Hybrid street lighting, an off-the-grid system using solar panels, wind turbines and an LED luminaire, is yet another sustainability-driven solution for overstretched municipal budgets.
Downers Grove, Ill., a suburb west of Chicago, became the first U.S. community to turn on hybrid lighting in a residential subdivision in March 2010. Today, not only is the 25-light system saving about $100,000 in electric and maintenance costs over its life cycle, but it’s also contributing to reduced carbon emissions and enhanced neighborhood safety.
“This is a great example of staff responding to the needs of our residents with a highly innovative and cost-effective solution,” said Downers Grove Mayor Ron Sandack, shortly after the hybrid system in the Prentiss Creek subdivision became operational after nearly two years of planning and construction.
The $282,500 project, sole-sourced to the StressCrete/King Luminaire Group location at Jefferson, Ohio, was partially funded through a 2009 Community Development Block Grant (CDBG) from the Dupage County Neighborhood Investment Program. It covered 45 percent of the total cost, which was slightly higher than that for conventional lighting.
The new hybrid streetlights are designed to last for 100,000 hours, as opposed to those used in traditional systems that need replacing after just 10,000 hours. Over a period of 30 years, the hybrid streetlights will save more than 500,000 kilowatts of electricity and reduce CO2 emissions by almost 350 tons.
Kevin Bobikiewicz, public services coordinator for Downers Grove, generated a lot of interest in the city’s hybrid lighting project at the American Public Works Association’s recent sustainability conference in Pittsburgh.
Downers Grove received the Technical Innovation Award for the Hybrid Street Light Project from the APWA’s Chicago Metro Chapter and Suburban Branch. This award category recognizes new and innovative applications of technology.
According to Bobikiewicz, sustainability has become a way of life in Downers Grove.
“We have a village innovation committee that works on sustainability ideas, as well as operating efficiencies and improvements. Downers Grove has completed several dozen sustainability projects including energy efficient lighting upgrades on several buildings, and heating efficiency projects with solar panels. We have a sustainable initiatives program for our fleet, using natural gas and E85 fuels for vehicles, as well as collecting used cooking oil for bio diesel fuels. We also have a furnace that burns used motor oil dropped off by residents to help heat our fleet maintenance garage,” he said regarding the community’s commitment to sustainability.
In August of 2008, the Prentiss Creek Homeowner’s Association (HOA) asked the committee to bring streetlights to its area. After meeting with residents and hearing their hopes and concerns, the committee decided to look into a system powered by alternative energy.
Hybrid lighting has many advantages if it can work for your community. Finding grants make it even more attractive. And everyone has to have input.
Bobikiewicz said there were a lot of options available and the choices were a bit overwhelming. “We had to see if alternative energy could work here. While we found there was not enough sun day-to-day, there was plenty of wind in Chicago, which led us to a hybrid solution.”
He added that there were a lot of equipment choices, for example, poles, and the sizes and kinds of solar panels and turbines. “We settled on a Gemini Grid-Free spun concrete streetlight (now Enlighten Solar & Wind (http://enlightenhybrid.com/) based on aesthetics and functionality and equipped with a sealed bearing wind turbine and a 175-watt solar panel on an articulated arm.”
“At first people were apprehensive because of the look of some of the options, but the response to the final product has been overwhelmingly positive,” said Jack Reidy, president of the Prentiss Creek HOA.
Installation was quick and easy, said Bobikiewicz. “Each 25-foot pole weighing 4,200 pounds had to be placed five feet in the ground in a 24-inch hole. The ones we used have no control boxes hanging on them and all of the components are at the top of the pole. The batteries are installed in an easily accessible, locked bottom compartment. The pole coating is graffiti-proof. And their height takes maximum advantage of the sun and wind.”
Since Prentiss Creek contains numerous, 30-year-old mature trees, residents did not want them disturbed. Conventional street lighting is spaced every 150 feet to assure enough coverage. “Since the hybrid poles are direct bury and self-contained, we had the flexibility of spacing them as close as 120 feet or as far apart as 160 feet. No trees had to be taken down.
“Overall impact to the neighborhood during installation,” Bobikiewicz continued, “was minimal, as no trenching was necessary to install in-ground wiring. We did not need to interfere with hydrants, signs, underground lines and were able to place lights at all intersections.”
LED lights are one of the things that make off-the-grid lighting more possible and efficient, said Bobikiewicz. “They have a very low voltage draw. We run a 56-watt fixture on 24 volts that has a warranty and longevity of up to 100,000 hours. Plus we can direct our luminaires to shine on the street rather than on front yards, which the residents prefer. You need to pick a quality LED fixture.”
Battery capacity and storage is very important. For example, explained Bobikiewicz, no matter how much capacity, you have to be able to charge batteries with the solar and wind capacity available. “Again, LED is an advantage because it draws on batteries a lot less. And we can add larger batteries if we have to.” It cost Downers Grove $300 per pole for deep cycle solar-powered batteries, which have a 10-year life.
Since the system was installed, technology has advanced so that the 25 lights in Prentiss Creek are now “smart” poles. “We have switched to a web-based controller, which makes them easy to program. We can log on from anywhere around the globe to monitor each pole and make adjustments, for example, if we want to turn lights on earlier, or redirect them. Controllers, too, are one of our only replaceables.”
How has Downers Grove hybrid lighting performed?
Bobikiewicz said as advertised. “The system is very durable and reliable and has gone through two winters. The solar side has performed best. We face the panels southwest for the best winter sun and tilt them so ice and snow slide off. On rare occasions, one or two poles may not get enough of a charge to stay lit all day. And, being in Chicago, wind turbines are a good thing. When we get blizzards and 40-mile-an-hour winds, they really spin.”
Hybrid lighting has a lot of applications, said Bobikiewicz. They include parks, parking lots, highways, unlit remote areas where it may be too costly to use conventional street lighting. “It is especially good for new developments. Municipalities can require developers to include it.
“Solar lighting is not new. But hybrid technology now offers cities like Chicago the option to use more alternative energy. This combination scored very well for us in getting our grant.”
“That’s why we decided on hybrid lighting based on our region and to use the combination of solar and wind power to get the best results for year-round dusk-to-dawn operation for the new lights,” he added.