Going Green: GIS is used to help Analyze the Efficiency of City Streetlights

​Recent improvements in the manufacturing practices of energy
efficient lighting solutions have made “going green” a more viable
option for local government. The City of Des Plaines has begun the
process of investigating these alternate lighting solutions for their
city-owned streetlights to become more environmentally friendly and to
provide a cost savings for the city.

The first step in the process of determining the viability of energy
efficient lighting is to compare the operating costs to that of the
city’s current lighting solutions. While the location of all the
city-owned streetlights was plotted in Geographic Information System
(GIS) before this project began, no additional data about each light was
available. It was determined that this missing information would need
to be populated before the Engineering and Public Works departments
could perform a cost savings analysis. To assist with this process, the
GIS Department divided the city into a grid and created a map for each
grid section showing the locations of city-owned streetlights. These
maps allowed the Public Works Department to systematically review the
city assets and document the necessary attribute information for each
light. The completed maps were then returned to the GIS department
where the attribute information gathered by the field crews was added to
the existing streetlight feature class.

For this project, the most important attribute gathered in the field
was the type of bulb being used in each light. Adding this information
to the data allowed the Engineering Department to gather not only a
general count of each light type, but also to see how they were
spatially distributed across the city. The ability to see this
distribution provided the Engineering Department with a resource to
locate areas where energy use was inefficient and where lights needed to
be updated.

Combining the information gathered in the field for city-owned lights
with existing information for ComEd lights within the city, the
Engineering Department was able to get a rough estimate on the number of
each light and its type. By comparing the current operating costs of
the existing lights against the costs of replacing each one with an
energy efficient alternative, the estimated cost savings for the city is
over $200,000 per year. This provided the department with a strong
argument to propose an update to more “green” lighting option.

Using GIS to assist in gathering information for this project allowed
the city to effectively calculate a significant potential cost savings
from implementing energy efficient streetlight solutions. In addition,
the city now has a comprehensive, spatial streetlight data layer that
can be used for future mapping needs and allows for a more efficient
review of the city’s current lighting assets.