Presentation by Blake Redfield, City of St. Cloud. An LED street lighting forum was hosted at the League of Minnesota Cities Annual Conference on June 19th, where a packed room of 40 people learned first-hand from a tremendously knowledgeable line-up of speakers from across Minnesota. Learn more at http://www.cleanenergyresourceteams.org/blog/better-light-and-more-savings-led-street-lights-conference-session-recap

1. CITY OF ST. CLOUD –
LED LIGHTING
2014 League of Minnesota Cities
Steve Lawrence & Blake Redfield

2. 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

3. 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

4. LED Lighting Basics

5. Driver: Converts
AC to low
voltage DC
Door:
Protects against
weather, insects,
creatures
DoorClamps:
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 DistributionTypes
*Note: Some fixtures use mirror
arrays to direct the light rather
than an LED lens
LED Light Engine

6. 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

7. Department of Energy’s
Projections of LED Efficiencies1

8. 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.

9. 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

10. Kilian &
Riverside
LED
Street
Light
Project
Location

11. Street light
style along
Kilian Blvd &
Riverside
Drive

12. 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?

13. 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

14. Test Deck

15. Konica Minolta Light Meter &
Self Aligning Shoe

16. 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

17. Data
Input
and
Report
Form

18. Two Dimensional Photometry Model from Test Deck

19. Three Dimensional Photometry Model from Test Deck

20. Predicting Light Levels from Pole Height

21. Color Temperature Distribution

22. LED Upgrade Statistics
Original 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.

23. LED Fixture Statistics
Kilian Boulevard
 Sternberg
 OldTown Series
 3500K CCT
 3300 lumens
 TypeV Dist.
 66Watts
 Qty: 55
Riverside Drive
 Sternberg
 Roadway Series
 3500K CCT
 1130 lumens
 Type III Dist.
 34Watts
 Qty: 50
Minnesota Boulevard
 Sternberg
 OldTown Series
 3500K CCT
 3160 lumens
 Type III Dist.
 66Watts
 Qty: 28

24. 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

25. Additional LED Test Equipment

26. Color Checker

27. Light Fixture
Lift Tower

28. Spectrum Analyzer

29. The Future of LED Street Lighting
in St. cloud

30. 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

31. $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
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41
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 Program
City 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 &
ElectricalCosts without
LED replacement

32. Other St. Cloud LED Street
Lighting Projects

33. Parking Ramp LED Upgrade

34. Smart Dimming Park-N-Ride Lot

35. Central Maintenance Building LED Street
Lighting and Exterior Lighting Upgrade

36. St. Cloud Water Plant LED Exterior
Lighting and Street Lighting Upgrade

37. Articles Cited
 1,2. U.S. Department of Energy, Energy
Efficiency of LEDs, PNNL-SA-94206, March 2013