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Cost-benefit analysis and emission reduction of lighting retrofits in residential sector
Energy and Buildings 37 (2005) 573–578 www.elsevier.com/locate/enbuild
Cost-benefit analysis and emission reduction of lighting retrofits in residential sector T.M.I. Mahlia*, M.F.M. Said, H.H. Masjuki, M.R. Tamjis Department of Mechanical Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia Received 26 April 2004; received in revised form 29 July 2004; accepted 30 August 2004
Abstract This study projects electricity savings, cost-benefit analysis and emission reduction of lighting retrofits in Malaysia residential sector. The cost-benefit is determined as a function of energy savings due to retrofit of more efficient lighting system. The energy savings were calculated based on 25, 50 and 75% of potential retrofits of inefficient lighting in residential sector. The study found that, this strategy save a significant amount of energy and consumers money. However, an effort to create energy efficiency awareness among consumers and subsidies efficient lighting should be identified, because this efficient lighting is quite expensive in Malaysia. # 2004 Elsevier B.V. All rights reserved. Keywords: Energy savings; Lighting retrofits; Energy efficiency; Cost-benefit analysis; Emission reduction; Malaysia
1. Introduction A lighting retrofit is replacing inefficient lighting with the efficient one. Electricity savings over time is significant enough to not only pay for the new lighting, but also produce return on the investment. This can be done by either reducing the input wattage or reducing the hours of operation of the lighting to reduce energy consumption. The studies on retrofitting inefficient lighting by reducing input wattage are presented by Refs. [1–4]. This study is also proposed to reduce wattage by retrofitting of incandescent lamp with more efficient compact fluorescent lamp (CFL) in residential sector in Malaysia. These can be replaced by energy efficient lamps that are available in 8, 14 and 18 W versions with the equivalent of 40, 60 and 100 Wof incandescent light bulbs [5]. CFL lamps start instantly under 0.1 s with energy consumption 80% less than incandescent light bulb and lasting more than 5000 h. However, this lamp is quite expensive in Malaysia, it is about RM 11.90–23.90 (US$ 1 = RM 3.8), which is 8–17 times of the price of incandescent bulb. This CFL can replace incandescent light bulbs without any modification. * Corresponding author. Tel.: +60 3 7959 5283; fax: +60 3 7959 5317. E-mail addresses: [email protected], [email protected] (T.M.I. Mahlia). 0378-7788/$ – see front matter # 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.enbuild.2004.08.009
In incandescent lamp, electricity heats up a wire filament, causing it to glow and give the light and that is why more than 90% of the energy produced by incandescent lights is heat, not light and therefore incandescent are inefficient light sources. Meanwhile an ordinary incandescent bulb’s lifetime is usually about 750 h before burning out. This study attempts to calculate potential electricity savings, emission reduction and cost-benefit analysis of lighting retrofit policy in Malaysia residential sector at national level. This is to encourage the authority and policymakers to implement this simple strategy to reduce rapid electricity consumption growth in residential sector. Successful experimentation in efficient lighting has been conducted in commercial sector [6].
2. Collected data Extensive data on lighting system can be found in lighting market source book presented in Ref. [7]. The uncertainty, sensitivity analyses, life-cycle cost and payback period of a lighting system can be found in Ref. [8]. However, the data required for this study are only the household data, number and wattage of incandescent bulb data. The saturation of household with electricity in Malaysia is about 97%.
574
T.M.I. Mahlia et al. / Energy and Buildings 37 (2005) 573–578 Table 3 Essential input data of incandescent bulb and CFL
Nomenclature A ANSLi B BSLi CRF d ECLi EMnp ERLi ESLi ICL NHi NRLi NSLi OHLi PCL PEni PFi PVðANSLi Þ STLi T Ydr
incandescent lamp annualized net dollar savings in year i of lighting retrofit (RM) compact fluorescent lamp bill savings in year i of lighting retrofit (RM) capital recovery factor (%) discount rate (%) energy consumption (GWh) emission p for fuel type n for a unit electricity generation (kg/kWh) emission reduction in year i of lighting retrofit (kg) energy savings in year i of lighting retrofits (GWh/year) increment cost of lighting retrofit (RM/ kWh) number of household in year i number of lighting retrofit in year i net saving in year i due to lighting retrofit (RM) daily operating hour of lighting power consumption of lighting (W) percentage of electricity generation in year i of fuel type n price of electricity in year i (RM/kWh) present value of annualized net savings in year i for lighting retrofit (RM) saturation of inefficient lighting in year i lifetime of lighting (year) Year of discount rate base
The number of incandescent bulbs were collected by conducting survey in 427 randomly selected household and the results are tabulated in Tables 1–4. The predicted household data, the percentage of electricity generation
Bulb type
Incandescent A1
A2
CFL A3
B1
B2
B3
Total watts (W) 40 60 100 8 14 18 Lifetime (h) 750 750 750 5000 5000 5000 Purchase price (RM) 1.40 1.40 1.40 18.50 18.50 18.50 Number of bulbs 7 7 7 1 1 1 Total bulb cost (RM) 9.80 9.80 9.80 11.80 15.90 23.90 Table 4 Fossil fuel emissions for a unit electricity generation Fuels
Coal Petroleum Gas Hydro Other
Emission (kg/kWh) CO2
SO2
NOx
CO
1.1800 0.8500 0.5300 0.0000 0.0000
0.0139 0.0164 0.0005 0.0000 0.0000
0.0052 0.0025 0.0009 0.0000 0.0000
0.0002 0.0002 0.0005 0.0000 0.0000
based on fuel type and fossil fuel emissions for a unit electricity generation were given by Refs. [9,10] and tabulated in Tables 4 and 5.
3. Methodology A survey is necessary to determine the saturation level of inefficient lighting, the operating hour of the incandescent bulb and the number of potential retrofit of the lighting system in Malaysia residential sector. Based on Table 3, lighting system A is referred to the incandescent lamp, while lighting system B is referred to CFL which is proposed lighting system that are more energy efficient. The data obtained from the survey was used to calculate projected electricity savings, emission reduction and cost-benefit analysis of lighting retrofits. The equations used for calculation are discussed in the following section. 3.1. Number of retrofits
Table 1 Wattage and saturation of incandescent bulb in the household Power (W)
Number of incandescent bulb
Saturation (%)
40 60 100
178 205 252
41.7 48.0 59.0
Table 2 Operation hours per day of incandescent bulb
Number of retrofits depends on the saturation level of inefficient lighting in the household with electricity. The number of retrofits is calculated by multiplication of number of household and the saturation levels of inefficient lamp. This can be represented by the following equation: NRLi ¼ NHLi STLi
(1)
3.2. Energy consumption
Operating hours
Central value
Households
0–2 2–4 4–6 6–8 8–10 10–12
1 3 5 7 9 11
21 87 64 12 10 6
Energy consumption by the lighting is the multiplication of the number of retrofits, power consumption and operating hour of the lighting. The annual energy consumption can be expressed mathematically by the following equation: ECLi ¼ NRLi PCL OHLi 365
(2)
T.M.I. Mahlia et al. / Energy and Buildings 37 (2005) 573–578
575
Table 5 Predicted electricity consumption, number of households and percentage of fuel type for electricity generation Year
Residential (GWh)
Household
Coal (%)
Petroleum (%)
Gas (%)
Hydro (%)
2006 2007 2008 2009 2010
15969 17055 18178 19337 20532
5552555 5711720 5873989 6039363 6207842
15.84 16.26 16.76 17.34 18.00
2.96 2.69 2.44 2.21 2.00
56.80 54.95 53.20 51.55 50.00
24.40 26.10 27.60 28.90 30.00
Table 6 Predicted number of incandescent bulb, electricity consumption and savings Year
Household
2006 2007 2008 2009
Number and wattage of incandescent bulb
5552555 5711720 5873989 6039363
Potential of electricity consumption and savings (GWh)
40 W
60 W
100 W
25% retrofits
50% retrofits
75% retrofits
A
B
Savings
A
B
Savings
A
B
Savings
2315415 2381787 2449453 2518414
2665226 2741626 2819515 2898894
3276007 3369915 3465654 3563224
223 229 236 60
44 45 47 12
179 184 189 48
446 459 472 121
88 91 93 24
358 368 378 97
669 688 707 181
132 136 140 36
536 552 567 145
3.3. Energy savings 3.5. Capital recovery factor Energy savings from retrofitting is the difference between energy consumption of inefficient and efficient lighting. This can be calculated using the following equation: LB ESLi ¼ ECLA i ECi
(3)
The capital recovery factor is the correlation between the discount rate and the lifetime of more efficient lighting, this correlation is calculated by the following equation: CRF ¼
3.4. Emissions reduction The environmental impact from retrofitting is potential reduction of greenhouse gasses or other element that caused negative impact to the environment. The common emission reductions are usually, CO2, SO2, NOx and CO. The emission reduction is a function of energy savings. The emission reduction can be expressed mathematically by the following equation: ERLi
¼
ESLi ðPE1i
EM1p
þ PE2i
EM2p
þ PE3i
EM3p þ þ PEni EMnp Þ
Fig. 1. Annual energy savings due to lighting retrofits.
d ð1 ð1 þ dÞT Þ
(5)
3.6. Bill savings The bill savings of lighting retrofit is a function of energy savings and the average price of electricity. The potential bill savings by lighting retrofit is calculated by the following equation: BSLi ¼ ESLi PFi
(6)
(4)
Fig. 2. Trend of electricity consumption in residential sector in terms of business as usual (BAU) and with lighting retrofits.
576
T.M.I. Mahlia et al. / Energy and Buildings 37 (2005) 573–578
Table 7 Predicted total potential electricity savings and emission reduction Items
25% retrofit
50% retrofit
75% retrofit
ES (GWh) CO2 (ton) SO2 (kg) NOx (kg) CO (kg)
774 303481 1791821 846409 186936
1548 606962 3583642 1692818 373872
2322 910443 5375463 2539227 560808
3.7. Net savings There are two methods to calculate economical impact of lighting retrofit i.e. annualized costs and cash flow. In the first method, the incremental cost spreads over the lifetime of the efficient lighting so that the pattern of expenditures matches the flow of bill savings. The method smoothens the net savings over time and calculated by the following equation: ANSLi ¼ ESLi PFi
T X
NRLi CRF ICLl
(7)
Fig. 5. Emission reduction by 75% retrofits.
energy efficiency is spreads over the lifetime of the lighting. The net savings in terms of actual cash flows is calculated by the following equation: NSLi ¼ ESLi PFi NRLi ICLl
(8)
i¼l
The second method is the cash flow over the lifetime of the efficient lighting, where the lighting is paid for full when it is installed. The purchasers incur the incremental cost when the lighting is purchased, but the benefit of higher
3.8. Cumulative present value The cumulative present value is calculated using the percentage of discount rate. The cumulative present value of the annualized net savings for lighting retrofit is calculated by the following equation: PVðANSLi Þ ¼
T X
ANSLi
i¼1
ð1 þ dÞðiYdrÞ
(9)
Table 8 Predicted total potential electricity savings and cost-benefit Items
25% retrofit
50% retrofit
75% retrofit
BS (RM) ANS (RM) NS (RM) PV(ANS) (RM)
141054171 116117603 45873748 100905550
282108342 232235205 91747496 201811100
423162513 348352808 137621244 302716650
Fig. 3. Emission reduction by 25% retrofits.
Fig. 4. Emission reduction by 50% retrofits.
Fig. 6. Life cycle cost by 25% retrofits.
T.M.I. Mahlia et al. / Energy and Buildings 37 (2005) 573–578
Fig. 7. Life cycle cost by 50% retrofits.
577
Table 7. The annual emission reduction are presented in Figs. 3–5. Based on essential input data of incandescent and CFL presented in Table 4 and the result of potential energy savings in Table 6, the life cycle cost analysis can be conducted with the discount rate 7%. And the average electricity price of RM 0.236/kWh The calculation results are tabulated in Table 8 and presented in Figs. 6–8. Figs. 6–8 show that, the four curves in the figures are deceasing sharply in the least year of analysis which is in 2009; these are due to the lifetime of the lighting type B. This is also the reason why the results for the net savings in that particular year have negative amount. 5. Conclusions
Fig. 8. Life cycle cost by 75% retrofits.
4. Results and discussions To calculate energy consumption and potential energy savings by lighting retrofit, it is necessary to have daily average operating hour of lighting in Malaysia household. Based on survey data collected in 427 households, the average operating hour of the incandescent bulb is about 4.21 h. Based on this data the energy consumption and potential energy savings can be calculated. For this study, the calculation will be conducted for 25, 50 and 75% of retrofits. The calculation result is tabulated in Table 6 and presented in Fig. 1. Fig. 1 shows that the energy savings in the year 2009 decreased sharply compared to previous year. This is because of the lifetime of the lighting type B is 5000 h, with the operating hour of 4.21 and therefore in the last year the lighting is only used for only 91 days. The trend of electricity consumption in residential sector due to lighting retrofits (Ret) and business as usual (BAU) is presented in Fig. 2. Based on potential energy savings in Table 6, the emission reduction can be calculated using Eq. (4). The results of total potential electricity savings and emission reduction of CO2, SO2, NOx and CO are tabulated in
The calculation result shows that lighting retrofit give significant impact on residential electricity consumption at national level. The program should be considered for implementation. This can be done by introducing consumer efficiency awareness campaign or subsidies the efficient lighting system. The result also shows that, the retrofitting of the lighting system A with B is very promising policy at national and household level in order to save energy and reduce emission in Malaysia. Furthermore, by using efficient lighting indirectly also reduce a significant amount of emission from power generation as presented in Table 7. Moreover, the total potential monetary savings are about RM 141 million for 25% retrofit, RM 282 million for 50% retrofit and 423 million 75% retrofit for 5000 operation hours of efficient lighting. It can be concluded that consumers should encourage using efficient lighting to replace existing inefficient lighting in their household. Hopefully, this piece of work can give an initiative for policymakers, government, practitioners and related organization to introduce this strategy especially in developing countries since the program is creating benefit for every one.
References [1] J.D. Stefano, Energy efficiency and the environment: the potential for energy efficient lighting to save energy and reduce carbon dioxide emissions at Melbourne University, Australia, Energy—The International Journal 25 (2000) 823–839. [2] A.H.W. Lee, Verification of electrical energy savings for lighting retrofits using short- and long-term monitoring, Energy Conversation and Management 41 (2000) 1999–2008. [3] F.M. Guan, E. Mills, Z. Qin, Energy efficient lighting in China, Energy Policy 25 (1997) 77–83. [4] E. Kazakevicius, E. Gadgil, D. Vorsatz, Residential lighting in Lithuania, Energy Policy 27 (1999) 603–611. [5] Philips, Product Catalogue—Family Detail: Lamps Compact Fluorescent Integrated, 2003. www.lighting.philips.com. [6] I. Turiel, B. Atkinson, S. Boghosian, P. Chan, J. Jennings, J. Lutz, J.E. McMahon, S. Pickle, G. Rosenquist, Advanced technologies for residential appliance and lighting market transformation, Energy and Buildings 26 (1997) 241–252.
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[7] D. Vorsatz, L. Shown, J. Koomey, M. Moezzi, A. Denver, B. Atkinson, Lighting market sourcebook for the U.S., Lawrence Berkeley Laboratory, University of California, Berkeley, 1997. [8] J. McMahon, X. Liu, I. Turiel, S.H. Hakim, D. Fisher, Uncertainty and Sensitivity Analyses of Ballast Life-cycle Cost and Payback Period, Lawrence Berkeley Laboratory, University of California, Berkeley, 2000.
[9] T.M.I. Mahlia, Emissions from electricity generation in Malaysia, Renewable Energy 27 (2) (2002) 293–300. [10] H.H. Masjuki, T.M.I. Mahlia, I.A. Choudhury, Potential electricity savings by implementing minimum energy efficiency standards for room air conditioners in Malaysia, Energy Conservation and Management 42 (2001) 439–450.
Cost-benefit analysis and emission reduction of lighting retrofits in residential sector T.M.I. Mahlia*, M.F.M. Said, H.H. Masjuki, M.R. Tamjis Department of Mechanical Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia Received 26 April 2004; received in revised form 29 July 2004; accepted 30 August 2004
Abstract This study projects electricity savings, cost-benefit analysis and emission reduction of lighting retrofits in Malaysia residential sector. The cost-benefit is determined as a function of energy savings due to retrofit of more efficient lighting system. The energy savings were calculated based on 25, 50 and 75% of potential retrofits of inefficient lighting in residential sector. The study found that, this strategy save a significant amount of energy and consumers money. However, an effort to create energy efficiency awareness among consumers and subsidies efficient lighting should be identified, because this efficient lighting is quite expensive in Malaysia. # 2004 Elsevier B.V. All rights reserved. Keywords: Energy savings; Lighting retrofits; Energy efficiency; Cost-benefit analysis; Emission reduction; Malaysia
1. Introduction A lighting retrofit is replacing inefficient lighting with the efficient one. Electricity savings over time is significant enough to not only pay for the new lighting, but also produce return on the investment. This can be done by either reducing the input wattage or reducing the hours of operation of the lighting to reduce energy consumption. The studies on retrofitting inefficient lighting by reducing input wattage are presented by Refs. [1–4]. This study is also proposed to reduce wattage by retrofitting of incandescent lamp with more efficient compact fluorescent lamp (CFL) in residential sector in Malaysia. These can be replaced by energy efficient lamps that are available in 8, 14 and 18 W versions with the equivalent of 40, 60 and 100 Wof incandescent light bulbs [5]. CFL lamps start instantly under 0.1 s with energy consumption 80% less than incandescent light bulb and lasting more than 5000 h. However, this lamp is quite expensive in Malaysia, it is about RM 11.90–23.90 (US$ 1 = RM 3.8), which is 8–17 times of the price of incandescent bulb. This CFL can replace incandescent light bulbs without any modification. * Corresponding author. Tel.: +60 3 7959 5283; fax: +60 3 7959 5317. E-mail addresses: [email protected], [email protected] (T.M.I. Mahlia). 0378-7788/$ – see front matter # 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.enbuild.2004.08.009
In incandescent lamp, electricity heats up a wire filament, causing it to glow and give the light and that is why more than 90% of the energy produced by incandescent lights is heat, not light and therefore incandescent are inefficient light sources. Meanwhile an ordinary incandescent bulb’s lifetime is usually about 750 h before burning out. This study attempts to calculate potential electricity savings, emission reduction and cost-benefit analysis of lighting retrofit policy in Malaysia residential sector at national level. This is to encourage the authority and policymakers to implement this simple strategy to reduce rapid electricity consumption growth in residential sector. Successful experimentation in efficient lighting has been conducted in commercial sector [6].
2. Collected data Extensive data on lighting system can be found in lighting market source book presented in Ref. [7]. The uncertainty, sensitivity analyses, life-cycle cost and payback period of a lighting system can be found in Ref. [8]. However, the data required for this study are only the household data, number and wattage of incandescent bulb data. The saturation of household with electricity in Malaysia is about 97%.
574
T.M.I. Mahlia et al. / Energy and Buildings 37 (2005) 573–578 Table 3 Essential input data of incandescent bulb and CFL
Nomenclature A ANSLi B BSLi CRF d ECLi EMnp ERLi ESLi ICL NHi NRLi NSLi OHLi PCL PEni PFi PVðANSLi Þ STLi T Ydr
incandescent lamp annualized net dollar savings in year i of lighting retrofit (RM) compact fluorescent lamp bill savings in year i of lighting retrofit (RM) capital recovery factor (%) discount rate (%) energy consumption (GWh) emission p for fuel type n for a unit electricity generation (kg/kWh) emission reduction in year i of lighting retrofit (kg) energy savings in year i of lighting retrofits (GWh/year) increment cost of lighting retrofit (RM/ kWh) number of household in year i number of lighting retrofit in year i net saving in year i due to lighting retrofit (RM) daily operating hour of lighting power consumption of lighting (W) percentage of electricity generation in year i of fuel type n price of electricity in year i (RM/kWh) present value of annualized net savings in year i for lighting retrofit (RM) saturation of inefficient lighting in year i lifetime of lighting (year) Year of discount rate base
The number of incandescent bulbs were collected by conducting survey in 427 randomly selected household and the results are tabulated in Tables 1–4. The predicted household data, the percentage of electricity generation
Bulb type
Incandescent A1
A2
CFL A3
B1
B2
B3
Total watts (W) 40 60 100 8 14 18 Lifetime (h) 750 750 750 5000 5000 5000 Purchase price (RM) 1.40 1.40 1.40 18.50 18.50 18.50 Number of bulbs 7 7 7 1 1 1 Total bulb cost (RM) 9.80 9.80 9.80 11.80 15.90 23.90 Table 4 Fossil fuel emissions for a unit electricity generation Fuels
Coal Petroleum Gas Hydro Other
Emission (kg/kWh) CO2
SO2
NOx
CO
1.1800 0.8500 0.5300 0.0000 0.0000
0.0139 0.0164 0.0005 0.0000 0.0000
0.0052 0.0025 0.0009 0.0000 0.0000
0.0002 0.0002 0.0005 0.0000 0.0000
based on fuel type and fossil fuel emissions for a unit electricity generation were given by Refs. [9,10] and tabulated in Tables 4 and 5.
3. Methodology A survey is necessary to determine the saturation level of inefficient lighting, the operating hour of the incandescent bulb and the number of potential retrofit of the lighting system in Malaysia residential sector. Based on Table 3, lighting system A is referred to the incandescent lamp, while lighting system B is referred to CFL which is proposed lighting system that are more energy efficient. The data obtained from the survey was used to calculate projected electricity savings, emission reduction and cost-benefit analysis of lighting retrofits. The equations used for calculation are discussed in the following section. 3.1. Number of retrofits
Table 1 Wattage and saturation of incandescent bulb in the household Power (W)
Number of incandescent bulb
Saturation (%)
40 60 100
178 205 252
41.7 48.0 59.0
Table 2 Operation hours per day of incandescent bulb
Number of retrofits depends on the saturation level of inefficient lighting in the household with electricity. The number of retrofits is calculated by multiplication of number of household and the saturation levels of inefficient lamp. This can be represented by the following equation: NRLi ¼ NHLi STLi
(1)
3.2. Energy consumption
Operating hours
Central value
Households
0–2 2–4 4–6 6–8 8–10 10–12
1 3 5 7 9 11
21 87 64 12 10 6
Energy consumption by the lighting is the multiplication of the number of retrofits, power consumption and operating hour of the lighting. The annual energy consumption can be expressed mathematically by the following equation: ECLi ¼ NRLi PCL OHLi 365
(2)
T.M.I. Mahlia et al. / Energy and Buildings 37 (2005) 573–578
575
Table 5 Predicted electricity consumption, number of households and percentage of fuel type for electricity generation Year
Residential (GWh)
Household
Coal (%)
Petroleum (%)
Gas (%)
Hydro (%)
2006 2007 2008 2009 2010
15969 17055 18178 19337 20532
5552555 5711720 5873989 6039363 6207842
15.84 16.26 16.76 17.34 18.00
2.96 2.69 2.44 2.21 2.00
56.80 54.95 53.20 51.55 50.00
24.40 26.10 27.60 28.90 30.00
Table 6 Predicted number of incandescent bulb, electricity consumption and savings Year
Household
2006 2007 2008 2009
Number and wattage of incandescent bulb
5552555 5711720 5873989 6039363
Potential of electricity consumption and savings (GWh)
40 W
60 W
100 W
25% retrofits
50% retrofits
75% retrofits
A
B
Savings
A
B
Savings
A
B
Savings
2315415 2381787 2449453 2518414
2665226 2741626 2819515 2898894
3276007 3369915 3465654 3563224
223 229 236 60
44 45 47 12
179 184 189 48
446 459 472 121
88 91 93 24
358 368 378 97
669 688 707 181
132 136 140 36
536 552 567 145
3.3. Energy savings 3.5. Capital recovery factor Energy savings from retrofitting is the difference between energy consumption of inefficient and efficient lighting. This can be calculated using the following equation: LB ESLi ¼ ECLA i ECi
(3)
The capital recovery factor is the correlation between the discount rate and the lifetime of more efficient lighting, this correlation is calculated by the following equation: CRF ¼
3.4. Emissions reduction The environmental impact from retrofitting is potential reduction of greenhouse gasses or other element that caused negative impact to the environment. The common emission reductions are usually, CO2, SO2, NOx and CO. The emission reduction is a function of energy savings. The emission reduction can be expressed mathematically by the following equation: ERLi
¼
ESLi ðPE1i
EM1p
þ PE2i
EM2p
þ PE3i
EM3p þ þ PEni EMnp Þ
Fig. 1. Annual energy savings due to lighting retrofits.
d ð1 ð1 þ dÞT Þ
(5)
3.6. Bill savings The bill savings of lighting retrofit is a function of energy savings and the average price of electricity. The potential bill savings by lighting retrofit is calculated by the following equation: BSLi ¼ ESLi PFi
(6)
(4)
Fig. 2. Trend of electricity consumption in residential sector in terms of business as usual (BAU) and with lighting retrofits.
576
T.M.I. Mahlia et al. / Energy and Buildings 37 (2005) 573–578
Table 7 Predicted total potential electricity savings and emission reduction Items
25% retrofit
50% retrofit
75% retrofit
ES (GWh) CO2 (ton) SO2 (kg) NOx (kg) CO (kg)
774 303481 1791821 846409 186936
1548 606962 3583642 1692818 373872
2322 910443 5375463 2539227 560808
3.7. Net savings There are two methods to calculate economical impact of lighting retrofit i.e. annualized costs and cash flow. In the first method, the incremental cost spreads over the lifetime of the efficient lighting so that the pattern of expenditures matches the flow of bill savings. The method smoothens the net savings over time and calculated by the following equation: ANSLi ¼ ESLi PFi
T X
NRLi CRF ICLl
(7)
Fig. 5. Emission reduction by 75% retrofits.
energy efficiency is spreads over the lifetime of the lighting. The net savings in terms of actual cash flows is calculated by the following equation: NSLi ¼ ESLi PFi NRLi ICLl
(8)
i¼l
The second method is the cash flow over the lifetime of the efficient lighting, where the lighting is paid for full when it is installed. The purchasers incur the incremental cost when the lighting is purchased, but the benefit of higher
3.8. Cumulative present value The cumulative present value is calculated using the percentage of discount rate. The cumulative present value of the annualized net savings for lighting retrofit is calculated by the following equation: PVðANSLi Þ ¼
T X
ANSLi
i¼1
ð1 þ dÞðiYdrÞ
(9)
Table 8 Predicted total potential electricity savings and cost-benefit Items
25% retrofit
50% retrofit
75% retrofit
BS (RM) ANS (RM) NS (RM) PV(ANS) (RM)
141054171 116117603 45873748 100905550
282108342 232235205 91747496 201811100
423162513 348352808 137621244 302716650
Fig. 3. Emission reduction by 25% retrofits.
Fig. 4. Emission reduction by 50% retrofits.
Fig. 6. Life cycle cost by 25% retrofits.
T.M.I. Mahlia et al. / Energy and Buildings 37 (2005) 573–578
Fig. 7. Life cycle cost by 50% retrofits.
577
Table 7. The annual emission reduction are presented in Figs. 3–5. Based on essential input data of incandescent and CFL presented in Table 4 and the result of potential energy savings in Table 6, the life cycle cost analysis can be conducted with the discount rate 7%. And the average electricity price of RM 0.236/kWh The calculation results are tabulated in Table 8 and presented in Figs. 6–8. Figs. 6–8 show that, the four curves in the figures are deceasing sharply in the least year of analysis which is in 2009; these are due to the lifetime of the lighting type B. This is also the reason why the results for the net savings in that particular year have negative amount. 5. Conclusions
Fig. 8. Life cycle cost by 75% retrofits.
4. Results and discussions To calculate energy consumption and potential energy savings by lighting retrofit, it is necessary to have daily average operating hour of lighting in Malaysia household. Based on survey data collected in 427 households, the average operating hour of the incandescent bulb is about 4.21 h. Based on this data the energy consumption and potential energy savings can be calculated. For this study, the calculation will be conducted for 25, 50 and 75% of retrofits. The calculation result is tabulated in Table 6 and presented in Fig. 1. Fig. 1 shows that the energy savings in the year 2009 decreased sharply compared to previous year. This is because of the lifetime of the lighting type B is 5000 h, with the operating hour of 4.21 and therefore in the last year the lighting is only used for only 91 days. The trend of electricity consumption in residential sector due to lighting retrofits (Ret) and business as usual (BAU) is presented in Fig. 2. Based on potential energy savings in Table 6, the emission reduction can be calculated using Eq. (4). The results of total potential electricity savings and emission reduction of CO2, SO2, NOx and CO are tabulated in
The calculation result shows that lighting retrofit give significant impact on residential electricity consumption at national level. The program should be considered for implementation. This can be done by introducing consumer efficiency awareness campaign or subsidies the efficient lighting system. The result also shows that, the retrofitting of the lighting system A with B is very promising policy at national and household level in order to save energy and reduce emission in Malaysia. Furthermore, by using efficient lighting indirectly also reduce a significant amount of emission from power generation as presented in Table 7. Moreover, the total potential monetary savings are about RM 141 million for 25% retrofit, RM 282 million for 50% retrofit and 423 million 75% retrofit for 5000 operation hours of efficient lighting. It can be concluded that consumers should encourage using efficient lighting to replace existing inefficient lighting in their household. Hopefully, this piece of work can give an initiative for policymakers, government, practitioners and related organization to introduce this strategy especially in developing countries since the program is creating benefit for every one.
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