ST have been attempted,

effects in system-wide energy data, we(even if they were suitably recorded and weresuggest that the best prospect for progressavailable) would be of little use for a country

in definitely evaluating the effect of DST on

as large as India.

energy use is simulation. Such simulation
should include a variety of building types inb)Even a simple simulation model is a daunting

representative climates and should address

task. Standard parameters necessary toboth lighting and thermal energy effects.

develop a basic econometric model, such as

9

Method Developed for Estimating Energy Changes

weather variables, lighting variables,

the energy use in the country based on income

population, their occupation, details of

distribution to study the effects of having time zones

building structures, vary widely from placeon energy saving (Natarajan et al, 1988). This

to place. A model developed with local

method was simplistic and unusable for the problem

parameters needs to be projected to theunder study. It is difficult, as stated by Aries andwhole country to yield reliable results.

Newsham (2008), to separate the effects of DST
from system-wide data, but it is from the collectivec)Data on electricity used specifically forload consumption that the investigators isolated thelighting do not exist in India or, for that matter,

effects of adjusting the standard times.

in most countries. In homes with meteredelectricity the installed meter reads the total

The method used in the present study was firstelectricity used for lights, fans/AC, water

developed by the investigators and published inheaters, pumps, television, refrigerators andAhuja et al (2007). It is distinctly different from anyother kitchen appliances. Without themethod reported so far. It relies on the statisticalinstallment of separate meters it is notaveraging of a very large number of random data.

possible to estimate the energy used only

Switching on or off of electricity for different uses

for lighting. Moreover, separate meters unlessin a household is a random process. But the sum

specially designed, would not tell when the

total of these random actions at the level of a city,

lights came on or were turned off. As things

state or a region, causes a pattern to emerge.

are now, there is no record at Domestic,
Commercial and Industrial levels of separate

It is in a load curve that such a pattern reveals

lighting loads by sample surveys.

itself. A load curve provides a record of theinstantaneous demand of Power met (ind)

Data for the parameters required for

Megawatts—MW) plotted against time for 24

constructing a dependable econometric

hours. Figure 2.1 shows All India Load Curves

model simply do not exist in the country.

for two seasons.

Extensive primary data collection over a long
period would need to be organized, to have

In India, these are recorded at various voltage

a dependable model which not only could

levels but properly aggregated data are available

be related to power consumption but also

for states and regions only. Figure 2.1 represents

to estimate the impact of adjusting IST on

All India load curves for a typical day in winterpower consumption.

and one in the summer of 2009. The increase indemand during the morning hours of winter is

A research organization in India made an attempt

believed to be due to water heating and theto construct a statistical model based on the income

general increase in power demand duringof a number of houses in the South Bombay andsummer months indicates increased load demand

their electrical energy consumption and estimate

for air cooling and circulation.

10

Options for Adjusting Indian Standard Time for Saving Energy

10000090000
80000

Power Supply (MWs)

70000
60000
50000

AI_JAN
AI_MAY

40000
30000
20000
10000
0
0:00

2:00

4:00

6:00

8:00

10:00

12:00 14:00

16:00

18:00

20:00

22:00

TIME (hours)

Figure 2.1: All India load curves for 2 typical days in January and May 2009.

The increase in demand of power towards thethe evening load is primarily due to lighting load.

evening hours irrespective of the season seems

No data are available with any of the electricity

to follow the fall in sunlight and therefore, isboards to buttress the assumption made except

conjectured to relate to the increase in lighting

for notional confirmation of a number ofload as domestic lights, some commercial andengineers concerned with power supply,

street lights that come on with progressive decline

distribution and utilization in the state, regionsof ambient luminance.

and the country at large.

The method of estimation of the energy saving is

2.1 Validity of the assumption that rise of

based on this portion of the load curve since thethe Evening Load is primarily due tosavings in energy is due to longer use of theLighting

evening sunlight, and consequently shorter useof electrical lights.

Three exercises have been carried out to lendsome evidence to this assumption. These have

The validity of the method of estimation depends

been detailed in Appendices 1, 2 and 3, andalmost entirely on the assumption that the rise of

indicate that:

11

Method Developed for Estimating Energy Changesi)the steady rise of load in the evening is

discussed in Appendix 1. The trailing section

related to the decline of luminance;of the luminance graphs indicating the onsetof evening has been found to correspond toii)

the extra power and energy supplied during

the monotonic growth of the peaking load

the evening (defined as peaking load orat different places and different seasons.

peaking energy (Figure 2.2) in this report,

Luminance graphs for a city in the North

as different from peak load and peak

(Delhi) and Thiruvananthapuram, a city inenergy measured above zero in Figure 2.3)

the South (close to the equator) wereare largely for residential and someobtained (Mani, 1980) for a few days incommercial loads.

different seasons and compared with load
curves on those particular days.

iii)

the peaking energy is largely season
independent and therefore, assumed to

The sunset times in Thiruvananthapuram

comprise mainly lighting load.

which is close to the equator do not varysignificantly with change of seasons. The

1)

The first exercise was based on Luminanceluminance curves almost coincide at thegraphs where ambient brightness of a day

trailing ends (Figure A1.3) and so do the loadplotted every hour is studied withcurves as they steeply rise on corresponding

corresponding Load curve. This has beendays (Figure A1.4).

100000Peaking Load
90000
80000
70000

MWs

60000
50000

Time of rise inevening demand(point of infection)

40000
30000

Additional evening
peaking energy supplied

20000
10000
0
0:00

2:00

4:00

6:00

8:00

10:00

12:00

14:00

TIME (hours)

Figure 2.2: Evening Peaking Load and Energy - Definition.

12

16:00

18:00

20:00

22:00

Options for Adjusting Indian Standard Time for Saving Energy

100000
90000
80000
70000

MWs

60000

Peak Load

50000
40000

Evening peakenergy supplied

30000
20000
10000
0

0:00

2:00

4:00

6:00

8:00

10:00

12:00

14:00

16:00

18:00

20:00

22:00

TIME (hours)

Figure 2.3: Evening Peak Load and Energy - Definition.

The sunset times in Delhi vary with seasonscarried out by one of the investigators, (Senand so do the times for the fading of

Gupta et al, 2005) along with his colleagues

luminance and the rate of rise of the peaking

in the Indian Institute of Science, Bengaluru

loads (Figure A1.5 and Figure A1.6).

and members of BESCOM from 1999 to 2004
on Power distribution in Karnataka state. By

This leads one to conclude that the rise of

special metering and analysis of bills paid,

the peaking load is primarily due to lighting

they were able to obtain separate loadloads when luminance declines.

curves for major consumers in Bengaluru
city. This exercise, detailed in Appendix 2This section of the load curve has little to do

showed that,with ambient temperature. The load curve ishigher during summer months (Figure 2.1)

i)the hump in the evening section of the

because of space cooling requirements. The

aggregate load curve (Figure A2.1) ortime of rise of the peaking load is delayed

the peaking energy looked very muchduring summer but the rate of rise remains

like the evening hump of the residential

almost unaffected by ambient temperatureload curve (Figure A2.2).

as may be seen from the Figure.
ii)
2)

The second exercise is based on studies

street lights and small commercial
loads (not the high end ones as in13

Method Developed for Estimating Energy Changes

Figure A 2.3) come on with theincreased by more than 15%. The coolingresidential evening loads with declining

loads increase the base load and contribute

ambient light and are clubbed together.

marginally to the evening peaking loads. In
fact the peaking loads during summer

Street lights are estimated to constitutemonths (May-August) are less than thoseabout 8% of the evening peaking load

during other months. This may be ascribed(Appendix 2). This percentage of street lights

to power/energy shortfalls and the inability

is said to be relatively large for metropolitanof the power suppliers to meet the total peakcities like Bengaluru compared to non-load (Table 1.1).

metropolitan cities and towns.
TVs are also often switched on before

3)Thus, evening residential and smallevening by elderly or younger members ofcommercial loads constitute more than 90%

the family and these loads are largely a partof the peaking load.

of the base load.

The third exercise was carried out to study

The peaking load in the evening mainly

to what extent the evening peaking load andcomprises lighting load and some televisionenergy are affected by seasonal variations.

load. The bulk of the load due to cooling

If the peaking loads are, by and large,

which is season dependent and a bulk of

independent of seasons there is a strong

TV load merge with base load.

likelihood that they do not include coolingloads (Fans and ACs) to that extent.

It is almost impossible to separate the load

(Electricity is not used much for spaceconsumptions by lighting, televisions andheating in India during winter months andother appliances. The exercises reported in

may be neglected). The peaking loads andAppendixes 1-3 are efforts to provide

energy for all months for 2008 and 2009

support to the assumption that the evening

were plotted and are shown in Appendix 3

peak is mainly due to lighting.

and it is evident that for all months
substantial fractions of the peaking load and

2.2 Method of Estimation of Energy

energy (not the total peak load) remain

Changesconstant and independent of seasons andare likely to be lighting load and possibly

Two more assumptions are implicit in the method

some load due to TVs (Appendix 3).

of estimation of energy savings with changes in

Residential cooling loads are turned on by

IST.

members staying at home wheneverrequired. During summer months theyenhance the total load which is generally

14

1)

Business hours and timings of industries will
not be alteredOptions for Adjusting Indian Standard Time for Saving Energy

2)

If the IST is altered marginally (advancingsets) are most often not provided with electricity

IST by half an hour) people’s habits will

during evening peaking hours. If they are

not be changed. Sleeping hours will be

provided, they constitute a part of the base loadconserved. One goes to bed half hourand still do not contribute to the evening peak.

sooner and wakes up half hour early, in the
Energy savings are contributed mainly by savings

above example.

in residential and small commercial lighting.
Energy saving is by reducing lighting energy inthe evening. Adjusting IST does not particularly

The method of estimating the savings is illustrated

affect industrial and the high end commercial

by choosing a load curve (Figure 2.4), for theloads (like shopping malls, etc., which have large

option of advancing IST by half an hour (Option

connected loads that are kept on throughout the2, Table 1.2). The load curve is from the North-day until closing time) since these loads (except

Eastern Region selected for their pronounced

some other commercial loads) do not depend on

humps, one in the morning and one in theambient light. Agricultural loads (irrigation pumpevening, for easy illustration of the methodology.

1600

1400

1200

MWs

1000

800

600

400

200

0
0:00

2:00

4:00

6:00

8:00

10:00

12:00

14:00

16:00

18:00

20:00

22:00

TIME (hours)

Figure 2.4 : A Typical double-hump Load Curve.

15

Method Developed for Estimating Energy Changes

On the basis of assumptions 1 and 2 (Section

to happen for all 24 hours of the day, by simply2.2), it may be inferred that advancing IST byshifting the same curve there would be no saving

half an hour will not change the load curve except

in energy (given in MWhs) which is the area underfor shifting its position. If the load demanded at

the load curve. This will however not happen for

7 a.m. before the change (shown in blue) is AB

all activities. Switching on of lights is determined(Figure 2.5) the same, A’B’ demand will be madeby ambient lighting and not by what the watch

say, at 7 a.m. in the new or advanced time regime

shows i.e., all activities and therefore the load

(shown by grey), i.e., at what was 6.30 a.m. before

demand will happen half hour sooner with respect

the change. This implies that activities will taketo the unaltered time except for the load

place half hour sooner than before and the loaddemanded for switching on of lights. The new

curve will be laterally shifted to the left. If this wereload curve for the advanced IST (grey) will not

1600

1400

1200
half
hour
1000

A’

MWs

A
800

600

400

200
7.00
B’

0
0:00

2:00

4:00

6:00

0:30

2:30

4:30

6:30

B

8:00

10:00

12:00

14:00

16:00

18:00

20:00

22:00

8:30

10:30

12:30

14:30

16:30

18:30

20:30

22:30

7.00

Figure 2.5: Shifting Load Curve by half an hour.

16

TIME (hours)

Options for Adjusting Indian Standard Time for Saving Energy

1600

1400

1200

MWs

1000

800

600

400

200

0
0:00

2:00

4:00

6:00

8:00

10:00

12:00

14:00

16:00

18:00

20:00

22:00

TIME (hours)

Figure 2.6: The duration of lighting required during the evening is reduced by half an hour and the shaded portion
provides a reasonably accurate estimate of the energy savings when the lights are switched half hour later. The areaof the shaded portion gives the daily saving in MWhs (MWh = 1000 kWhs = 1000 units).

follow the track DD’ but keep to the earlier CC’

There are limitations to this method leading towhich followed the decline of ambient light (Figuresome over-estimations and under-estimations

2.6). Therefore, by advancing IST the ambient light

as discussed in Chapter 4 after presenting

is being used half hour longer in the evening andthe results in Chapter 3. Considering the inherent

this leads to the reduction of lighting energy use

uncertainties and possibilities of errors involvedor the energy saving given by the shaded areain trying to estimate energy saving by changing

CC’D’D. After identifying the point in time when thestandard times from samples of dwellings

evening load begins to rise monotonically (the(residential lightings etc.), the proposed method

point may be referred to as the “point of inflection”

appears to the investigators to be more robust

for convenience), the area is easily calculated.

and dependable.

17

18

3. Resulting Changes in Electricity
Consumption
In this chapter are presented results ofrow, or compare results in rows for each column.

the changes in electricity consumption for all

Both analyses will yield the same conclusions.

the options listed in Chapter 1 using theCompare results for the Options 1, 4 and 7

methodologies (and caveats) described in Chapter(shaded grey). It is clear that the status quo is

2 and the Appendices. For each option, data forbetter as far as energy conservation is concerned

241 days in 2009 and for 252 days in 2008 werethan the corresponding option of daylight saving

used and energy changes in all the five regions intime. Option 4 which would cause an increase in

the country (North-eastern, Eastern, Northern,consumption of 0.14 billion units in the year. The

Western and Southern) were estimated. The

option of DST in turn is better than theconsequences of using regions as a unit of spatial

corresponding option of two time zones,

aggregation and analysis are discussed both in

Option 7, which would cause an increase of about

Section 4.1.1 and in Appendix 4. The changes for1 billion units in a year.

the country as a whole (All-India) were obtainedby summing the changes in the regions.

Next, compare the estimates of energy savingsin the second row shaded light blue. Option 2

The results are shown in Table 3.1 for the year

(advance IST by half an hour, UTC+6:00) yields

2009 and in Table 3.2 for the year 2008. Thesean annual energy saving of 2.1 bU, as againstchanges were compared with the status quo

1.92 bU saving from option 5 (DST UTC+5:30(Option 1, one time zone UTC +5:30, no DST).

winter; +6:30 summer) and 0.89 bU saving fromThe entry for Option 1 is therefore by definition

option 8 (two time zones; 5:30 in the western time

zero. A negative value for energy savings

zone and 6:30 in the eastern time zone). Of theindicates an increase in electricity consumption.

three options, dividing the country into two time

This will happen any time IST is retracted insteadzones offers minimum energy saving.

of advanced as it would happen in winter in theentire country (in Option 4) and in the western

Finally, compare the numbers shaded inzone for the entire year in Option 7. The values

blue. Once again, one can observe that theshown in the tables are annual averages in billion

option of year-round DST (Option 3) yields

units (kWh).

higher savings than that of bi-annually cycling
DST (Option 6) and this in turn yields greater

In order to rank order options in Table 3.1, one

savings than the corresponding time zones

can either compare results in columns for each

(Option 9).

19Resulting Changes in Electricity Consumption

Table 3.1: Average Annual Peaking Energy Savings in billion units in 2009 (n=241)
Advance ISTOne ST, no zones

Daylight Saving Time
Oct-Mar

Option 1

Apr-Sep

Two Time Zones
Total

Western

Option 4

Eastern

Total

Option 7+5:30 (Status Quo)

+5:00

+6:00

--

+5:00

+6:00

--

0.00

- 1.11

0.97- 0.14- 1.590.46- 1.13

Option 2

Option 5

Option 8

+6:00

+5:30

+6:30

--

+5:30

+6:30

--

2.10

0

1.92

1.92

0

0.89

0.89

Option 3

Option 6

Option 9

+6:30

+6:00

+7:00

--

+6:00

+7:00

--

4.04

1.1

2 .81

3.91

1.62

1.27

2.89

Thus, an examination of results in Table 3.1 for the

Option 3 with a one hour advancement saves,year 2009 leads to the following two conclusions:as one might expect, almost twice as much with a
one-hour advancement (4.04 billion units/year).

1.

DST in every case for India leads to greater
electricity savings than having Two TimeThe analysis for 2009 was repeated for 2008

Zones (with nominally the same times) by

where usable data were available for regions forapproximately 1 billion units annually.

252 days in the year. The results are shown in
Table 3.2. The results are consistent with Table

2.

Year-round daylight saving time (advancing

3.1 obtained for the year 2009 and strengthen

IST) in every case for India leads to (slightly)

the conclusions reached for 2009. Appendix 7 lists

greater electricity savings than having

results for option 2 for all 252 days.

Daylight Saving Times with biannuallychanging winter and summer times.

The reasons for these conclusions are not far toseek. The two time zones options have the lowest

To reiterate, one Standard Time through-out theelectricity savings associated with them becauseyear (no zones, YRDST) leads to greater

the high energy consuming western part of theelectricity savings for the entire country compared

country (i.e., the northern, western and southern

to both DST and creating two Time Zones. Withinregions) get the least benefit of daylight, whereas

the first column, it is evident that one-hour

the low-energy consuming eastern part derives theadvancement in IST (Option 3) will save moremost benefit. Similarly, YRDST options yield greater

electricity than with half-hour advancementsavings than DST options because the savings in(Option 2). Option 2 saves 2.1 billion units/year

YRDST are available throughout the year evenfor a half hour advancement of IST, whereas

for half-hour, whereas the savings from one-hour

20Options for Adjusting Indian Standard Time for Saving Energy

Table 3.2: Average Annual Peaking Energy Savings in billion units in 2008 (n=252)
Advance IST

Daylight Saving Time

One ST, no zones

Oct-Mar

Option 1

Apr-Sep

Two Time Zones
Total

Western

Eastern

Option 4

Total

Option 7+5:30 (Status Quo)

+5:00

+6:00

--

+5:00

+6:00

--

0.00

- 1.100.96- 0.14- 1.570.41- 1.16

Option 2

Option 5

Option 8

+6:00

+5:30

+6:30

--

+5:30

+6:30

--

2.00

0

1.92

1.92

0

0.80

0.80

Option 3

Option 6

Option 9

+6:30

+6:00

+7:00

--

+6:00

+7:00

--

4.15

1.08

2 .75

3.83

1.63

1.18

2.81

shift are available only half the months of the year

IST that will put the whole country on year-roundin DST. If monthly distribution of savings in Option

daylight saving time. Whether this is a feasible option

2 were plotted, (Figure 3.1), one can see that DST

and the results meet the required confidence levelis not used in the months (October to March)are discussed in chapter 4 and 6.

where larger savings could potentially accrue.
In the next chapter is discussed the confidence
To summarize, the Option that yields the greatest

one can have in these results and the factors

amount of electricity savings both for 2008 andthat would either under-estimate or over-estimate

2009 is Option 3, i.e., a one hour advancement ofthese energy savings.

7.00
6.00
5.00
4.00
2008

3.00

2009
2.00
1.00
0.00

JAN

FEB

MAR

APR

MAY

JUN

JUL

AUG

SEP

OCT

NOV

DEC

Figure 3.1: Monthly distribution of energy savings (2008 and 2009).

21

22

4. Discussion of Confidence in Results

There are two kinds of factors that lead to a lack

From this limited analysis, one can conclude thatof confidence in the results. One is the lack ofthis choice under-estimates savings from a half-

confidence engendered by the inherent statisticalhour advancement (Option 2) by 15±5%.

variability in the data. The other is due to factorsthat cause “systemic” bias in the results causing
either a systematic under-estimate or an over-4.1.2 Load shedding in summer months underestimates savings

estimate in the results. These factors are
discussed In Section 4.1. Section 4.2 deals with

The electricity supply cannot meet the demand

the calculation of confidence limits for thefor peak loads in the summer. As a result, theestimates of energy savings due to adjustments

peaks in the load curves in the summer are

in IST presented in Chapter 3.

truncated. Thereby, peaking loads are less insummer than they are during winter even though

4.1 Sources of Systematic Bias

the peak loads are higher in summer. This isevident from Figures A3.1 and A3.3. Restricted

There are at least six factors that introduce some

supply during summer months reduces thebias in the results obtained. Three of them tend

estimates of savings as seen from the Figure 3.1.

to provide an under-estimate of the savings,

In the last two years, there has been a power

whereas three others tend to over-estimate theshortage (peak capacity) in the country ofsavings. The first of the factors that under-

12-13%. However, since the peak shortage isestimate savings comes from the choice ofaccentuated in the three months of June, Julyregions as the unit of analysis.

and August (See Figure A3.1), on an annual
basis it can be inferred that the peak-shortage

4.1.1 Using Region as a Unit of Analysis under-

will under-estimate savings by approximately 3%.

estimates Savings
4.1.3 Increase in lighting–related peaking loads
As discussed in Appendix 4, the higher the spatialin summer is “masked” by simultaneous

aggregation as a unit of analysis, the lower will

decrease in cooling loads

be the estimate of savings. The choice of regions,instead of states, as a unit for analysis will under-

There is another factor which tends to under-

estimate the Southern region savings by at least

estimate savings during summer months. The

11% and in the western region by at least 19%.

identification of the point of inflection where the23Discussion of Confidence in Results

peaking load begins to rise in the evenings islight outside begins to fade. These commercial

difficult in the summer months in regions whereloads contribute to energy changes due to IST

cooling loads are a large part of the power

adjustment just as residential lights and may be

demand. The increase in the load during the day

treated the same way and no correction isis due to the use of coolers and air-conditioners

necessary to account for their presence.

mainly in offices. As people leave offices, ACs andfans are turned off and the load begins to drop.

Street lights present a more complicated picture.

This coincides with the rise in the load as lights

In some cities street lights are switched on

are switched on at homes. This tends to “flatten”

automatically when natural light fades andthe load curve and “mask” the point of inflection

switched off in the morning when it begins to lightwhich appears later when the lighting load exceeds

up. Shifting IST makes no change in such cases

the cooling load. The true peaking load identified

since whatever may be gained by advancing IST

for estimating the savings is reduced on accountin the evening is lost in the morning. However,of load shedding and the shift in the point ofsome amount of street lights is included in theinflection. Both these combine to under-estimate

part of energy savings in the estimates made in

the saving. Figure 3.1 shows that the savings inthis report and the enhancement in saving due

the months of June, July and August are on an

to street lighting should be subtracted from theaverage 1 million units per day less than in otherestimated saving. If street lights contribute aboutmonths, or about 5% on an annual basis. In other

4-8% to the evening peaking load thenwords, the estimate of savings would increase byapproximately 6% should be subtracted from theabout 5% if shortage of power together with theestimates of energy savings to account for thismasking of the peaking did not restrict theover-estimate (see also Appendix 2). Functioning

consumption. Since approximately 3% isstreet lights are about 8% of the evening peaking

attributable to load shedding, one can attributeload in the Bengaluru Metropolitan region,

approximately 2% to this masking effect.

but this figure is smaller for smaller towns(Muniswamy, 2010). Therefore 5% would be an

4.1.4 Street lights in the evening peaking load

acceptable approximation.

over-estimate savings
4.1.5 That habits will not change is less tenable
There are two other sources of lighting that comefor one-hour and longer shifts

on at the same time as lights in residences—these
are lights in some commercial establishments and

The two assumptions made in Chapter 2 of thisstreet lights (Appendix 2). Their influence onreport are that that adjustment of standard timesavings estimated has to be disentangled. Light

does not change:

using behaviour in smaller commercial
establishments is similar to the behaviour ina)Working times of offices and factories; andresidences; electric lights are turned on just asb)people’s habits.

24

Options for Adjusting Indian Standard Time for Saving Energy

Whereas working hours may be kept unalteredcontinue to go to bed at the same time if the shift

one cannot legislate human habits. The

is one hour or longer since several activities ofassumption that our habits do not change is more

the evening may have to be covered within atenable if the change is not large (half hour for

shorter time. People may switch off lights later

example). On the basis of this assumption one

than before. In such a case, one cannot assume

presumes that sleep is conserved and sleepingthat the trailing end of the load curve EE’ (Figure

and waking times do not change as mentioned in4.1a), which depicts switching off of lights will

Chapter 2.

remain unaltered. As people switch off lights later,
the section EE’ of the load curve gets shifted toEven though assumption has been made by otherFF’(Figure 4.1b). This means additional energy

investigators (see Aries and Newsham, 2008) thatis used, although it is impossible to predict to what

people’s habits remain unchanged even for shifts

extent. EE’F’F is the amount of additional energyof one hour in the context of DST, it is difficult to(b) to be subtracted from saved energy (a). The

assert with conviction that a person will still

estimated energy saving for one hour shift will

1600

1400

1200

MWs

1000

800

600

400

200

0
0:00

2:00

4:00

6:00

8:00

10:00

12:00

14:00

16:00

18:00

20:00

22:00

TIME (hours)

Figure 4.1a: Estimate of Energy Saving for a shift of one hour in IST.

25

Discussion of Confidence in Results

1600

1400

1200

1000

MWs

a

b

800

600

400

200

0
0:00

2:00

4:00

6:00

8:00

10:00

12:00

14:00

16:00

18:00

20:00

22:00

TIME (hours)

Figure 4.1b: For one hour or longer advancement, the energy savings would not be estimated by the shaded area‘a’, but by (a-b).

not be nearly double of the energy saved for half

A number of studies in other countries (see forhour shift as calculated (Table 3.1) but distinctly

example Kellogg and Wolff, 2007) have indicatedless. It is virtually impossible to estimate thehow energy savings following the implementation

change in people’s habits following an hour’sof DST (one hour shifts) are offset by increases

change in IST. If, office hours are unchanged,in space heating and lighting loads in the morning.

some people may be forced to maintain their

The bulk of the peaking load in mornings in India

habits to make it to the office at scheduled hours.

is due to water heating, especially during winterThis leads to the conclusion that energy savings

months. (In some cooler cities like Bengaluru,

estimated for shifts of one hour or longer (Tables

water heating requirements are year-round

3.1 and 3.2) may have been over-estimated.

(Figure A2.1)). Advancing IST will not change theenergy consumed since a family’s hot water

4.1.6 Some of the evening savings will be offset
by increased lighting in the mornings

26

needs will not change.

Options for Adjusting Indian Standard Time for Saving Energy

The eastern region gets sufficiently lighted

advancement in IST, one can see from table 4.1,

irrespective of the season and lights are seldom

the under-estimates due to load shedding, theswitched on in the mornings. The northern andmasking of point of inflection in the months ofnorth-western regions remain dark longer during

June, July, and August are equal to the effectwinter months and advancement of IST may makeintroduced by street lighting throughout the year.

people switch on lights in the mornings. It is known

So, one is left with the conclusion that the Figuresthat the increase in lighting loads in the mornings

for savings presented in Chapter 3, using thedoes not fully negate the decreases in themethodology of Chapter 2 are lower by 15±5%.

evenings due to DST, but it would be virtually
impossible to estimate more exactly what this

It follows from Table 4.1 that the energy savings

number might be in India.

from half hour advancement of time whencorrected as above comes within the range

By disregarding this, the methodology employed

2.3 – 2.5 bU for the year 2009.

results in overestimation of the energy saving.
The additional use of energy in the morning

The other conclusion one can draw is that the

however occurs for 3 months in the winter.

estimates for Options that include a one-hour shift

Anyway whenever and wherever it may occur due(Options 3, 5 and 8) or for a one and a half-hourto the advancement of IST, it should be subtracted

shift (Options 6 and Option 9) will over-estimate

from the energy saving estimated in Tables 3.1

savings due to possible changes in habits andand 3.2.

larger lighting loads in the morning. Although theextent of these over-estimations is difficult to

4.1.7 Summary

quantify, there is a clear possibility that they
reduce the savings further and strengthen the

Now a summary of the preceding discussion

conclusion in Chapter 3 that savings from YRDST

can be attempted. For Option 2 (half-hour

for a half-hour shift is larger than the savings from

Table 4.1: Factors tending to under-estimate and over-estimate savings(Results are for half an hour advancement)
FactorUsing Region as a Unit of Analysis

Approximate effect on the estimate of Savings-15 ± 5%

Load Shedding in June, July, and August-3%

Simultaneity of lighting load increase with coolingload decline in June, July, August-2%

Street Lighting+5%

Assumption of no change in sleeping and working
habitsNo change for half-hour shifts; over-estimate
savings for one hour or longer shifts

Increased lighting loads in the morning

No change for half-hour shifts; over-estimate
savings for one hour or longer shifts

27Discussion of Confidence in Resultscorresponding DST and still larger than from two

The standard deviations for the estimates oftime zones.

energy savings in Option 2 were 0.77 and 0.82
for 2008 and 2009, respectively. It can easily be

4.2 95% Confidence Limits on Energy
Savings

calculated that for 2008, estimate of average dailysavings is 5.6 ±0.1; for 2009 estimate of energy
savings is 5.7±0.1 million units. This gives the

The second source of uncertainty comes from95% confidence limits as ±2%.

the fact that both for 2008 and 2009, data havebeen analyzed for 252 and 241 days instead of

Quite clearly, the largest source of error comes

366 and 365 days. Given the mean and standard

from the choice of the regions as units of analysis,

deviations for the savings, one can calculate theleading to under estimation. All the other sources

limits that the population mean will actually lie

are small for a half hour shift. Before one canwithin these bands with 95% confidence. Sincesuggest the optimal option for the country, it is241 and 252 are both large numbers, theuseful to consider the non-energy implications ofconfidence limits can be expected to be narrow.

shifts in IST. This is the subject of the next chapter.

28

5. Non-Energy Implications

Time observances affect many aspects of life andbut these are dwarfed by the larger reductions in

any change will have many consequences beyond

the evening. First of all, pedestrians are two toenergy conservation. Several other classes offour times as likely to be killed in darkness thanbenefits accrue to societies that opt for having

in daylight (Aries and Newsham, 2008, p. 1863;

more daylight in the evening hours instead of in

Sullivan and Flanagan, 2002, Ferguson et al.,the morning hours. Many of them are not easily1995). There are more drivers (and pedestrians)

quantifiable but are real benefits nonetheless. Of

on the road in the evening rush hour than in thecourse, not everyone benefits, nor does every

morning. The drivers are more likely to be tired

sector. There could be disadvantages as well.

and anxious to get home and therefore more

The use of daylight saving time, whether year-

prone to accidents. In Britain, there are 50% moreround or in summer, involves trade-offs, and in

fatal and serious road accident injuries amongassessing these trade-offs one must consider all

adults between 1600 and 1900 hours thanthe costs and benefits. This chapter discusses

between 0700 and 1000 hours. As compared to

the non-energy implications of different options

this morning period, accident rates involving

for changing IST.

children are three times during 1500 and 1800
hours (Hillman, 1993). In the United States, there

5.1 Reduction in Traffic and Pedestrian
Accidents

are twice as many fatal accidents during evening
hours than they are during morning hours(Sullivan and Flanagan, 2002).

Besides energy savings, the other most important
benefit is a net reduction in traffic fatalities andIn a review of the YRDST in the US, Ebersole et al

injuries due to road accidents. An assessment of(1974) found an increase in fatalities during darker

the impacts on accident rates is similar to themorning hours but an offsetting decrease inassessment of electricity savings—there areaccidents during early evening hours. An analysis

savings in the evenings, there may be increaseof the Britain’s experiment with YRDST concludedin the morning but these are not enough to wipethat approximately 2500 fewer people had beenout the savings in the evening. What should bekilled or seriously injured during the experiment’sof concern are always net savings.

first two winters. The Royal Society for thePrevention of Accidents (2005) reviewed several

The literature from western countries does show

studies and concluded that on balance, casualties

a slight increase in traffic accidents in the morning,

are reduced by the introduction of DST.

29

Non-Energy Implications

While DST saves lives, the twice-yearly changes

developed countries on the basis of number ofare not without adverse consequences because

vehicles and twice on the basis of population.

of the subtle changes in sleep patterns theycause for a few days after the change. Some US

There is little information in India on accident rates

studies have concluded that accidents increaseby time of day. A study from Patna states thatin the week following both summer and winter time

data merely report whether the accident occurredchanges (Bernstein, 2005; Hicks et al, 1983).

in daylight or darkness (Singh and Mishra, 2001).

Coren (1996) on the other hand, found that

A study from Puducherry reported that theaccidents during the week of spring daylighthighest number of road traffic accidents tooksaving time advancement increased by 6.5%

place in January and the peak time for accidents

compared with the week before, but the changes

was from 1600 to 1700 hours and a second peakafter the retraction in the falls were statisticallywas from 1800 to 1900 hours (Jha et al, 2004).

insignificant.

This study collected data for fatal and non-fatal
accidents in Bengaluru for the years 2008 andAccording to the World Health Organization, in2009 (Gururaj, 2010). These, as shown in Figure

1998 India had the highest number of traffic

5.1 reveal a steady increase in accident rates

fatalities (approximately 0.2 million) and thefrom 1400 hours to 2000 hours and declines

highest number of injuries (7.2 million) in thethereafter. From these data, it would beworld, more than entire other continents. Accident

reasonable to infer that adoption of YRDST willrates in India are ten times more than those inannually save many lives (thousands) in India,

8.0
7.0

percentage

6.0
5.0
2008_fatal%

4.0

2009_fatal%
3.0
2008_nonfatal%
2.0

2009_nonfatal%

1.0
0.0
0

2

4

6

8

10

12

14

16

18

20

22

24

Time of Day

Figure 5.1: Fatal and Non-fatal accident by the time of day for Bengaluru (2008 and 2009).

30

Options for Adjusting Indian Standard Time for Saving Energy

although an estimate exactly how many would be

the morning in summer and very early sun-setsdifficult to make.

in the evenings in winter (see for example, Barua,
2010). In the north-east, it gets bright before

5.2 Reduction in Crime

4 a.m. in June and dark by 5 p.m. in November(Ahuja et al, 2007). By having more usable

The third important category of benefits after

daylight in the mornings and in the evenings,

reduction in energy consumption and traffic

advancing IST would reduce some of theiraccidents is reduction in crime. Most of thehardship.

evidence however comes from studies in the US.
Felson and Poulsen (2003) concluded that crime

5.4 Mainstreaming(in the US) varies more by hour of day than by

globalizing world

thecountryinaany other predictor they knew. Their findings
demonstrate that individuals are more likely to

Of all the 405 different time zones and regions in

be victims of robbery during the late afternoon

the world, irrespective of whether they observeand evening, rather than during the morning.

DST or not, only 3.7% of the regions have times

They cite other studies that show that otherthat differ from UTC (GMT) by non-integral hours.

crimes—such as assault, larceny, motor vehicle

These regions are said to have offset zones.

theft, and juvenile crime are sparse duringThus advancing IST by half hour would bring themorning hours and peak during late afternoon

country in conformity with the choices made by

and evening hours.

96.3% of the regions of the world as shown in
Table 5.1.

Indian statistics on crime by time of day are
difficult to find, especially on what has been

5.5 Other Miscellaneous Implications

considered as “petty” crime. Anecdotal evidence
indicates purse and chain snatchings from womenSome of the most ardent supporters of daylightincrease during dusk. As more people will be ablesaving time in western (northern) countries haveto get home before dusk, some crime rates

been the retailers, since they experience an

can be expected to reduce. Some amount of

increase in sales during DST. DST is said to

additional darkness in the morning would be an

account for an increase in the sales at the 7-11

acceptable trade-off as most crime rates are low

Chain stores by $30 million annually (Stockton,

during morning hours.

2010). Besides an increase in shopping, outdoor
activities too can be expected to increase. Fewer

5.3 Mainstreaming the North-east

sporting events would need to be postponed
because of failing light. Similarly, fewer flights

Much of the impetus for the demand for two time

would have to be postponed in the country

zones comes in India from the north-east, that

because of winter morning fog conditions. Somebears the twin burden of very early sun-rises inhave postulated (a slight) increase in office31

Non-Energy Implications

Table 5.1: Differentiations of Time Zones around the world based on use of
DST and offset times
Time Zones

Differing from UTC
by integral hours

Offset Zones differing
by non-integral hours

Total

With DST

170 (42.0%)

7 (1.7%)177 (43.7%)

Without DST

220 (54.3%)

8 (2.0%)228 (56.3%)

Total

390 (96.3%)

15 (3.7%)405 (100%)

productivity especially amongst those whosome amount of increased driving andattempt now to reach home before dark duringconsumption of automotive fuel have been

winter months. Not all impacts are positive, andreported from countries observing DST.

32

6. The Optimal Option for India

6.1 Experienceof

Neighbouring

andthe Asian region have experimented with daylightsaving time with the hope of saving energy and

Related Countries

then have abandoned it when the resulting
There are several countries that share India’ssavings did not seem to justify the consequences

latitudes (or longitudes) but have never had

associated with twice-yearly changing of time.

daylight saving time. Thus Afghanistan,

Table 6.1 shows the years when the experiments

Cambodia, Myanmar, Chad, Ethiopia, Guinea,

were tried in several Asian regions and then

Libya, Mali, Myanmar, Mauritania, Niger, Nigeria,

subsequently abandoned.

Nepal, Oman, Saudi Arabia, Senegal, Sudan,
Thailand, Venezuela, Vietnam and Yemen are

Thus Bangladesh experimented with DST in 2009

some examples of countries that at least partly

but abandoned it next year. Pakistan has twice

lie in the same latitude band as India and which

had experiments with DST that did not last. Even

have never used DST. What may be more

China experimented with DST starting in 1986 but

interesting is the fact that several countries inabandoned it in 1992. Japan had DST during its

Table 6.1 Asian Regions experimenting with DST and then abandoning it
Asian Region

Year DST Started

Year DST Abandoned

Bangladesh

2009

2010

China

1986

1992

Iraq

2003

2008

Japan

1948

1952

Kazakhstan

1981

2005

Kyrgyzstan

1981

2005

Malaysia

1933

1981

Pakistan

2002, 2008

2003, 2010

Philippines

1986

1998

South Korea

1948, 1955, 1987

1951, 1960, 1988

1945, 1974

1962, 1976

Taiwan33

The Optimal Option for India

occupation but not had it since. South Korea has

which is to its east thus also giving the entire

thrice started using DST and has given it up eachcountry the benefit of YRDST.

time. What is most interesting, however, is theexperience of certain countries that have opted

Sri Lanka is a special case in that it is the only

for having a standard time that is either near thecountry in the region that has experimented

eastern end of their zone (as China) or even morewith YRDST and then abandoned it (seeeast than the eastern most boundary of the

Gunawarddene, 2006). In May 1996, faced withcountry. In this category it is useful to examine

a major electricity crisis, the government of Sri

the experiences of China, Kyrgyzstan, Malaysia,

Lanka changed the standard time from UTC

Singapore, South Korea, and Sri Lanka+5:30 to UTC +6:30. In October 1996 the same

(Table 6.2).

year it decided to change it to UTC +6:00. Partly
because the Tamil Tigers continued to be on UTC

China used to have 5 time zones until 1949. Right+5:30, the Government decided in April 2006

now, they have only one zone which is UTC +8:00.

changed it back to UTC +5:30.

While, its central longitude is close to 105°
degrees E and it could have had its time as 7hours ahead of UTC, it has chosen to be 8 hours

6.2 Drawbacks of the Different Options for
Adjusting or Retaining IST

ahead of UTC thus giving a large part of thecountry the benefit of year-round daylight saving

Changing IST will also have some potential

time. Kyrgyzstan in 2005 decided to adopt its

drawbacks, which need to be addressed. In ordersummer time as the year-round standard time.

to recommend the optimal option for India, it is

Malaysia in 1982 combined the time of Westernnecessary to narrow down the options that have

Malaysia and Eastern Malaysia and used the time

been presented by considering the drawbacks.

of Eastern Malaysia for the whole country, thus

It has been demonstrated in Chapter 3, that thegiving Western Malaysia the benefit of year-longoptions of having two time zones in India yield

daylight saving time. Singapore followed suit.

the smallest benefit as far as energy savings are

South Korea has kept the same time as Japan

concerned. In addition, these options have theTable 6.2: Asian Countries on YRDST34Country

Central Longitude

Standard TimeLongitude Shift

China~104 deg E

120 deg E+16 deg E

Kyrgyztan

75 deg E

90 deg E+15 deg E

Malaysia

112.5 deg E

120 deg E+ 7.5 deg E

Singapore

104 deg E

120 deg E+16 deg E

South Korea

127 deg E

135 deg E+8 deg E

Options for Adjusting Indian Standard Time for Saving Energy

added disadvantage that would require citizens

experimented with and have abandoned DST.

and visitors to change their watches every time

Finally, in countries that still retain DST, such as

they cross the zonal boundary. Because several

the UK (Hill et al, 2010) and the USA (Calandrillo

places in the country have single railway tracks

and Buehler, 2008) there are calls for theand manual switching, there is a likelihood of

adoption of year-round DST.

increased frequency of railway accidents that
could reduce benefits that might accrue from the

The options of YRDST need to be compared nextchange-over to two time zones.

with the status quo. The following table 6.3
compares the advantages and drawbacks of

The second set of options we can consider andadopting YRDST in India with those of the status

discard are those associated with Daylightquo. This table summarizes the discussions in this

Saving Time. This would involve twice-yearlyreport. The peaking energy will be easier tochanging in times throughout the country.

supply in the sense that instead of the 10%

Instead of merely at zonal boundaries, theshortage in the country now, there will only be aincreased risk of train accidents will now be aapproximately 8% shortage. Additionally one canreal possibility twice a year throughout the

expect reductions in road accident rates, crimecountry. In Chapter 5 it was pointed out that roadrates, in postponed flights due to winter morning

accidents increase just after these twice-yearlyfog, and postponement of sports events because

time changes. Added to this is the fact thatof failing light conditions. Shopping, outdoor

several countries in the neighbourhood haveactivities, and to some extent office productivity

Table 6.3: Comparison of Status Quo and YRDST
Category

Status Quo (+5:30)

YRDST (+6:00)

Peaking Energy

Difficult to meet

Easier to supply

Early Sunrises

Complaints from NE in summer

Fewer Complaints

Early Sunsets

Complaints from NE in winterFewer complaints

Late Sunrises—

Complaints from NW in winterRoad Accidents

Peak during Evening times

Can expect a net reduction

Street Crime Rates

Increase during dusk

Can be expected to reduce

Shopping

Baseline

Can be expected to increase

Outdoor Activities

Baseline

Can be expected to increase

Postponement of Flights

Several during winterCan be expected to reduce

Postponement of Sports Events

Some (baseline)

Can be expected to reduce

Office Productivity

Baseline

Can be expected to increase

Conformity with time zones

3.7% have offset times

96.3% have integral times

Costs of Change-overNot Applicable

One-time costs, not estimated35

The Optimal Option for India

can all be expected to increase if the country

higher energy savings associated with Option

decided to adopt YRDST. To these benefits, must

3, there are at least five reasons for preferring

be added the reduced complaints from the north-

Option 2.

eastern parts of the country regarding earlysunrises in the summer and early sunsets in the1.

The energy savings in Option 3 are likely to

winter. Complaints about late sunsets are not

be over-stated as discussed in Section

expected from any part of the country. Decision-

4.1.5.

makers will have to weigh these benefits against
the one-time costs of switch-over and the2.

Advancing IST by one-hour will lead tocomplaints that would result from the north-west

counter complaints from the north-western

about later sunrises in the winter.

parts of the country about late sunrises in
the winter months.

6.3 The Optimal Option for India
3.

The experience of Sri Lanka is illustrative.

It is difficult to make a recommendation of the

They shifted from +5:50 to +6:30, but in abest option for India. From the preceding

matter of 6 months, went to +6:00;

discussion, the investigators are convinced thatthe adoption of YRDST will yield far more

4.

When it was last tried in India between 1942
and 1945, war time (Option 3) was unpopular.

benefits to the country than either dividing thecountry into two times zones, or dividing the year
into two times (DST), or staying with the status

5.

The country would again be in an off-set timezone of +6:30 (Table 5.1).

quo. They are also convinced that the benefits
would exceed the costs it would incur as aconsequence of this switch-over from the status

It appears more prudent therefore to advance ISTquo. There is still the question of choosing

by half-hour. Shifting ahead by one-hour could

between half-hour advancement (Option 2) andcause a backlash that would then make it difficult

one hour advancement (Option 3). Despite theto try a half-hour advancement thus causing theTable 6.4: Annual Electricity Savings for Option 2 for the Years 2009 and 2008
Parameter

Year

2009

2008

n = 241n = 252

Average Annual Savings (billion units--kWhs)

2.1

2.0

Average Daily Savings (million Units--kWhs)

5.7

5.6

Savings as a percent of average daily energy consumption

0.3%

0.29%

Savings as a percent of evening peaking energy

17.5%

18.1%

Savings as a percent of average peak energy supply for 4 hours

1.7%

1.6%

Number of Days Analyzed

36

Options for Adjusting Indian Standard Time for Saving Energy

country to forego all the benefits it mightenergy, one uses the shaded area in Figure 2.3.

otherwise harvest.

Averages are obtained by summing the results
for all days and dividing by the number of days.

The investigators suggest that the country
seriously consider advancing IST by half-hour to

At Rs. 5.36 per unit (the average of traded power

UTC +6:00 and later strive to make this a Common

in the evenings in 2009 (Varshney, 2010), theRegional Standard Time adopted by Nepal andsavings come to Rs. 1125 crores per annum in

Sri Lanka. Bhutan and Bangladesh are already2009, and Rs. 1072 crores in 2008. Based on

on UTC+6:00

the discussion in Section 4.1.7, these Figures
are under-estimated by 10-20%. The “actual

6.4 Energy and Rupee Savings

savings” would be between 1250 and 1450
crores per annum. This number could be

Table 6.4 shows the consequences of thisexpected to increase moderately in subsequent

electricity saving in Option 2 for both the years.

years.

Again both 2008 and 2009 yield a consistentpicture. The average annual savings in 2009 areapproximately 2.1 billion units. While it is a small

6.5 Future Changes that will alter theestimates of energy savings

percentage of the average daily load (0.3%), it
is a significant fraction of the evening peaking

Chapter 4 discussed three factors that presently

energy (17.5%) which presents the most difficult

tend to cause the savings from adjusting IST tochallenge to Indian utilities to meet. As a percent

be under-estimated and three other factors thatof the peak energy supplied for 4 hours in thecause these savings to be over-estimated. Thisevening, the number is close to 1.7%.

section briefly touches upon the factors that havethe potential to increase or decrease savings in

To understand how these percentages were

the future. As more and more households arecalculated, it is helpful to refer to some of theelectrified, especially in rural areas, where 7

diagrams in Chapter 2. The energy saving for acrores out of 15 crore households are still un-

typical half hour advancement is given by theelectrified; as more of the evening peaking energy

shaded area CC'D'D shown in Figure 2.6. Thisis met in the country; as share of domestic lighting

constitutes the numerator. When divided by theincreases with the development of the country,

total area under the load curve for that day (sayone should expect that the savings fromas shown in Figure 2.4), the fraction as aadvancing IST will be larger in the future. The

percentage of daily consumption is obtained. To

factor that will tend to depress the magnitude ofobtain the fraction as a percent of evening

savings will be the increasing penetration of CFLs

peaking energy, the denominator used is theand LEDs in the future. It is very difficult to provide

shaded area shown in Figure 2.2. Finally, tonumerical estimates or bounds of the extent ofobtain the fraction as a percent of evening peakthese changes, but it may be surmised that at

37

The Optimal Option for India

Table 6.5: Partial List of Stakeholders who will need to Adapt
1.

Banks

6.

Schools and Educational Institutions

2.

Airlines

7.

Computer Software and Satellite Programmers

3.

Railways

8.

Broadcast Media

4.

State Road Transport Corporations

9.

Morning Walkers

5.

Electricity Suppliers

10.

Astrological Charts Preparers

least in the intermediate term, future energy

in the order of the extent of adaptation required.

savings will be larger than they are today.

Transport providers will need to re-publish theirtime tables. It is expected that it would take6.6 Sectors and Stakeholders who will needto adapt

between 1-2 years of planning for a smoothtransition. For there to be the least amount of
disruption, it should be implemented on an early

Every change from status quo entails adaptation

Sunday morning in June when the days are thefrom different stakeholders. Changing IST is nolongest. In order to document impacts, theexception. Table 6.5 provides a partial list ofswitchover should be preceded by careful

stakeholders who would need to adapt, but notbaseline measurement studies.

38References

Ahuja, D.R., Sen Gupta, D.P., Agrawal, V.K., 2007.

Ebersole et al, 1974. The Year-Round Daylight

Energy savings from advancing the Indian

Saving Time Study, vol. I. Interim Report on theStandard Time by half an hour, Current Science,

Operation and Effects of Year-Round DaylightVol. 93, No 3, 10 August 2007, pp. 298 - 302

Saving Time. US Department of Transportation,
Transportation Systems Center, Cambridge, MA,

Aries, Myriam B. C., Newsham, Guy R., 2008.

USA.

Effect of daylight saving time on lighting energy
use: A literature review, Energy Policy 36 : 1856 -Felson Marcus, Poulsen Erika, 2003. Simple

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Indicators of Crime by Time of Day, 19 INT’L J.
FORECASTING, 595.

Barua, Jahnu, 2010. The line that divides
India, GovernanceNow, February 28, Vol 01,

Ferguson, Susan A., et al., 1995. Daylight Saving

Issue<http://

Time and Motor Vehicle Crashes: The Reduction

www.governancenow.com/news/regular-story/

in Pedestrian and Vehicle Occupant Fatalities,

line-divides-india-2>, last accessed October

85, AM. J. PUB. HEALTH, 92, 95.

2.

Available

onlineat2010
Gunawarddene, 2006. Science loses in Sri Lanka’sBernstein, Sharon,2005. Time Change May Put

debate of standard time. Available online at <http:/

Sleepier Drivers on Road, LA TIMES, March 31,/www.sciden.net/en/opinions/science-loses-sri-

2005, B2.

lankas-debate-on-standard-time-ti.html>

Calandrillo, Steve P., Buehler, Dustin E., 2008.

Gururaj, 2010. Personal Communication.

Time Well Spent: An economic analysis of daylightsaving time legislation, Wake Forest Law Review,

Hicks, Robert A., et al., 1983. Daylight Saving

Vol. 43, pp 45 - 91

Time Changes Increase Traffic Accident, 56
Perceptual & Motor Skills, 64 - 65.

Coren, S., 1996. Sleep deficit, fatal accidents,
and the spring shift to daylight savings time.

Hill, S.I., Desobry, F., Gamsey, E.W., Chong, Y.F.,

Available online at <http://www.msmaster.ca/

2010. The impact on energy consumption

inabis98/occupational/coren0164/index.html>,

of daylight saving clock changes. Energy

last accessed March 2007.

Policy 38, Issue 9, pp 4955 - 4965

39

References

Hillman, M., 1993. Time for Change: Setting

Prerau, D.S., 2005. Seize the Daylight:

Clocks Forward by One Hour Throughout the

The Curious and Contentious Story of Daylight

Year; a New Review of the Evidence. Policy

Saving Time. Thunder’s Mouth Press, New York,

Studies Insitute, London.

p. 30.

Jha, Nilambar, Srinivasa, D.K., Roy Gautam,

Royal Society for Prevention of Accidents

Jagadish, S., 2004. Epidemiological study of road

(RoSPA), 2005. Single/double summer time.

traffic accident cases: A study from South India.

Position paper. Available online at <http://

Indian J. Commun. Med., 29, 20 - 24w w w. r o s pa . c o m / r a o d s a f e t y / i n f o /summertime_paper.pdf>, last accessed October

Kellog, R., Wolff H., 2008: “Daylight Time and2006.

Energy: Evidence from and Australian
Experiment”, Journal of Environmental Economics

Sen Gupta, D.P., et al., 2005. Energy Accounting

and Management 56, 207-220.

and Rationalization of Distributing System. Indian
Institue of Science and Karnataka PowerMani, Ana, 1980. Handbook of solar radiation data

Transmission Corporation Ltd., Bengaluru.

for India, Allied Publisher, New Delhi.
Singh, S.K., Mishra, A., 2001. Road accident
Ministry of Power, 2010. Electricity Deficit inanalysis: A case study of Patna city. Urban

India 2007 – 2010. Available online atTransport J., 2, pp 60 - 75

<www.powermin.nic.in>
Stockton, Rachel (2010): The economic effects
Muniswamy, 2010. Personal Communication.

of Daylight Saving Time, www.helium.com/
accessed on 22-09-2010.

Natarajan et al, 1988. Two strategies for electricload leveling for India: Phase II – Final report

Sullivan, John M., Flanagan, Michael J., 2002.

submitted to the Advisory Board on Energy, TERI,The Role of Ambient Light Levels in Fatal

New Delhi, June 1988.

Crashes: Inferences from Daylight Saving Time
Transitions, 34 ACCIDENT ANALYSIS &Planning Commission, 2006. Integrated Energy
Policy, New Delhi, August 2006, p. 85.

40

PREVENTION 487 - 493.

Appendix 1
Correspondence between Luminance and Evening Peaking Loads

Luminance data for various cities in India are(28.5°N, 76.5°E), two cities at different latitudes,

available (Mani, 1980) based on local apparent

but nearly the same longitude, were chosen fortime (LAT, i.e. wherein noon is the time when thea number of reasons:

sun reaches the mid sky locally). Suitable
equations are available to convert LAT to IST.

1)

The primary objective is to study whether

Figures A1.1 and A1.2, represent the seasonalseasonal variations in luminance areluminance curves for Thiruvananthapuram andreflected on the load curves or not. Had one

Delhi respectively. The interest is focused on thechosen two cities on the same latitude but

tail ends of these graphs towards the evening

different longitudes (e.g., Bhuj (24°N, 70°E)

shown in Figures A1.3 and A1.5.

and Aizal (24°N, 93°E), seasonal changes
in sunset times and luminance at sunset in

Luminance (kW/sq.m.)these cities would be similar in every season
although the sunset times are different,
sunset time at Aizal preceding that of Bhuj
by almost one and a half hours. Comparing
their load curves and the luminancecurves would not serve the purpose.
The luminance in a city close to the equator

Local Apparent Time(as in Thiruvananthapuram) is not so much

Figure A1.1: Thiruvananthapuram Seasonal
Luminance.

dependent on seasons as a city latitudinallyaway from the equator (as in Delhi), which

Luminance (kW/sq.m.)varies with variable sunset times in different
seasons and the seasonal variations arereflected in the corresponding load curves.
Other relatively minor reasons to choose
Local Apparent Timethe cities, Delhi and Thiruvananthapuram are

Figure A1.2: Delhi Seasonal Luminance.

listed below:

Luminance curves and Load Curves of1)

Thiruvananthapuram (8.5°N, 76.5°E) and Delhi

Load curves for Delhi are readily available
as Delhi is a state

41

Correspondence between Luminance and Evening Peaking Loads

2)

For a southern state data on Puducherry

3)

Data for daily load curves for Kerala arewhich does have data for daily load curves

readily available and the assumption had tohas been collected but frequent load

be made, that since Kerala lies within ashedding renders them unusable for thisnarrow band of East-West longitudes,

study. Load curves for Bengaluru could not

the luminance of the rest of Kerala would

be obtained.

not be significantly different from that of

Figure A1.3: Thiruvananthapuram Luminance in
Evening.

Figure A1.4: Kerala Seasonal Load Curves.

Figure A1.5: Delhi Seasonal Luminance.

Figure A1.6: Delhi Seasonal Load Curves.

Figure A1.7: Sunset
Thiruvananthapuram.

42

vsPeaking

timefor

Figure A1.8: Sunset vs Peaking time for Delhi.

Options for Adjusting Indian Standard Time for Saving Energy

Thiruvananthapuram for which luminance

DELHI

data were available.

Luminance curves for Delhi (Figure A1.2) show
wide variations in luminance during winter andFigures A1.3 and A1.4 represent Luminance andsummer months which persists during the evening

Load curves respectively of Kerala for four days

hours (Figure A1.5).

representing four seasons of the year. The
following observations are of interest.

Load curves for Delhi (Figure A1.6) represent a
different pattern.

KERALAThe luminance curves (Figure A1.3) for1)

The evening peaks rise at different times,

different seasons do not show a significant

fairly early during winter months and muchvariation at corresponding times in the evening.

later during summer months. The times of

The curves are similar and lie within a narrowsunset are also very different. Figure A1.8

band.

shows a wide dispersion, sunset time varying
from 17hrs 30 mins, during winter months

1)

Correspondingly, one may observe that theto 19 hrs 25 minutes during summer months.

times of rise of the evening loads are close

Correspondingly, peaking time varies from 15

to each other (Figure A1.4). The sunset

hrs 45 minutes to 19 hrs in summer months.

times, as may be expected, do not vary widelywith seasons (irrespective of the season, theThe seasonal difference between the gaps insun rises and sets exactly at 6 on thesunset times and switching on times are not greatly

equator). Figure A1.7 represents thedifferent in Kerala (Figure A1.7). In Delhi, thevariation of peaking time (the time when theswitching on times during winter months precedeload begins to increase monotonically) withsunset times quite significantly (Figure A1.8)

sunset time (monthly averages of data foralmost every day). The monthly or seasonal2)

The rate of peaking on the other hand arevariations are not significant (sunset varies

dissimilar but close during the months offrom 18 to 18hrs 45 minutes and peaking

March and September, when the load curves

time varies from 17 hours to 18 hours 15

also rise at the same time.

minutes).
3)
2)

The rate of rise of the peaks is also similar,

The peaking power values once again vary
within a limited range.

rising as the luminance declines.
The seasonal variations of Luminance in Kerala
3)

The magnitudes of evening peaks varyin the evenings are marginal and are clearly

within a limited range from one season toreflected in the evening load curves ofanother.

corresponding days and the large seasonal43

Correspondence between Luminance and Evening Peaking Loads

variations in the evening Luminance in Delhi arecases that were tested lead one to infer

reflected in the load curves for the city. (Figuresthat the rise in the evening load is largely

A1.5 and A1.6)

caused by switching on of electric lights but
this correspondence does not tell exactly

The correspondence between the fall of

how much of the peaking load is due toluminance and the rise of load in all thelighting.

44

Appendix 2
Evening Peaking Power is Largely Residential and Small Commercial
Loads
Bengaluru city load mainly comprises Residential,

reported in Sen Gupta et al (2005) confirms someCommercial and Industrial loads. Feeders thatof these notions.

supply agricultural load were not included in thesection of the reference (Sen Gupta et al, 2005)

Commercial lighting loads are generally switchedfrom which results are quoted in this study.

on in the morning, along with other loads, the totalload progressively building up as various

The data presented here are for the year

commercial establishments begin to function. High

1999-2000 and since then the development

end commercial loads from shopping malls etc.

of the city has substantially increased power

remain almost constant throughout the day andand energy consumption. Load curves forstep down from around 9 p.m. (Figure A2.3).These

different groups of consumers and thecommercial loads contribute to the total evening

aggregated load curves for recent years werepeak load but not to the building up of the evening

unavailable from any source. Assuming that thepeaking load. Smaller commercial loads, shops

general patterns of load consumption remain

and lights for advertisements are switched on much

unaltered, certain conclusions may be drawn

like residential loads with declining luminance.

from the graphs presented here (Figures A2.1,
A2.2, A2.3, A2.4) quoted from Sen Gupta et al,

The high-tension industrial loads are switched2005.

on early in the morning and begin to drop after
9 – 10 hours’ shift and with normally one shift

Load curves for the months of April and July haveoperation continue to reduce as the industries

been presented, April with load shedding and theshut down (Figure A2.4).

July load curves without load shedding to indicate
how load curves at lower levels of aggregation

The hump in the evening residential load (Figure

are grossly distorted and cannot be relied upon

A2.2) is almost identical in shape to the evening

for the study undertaken.

hump in the Aggregate or Total load curve (FigureA2.1) and substantiates the belief that the

It is generally believed that the evening hump inevening hump is caused mainly by Residential

a load curve (Figure A2.1) is primarily caused byload (as per Figure A2.2).

residential, some commercial lighting loads andstreet lights. There are no data however to

The difference in the areas of the humps in thesubstantiate this. The study carried out andtotal and Residential load curves in Figures A2.1

45

Evening Peaking Energy is Largely Residential and small Commercialand A2.2 respectively, would account for

600 MW (see Muniswamy, 2010). The percentage

contributions from sources other than Residential

contribution of street lights to the evening peaking

to the evening peaking energy and comes to about

load comes approximately to 8% (which is said to30% of the total peaking load in Figure A2.1.

be high since Bengaluru is a Metropolitan city).
Street lighting enhances the estimate of evening

This load is very likely the contribution from someenergy savings as discussed in Chapter 4.

commercial loads and street lighting loads. (Street
lights will enhance the estimation of savings in

So far as the major commercial loads areenergy due to changing IST. This is discussed inconcerned, the energy consumption during theSection 4.1.4).

evening comes to as estimated from figures A2.1
and A2.3, 20-25% of the total peaking energy inSeparate data for street lighting were not statedthe evening. Commercial loads in Bengaluru havein Sen Gupta et al (2005). For 2010 installed

increased at a greater pace than residential

capacity of street lights in Bengaluru is said to belighting loads. Although it is difficult, it is not

64 MW and with about 75% usage contributes

necessary to separate residential and commercial

about 48 MW to the evening peaking load of about

loads situated in residential areas nor is it

Figure A2.1: Load curves of Bengaluru.

Figure A2.3: Commercial curves of Bengaluru.

Figure A2.2: Residential curves of Bengaluru.

Figure A2.4: Industrial curves of Bengaluru.

46

Options for Adjusting Indian Standard Time for Saving Energy

necessary for the present study since the study

exercise are thatis concerned with lights that are turned on witha)

The evening humps in Load curves are

declining ambient light and they are treated themainly caused by Residential and small

same way, except for street lights (chapter 4).

commercial loads for Bengaluru (over 90%).

In absence of any other available data, thetentative conclusions that may be drawn from thisb)Street lights contribute less than 10% to this
load.

47

48

Appendix 3
Evening Peaking Load is Primarily Lighting Load

If the evening peaking load is mainly due to

It is evident from Figure 2.1, (Chapter 2) that

Residential load, and some Commercial andpower demand met during summer months isStreet lighting load, it may not necessarily be

about 15% higher than that during winter months.

lighting load alone and may comprise other loads
as well. For example cooling loads (such as fans14large as cooling loads in India) during winter8
6

seasons and loads due to the use of TV sets

4

may all add up to make the Peaking load or the20

hump in the evening. If so, the peaking load
would obviously become weather dependent,

2008

10

GWs

certain amount of space heating loads (not as

2009

12

and Air-conditioning) during summer months, a

JAN

FEB

MAR

APR

MAY

JUN

JULY

AUG

SEPT

OCT

NOV

DEC

Figure A3.1: Monthly variations of the evening peaks.

since fans and ACs are turned off during wintermonths.

120
100

India load data for the years 2008 and 2009 were

MW/min80

In order to find an answer to this question Allstudied and presented in Figures A3.1, A3.2 and

40
20
0

A3.3
i)

60

JAN

the average values of peaking loads for

FEB

MAR

APR

MAY

JUN

JULY

AUG

SEPT

OCT

NOV

DEC

Figure A3.2: Growth Rate of Peaking Load over the year
(MW/min).

every evening of the year and for each month45

are presented in Figure A3.1

2009

40

2008

ii)

the average values of rate of growth ofpeaking loads, the average values for every
month are presented in Figure A3.2

million units

35
30
25
20
15
10
5

iii)

the average values of total additional energy
required, for peaking in every month arepresented in Figure A3.3

0
JAN

FEB

MAR

APR

MAY

JUN

JULY

AUG

SEPT

OCT

NOV

DEC

Figure A3.3: All India energy consumption during evening
peak hours (2008 and 2009).

49

Evening Peaking Load is Primarily Lighting Load

This is largely due to cooling required during

during winter months (Fig 2.1), the peaking load

summer months that raises the base load,

however, remains the same.

particularly in metropolitan cities.
On studying these graphs it appears that a bulk
The average value of the peaking loads come toof the evening peaking load are almost

9.2 GW (2008) and 9.3 GW (2009). It has been

unaffected by the seasons and therefore unlikely

confirmed from Power Grid Corporation of India

to comprise cooling or heating loads.

that at times 90 to 100 MW needs to be provided
every minute for one and half hours to partially

It may be reasonable to infer that the evening

meet most but not all of the demand. There aredemands from the months of October to Februarysome variations around the average values. In(when power required for cooling is significantly

2009, the mean peaking load is 9.3 GW. In theless and as observed earlier electrical spacemonth of July, the average peaking load is 8 GW,

heating loads in India are insignificant) reflect

which reaches 11.8 GW in the month of November.

the true demand for lighting and a certain

The relatively low values of peaking loads during

amount for TV sets. Loads for these months are

the summer months may have been caused byindependent of seasons and require lesser loadlarger peak loads that the power supply agencies

shedding.

are unable to supply [Table 1.1]. There is atpresent a shortfall of 12.7 % in power supply and

It would be rather difficult to infer how much of

10.1 % of energy supply. Figure A3.1 indicates,

the evening peaking power is caused by the

however that a large portion of the peaking loads

switching on of lights or by Television sets. It is

are not dependent on the season.

possible that a large number of TV sets are
switched on during the day before darkness sets

The average all India daily energy consumptionin, especially by elder or younger members ofduring the evening hours of peaking, come tothe family.

about 33 million units (Fig A3.3, year 2009). It is
1.65% of the daily average energy consumption

In the same way, one can conjecture that coolingof 2 billion units per day. The average evening

loads (Fans/AC) are also turned on throughout

energy consumption during the months ofthe day and night when required and constituteDecember, January and February drops to 27

parts of the base load and are not significant

million units since people switch off lights earlier

parts of the evening peaking loads.

50Appendix 4

In this appendix are compared the energy savings

based on All-India Load curves with savings based

obtained from advancing Indian Standard Timeon Regional load curves. In section A4.3.2, theby half an hour at various levels of spatial

latter are compared with savings from load curves

aggregation in order to select the level of analysis

at State level. Because the increase in evening

for the study. There are at least three options forloads are primarily lighting-related, one should adoing the study: All-India, Regional or at the level

priori expect more accurate estimates to emergeof States. In section A4.3.1 are compared savings

from lower levels of aggregation because higher

ΔE
Y- ΣΣ(Regions)_Δ

ΔE
Y- ΣΣ(Regions)_Δ

Choice of the Appropriate Level of Spatial Aggregation

X- All India ΔE

X- All India Δ E

Figure A4.1: 2009 Energy (mU) Savings ΣRegions & All
India.

Figure A4.2: 2008 Energy (mU) Savings ΣRegions vs All
India; n=252.

All India

All India
ΣRegions

Percentage

Percentage

ΣRegions

Range

Range

Figure A4.3: 2009 Energy (mU) Savings ΣRegions & All
India.

Figure A4.4: 2008 Energy (mU) Savings ΣRegions & All
India.

51

Choice of the Appropriate Level of Spatial Aggregationlevels comprise summation (aggregation) of

savings estimated from the All India load curve,

many sequential levels of luminance declines andwhich is the aggregate of regional loads and thetherefore summation of sequential levels of riseevening peaking load being a summation of thein the load curves in the evening. For example,

regional loads and the time of rise an average ofsunsets in Madhya Pradesh occur earlier than

the regional times of rise, and as a result lesssunsets in Gujarat. Correspondingly, the decay

accurate.

in luminance and evening rise in load curves in
Madhya Pradesh precede those in Gujarat. Load

4.3.1 Comparison of Savings obtained from
All-India and Regional Load Curves

Curve of the western region, being the sum of
average time of rise, and the estimate of energy

As already explained, one can get an All-India

savings based on individual states is expectedload curve for any day by aggregating the five

to be more accurate than that estimated from theregional load curves for that day. For any given

load curve of the region. The same applies to

day with acceptable data, it is possible to estimate

ΔE
Y- ΣΣ(States)_Δ

ΔE
Y- Σ
Σ(States)_Δ

loads in all the states in the region indicates the

X- Southern Region Δ E

X- Western Region Δ E

Figure A4.5: 2009 Energy (mU) Savings ΣStates vsSouthern Region; n=149.

Figure A4.6: 2009 Energy (mU) Savings ΣStates vsWestern Region; n=128.

Western Region

Southern Region

ΣStates

Percentage

Percentage

ΣStates

Range

Range

Figure A4.7: 2009 Energy (mU) Savings ΣStates vsSouthern Region.

Figure A4.8: 2009 Energy (mU) Savings ΣStates vsWestern Region.

52

Options for Adjusting Indian Standard Time for Saving Energy

4.3.2 Comparison of Savings obtained fromenergy savings from the aggregate load curve

Regions and State Level dataor from the individual regional curves.
A simple visual way to compare the energy

A similar analysis was conducted for the Southernsavings from All India (X-the horizontal axis) andand Western regions for the year 2009.

Regional Load Curves (Y-the vertical axis) may
be using a scatter-gram as in Figs A4.1 and A4.2.

Once again, a priori one should expect theIn the figures the diamonds indicate an Identity

estimates obtained from summing individual

Line i.e. Y=X line is shown. Results for n points

states to be higher than those obtained fromare plotted. If Y ≈ X, the points are equally

the regions. These results are shown in Figure

distributed about the Identity Line. If the points

A4.5 and Figure A4.6 for the southern and thegenerally aggregate above the Identity line, one

western regions respectively. Even though data

can conclude that Y is larger than X.

for the state of Puducherry in the southern
region, and those for Goa and Dadra andFor 2009, these results are shown in Figure A4.1.

Nagar Haveli in the western region were

As is evident, most of the data points lie above

excluded, once again most of the points lie

the identity line indicating that the estimates

above the diagonal confirming that estimatesobtained from the regions are higher than thosefrom states are higher than those at regional

obtained from the All-India load curve. The

level. The next two Figures, Figure A4.7 andscatter-gram for 2008 in the next Figure A4.2

Figure A4.8 show the histograms comparing there-confirms this observation. These scatter plots

values of savings obtained from the states andfor 2009 and 2008 are shown as histograms in

the regions. The Figures show that the average

Figure A4.3 and Figure A4.4 respectively. The

daily savings from the southern regional

average savings in 2009 from a regional analysis

load curves is 1.6 MU/d and from the states it

is 5.7 MU/d and from All-India, is estimated to beis 1.8 MU/d. For the Western region the

an average of 4.8 MU/d. The corresponding

corresponding numbers are 1.41 and 1.75 MU/

numbers for 2008 are 5.6 MU/d for regions andd, respectively. These results are summarized

4.8 MU/d for All-India.

in the following Table-A4.1.

Table-A4.1 Choosing the Level of Aggregation
Year

Data Points

All-India

Savings (MU/d)Regions

States% Diff.

2009

n = 241

4.8

5.7

—

+16%

2008

n = 252

4.8

5.6

—

+14%

Southern

2009

n = 149

—

1.6

1.8

+11%

Western2009

n = 128

—

1.4

1.7

+19%

53

Choice of the Appropriate Level of Spatial Aggregation

These results reinforce the observation thatthe above table), and unavailable at levels lower

lower the level of spatial aggregation higher (andthan that of a state, estimates at the regional

more accurate) will be the estimates of energy

level — had to be settled for despite the realization

savings one would get. However, because thethat the latter will underestimate the savings toavailability of load supply data is erratic even at

be obtained from advancing IST by half hour by

the state level (see the column for data points in

15 ± 5%.

54

Appendix 5
Expert Advisory Committee

1.

Dr. Ajay Mathur, Chairman

6.

Dr Arvind Bharti, Scientist ‘G’ &Director General

Associate Director

Bureau of Energy Efficiency

Directorate of Planning & Coordination

4 Floor Sewa Bhawan

Ministry of Defence/R&D Organisation

R.K. Puram, New Delhi-110 066

DRDO Bhawanth

New Delhi - 110 105
2.

Ms. Rita Acharya, Director
Energy Conservation

7.

Mr. A K Bhatnagar, Additional Director

Ministry of Power

General of Meteorology

Shram Shakti Bhawan, Rafi Marg

India Meteorological Department

New Delhi – 110 001

Mausam Bhavan
Lodi Road

3.

New Delhi – 110 003

Mr. V K Agrawal, General Manager
Northern Regional Load Despatch Centre
Power Grid Corporation of India Ltd

8.

Mr. S Bhattacharyya, Scientist – F (PGD)

18-A, SJSS Marg, Katwaria Sarai

Production and General Engineering

New Delhi 110 016

Department
Bureau of Indian Standards

4.

Mr. Surajit Barooa, Chief Electrical

Manak Bhavan,

Inspector-cum-Adviser

9 Bahadur Shah Zafar Marg

Government of Assam

New Delhi 110 002

Mahabhairab Building, Pub Sarania Road
Guwahati-781 003

9.

Mr. Raghu Cavale, Vice President
India Business Unit

5.

Mr. M L Batra, Former Member Secretary

Infosys Technologies Ltd(Southern Regional Electricity Board)

44, Electronics City

Res: M-51, Swathi Apartments

Hosur Road,

12 Patpar Ganj, New Delhi 110 092

Bengaluru 560 100

55

Expert Advisory Committee

10. Dr. S K Chakravorty, Deputy. Director

16. Mr. Shahid Hasan, Associate Director

General (TS)The Energy and Resource InstituteNational Productivity Council

Darbari Seth Block, I.H.C. Complex

Utpadakta Bhawan, Lodhi Road

Lodhi RoadNew Delhi – 110 003

New Delhi – 110 003

11. Maj Gen A K Chaturvedi, Chief Engineer

17. Prof. H P Khincha,

HQ Northern Command

Department of Electrical Engineering

Engineers Branch

Indian Institute of Science

Pin 914 698 C/o 56 APO

Bengaluru 560 012

12. Mr. S R Chaudhari, General Manager (EC)18. Mr. Sushil Kumar, Director Electrical

Maharashtra Energy Development Agency

Engineering (PS)MHADA Commercial Complex

Railway Board

2 Floor, Opp. Tridal Nagar

Room No. 164, Raisina Road

Yerwada, Pune – 411 006

Rail Bhawan, Rafi Margnd

New Delhi-110 001
13. Mr. S P Goel, Director (IC)Petroleum Conservation Research

19. Mr. D N Lahon, Director

Association

AED, DGCA, C-CAD

Sanrakshan Bhavan

National Aerospace Laboratories

10, Bhikaji Cama PlacePB 1779, Bengaluru 560 017

New Delhi 110 066
20. Mr. H L Meena, Deputy Adviser
14. Mr. R Guhan, Joint Advisor
Petroleum and Natural Gas Regulatory

Planning Commission

Board

Room No. 314–A

I Floor, World Trade Centre

Yojana Bhawan, Sansad Marg

Babar Road, New Delhi – 110 001

New Delhi – 110 001

15. Mr. Sumant Gupta,

56

Power and Energy Division

21. Mr. P K Mishra, Director

Deputy Director General(Infrastructure & Energy)

Mission-IV, Northern Region

Department of Economic Affairs

Geological Survey of India

Ministry of Finance

Vasundhara, GSI complex, Sector-E,

Room No. 70-C, North Block

Aliganj, Lucknow – 226 024

New Delhi 110 001

Options for Adjusting Indian Standard Time for Saving Energy

22. Mr. Y P Mittal

26. Mr. Ajay Talegaonkar, Superintending

Economic Advisor (SE & L)

Engineer-Operations

Room No. 233 ‘C’ Wing

Northern Region Power Committee

Department of School Education and

18-A, Jeet Singh Marg

Literacy

Katuwaria Sarai

Ministry of Human Resource Development

New Delhi 110 016

Shastri Bhavan, New Delhi 110 001
27. Mr. R K Trehan, Scientist – F & Head
23. Mr. M A Patil, Director(ETD)

Resource Conservation and Management

Electro-technical Department(RCM)

Bureau of Indian Standards

Federation of Indian Chambers of

Manak BhavanCommerce and Industries

9 Bahadur Shah Zafar Marg

Federation House, Tansen MargNew Delhi, 110 002

New Delhi – 110 001
28. Mr. Toine van Megen
24. Mr. Arvind Kumar Sahu, Manager

Matrimandir Nursery(Electrical)

Auroville 605 101

Premises Department, State Bank of India

Puducherry

Corporate Centre, Floor-9
State Bank Bhavan

29. Dr. Ram Varma, ACE, Pr Dir Works (Utility)

Madame Cama Road

Directorate of Works, E-in-C’s Branch

Mumbai – 400 021

IHQ of Ministry of Defence (Army)
Kashmir House, Rajaji Marg

25. Dr. S Seetharamu, Additional Director

New Delhi – 110 011

Material Technology Division
Central Power Research Institute

30. Mr. P Varshney, Senior Vice President

Prof. Sir C.V. Raman Road,PTC India Ltd.

Sadashivanagar

2nd Floor, NBCC Tower

P.B. No. 8066

15 Bhikaji Cama Place

Bengaluru – 560 080

New Delhi – 110 066

57

58

Appendix 6:Interministerial GroupInterministerial Group meeting was held under the Chairmanship of Shri. G. B. Pradhan, Additional Secretary,
Ministry of Power, on December 15, 2010 inviting Ministries/Agencies to consider the draft report presented by
NIAS and written comments were received thereafter:
Ministries / Agencies
Ministry of PowerNew Delhi

Participants

Written Comments

Bureau of Energy Efficiency
MOP, New Delhi

Shri G B Pradhan,
Additional Secretary (Chair),Shri. Devender Singh
Joint Secretary,
Shri. K Vasudevan
Under Secretary (EC) &Ms. Rita Acharya
Director, EC Division
Dr. Ajay Mathur
Director General

Government of Assam
Guwahati
Department of Science &Technology, New Delhi

Shri Surajit Barooa
Chief Economic Advisor
Shri. Milind Kulkarni
Scientist 'F'---

Department of Economic Affairs,
New Delhi

Shri P K Mishra
Director (I&I)---

Ministry of Home Affairs
New Delhi

Shri R P NathJoint Secretary (Administration)

Shri Arvind Mukherjee
Under Secretary
February 3, 2011

Government of Rajasthan
JaipurShri N K Pandey
Director (Tech.)
Jaipur Vidhyut Vitaran Nigam Ltd---

Railway Board
Ministry of Railways
New Delhi

Shri S K Saxena
Executive Director(Electrical Energy Management) &Shri R N Lal
Additional Member (Electrical)

Shri Sushil Kumar
Director, Elect. Engg (PS)
February 23, 2011
Shri. Ajay Kakkar
Assistant Elect. Engg.
May 23, 2011

Military Engineer Services (MES)
E-in-C's Branch, New Delhi

Shri V K Gulati
SE / Director---

Ministry of Development of NorthEast Region
New Delhi---

Shri Brajesh Mishra
Director-(BM)February 21, 2011

Ministry of Tourism
New Delhi---

Shri Kalyan Sengupta
Asst. Director General (P&C)
April 20, 2011

Ministry of Agriculture
New Delhi---

Shri M K Nirbheek
Under Secretary
January 12, 2011

Ministry of Civil Aviation
New Delhi---

Ms. Sushila Ananth
Under Secretary
May 6, 2011---

Shri K K Chakarvarti
Energy Economist
May 23, 2011

Shri Milind Kulkarni
January 13, 2011

59

60

Appendix 7:
Energy Savings for Half Hour Advancement for 2008
DATE

Northern

Western

Sourthern

Eastern

Northeastern

SUM

All-India

1/5/2008

1.49

1.03

1.32

0.68

0.23

4.75

4.53

1/6/2008

2.00

1.22

1.23

0.85

0.25

5.55

5.33

1/7/2008

1.55

1.48

1.25

0.79

0.28

5.35

4.54

1/8/2008

1.54

0.89

1.07

0.81

0.26

4.57

4.28

1/9/2008

1.56

1.16

0.90

0.67

0.23

4.52

3.96

1/10/2008

1.66

1.23

1.06

0.78

0.25

4.98

4.29

1/13/2008

1.60

0.98

1.44

0.95

0.18

5.15

4.59

1/15/2008

1.56

1.04

1.36

0.85

0.26

5.07

4.04

1/17/2008

1.61

0.82

1.46

0.85

0.21

4.95

3.85

1/19/2008

1.85

1.05

1.52

0.76

0.21

5.39

4.64

1/27/2008

1.70

1.12

1.40

0.76

0.23

5.21

4.66

1/28/2008

1.58

1.49

0.93

1.06

0.25

5.31

4.78

1/29/2008

1.65

1.42

1.42

1.04

0.25

5.78

4.78

1/30/2008

1.81

1.53

1.40

0.90

0.18

5.82

4.73

2/2/2008

1.58

1.25

1.56

0.92

0.25

5.56

5.27

2/3/2008

1.44

1.46

1.69

1.04

0.29

5.92

5.50

2/4/2008

1.44

0.97

1.36

0.95

0.28

5.00

4.10

2/5/2008

1.40

1.39

1.64

0.67

0.25

5.35

3.96

2/6/2008

0.85

1.66

1.55

0.93

0.19

5.18

4.32

2/8/2008

1.68

1.26

1.19

0.99

0.15

5.27

4.38

2/9/2008

1.55

1.46

1.21

1.01

0.17

5.40

4.47

2/10/2008

1.66

1.26

1.51

1.22

0.22

5.87

5.08

2/11/2008

1.65

1.32

1.80

1.05

0.19

6.01

5.54

2/12/2008

0.19

0.99

1.86

0.91

0.20

4.15

5.58

2/13/2008

1.84

1.21

1.89

1.03

0.19

6.16

5.73

2/15/2008

1.52

0.84

1.94

0.86

0.18

5.34

4.55

2/16/2008

1.82

1.43

2.07

0.83

0.20

6.35

5.38

2/17/2008

2.16

1.60

2.01

0.85

0.22

6.84

5.80

2/18/2008

1.82

1.41

1.94

0.87

0.20

6.24

5.30

2/19/2008

1.83

1.24

1.76

0.75

0.25

5.83

5.91

2/20/2008

1.77

1.42

1.66

1.26

0.22

6.33

4.89

2/21/2008

1.82

1.34

1.57

1.16

0.26

6.15

5.26

2/23/2008

1.77

1.76

1.22

0.95

0.28

5.98

5.43

2/24/2008

1.77

1.07

1.90

1.04

0.28

6.06

5.03

2/25/2008

1.75

1.58

1.47

0.90

0.30

6.00

5.39

2/27/2008

2.01

1.07

1.57

0.83

0.31

5.79

4.59

2/28/2008

1.48

1.43

1.59

0.87

0.29

5.66

4.82

3/2/2008

1.55

1.30

1.37

1.03

0.28

5.53

4.70

3/3/2008

1.77

1.52

1.50

0.83

0.32

5.94

4.10

3/5/2008

1.96

1.23

1.79

1.12

0.26

6.36

5.05

3/6/2008

1.25

1.33

1.72

0.85

0.26

5.41

4.37

61

62

DATE

Northern

Western

Sourthern

Eastern

Northeastern

SUM

All-India

3/7/2008

1.62

1.38

1.81

0.80

0.29

5.90

5.04

3/8/2008

1.61

1.26

1.61

1.00

0.28

5.76

4.87

3/9/2008

1.97

1.51

1.84

1.01

0.27

6.60

5.13

3/10/2008

2.09

0.91

1.71

0.95

0.31

5.97

4.70

3/11/2008

2.07

0.74

1.51

0.92

0.30

5.54

4.19

3/14/2008

2.06

1.06

1.52

0.90

0.21

5.75

4.34

3/15/2008

2.26

1.17

1.74

0.70

0.28

6.15

5.52

3/16/2008

2.26

1.26

2.04

0.93

0.25

6.74

5.33

3/19/2008

1.78

1.11

2.07

0.58

0.26

5.80

4.70

3/21/2008

1.95

0.99

1.83

0.94

0.24

5.95

4.87

3/22/2008

2.36

0.92

2.07

0.75

0.24

6.34

6.05

3/23/2008

2.14

1.01

2.46

0.91

0.18

6.70

6.40

3/24/2008

2.06

1.23

2.25

0.84

0.22

6.60

5.91

3/25/2008

1.88

1.00

2.36

0.68

0.22

6.14

5.33

3/26/2008

1.86

0.97

2.33

0.49

0.23

5.88

5.26

3/27/2008

1.82

1.27

2.42

0.50

0.22

6.23

5.48

3/28/2008

2.54

0.96

1.91

0.63

0.24

6.28

5.47

3/30/2008

2.00

1.19

1.85

0.87

0.16

6.07

5.20

4/1/2008

1.94

0.98

2.35

0.81

0.17

6.25

5.25

4/2/2008

1.63

1.19

2.26

0.73

0.20

6.01

5.40

4/3/2008

1.64

1.30

2.25

0.59

0.19

5.97

5.13

4/4/2008

1.96

0.83

2.33

0.68

0.20

6.00

4.96

4/5/2008

1.58

1.31

2.16

0.92

0.16

6.13

5.37

4/6/2008

1.95

0.94

2.17

0.93

0.20

6.19

5.36

4/7/2008

2.11

0.99

2.84

0.98

0.17

7.09

6.35

4/8/2008

2.04

1.01

2.03

0.94

0.22

6.24

5.06

4/9/2008

1.91

1.02

2.03

0.72

0.22

5.90

5.03

4/10/2008

2.09

0.97

2.19

0.98

0.18

6.41

5.42

4/11/2008

1.73

1.16

2.16

0.96

0.21

6.22

5.02

4/12/2008

1.53

1.12

2.00

0.87

0.24

5.76

4.71

4/13/2008

1.91

1.06

2.10

0.39

0.26

5.72

4.95

4/14/2008

1.64

0.93

2.04

0.59

0.21

5.41

4.84

4/15/2008

1.17

0.84

1.82

0.76

0.22

4.81

3.89

4/16/2008

1.35

1.06

1.92

0.33

0.22

4.88

3.78

4/17/2008

1.49

1.23

1.66

0.77

0.20

5.35

4.62

4/18/2008

1.48

1.07

1.86

0.81

0.22

5.44

4.71

4/19/2008

1.64

0.95

2.04

0.74

0.20

5.57

4.76

4/21/2008

1.41

1.14

2.11

0.82

0.19

5.67

4.92

4/22/2008

1.88

1.20

2.04

0.73

0.21

6.06

5.16

4/23/2008

1.70

1.89

2.00

0.71

0.23

6.53

5.15

4/24/2008

1.75

0.86

2.36

0.74

0.18

5.89

5.27

4/26/2008

1.73

0.98

1.87

0.53

0.12

5.23

4.68

5/1/2008

1.65

1.40

2.04

0.79

0.21

6.09

5.21

5/2/2008

2.13

1.47

2.18

0.74

0.23

6.75

6.11

5/3/2008

1.63

1.27

2.03

0.46

0.21

5.60

4.72

5/4/2008

1.94

1.28

2.15

0.66

0.20

6.23

5.11

DATE

Northern

Western

Sourthern

Eastern

Northeastern

SUM

All-India

5/5/2008

0.62

1.31

2.10

0.72

0.18

4.93

4.07

5/6/2008

2.02

1.04

2.00

0.85

0.22

6.13

5.30

5/7/2008

1.74

1.11

1.92

0.83

0.23

5.83

5.40

5/8/2008

1.71

0.85

1.65

0.62

0.05

4.88

3.96

5/10/2008

1.94

1.46

1.74

0.84

0.27

6.25

5.26

5/11/2008

1.83

1.17

2.30

0.80

0.26

6.36

5.53

5/12/2008

1.91

1.19

1.79

0.81

0.20

5.90

5.01

5/14/2008

2.07

1.06

2.06

0.72

0.19

6.10

5.35

5/17/2008

1.67

1.04

2.12

0.64

0.19

5.66

4.80

5/18/2008

1.30

1.22

2.12

0.54

0.19

5.37

4.66

5/19/2008

1.42

0.86

1.75

0.45

0.19

4.67

3.93

5/20/2008

1.36

1.00

2.06

0.70

0.20

5.32

4.92

5/21/2008

1.35

1.07

1.59

0.79

0.16

4.96

5.68

5/22/2008

1.24

1.05

1.90

0.75

0.15

5.09

4.12

5/23/2008

1.61

1.12

1.60

0.76

0.13

5.22

4.77

5/24/2008

2.06

0.89

1.85

0.81

0.16

5.77

5.34

5/25/2008

1.74

0.91

1.96

1.08

0.18

5.87

5.07

5/30/2008

1.43

1.15

1.80

0.64

0.17

5.19

4.81

6/2/2008

1.46

1.11

1.77

0.48

0.20

5.02

4.04

6/3/2008

1.56

1.10

2.28

0.47

0.18

5.59

5.39

6/4/2008

1.54

0.80

2.17

0.89

0.22

5.62

4.73

6/5/2008

1.31

1.08

2.14

0.75

0.17

5.45

4.65

6/6/2008

1.15

0.60

2.04

0.86

0.17

4.82

4.39

6/7/2008

1.14

0.87

2.06

0.87

0.17

5.11

4.27

6/8/2008

1.10

0.87

2.03

0.96

0.21

5.17

4.35

6/9/2008

1.33

0.55

2.04

0.83

0.13

4.88

4.23

6/11/2008

1.79

1.08

1.86

0.90

0.16

5.79

4.22

6/14/2008

1.22

1.04

1.91

0.81

0.14

5.12

4.34

6/15/2008

1.36

0.97

2.19

0.76

0.15

5.43

4.72

6/16/2008

1.21

1.02

1.65

0.78

0.19

4.85

3.98

6/19/2008

1.54

0.97

1.90

0.48

0.19

5.08

3.98

6/20/2008

1.48

0.65

1.67

0.53

0.15

4.48

3.35

6/21/2008

1.44

0.79

1.83

0.63

0.14

4.83

3.88

6/22/2008

1.70

0.61

1.78

0.72

0.18

4.99

4.20

6/25/2008

1.00

1.22

1.73

0.60

0.15

4.70

3.56

6/26/2008

0.95

1.37

1.26

0.59

0.13

4.30

3.53

6/27/2008

1.08

1.33

0.91

0.75

0.18

4.25

3.10

6/28/2008

1.18

1.10

1.07

0.65

0.17

4.17

3.65

6/30/2008

1.35

1.39

1.56

0.65

0.17

5.12

3.88

7/1/2008

1.28

1.15

1.26

0.69

0.15

4.53

3.75

7/3/2008

1.50

1.53

1.25

0.61

0.15

5.04

4.20

7/4/2008

1.23

0.66

0.89

0.71

0.12

3.61

2.96

7/5/2008

1.30

0.52

0.95

0.75

0.17

3.69

3.26

7/7/2008

1.43

0.95

1.42

0.62

0.16

4.58

3.51

7/8/2008

1.46

0.69

1.35

0.59

0.16

4.25

3.45

7/10/2008

1.48

0.65

1.06

0.92

0.12

4.23

3.65

63

64

DATE

Northern

Western

Sourthern

Eastern

Northeastern

SUM

All-India

7/13/2008

1.90

1.21

0.98

0.96

0.12

5.17

4.02

7/14/2008

1.09

1.37

0.66

0.69

0.14

3.95

3.17

7/15/2008

1.26

0.96

0.96

0.71

0.13

4.02

3.30

7/17/2008

1.13

0.71

1.34

0.56

0.17

3.91

3.45

7/19/2008

1.34

0.57

1.73

0.75

0.19

4.58

3.46

7/21/2008

1.14

0.69

1.49

0.63

0.20

4.15

3.21

7/22/2008

1.26

0.45

1.49

0.55

0.14

3.89

4.00

7/25/2008

1.65

1.04

1.43

0.79

0.10

5.01

4.30

7/26/2008

1.17

1.05

1.43

0.79

0.10

4.54

4.30

7/31/2008

1.07

1.19

1.48

0.88

0.15

4.77

3.75

8/2/2008

1.26

0.85

1.43

0.60

0.14

4.28

3.65

8/3/2008

1.35

0.82

1.25

0.82

0.13

4.37

4.34

8/4/2008

1.08

1.37

1.37

0.63

0.11

4.56

3.72

8/5/2008

1.40

0.94

1.47

0.70

0.10

4.61

3.90

8/6/2008

1.60

0.85

1.45

0.47

0.13

4.50

4.00

8/7/2008

1.41

1.28

1.45

0.89

0.09

5.12

3.85

8/8/2008

1.25

1.27

1.18

0.59

0.11

4.40

3.55

8/10/2008

1.13

0.69

1.39

0.71

0.19

4.11

3.23

8/11/2008

1.45

0.66

1.42

0.42

0.18

4.13

3.42

8/13/2008

0.90

0.99

1.92

0.73

0.10

4.64

4.14

8/14/2008

1.10

0.98

1.93

0.63

0.16

4.80

3.80

8/16/2008

1.43

0.84

1.86

0.99

0.21

5.33

5.10

8/18/2008

1.17

1.13

1.88

0.88

0.24

5.30

4.23

8/19/2008

0.77

1.12

1.87

0.61

0.17

4.54

4.04

8/20/2008

0.75

1.08

1.90

0.59

0.16

4.48

4.00

8/21/2008

1.13

1.19

1.63

0.59

0.13

4.67

3.61

8/22/2008

1.07

1.00

2.11

0.52

0.86

5.56

4.16

8/23/2008

1.17

1.45

1.74

0.80

0.12

5.28

4.18

8/24/2008

0.95

1.65

1.83

0.83

0.11

5.37

4.35

8/25/2008

0.94

0.88

1.23

0.73

0.15

3.93

3.46

8/26/2008

0.68

1.11

1.29

0.93

0.13

4.14

3.07

8/28/2008

0.90

0.93

1.35

0.64

0.15

3.97

3.02

8/29/2008

0.93

0.64

1.40

0.78

0.13

3.88

3.03

8/30/2008

0.89

1.53

1.13

0.74

0.13

4.42

3.52

8/31/2008

1.46

0.99

1.81

1.08

0.17

5.51

4.95

9/2/2008

1.72

1.18

1.77

0.86

0.15

5.68

3.70

9/3/2008

1.75

1.19

1.81

0.90

0.07

5.72

4.24

9/5/2008

0.56

2.22

1.80

0.96

0.06

5.60

3.70

9/7/2008

1.88

1.48

1.91

0.90

0.21

6.38

5.76

9/8/2008

1.99

1.33

2.40

0.92

0.19

6.83

4.58

9/9/2008

2.04

1.15

2.22

0.98

0.22

6.61

5.40

9/10/2008

1.74

1.05

1.60

0.90

0.19

5.48

4.58

9/11/2008

1.96

1.53

1.81

1.01

0.19

6.50

5.42

9/12/2008

1.99

1.49

1.96

0.75

0.19

6.38

4.94

9/13/2008

1.50

1.35

1.57

0.98

0.15

5.55

4.34

9/15/2008

2.09

1.64

1.60

0.76

0.18

6.27

4.87

DATE

Northern

Western

Sourthern

Eastern

Northeastern

SUM

All-India

9/16/2008

1.70

1.60

1.45

1.20

0.16

6.11

4.76

9/17/2008

1.78

1.70

0.93

1.05

0.21

5.67

3.90

9/19/2008

0.78

1.52

1.36

1.00

0.11

4.77

4.22

9/20/2008

1.05

1.78

1.22

0.70

0.09

4.84

3.96

9/21/2008

1.20

1.80

1.55

0.86

0.09

5.50

4.75

9/22/2008

1.42

1.35

1.41

0.87

0.10

5.15

4.16

9/23/2008

1.40

1.35

1.41

0.87

0.10

5.13

4.22

9/24/2008

1.65

1.41

1.65

2.15

0.07

6.93

6.10

9/25/2008

1.75

1.30

1.83

0.87

0.08

5.83

4.80

9/27/2008

1.55

1.50

1.70

1.06

0.19

6.00

4.92

9/28/2008

1.88

1.56

1.42

1.09

0.14

6.09

5.03

9/30/2008

1.22

1.72

1.30

0.94

0.12

5.30

4.25

10/2/2008

1.78

1.92

1.62

0.96

0.19

6.47

5.97

10/5/2008

1.79

1.94

1.74

1.12

0.20

6.79

6.48

10/6/2008

1.85

1.78

1.41

1.23

0.18

6.45

5.76

10/7/2008

1.97

1.63

1.67

1.23

0.19

6.69

5.95

10/8/2008

1.69

1.92

1.75

1.32

0.21

6.89

5.76

10/9/2008

1.67

1.72

0.74

1.04

0.22

5.39

5.20

10/10/2008

1.72

1.39

1.93

0.92

0.22

6.18

6.62

10/11/2008

1.96

1.63

2.07

0.89

0.19

6.74

5.62

10/12/2008

1.99

1.58

1.96

0.75

0.13

6.41

5.05

10/13/2008

1.50

1.32

1.57

1.04

0.15

5.58

4.34

10/14/2008

2.21

1.64

1.52

0.94

0.19

6.50

5.79

10/15/2008

2.09

1.64

1.60

0.61

0.17

6.11

4.87

10/17/2008

1.78

1.46

0.93

0.95

0.21

5.33

3.99

10/18/2008

1.84

1.62

1.75

0.72

0.22

6.15

5.46

10/19/2008

2.05

1.55

1.49

1.06

0.13

6.28

5.65

10/20/2008

1.32

1.50

1.35

1.00

0.12

5.29

3.51

10/21/2008

1.64

1.64

1.42

1.00

0.14

5.84

5.46

10/24/2008

2.05

1.50

1.51

1.19

0.15

6.40

6.13

10/25/2008

1.70

2.00

1.37

1.56

0.18

6.81

5.98

10/26/2008

1.65

2.25

1.46

1.28

0.15

6.79

6.33

10/27/2008

2.32

1.79

1.46

1.48

0.22

7.27

6.83

10/31/2008

2.34

1.18

1.25

1.31

0.19

6.27

6.10

11/1/2008

1.98

1.55

0.76

1.27

0.20

5.76

5.35

11/2/2008

2.08

1.76

1.27

1.33

0.22

6.66

6.53

11/6/2008

1.87

1.46

1.10

1.16

0.21

5.80

5.00

11/7/2008

2.02

1.50

0.88

1.57

0.20

6.17

5.75

11/9/2008

2.00

1.55

0.78

1.33

0.24

5.90

5.57

11/11/2008

1.85

1.46

0.81

1.33

0.25

5.70

5.21

11/12/2008

2.13

1.44

1.04

1.16

0.25

6.02

6.05

11/14/2008

2.01

1.72

0.88

1.26

0.27

6.14

6.16

11/16/2008

1.69

0.98

0.74

1.52

0.21

5.14

4.77

11/17/2008

1.72

1.34

1.34

1.44

0.23

6.07

5.70

11/19/2008

2.06

1.33

1.44

1.13

0.19

6.15

5.78

11/21/2008

2.30

1.38

1.30

1.24

0.25

6.47

6.32

65

DATE

Northern

Western

Sourthern

Eastern

Northeastern

SUM

All-India

11/23/2008

2.11

1.15

1.32

1.61

0.21

6.40

5.91

11/25/2008

2.03

1.36

1.41

1.17

0.20

6.17

5.93

11/27/2008

2.04

1.60

1.18

1.17

0.18

6.17

6.29

11/30/2008

1.78

0.89

2.02

1.60

0.21

6.50

6.35

12/1/2008

1.98

1.43

1.66

1.48

0.21

6.77

6.21

12/2/2008

1.97

1.12

1.79

0.99

0.22

6.10

5.86

12/3/2008

2.12

1.29

1.86

1.35

0.15

6.77

6.53

12/4/2008

2.16

1.25

2.07

1.48

0.22

7.19

6.84

12/5/2008

2.10

1.21

1.94

1.37

0.22

6.84

6.18

12/7/2008

1.81

1.08

1.74

1.66

0.24

6.53

6.10

12/8/2008

2.09

0.92

1.39

1.57

0.25

6.22

5.62

12/9/2008

2.03

0.84

1.04

1.49

0.27

5.67

5.54

12/10/2008

1.77

1.12

1.52

1.48

0.18

6.07

5.58

12/14/2008

1.91

0.84

1.25

1.27

0.20

5.47

5.03

12/16/2008

2.23

1.47

1.27

1.50

0.21

6.68

5.84

12/17/2008

2.07

1.41

0.86

1.56

0.25

6.15

5.39

12/18/2008

2.28

1.11

1.07

1.35

0.28

6.09

5.52

12/19/2008

1.75

1.70

1.13

1.15

0.25

5.97

5.51

12/20/2008

1.04

1.04

1.04

1.39

0.23

4.75

4.68

12/21/2008

2.00

1.18

0.77

1.43

0.24

5.62

5.07

12/25/2008

1.79

1.14

0.93

1.50

0.29

5.66

4.89

12/26/2008

1.50

1.09

1.37

1.51

0.16

5.64

4.80

12/27/2008

1.65

1.38

0.97

1.35

0.21

5.56

5.17

12/28/2008

1.55

1.29

1.13

1.51

0.21

5.70

5.06

12/29/2008

1.55

1.56

1.08

1.22

0.22

5.64

5.09

12/30/2008

1.84

1.51

1.00

1.26

0.22

5.83

5.32

12/31/2008

1.70

1.53

1.21

1.37

0.26

6.06

5.74

Total

1407.131214.40

66

Average

5.58

4.82

Maximum

7.27

6.84

Minimum

3.61

2.96