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.

IMPROVEMENT OF ENERGY EFFICIENCY

IN THE STREET LIGHTING SYSTEM OF THE

COLOMBO CITY

H.K. ILLEPERUMA

H.R.P. WANNIARACHCHISRI LANKA ENERGY MANAGERS ASSOCIATION

H.H.D. NANDASENACOLOMBO MUNICIPAL COUNCIL

Contents1.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

Area 37 sqkmPopulation 1.7 millionNo of Retail Customers 120,000No of Bulk Customers 1200 Total Electricity Sales790 GWh/yearElectricity Units billed

for Street lighting 10 GWh/year

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

Colombo City

250W SV Main Roads

250W MV and Others By roads

150W SV By roads /Footpaths

125W MV Footpaths/Gardens

Present Street Lighting System

Recently CMC has adopted following basis in installation of Street Lights

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

Present System Contd..

Number of Street Light Luminaries

45%

15% 20%

20%

250W SV

150W SV

125W MV

250W MV andothers

Street Light Load in kW

1687.5

337.5

375

525250W SV

150W SV

125W MV

250W MV and others

Present System Contd..

Operation of Street Lights 30% Automatically using photocells 70% Manually

Electricity Supply to Street Lights are from both overhead and underground lines

Load of Different Type of Lamps in the District 4 (Kirulopane Area)

26%

28%

1% 12%

33%

70 W SV

150W SV

250W SV

125W MV

250W MV

Present Street Lighting System- Kirulopane Area

Number of lamps in the District 4 (Kirulopane Area)

66262

448

716

385

70 W SV

150W SV

250W SV

125W MV

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 250W SV 150W SV 250W MV 125W MV26 30 32

GAJABA ROAD 15 1 9 5MAHINDA PLACE 8 5 3LAKSHMAN PLACE 1 5 6BALAHENA MULLA 1 8 5 2 3JAYASINGHA ROAD 5 9 9 4ROBERT GUNAWARDANA MAWATHA 4 16 18 2MUGALAN ROAD 11 11BALAPOKUNA ROAD 2 16 18HALGASWATTA ROAD 9 5 4NANDIMITTRA PLACE 1 7 3 5SURANIMALA PLACE 1 7 7 1PURANAVIHARA ROAD 1 2 3BALAPOKUNA PLACE 6 6MAHAWELA PLACE 6 3 4 5Total 12 22 14 96 70 35 39

POLE HEIGHT (FEET)

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 PolesLuminaire Position Switching SystemsLumen output of Lamps & Type of Lamps Maintenance of Street Lighting System

Use high efficacy bulbs & ballastUse more efficient luminariesTimely Switching on/offBy proper lighting designBy switching off some lights during low traffic

periodsBy dimmer units, reducing luminance during low

traffic hoursProper maintenance scheme.

Possible Energy Saving Measures

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

Annual Saving Life Cycle Saving

Rs.66,961Rs.293,4912

Rs.1,841,440Rs.8,068,830

Pay-back Period 13 months 13 months

125W MV Lamps70W 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

Lumen output 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

Life cycle Saving   Rs. +10,396

Comparison between the replacement of 125W MV complete fitting and replacement of 125MV bulb & ballast only.

  Complete fitting

Bulb only

Annual energy saving 241 kWh 241kWh

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

Possible Energy Saving Measures

Timely switching on/offFixing 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 LabourTotal Saving

Rs.15,374Rs.73,000Rs. 88,374

Rs. 170,229Rs.511,000Rs.681,229

Rs. 1,106,060Rs.3,285,000Rs.4,391,060

Payback Period 12 months 14 months 14 months

The level and uniformity of luminance along a road depend on several factors Lumen output of the light source Luminaire distribution Mounting height Luminaire position and Spacing Installation arrangement

Possible Energy Saving Measures

By proper system design

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.

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.

Possible Energy Saving Measures

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 agingSupport Structure MaintenanceElectrical Distribution and Control System

MaintenancePruning of trees which disrupt light distribution

Implementation Action Plan

Proposal Investment Saving PaybackPeriod

Stage 1- No cost & low cost measures

Installation Photo Electric cells in the Study Area. Rs. 86400 Rs. 88,374 12 month

Replacement of 250W Mercury Vapour lamps with110W Sodium Vapour Lamps in the study area.

Rs. 73,500 Rs. 66,961 13 months

Replacement of 125W Mercury Vapour lamps in thenew fittings with 70W Sodium Vapour Lamps (Lamponly)

The statistics for thenew fittings are not

available

13 months

Carry out an audit to assess the energyconsumption of the street lighting system of CMC bythe Ceylon Electricity Board

Installation of 70W Sodium Vapour lamps only in theresidential areas which are new installations.

No additionalinvestment Rs. 12,327 per

lamp

Implementation Action Plan

Proposal Investment Saving PaybackPeriod

Stage 2- Medium cost measures

Installation Photo Electric cells in the District 4. Rs. 780000 Rs. 681,229 14 months

Replacement of 250W Mercury Vapour lamps with110W Sodium Vapour Lamps in the District 4.

Rs. 2,021,250 Rs. 1,841,440 13 months

Replacement of 125W Mercury Vapour lamps in thenew fittings with 70W Sodium Vapour Lamps (Lamponly) – in the District 4.

The statistics for thenew fittings are not

available

13 months

Implementation of Proposed maintenance Programin the District 4.

Rs. 800,000 + avehicle with a bucket

Implementation Action Plan

Proposal Investment Saving PaybackPeriod

Stage 3 – High cost measures

Installation Photo Electric cells in the whole CMC. 5040000 4,391,060 14 months

Replacement of 250W Mercury Vapour lamps with110W Sodium Vapour Lamps in the Whole CMCArea.

13 months

Replacement of 125W Mercury Vapour lamp fittingswith 70W Sodium Vapour Lamp fittings

29 months

Implementation of Proposed maintenance Programin the Whole CMC area.

Rs. 8,000,000+vehicles

Thank You !