CITY OF ST. CLOUD –LED LIGHTING
2014 League of Minnesota Cities
Steve Lawrence & Blake Redfield
City of St. Cloud LED Street Lighting Goals Reduce electrical costs Reduce maintenance costs Provide high quality roadway lighting Reduce glare to the motorist Improve pedestrian and residential security Reduce street light outage times Minimize light trespass onto private properties Become more dark skies compliant
LED Street Light Installation Considerations Quality of light & fixture Complexity of the LED light source Cost effectiveness of fixtures Implementation process Complete Staggered
Ownership methods Organization purchasing fixtures Allow outside investors to purchase & reap benefits of
energy (cost) savings When to get aboard the LED street lighting world
LED Lighting Basics
Driver: Converts AC to low
voltage DC
Door:Protects against weather, insects,
creatures
Door Clamps:Secures Door
Fixture Clamps:Secures Fixture
to Pole
Surge Suppressor:Protects Driver from
Voltage Surges
Terminal Block: Electrical Connection to
AC Power Source
Labels:Provide
certifications and model numbers
Body: Provides support for LED circuit board and
cooling for the LED’s
LED:Small Solid State Device
that Emits Light
LED Lens*:Directs Light for even Distribution and
Various Distribution Types
*Note: Some fixtures use mirror arrays to direct the light rather
than an LED lens
LED Light Engine
Efficacy Lumens of light / Watt of electricity Efficiency of driver Spectral efficiencies
Cool color temperatures Higher output levels Lower color rendering indexes
Warm color temperatures Lower output levels High color rendering indexes
P-N junction temperature efficiencies LED efficiencies drop as temperatures rise above normal levels
Delivery system efficiencies Lens losses Reflective losses Aiming losses
System losses can exceed 30% of potential light output when any of the components have losses or are not matched to the system2
Department of Energy’s Projections of LED Efficiencies1
LED Efficiencies since 2005
2005
•60 lm/wt•Baseline
2015
•190 lm/wt•+315%
2025
•266 lm/wt•+443%
Average of 10.3% increase per year for 20 years.
The St. Cloud LED Street Lighting Story 2010 awarded ARRA funds for LED lighting
projects Developed test methodologies for street lights Developed plans and specifications for light
fixtures that passed our test criteria 2010-2011 installed lighting systems on Kilian
Boulevard and Riverside Drive
Kilian & Riverside LEDStreet Light Project Location
Street lightstyle along Kilian Blvd & Riverside Drive
Problems Encountered when Reviewing Decorative LED Street Lights Photometric files did not always match real world
testing Shadows were a major problem at the base of light
poles Electrical power consumption measurements were
not consistent Thermal management varied considerably from
fixture to fixture Quality of the fixture materials and ability to do
maintenance varied from fixture to fixture Was the LED color temperature correct with the
manufacturer’s claims?
Solutions for Reviewing LED Street Light Fixtures Develop a standard battery of tests that every street
light sample would go through Develop a test lab for performing the battery of tests Develop an evaluation methodology for each of the
LED fixtures Develop visual photometric modeling that would
better illustrate the light outputs of the LED fixtures than traditional modeling
Make fixture reviews as objective as possible
Test Deck
Konica Minolta Light Meter & Self Aligning Shoe
Data Collected & Inputs from Testing / Review Measure footcandles
at 64 points on test deck
Measure CCT at 64 points on test deck
Measure thermal temperature of heat sink unit
80 & 90 degree cut-off level measurements
Rate workmanship Rate quality of materials Rate finish/coating Rate electrical component
replacement Rate diffuser replacement Rate product standards Rate warranty Rate driver components Rate LED components
Data Input and Report Form
Two Dimensional Photometry Model from Test Deck
Three Dimensional Photometry Model from Test Deck
Predicting Light Levels from Pole Height
Color Temperature Distribution
LED Upgrade StatisticsOriginal Lighting Updated LED Lighting Kilian Boulevard 110 - 70 watt twin HPS fixtures
on 12’ poles
Riverside Drive 50 – 100 watt HPS fixtures on
9’ poles
Minnesota Boulevard 28 – 100 watt HPS fixtures on
12’ poles
Kilian Boulevard 55 – 66 watt single LED fixtures
on 12’ poles
Riverside Drive 50 – 35 watt LED fixtures on
9’ poles
Minnesota Boulevard 28 – 66 watt HPS fixtures on 12’
poles
Reduced power consumption 51% from 15,500 watts to 7,560 watts.Entire project cost was approximately $263,000.
LED Fixture StatisticsKilian Boulevard
Sternberg
Old Town Series
3500K CCT 3300 lumens
Type V Dist.
66 Watts Qty: 55
Riverside Drive
Sternberg
Roadway Series
3500K CCT 1130 lumens
Type III Dist.
34 Watts Qty: 50
Minnesota Boulevard
Sternberg
Old Town Series
3500K CCT 3160 lumens
Type III Dist.
66 Watts Qty: 28
Conclusions of Kilian & Riverside LED Lighting Project
Positives Negatives
Significant decrease in electrical costs
Significant reduction in maintenance
Much better quality of light Much better light levels
A couple of residents along Kilian Boulevard complained about losing the twin fixtures from an aesthetics standpoint
A couple of residents along Kilian Boulevard complained that the light is now too bright
Additional LED Test Equipment
Color Checker
Light FixtureLift Tower
Spectrum Analyzer
The Future of LED Street Lighting in St. cloud
City of St. Cloud Develop has developed a cost analysis on a 100% LED change-out program over a 40 year timeframe Five year phase in plan LED expected light fixture life of 20 years Assume 1% annual increase in electrical costs Assume 2% annual increase in maintenance costs Assume 5% annual increase in LED efficiency Assumes cost reduction in light fixtures over time Assumes significant maintenance reduction costs Creates an $18.5 million dollar savings in 40 years
$0.00
$200,000.00
$400,000.00
$600,000.00
$800,000.00
$1,000,000.00
$1,200,000.00
$1,400,000.00
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Electrical Costs With LED Replacement Program
Electrical Costs Without LED Replacement Program
Maintenance and install costs with LED Upgrades
Maintenance Costs without LED Upgrades*
Total of Maint & Elect. With LED Upgrades
Total of Maint. & Elect. Without LED Upgrades
LED Street Lighting ProgramCity of St. Cloud
Period of 40 years
Years
Electrical costs without LED upgrades
Electrical costs with proposed LED program
Total of LED replacement, Maintenance & Electrical
Costs
Maintenance Costs without LED Upgrades
Maintenance and installation costs with
LED replacement
Total Projected Savings in 40 Years with Proposed LED Upgrades: $18.5 Million
Total of Maintenance & Electrical Costs without
LED replacement
Other St. Cloud LED Street Lighting Projects
Parking Ramp LED Upgrade
Smart Dimming Park-N-Ride Lot
Central Maintenance Building LED Street Lighting and Exterior Lighting Upgrade
St. Cloud Water Plant LED Exterior Lighting and Street Lighting Upgrade
Articles Cited
1,2. U.S. Department of Energy, Energy Efficiency of LEDs, PNNL-SA-94206, March 2013