Transcript IMPROVEMENT OF ENERGY EFFICIENCY IN THE STREET LIGHTING

IMPROVEMENT OF
ENERGY EFFICIENCY
IN THE
STREET LIGHTING SYSTEM OF THE
COLOMBO CITY
H.K. ILLEPERUMA
H.R.P. WANNIARACHCHI
SRI LANKA ENERGY MANAGERS ASSOCIATION
H.H.D. NANDASENA
COLOMBO MUNICIPAL COUNCIL
Contents
1.Colombo City – Statistics
2. Present Street lighting system- Colombo City
3. Present Street lighting system-Selected Area
4. Findings of the Survey
5. Possible Energy Saving Measures
6. Implementation Plan
Statistical Data of
Colombo City

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

Area
Population
No of Retail Customers
No of Bulk Customers
Total Electricity Sales
Electricity Units billed
for Street lighting
37 sqkm
1.7 million
120,000
1200
790 GWh/year
10 GWh/year
Colombo City
 Electricity Distribution System is
operated and maintained by Ceylon
Electricity Board
 Street Lighting System is operated and
maintained by Colombo Municipal
Council (CMC) under 6 districts
Present Street Lighting System
Recently CMC has adopted following basis in
installation of Street Lights
250W SV
Main Roads
250W MV and Others
By roads
150W SV
By roads /Footpaths
125W MV
Footpaths/Gardens
Present System Contd..
 There are about 12,000 Street Lamps in the
CMC Area
 834 MWh of energy is consumed per
month @ Rs 7.80 per unit, results in a
monthly bill of Rs 6.5 million
Number of Street Light Luminaries
250W SV
15%
20%
150W SV
125W MV
45%
20%
250W MV and
others
Street Light Load in kW
525
250W SV
150W SV
375
1687.5
337.5
125W MV
250W MV and others
Present System Contd..
 Operation of Street Lights


30%
70%
Automatically using photocells
Manually
 Electricity Supply to Street Lights are from
both overhead and underground lines
Present Street Lighting System- Kirulopane Area
Number of lamps in the District 4 (Kirulopane
Area)
385
66
262
70 W SV
150W SV
448
250W SV
125W MV
250W MV
716
Load of Different Type of Lamps in the
District 4 (Kirulopane Area)
1%
12%
28%
70 W SV
150W SV
33%
250W SV
125W MV
26%
250W MV
In Study Area ....
Classification of Roads
1. Main roads with high vehicular traffic
2. Roads connecting to main roads with
substantial vehicular traffic and
pedestrian traffic
3. Roads leading to residential areas and
terminating.
Details of Street Light Luminaries
in the Study Area
ROAD NAME
GAJABA ROAD
MAHINDA PLACE
LAKSHMAN PLACE
BALAHENA MULLA
JAYASINGHA ROAD
ROBERT GUNAWARDANA MAWATHA
MUGALAN ROAD
BALAPOKUNA ROAD
HALGASWATTA ROAD
NANDIMITTRA PLACE
SURANIMALA PLACE
PURANAVIHARA ROAD
BALAPOKUNA PLACE
MAHAWELA PLACE
Total
250W SV 150W SV 250W MV 125W MV
15
1
1
5
4
8
5
8
9
16
11
2
1
1
1
12
6
22
14
16
9
7
7
2
6
3
96
POLE HEIGHT (FEET)
30
26
32
1
9
5
5
3
6
5
2
3
9
4
18
2
11
18
5
4
3
5
7
1
3
6
4
5
70
35
39
Robert Gunawardana Mw and Balapokuna Road connect to other main
roads, carry considerable vehicular traffic.
Findings of the Survey
 Luminaire Mounting Height & Height of
Pole
 Spacing of Lamps & Span of Poles
 Luminaire Position
 Switching Systems
 Lumen output of Lamps & Type of Lamps
 Maintenance of Street Lighting System
Possible Energy Saving Measures
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Use high efficacy bulbs & ballast
Use more efficient luminaries
Timely Switching on/off
By proper lighting design
By switching off some lights during low traffic
periods
 By dimmer units, reducing luminance during low
traffic hours
 Proper maintenance scheme.
Possible Energy Saving Measures
 Use high efficacy Lamps & ballast
 Replacement of Mercury Vapor lamps with
High pressure Sodium Vapor lamps.
• 125W MV ----> 70W SV
• 250W MV ----> 110W SV
 This can be done in two ways

Replace complete fitting for very old lights

Replace only the bulb & ballast for fairly new
lights
 Replacement of Mercury Vapour Lamps with
Sodium Vapour Lamps

250W MV Lamps 
110W SV Lamps
Description
Study Area (14 lamps)
District 4 (385 lamps)
Investment
Rs.73,500
Rs.2,021,250
Rs.66,961
Rs.293,4912
Rs.1,841,440
Rs.8,068,830
13 months
13 months
Annual Saving
Life Cycle Saving
Pay-back Period
125W MV Lamps70W SV Lamps
 Can be installed along roads in residential
areas
 Recommended Mounting height is 6m at
30 to 35 m intervals
 In future all the new installation in the
residential areas should be with 70W SV
Comparison Between 125W MV & 70W SV
125W MV
70W SV
6875
8750
Annual energy consumption
548 kWh
307 kWh
Annual energy cost
Rs. 4,271
Rs. 2,391
Life cycle energy cost
Rs. 23,400
Rs. 13,104
Cost of fitting
Rs. 4,600
Rs. 4,500
Life cycle cost
Rs. 28,000
RS. 17,604
Lumen output
Life cycle Saving
Rs. +10,396
Comparison between the replacement of 125W MV
complete fitting and replacement of 125MV bulb &
ballast only.
Annual energy saving
Complete
fitting
241 kWh
Bulb only
Annual energy saving
Rs. 1,879
Rs. 1,879
Life cycle energy saving
Rs. 10,296
Rs. 10,296
Investment
Rs. 4,500
Rs. 2,000
Payback period
29 months
13 months
Life cycle saving
Rs. 5,796
Rs. 8,296
241kWh
Possible Energy Saving Measures
 Timely switching on/off
 Fixing of photoelectric cells for automatic
operation of lamps (for circuits & individual
lamps)
Costs & Benefits of the Proposal
Description
Study Area
District 4
Colombo
City
Investment
Rs.86,400
Rs.780,000
Rs.5,040,000
Annual Saving :
Energy
Labour
Total Saving
Rs.15,374
Rs.73,000
Rs. 88,374
Rs. 170,229
Rs.511,000
Rs.681,229
Rs. 1,106,060
Rs.3,285,000
Rs.4,391,060
Payback Period
12 months
14 months
14 months
Possible Energy Saving Measures
By proper system design
 The level and uniformity of luminance
along a road depend on several factors
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Lumen output of the light source
Luminaire distribution
Mounting height
Luminaire position and
Spacing
Installation arrangement
Luminaire Mounting Height &
Height of Pole
Recommended Height of poles for different sizes of roads
Road Type
Height of pole
Mounting Height
Main roads
32 feet poles
9m
By roads
30 feet poles
7-8m
Foot paths/Gardens
26 feet poles
6m
Spacing of Lamps
 It is required to maintain equal
distances between street lamp poles.
 Most effective distance is 35m to 40m.
 It is not economical to erect additional
poles for street lighting to maintain the
equal spans in the existing system.
Overhang & Angle of Tilt
 Overhang and Angle of tilt vary with the
following
 Width of road
 Lumen Output of the lamp
 Height & Spacing of the poles
 The most effective angle of tilt is 5 to 10
degrees and overhang is 0.75 to 1.5 meters,
depending on the width of the road.
Possible Energy Saving Measures
Maintenance Scheme for Street Lighting
 Improve the light levels in the city and
gradually the wattage of the lamps could be
reduced.
 Provide benefits not only the energy
conservation but also the other benefits in
terms
of
public
safety,
security,
convenience and comport during darkness.
 Maintenance program twice a year.
Maintenance of the Street Lighting Should
Include ....
 Luminaire Maintenance
 luminaire cleaning is required to maintain
designed lighting levels.
 loss of lumen output of light sources due to
normal aging
 Support Structure Maintenance
 Electrical Distribution and Control System
Maintenance
 Pruning of trees which disrupt light distribution
Implementation Action Plan
Proposal
Investment
Saving
Payback
Period
Installation Photo Electric cells in the Study Area.
Rs. 86400
Rs. 88,374
12 month
Replacement of 250W Mercury Vapour lamps with
110W Sodium Vapour Lamps in the study area.
Rs. 73,500
Rs. 66,961
13 months
Stage 1- No cost & low cost measures
Replacement of 125W Mercury Vapour lamps in the The statistics for the
new fittings with 70W Sodium Vapour Lamps (Lamp new fittings are not
only)
available
13 months
Carry out an audit to assess the energy
consumption of the street lighting system of CMC by
the Ceylon Electricity Board
Installation of 70W Sodium Vapour lamps only in the
residential areas which are new installations.
No additional
investment
Rs. 12,327 per
lamp
Implementation Action Plan
Proposal
Investment
Saving
Payback
Period
Rs. 780000
Rs. 681,229
14 months
Rs. 2,021,250
Rs. 1,841,440
13 months
Stage 2- Medium cost measures
Installation Photo Electric cells in the District 4.
Replacement of 250W Mercury Vapour lamps with
110W Sodium Vapour Lamps in the District 4.
Replacement of 125W Mercury Vapour lamps in the The statistics for the
new fittings with 70W Sodium Vapour Lamps (Lamp new fittings are not
only) – in the District 4.
available
Implementation of Proposed maintenance Program
Rs. 800,000 + a
in the District 4.
vehicle with a bucket
13 months
Implementation Action Plan
Proposal
Investment
Saving
Payback
Period
5040000
4,391,060
14 months
Stage 3 – High cost measures
Installation Photo Electric cells in the whole CMC.
Replacement of 250W Mercury Vapour lamps with
110W Sodium Vapour Lamps in the Whole CMC
Area.
13 months
Replacement of 125W Mercury Vapour lamp fittings
with 70W Sodium Vapour Lamp fittings
29 months
Implementation of Proposed maintenance Program
in the Whole CMC area.
Rs. 8,000,000
+vehicles
Thank You !