Cottage Grove Sheds Some Light on Its Recent Sustainability Initiatives
Cottage Grove, a city located near the confluence of the Mississippi and Saint Croix Rivers, was ready to make some energy efficiency improvements when a new financing opportunity from the Department of Energy was introduced.
The city was already tracking the energy use of many of their city facilities when the Energy Efficiency and Conservation Block Grant (EECBG) funding—part of the American Recovery and Reinvestment Act of 2009—became available. The city had been using the Minnesota B3 benchmarking tool, but there were a lot of gaps in the data until the city received the EECBG grant, which provided the impetus to update the data.
Based on the updated B3 information, the city identified two public buildings that were in need of some energy improvements: the Public Works garage and Fire Station 2. They also considered proposing some projects in City Hall, but as City Engineer Jennifer Levitt explained, “there were plans to build a new City Hall, so we didn’t want to make the investment on a building that might be torn down.”
The EECBG funding covered lighting retrofits and controls, and HVAC improvement in the two buildings. In the Fire Station, the biggest opportunity was to upgrade the lighting. There were 59 existing T-12 fixtures that were replaced with 34 high output T8 fixtures, and the lamps were upgraded from T12s to 25 watt T8 fluorescents. The ballasts in the building, which regulate how much current goes to the lamp, were outdated and also needed upgrading. So they switched 35 magnetic ballasts in the Fire Stations to electronic ballasts, which use less energy and do not hum or cause flickering like typical magnetic ballasts.
In the Public Works Garage, the project addressed HVAC systems and lighting. The existing 18 heating units were replaced with 8 gas fired and 1 forced air unit. In addition to replacing incandescent lights with high output fluorescent fixtures, bulbs and ballasts, they installed occupancy lighting controls in the buildings to turn off the lights when the space was unoccupied.
By installing newer, higher efficiency and higher output lighting fixtures and bulbs, fewer bulbs were necessary to light the space. This process of delamping, removing unnecessary light bulbs/fixtures in areas that are producing greater-than-needed illumination, saves energy and money in both reduced bills and maintenance and equipment costs. The project work was completed in 2010, and the City has seen a decrease in electricity usage in both buildings.
“The projects resulted not just in improved energy efficiency, but also a more comfortable working environment,” commented Jennifer Levitt, City Engineer for Cottage Grove and one of the lead staff on the projects. “The lighting was a big improvement in terms of quality,” continued Levitt, “Heating was also a drastic change and we got good feedback from staff on both.” The successful implementation of the projects was a result of cross-department efforts between community development, building division, engineering and others.
Having tackled lighting improvements in some of their buildings, the city is now looking at opportunities in retrofitting street and traffic signal lights. Cottage Grove owns and operates 90% of the street lighting in town, which totals over 2,200 lights. It is relatively rare for a city to own and operate them rather than a utility company. The city is taking advantage of its unique position to pilot LEDs in some of the street lights in town, experimenting with a few different styles and collecting feedback from residents on their look and feel. Another effort is being made in the area of traffic signal systems. The city is analyzing the timing of the traffic signals to look for ways reduce idle time, emissions, and efficiency of the signal timing. With reduced idling at traffic lights, the city hopes to reduce vehicle emissions.
Given that this was their first experience working on a federal grant, the staff involved learned quite a bit from the process. “We learned that you should ask a lot of questions and pay attention to what will be expected of you,” said John Burbank, Senior Planner involved with the project. The support and assistance from the Minnesota Division of Energy Resources staff was appreciated by everyone involved, especially in completing all the reporting and paperwork.
Now that the project is complete, Jennifer Levitt thinks it’s important to share the stories of these projects. “It would be nice to show what other cities and communities have done, and promote the payoff benefits of these types of projects.” The Cottage Grove EECBG projects, for instance, benefited the city not only by saving money and energy, but also in providing improved working conditions and generating work opportunities for contractors in electrical, heating and plumbing trades.
For more information, contact Jennifer Levitt, Engineer at the City of Cottage Grove, at firstname.lastname@example.org or 651-458-2890.
- : City of Cottage Grove, Washington County
- : Lighting retrofits; occupancy lighting controls, HVAC
- : The city of Cottage Grove completed lighting and HVAC retrofits in their Public Works Garage and Fire Station.
- : 8792 kWh/year electric; 948,000 kBtu gas,
- : $112,080.00
- : American Recovery and Reinvestment Act Energy Efficiency Conservation Block Grant program ($54,196); City funding ($39,660); Utility rebates ($18,224)