City of Detroit – LED Conversion: Case Study

LIGHTING THE WAY® TO A BRIGHTER FUTURE IN DETROIT, MICHIGAN

THE CHALLENGE

By mid-2013, the City of Detroit estimated that over 50% of their 88,000 streetlights were no longer functioning. A lack of funds for the upkeep of the City’s infrastructure meant that many streetlights burned out without hope of replacement. Many other concerns faced Detroit’s aging streetlight system including an increasing number of copper theft incidents, maintenance staff shortages, pole and substation deterioration, and an existing series-wired circuit setup, which caused all the streetlights in a circuit to go dark if one was inoperable. As a result, many residents began to avoid going out at night for fear of their personal safety; and local businesses were affected due to the decrease of foot traffic.

THE SOLUTION

After Detroit declared bankruptcy in 2013, Michigan’s governor appointed an Emergency Manager tasked with establishing and overseeing the Public Lighting Authority (PLA), which aimed to restore Detroit’s streetlight system.

• • The conversion of an original system of 88,000 operating HPS lights to 65,000 LED lights improves illumination, maximizes energy and cost savings, lowers maintenance costs, and produces a significant reduction of environmental emissions
• The new LED lights are twice as bright as the old lights and deliver the illuminance requirements of the Detroit specification with a reduced number of streetlights while increasing energy efficiency
• The PLA partnered with King Luminaire to provide 4,900 brighter, more reliable, and more energy-efficient decorative LED light fixtures. The LED luminaires only need replacement after approximately 15-20 years, versus re-lamping the old HPS lights every 4-5 years and King Luminaire backs the LED lights with a 7-year warranty
• To improve reliability, the PLA switched from the old copper wiring to LED compatible aluminum wiring – greatly reducing theft
• In addition, the new lighting system is a multiple series circuit system – if one light goes out, the others stay on

The net result is a system that is brighter, more efficient and more reliable than the old system that will assure state-of-the-art public lighting for Detroit far into the future.

Public Lighting Authority, Detroit, Michigan

THE RESULTS

Electricity and Maintenance Savings:

• The new LED system saves about 46 million kWh in electricity every year, while bulb replacement frequency has been reduced by 80%

Energy Cost Savings:

• The use of LED lights delivers energy cost savings of $2.9 million each year that results in a luminaire replacement payback period of just 2.3 years

Emission Reductions:

• The conversion to LED lights results in an annual emissions reduction of 134 tons SO2, 41 tons NOX, 40,418 tons CO2 and 1.48 lb Hg

Increased Safety:

• LEDs produce bright white light — not the orange glow of sodium lights — so objects such as people and bicycles are seen more clearly
• 5,400 brighter lights along school safe routes help keep children safe on their way to and from school

Higher Foot Traffic:

• Neighborhoods have experienced an increase in foot traffic after dark – a benefit for retail businesses and restaurants

Overall:

• The entire LED conversion came in under budget and on time
• Detroit’s delivery on its promise to turn the lights back on restored the trust in city government among residents