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March 9, 2017
PORTSMOUTH, NH – Last year, the Department of Public Works conducted a successful pilot
program installing Light Emitting Diode (LED) street light technology in several areas of the City that
demonstrated reduced energy consumption and financial benefits. After evaluating the pilot program,
working with Eversource and conducting extensive research, the City has selected Affinity LED Lighting
to assist in converting all of its high pressure sodium (HPS) street lights to LED lights. With this citywide
implementation, the City will experience further reductions in energy consumption, costs and light
pollution, along with improved visibility and safety on the roads.
“The wide spread industry adoption of LED lights presents an important opportunity to improve
energy efficiency while providing tangible upgrades to the City’s infrastructure,” said Jacob Levenson,
Solid Waste and Sustainability Coordinator for the City. “We’re excited to officially have this project
underway and further elevate our status as an eco-municipality.”
The City has been coordinating with Eversource throughout this process to identify and repair
non-working streetlights. The NHPUC Tariff states that Eversource must perform all maintenance of
lighting fixtures. Bulb or ballast replacements are included in the monthly rate the City pays Eversource;
however, the entire fixture head replacement is a separate additional charge to the City. In preparation of
the full LED streetlight conversion, Public Works has replaced 27 broken cobra head streetlights with
new Affinity LED cobra heads and installed LED retrofits in 42 unique streetlight fixtures along the
Newington Street entrance to Pease International Tradeport. Rebates totaling $7,425 were secured to
repair and/or replace these existing streetlight fixtures with LED lights.
Public Works has also successfully secured Eversource rebates totaling $100,000 for the
conversion of existing streetlight fixtures to LED lights. With the rebates secured, Public Works
anticipates a two and a half year net payback once all 1,610 streetlights have been converted to LED. By
converting streetlights to LED equipment, the City will save $120,000 in annual cost, 494,000 kWh of
annual electricity consumption, and prevent over 300 metric tons of CO2 emissions per year.
While reduced energy consumption and CO2 emissions bring significant benefits, Public Works
has also paid close attention to ensure the new lights comply with emerging American Medical
Association (AMA) guidelines regarding best practices for LED street lighting and how to minimize
potentially harmful effects. According to the AMA, LEDs that are rated above 4,000 Kelvin (K), using
the temperature measurement by which light color is measured, should be avoided. The problem isn’t
brightness so much as wavelength, light that appears white to the naked eye contain larger amounts of
blue light. Our eyes treat “white” blue-heavy light, such as the glow of a smartphone, like the midday sun.
The science is still evolving, and recent studies have postulated a link between blue light and our bodies’
responsiveness that set our daily circadian rhythm.
LED lights are typically hailed as a positive for the environment because they consume much less
electricity and last much longer than high pressure sodium lights. While the AMA welcomes the reduced
emissions and energy efficiency benefits of LED lights, they encourage proper attention to optimal design
and engineering features to minimize potential health and environmental effects caused by too much
“white” blue light. The City’s LED lights will shine at warm 3,000K, are Dark Sky compliant and will
provide more accurate color rendering. By correctly reproducing the colors of objects in comparison to
the light source, improved color rendering makes it easier for drivers to recognize potential road hazards,
crosswalks, pedestrians, etc.
Affinity will begin installations this month. For cost efficiency, this project will be split into two
years with an anticipated completion in early 2018. During installations, residents may notice a bucket
truck and a support vehicle with a team of three workers to install the new cobra light head fixtures which
are produced by Affinity-employed U.S. veterans in Dover. Once installations begin, Public Works will
have a real-time map displaying targeted and completed light replacements at www.cityofportsmouth.com
so residents can track the progress of this project. For more information, please contact Jacob Levenson at
766-1412 or [email protected]