AC 2009-2411: A STUDENT RESEARCH PROJECT: MYTH AND FACTS ONINRUSH POWER CONSUMPTION AND MERCURY CONTENT OFINCANDESCENT VERSUS COMPACT FLUORESCENT LIGHTS

Mike Hay, University of Northern IowaMr. Mike Hay holds a BT in Industrial Technology/Mechanical Design from the University ofNorthern Iowa and an MA in Industrial Technology from the University of Northern Iowa. Mr.Hay has over 30 years of professional work experience in various Engineering positions and islisted on seven US patents. His graduate research was in planning optimum small-scalewind-electric systems. He has worked on several renewable energy and electric vehicle projectsas well.

Recayi "Reg" Pecen, University of Northern IowaRecayi “Reg” Pecen, Ph.D. Dr. Pecen holds a B.S.E.E. and an M.S. in Controls and ComputerEngineering from the Istanbul Technical University, an M.S.E.E. from the University of Coloradoat Boulder, and a Ph.D. in Electrical Engineering from the University of Wyoming (UW, 1997).He has served as graduate assistant and faculty at the UW, and South Dakota State University. Heis currently an associate professor and program coordinator of Electrical and InformationEngineering Technology program at the University of Northern Iowa. He serves on UNI Energyand Environment Council, CNS Diversity Committee, University Diversity Advisory Board, andGraduate College Diversity Task Force Committees. His research interests, grants, andpublications are in the areas of AC/DC Power System Interactions, distributed energy systems,power quality, and grid-connected renewable energy applications. He is a member of ASEE,IEEE, Tau Beta Pi National Engineering Honor Society, and NAIT. Dr. Pecen was recognized asan Honored Teacher/Researcher in “Who’s Who among America’s Teachers” in 2004-2008. Hewas also nominated for 2004 UNI Book and Supply Outstanding Teaching Award, March 2004,and nominated for 2006, and 2007 Russ Nielson Service Awards, UNI. Dr. Pecen is anEngineering Technology Editor of American Journal of Undergraduate Research (AJUR). He hasbeen serving as a reviewer on the IEEE Transactions on Electronics Packaging Manufacturingsince 2001. Dr. Pecen has served on ASEE Engineering Technology Division (ETD) in AnnualASEE Conferences as a paper reviewer, session moderator, and co-moderator since 2002. He iselected to serve as an officer on ASEE Energy Conversion and Conservation Division and servingon advisory boards of International Sustainable World Project Olympiad (isweep.org) andInternational Hydrogen Energy Congress.

© American Society for Engineering Education, 2009

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A Student Research Project – Myth and Facts on inrush power consumption

and mercury content of incandescent versus compact fluorescent lights

Abstract

Green is now a new buzz word for many industries as well as on university campuses. The right

amount and quality of light needed for the application is the first consideration in any lighting

project. For over thirty years that authors know of, there have been stories - possibly "urban

legends" - that someone has calculated that fluorescent lights consume more power in start-up

than it takes to run them for up to an hour. For one able to understand the implications of these

statements, they are absurd. However the stories and myths have circulated for many years. One

way to combat these stories is to conduct a well-constructed experimental study to measure and

compare the actual power consumed during the starting phase of these devices compared to

steady state operation after the inrush has occurred, then publish the results appropriately.

The power consumed should be compared for incandescent bulbs, compact fluorescent bulbs, T8

fluorescent tubes and possibly comparable (Light Emitting Diode) LED devices. Voltage and

current, and thus power, would be measured during starting and running phases for each type of

device. From that data, the time that it is more economical to leave the lights on or turn them off

can be calculated to a fraction of a second for each type of device. A research team consisting of

graduate and undergraduate students has investigated power consumption amount for

incandescent and compact fluorescent bulbs during the inrush operation.

This paper reports a number of case studies on inrush power consumption of incandescent and

compact fluorescent bulbs. It also includes a brief study of another misconception – mercury

content and environmental impacts. The United States Environmental Protection Agency (EPA)

concludes that a typical compact fluorescent light (CFL) over the course of its life will put less

mercury in to the environment than using incandescent light to produce equivalent lighting.

Since coal is currently a major source of energy and a byproduct of its burning is mercury,

therefore by requiring more energy to operate use of incandescent bulbs, is actually responsible

for releasing more mercury into the environment than using CFL bulbs. It is expected that this

student project results may help to clear the misconceptions about using more CFLs in our daily

lives of residential and commercial lighting needs. This specific student project is adopted as a

laboratory activity for 330:166g Advanced Electrical Power Systems class in the EET program.

Inrush power issues in lighting electrical systems

As the world experiences the lack of sustainable energy resources and steadily increasing

demand on energy, the need for energy savings as well as the reduction of purchase cost and

maintenance of all electric systems has become imperative. One of the potential areas of energy

conservation is the efficient lighting practices in residential, commercial, and industrial

buildings. Since electricity is a relatively expensive energy source, lighting systems cost more to

operate than other building energy systems, such as heating, that use natural gas or other fossil

fuels. The business sector of the economy, citizens and companies producing lighting systems of

all kinds are involved in this effort. According to Midwest Energy Efficiency Alliance1

(MEEA), lighting constitute approximately 30% of the energy use in US commercial buildings

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while the cost of energy for lights is about 45% . Although tungsten filament-based incandescent

lamps are soon to be history, they are still in very widespread use. At the instant of switch on, a

tungsten filament lamp draws an inrush current that can be anything up to ten to sixteen times its

normal operating current. To put this into context, a motor started direct on line will normally

only draw a peak current of around eight times its full load current. Therefore, switching a bank

of filament lamps might lead particularly severe duty for contactors in electrical systems.

On the other hand, the initial inrush current drawn by many electronic loads during startup can

be relatively large compared to nonelectronics loads. This is particularly true for electronic

ballasts and compact fluorescent lamps because they are usually banked together and

simultaneously switched on in large commercial and industrial settings. The resulting inrush of

current may cause the lighting controls such as occupancy sensors, toggle switches, energy

management systems (EMS), and other relay based equipment to wear out and fail.

The starting behavior of fluorescent lamps is largely determined by the type of ballast. With

conventional choke-and-starter switching, a pre-heating current of around 1.25 times the normal

operating current flows for a few seconds before the lamp strikes.

Note, however, that power-factor correction capacitors are frequently used to compensate for the

reactive current produced by the choke. These capacitors draw a very large current spike as they

charge up at switch on. This must be taken into account when selecting contactors for switching

fluorescent luminaires. When electronic ballasts are used, as they are in many modern luminaires

for conventional fluorescent tubes as well as in all CFLs, short but large current peaks are

generated at switch on, caused by the charging of capacitors in the electronic ballast circuitry.

As lighting technology improvements are continuously being introduced to the marketplace, if

no lighting improvements have been implemented at any major commercial and industrial

facility for several years, it is very likely that major reductions in lighting energy consumption

together with gains on reduced inrush power can be achieved.

Literature Review

D.T. Bradshaw concluded that future of energy development and expansion in the U.S. and

eventually the world is that energy efficiency (better insulation, CFLs, LEDs, improved heat

pumps and air conditioners, etc.) will be maximized to cut energy demand 10 % or more2. But

that will bring several unintended consequences: system power factors will become worse,

increasing demand for reactive power compensation (shunt capacitors and dynamic sources of

reactive compensation like static VAR compensators), power quality will worsen, and inrush

currents during outages will increase, making fault-induced voltage recovery (FIDVR) more

difficult and potentially leading to voltage collapse2. Peak loads will be better managed in the

future with aggregation of demand response like Smart Grid SCADA control of HVAC,

refrigerators, dryers, etc., during system emergencies or periods of peak capacity shortfalls. This

will be further improved as distribution SCADA is universally installed and software

implemented that optimizes all methods of distribution power flows (capacitor, voltage regulator, Page 14.116.3

transformer load tap change, etc.) and demand response (DR) on the system to minimize peak

loads and reduce distribution losses as well.

With regard to electric lamps, the effort is focused mainly on the increase of the system

efficiency for every consumed Watt, longer lamp life and system life in general and finally

better light quality and less disturbances in the electrical distribution system. Chondrakis and

Topalis described an experiment to determine the values of certain parameters which affect the

life of fluorescent lamps driven by electronic ballast3. The long-term purpose of fluorescent

lighting systems is to find a correlation between lamp life and the duration of the corresponding

cycle while controlling inrush current in a reasonable limit 4-7

.

The efficiency of electric lighting has increased significantly, since 1900. Incandescent lamps at

the time were about 1% efficient based on 4 lumens/W. By 1970, the efficiency of incandescent

lamps had risen to 5% (with much of the improvement taking place between 1905 and 1910, due

to the introduction of tungsten filaments)4-5

. There was not much improvement after 1930.

Fluorescent lamps, introduced in the 1930s, were about 8% efficient in 1940 and 20% efficient

by 1970. According to General Electric Co. (quoted by Summers), fluorescent lamps provided

70% of total illumination in 1970, while incandescent and ‘high-intensity’ lamps split the

remainder4-5

.

However, a more detailed calculation in the late 1980s concluded that the average output of

incandescent, fluorescent and high-intensity lamps was 16, 66 and 48 lumens/W, respectively,

for an overall average of 44 lumens/W or 11% average efficiency.

Mercury content of incandescent versus compact fluorescent lights

In addition to inrush current issues, mercury content of CFLs have been subject of a number of

research studies. Although CFLs use about 70% less energy than incandescent bulbs, and they

can last approximately 10 times longer, the energy efficiency comes with a price – mercury.

Mercury has long been identified as highly toxic. In humans, it can harm the brain, heart,

kidneys, lungs, and overall immune system. According to the EPA “High levels of methyl-

mercury in the bloodstream of unborn babies and young children may harm the developing

nervous system, making the child less able to think and learn”. At the same time mercury is an

ingredient in scores of consumer products such as cosmetics (eyeliner, mascara, and skin

creams), sneakers, thermostats, and fluorescent lights. The amount of mercury in CFLs is

comparatively small in older CFLs in the amount of 5 to 10 mg per bulb. Newer bulbs are using

as little as 1.4 mg per bulb and the amount is steadily dropping 8-9

. Much of the mercury is bound

up in the coatings inside the bulb8. Since the generation of electricity usually involves burning

coal – which releases mercury into the atmosphere – using less power can more than offset the

amount of mercury that could potentially be released into the environment even if all CFLs were

broken and not recycled. This is quantified below.

A 13W CFL will use 104 kWh of power in 8000 hours of use. This is a reasonable estimate for a

CFL’s lifespan. Using the U.S. average Hg emission of 0.012 mg of Hg / kWh this comes to 1.2

mg of Hg emissions for a CFL across 8000 hours8. If each bulb contains 5mg of Hg and all but

14% is bound up in internal coatings of the bulb, only 0.7mg remains free to enter the

environment8. Considering both fossil fuel based energy generation and manufacturing of a CFL,

Page 14.116.4

1.9 mg of mercury released to the environment for a CFL during its life span where a 1.2 mg

from power plant emissions and 0.7 mg from the bulb itself.

A 60W incandescent bulb is equivalent to a 13W CFL in light output in the amount of 60W x

8000 h = 480 kWh. 480kWh x 0.012 mg/ kWh of Hg emission yields 5.8 mg Hg released into

the atmosphere for 8000 hours of use. There is no mercury contained in the incandescent bulb, so

the total is 5.8 mg for 8000 hours of use. Therefore, there would be over three times the mercury

released to the environment by incandescent bulbs than CFLs. Not only is this a clear

misconception, but table 1 below indicates there are obviously bigger potentials in other things

that do not get the press this issue has. Mercury is used in many industrial and consumer goods.

Its’ unique properties have made it a choice in a wide variety of applications. Major categories

and their annual usage are given in table 1 below.

Table 1 US usage of mercury and its’compounds measured in pounds9.

Category 2001 2004 3 yr Notes*

usage usage change

Switches and relays 119,660 102,162 -17,498 1

Dental Amalgam 61,537 60,781 -756

Thermostats 30,971 29,943 -1028

All lighting 21, 438 20,118 -1320 2

Fluorescents without CFL’s 16,657 14,372 -2285

CFL’s 877 1,479 602

Pumps 12,382 13,410 1028

Measuring devices 11,945 9,525 -2420 3

Batteries 5,914 5,122 -792 4

Ranges 4,663 2,363 -2,300

Formulated products 2,060 1,810 -250 5 *Notes

1. This includes: Tilt, float, flame, reed and vibration switches.

2. This includes all fluorescents and CFL’s as well as High Intensity Discharge (metal

halides, ceramic metal halides, high-pressure sodium and mercury vapor), Mercury

Short Arc, Neon and miscellaneous lights.

3. Examples are: Barometers, Thermometers, manometers, hydrometers,

sphygmomanometers, strain gages and pyrometers.

4. Mostly smaller cells like zinc-air, Silver oxide, Alkaline Manganese Oxide button

cells and mercuric oxide battery chemistries.

5. A wide variety of applications including vaccine preservatives, other bacterial

contamination products, leather tanning, catalysts and plating. Phase outs and bans

are progressing.

Differences in methods of dispersion and routes of ingestion or absorption to some extent

obfuscate the relative probabilities and risks involved, and for this study will not be weighed

against each other. We will treat all methods of dispersion and routes of absorption equal for

reasons of simplicity. Methods of dispersion would be things like emissions from burning

Page 14.116.5

coal, run-off from landfills, waterborne accumulations, and tissue of living organisms that are

eventually ingested or decomposed10

. Routes of absorption would include but not be limited

to food, water, inhalation, and skin contact 10

.

The immediate symptoms of mercury exposure are chills, nausea, general malaise, tightness

in chest, chest pain, cough, gingivitis, salivation and diarrhea10

. Long-term exposure would

add weakness, fatigue, weight-loss and GI tract disturbances10

. Tremors, spasms, memory

loss, irritability, insomnia and behavioral changes may also occur. Damage to lungs,

kidneys, skin, eyes, and the nervous system have been observed 10

. Emergency treatment

could take the form of activated charcoal, IV chelating therapies and other medications.

Hemodialysis is used if kidney damage has occurred 11

.

Test Setup for Monitoring and Measuring Inrush Current and Power for a variety of

Incandescent Lights and CFLs in the Electrical Engineering Technology Program at the

University of Northern Iowa

Figure 1 shows experimental setup of for measuring inrush current and power of variety of light

bulbs where (a) is the custom made light bulb testing apparatus, voltage and current sensors, (b)

is the DATAQ data acquisition module that providing digital input to the computer, and (c) and

(d) are showing undergraduate student working during the testing.

a

b

c

d

Figure 1. Experimental Setup for measuring inrush current and power of variety of light bulbs.

Page 14.116.6

Figure 2. Inrush current and power characteristics for a Sylvania Dulux 11 W, 120 V, 0.19 A

CFL recorded during 5 s of operation.

Figure 3. Inrush current and power characteristics for a GE Helical 40W, 120 V, 0.37A CFL

recorded during 5 s of operation.

Figure 4. Inrush current and power characteristics of Sylvania Movie Flood Light Bulb.

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Figure 5. Inrush current and power characteristics of Sylvania, 130 V 200 W incandescent bulb.

Figure 6. Inrush current and power characteristics of a GE 120 V, 150 W incandescent bulb.

Figure 7. Inrush current and power characteristics of a GE 120 V, 25 W incandescent bulb.

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Figure 8. Inrush current and power characteristics of a GE 120 V, 5.8A, 700 W, Eagle Heater.

Figure 9. Inrush current and power characteristics of a GE 120 V, Dark Light 24 W.

Figure 10. Inrush current/power characteristics of a GE PhotoFlood, 250 W incandescent bulb.

Conclusions and Recommendations

This undergraduate and graduate research project concluded that there are four major points to be

made as follows:

1. Infrastructure improvement requirements in power distribution will be further

emphasized by the increased use of CFLs.

2. Mercury releases into the environment will be less with CFLs.

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3. Although there is a slight increase in the inrush current, it is not enough to amount to a

need for changing consumer habits.

4. This work is an excellent educational learning experience for undergraduate students

studying inrush theory of different loads. This laboratory setup is adopted to be used at

Advanced Electrical Power Systems class in the EET program during spring 2009.

Infrastructure improvements in the distribution system will become more urgent. Discussions of

the frailty of the grid usually do not take into account the added strain that widespread use of

CFL's will bring about. Additional reactive power compensation will be required. Contactors

will need to be upgraded in some cases. The inrush power seen upon reconnection after a power

outage will increase. All of these factors and more will be challenges the utilities as a group will

need to address in the coming years.

Mercury releases to the environment are the big picture and the issue needs to be looked at in

that manner. With CFLs, the overall releases are smaller, not larger. Small, much localized

releases do occur in the instance of a bulb breaking. Simple procedures to minimize personal

exposure and care in clean-up and disposal are all that is required in that occurrence. The worst

case comparison was illustrated in the text of this paper and in that extreme case, CFLs gave

approximately 1/3 the release of mercury into the environment that incandescent bulbs do. In

reality, the ratio grows in favor of CFLs.

The inrush current myth is just that, a myth. A small increase in inrush current is experienced,

per bulb. This is multiplied out in the big picture to have noticeable effects on the grid. But to the

individual, no change in habits for operating their lights need take place. Quantifying these

increases can be done on two levels, by inspection and calculating. An informed look at the

graphs shows that when the entire curve is analyzed, less than a seconds' worth of run time

current is expended during the inrush phase. It is actually more like a quarter to a half.

References 1. Midwest Energy Efficiency Alliance (MEEA), Building Operator Certification (BOC) Programs,

http://www.mwalliance.org/

2. D. T. Bradshaw, “Our Electric System of the Future, and its Unintended Consequences,” The Electricity

Journal, Elsevier Ltd, Volume 21, Issue 4, May 2008, Pages 76-80.

3. N.G. Chondrakis, F.V. Topalis, “Starting characteristics of fluorescent tubes and compact fluorescent

lamps operating with electronic ballasts,” Elsevier, The Measurement Journal, 42 (2009) pp. 78-86.

4. N. Hamza, D. Greenwood, “Energy Conserv. Regulations: Impacts on design & procurement of low energy

buildings,” Building and Environment, Elsevier Ltd, Sci. Direct, Vol. 44, Issue 5, May 2009, pp 929-936.

5. Y. Ji, R. Davis, C. O’Rourke, E.W.M. Chui, “Compatibility testing of fluorescent lamp and ballast

systems,” IEEE Transactions on Industry Applications 35 (6) (1999), pp. 1271–1276.

6. P.F. Keebler, R. Gilleskie, “In-rush currents of electronic ballasts and compact fluorescent lamps affect

lighting controls,” Industry Applications Conference, 1996. Thirty-First IAS Annual Meeting, IAS

apos;96., Conference Record of the 1996 IEEE Volume 4, Issue , 6-10 Oct 1996, pp. 2201 – 2208.

7. Dr. LeTang, Technology Recommendations from the T&D Sector, Grid Week, April 23–26, 2007.

8. http://www.osha.gov/SLTC/healthguidelines/mercuryvapor/recognition.html retrieved 02 Feb 2009

9. http://www.newmoa.org/prevention/mercury/imerc/Factsheets retrieved 06 Jan 2009

10. http://www.energystar.gov/ia/partners/promotions/change_light/downloads/Fact_Sheet_Mercury.pdf

retrieved 01 Feb 2009

11. http://www.emedicine.medscape.com/treatment for mercury poisoning.html retrieved 06 Feb 2009.

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