Converting Streetlights To LED

Converting Streetlights To LLED

Lessons learned from a plan to switch out 40,000 fixtures in Montana

By Steven Schmitt

Converting Streetlights To LLEDAs an attendee at the 2019 IES Street and Area Lighting Conference I had a unique opportunity to see some of the latest cutting-edge applications of LED street lighting. We’ve seen motion sensing technology coupled with programmed logic to effectively reduce the amount of energy used for street lighting even above the 50% reduction gained by moving from HID to LED. We already have a number of examples of effective smart-city technology such as the City of San Diego Police Department using video feed to aid in the investigation of criminal cases. This capability, coupled with transparent regulation of the technology, can act as a force multiplier for a police department while simultaneously protecting our rights to privacy.

The list of advanced applications goes on and on, but what may interest many of us has more to do with getting the fundamentals right. How do we convert to LED technology in a way that meets the needs of our community, reduces energy consumption, reduces sky glow, preserves historical ambiance and still provides safety and security?

In 2018 my utility, NorthWestern Energy in Montana, embarked on a four-year project to convert over 40,000 street and area lights from HID to LED. We started with a simple approach: find LED lights equivalent in form factor and light output to our existing lights and replace just the fixturehead. We soon found out, there was more to it than that. Here are a few lessons we have learned just over a year into the project.

1. Work With Your Stakeholders
The conversion from HID to LED sounds like a slam dunk. After all, LEDs use over 50% less energy, have a more defined lighting pattern, have a better CRI and require less maintenance. Be ready to tell this story, but while your stakeholders may like these benefits, they will have some additional requirements you may not anticipate. Be willing and able to take their comments and suggestions into account as you begin the engineering phase of your deployment. Seek their input very early in the process so you have time to adopt their comments and suggestions into your standards. If you are able to take their input into account, you’ll be able to make an LED deployment a positive news story rather than a negative one.

We soon found out that a simple one-for-one conversion from HPS to LED did not work as easily as we planned. People who had ignored HPS light trespass issues and excessive lighting took issue when the lights were changed to LED. Some noticed the refreshed lighting and found it intrusive. As a result we are learning to proactively identify where light will trespass onto private property. You should plan this effort into your conversion ahead of time to avoid customer complaints.

2. Streamline the Inventory
In Montana, our 40,000-plus light conversion project involves over 100 small cities. Many of these cities have unique lighting ordinances. In order to simplify our product offerings we look for fixtures that meet the strictest ordinances and deploy them everywhere. This helps reduce the number of products we carry in inventory and will help with maintenance issues in the future. In some cases, we find extremely unique historical fixtures that do not have readily available replacements. In those cases, we have the fixtures custom engineered for LED inserts and have found a reputable company that can provide those solutions inexpensively.

3. Review Local Ordinances
Keep an eye out for poorly written ordinances that will inhibit your plans for a retrofit. In some cases, we found ordinances that unintentionally did not allow for a retrofit of post-top style lighting. These lights, installed over 30 years ago, intentionally light up private property along with the street immediately adjacent. Originally installed more as “courtesy” lighting, as opposed to street lighting, any retrofit without changing the placement and style of the fixtures violates the city’s ordinance. Changing a city ordinance involves the input of a variety of stakeholders. We plan on a 12- to 24-month process to work with the city on a solution.

4. Prepare for Technology to Change
What is the current state of technology? The answer to that question depends on when you read this article. Prepare your standards engineers to get used to 18- to 24-month product lifecycles for street and area lighting. Historically, our standards in the electric distribution world last for a decade or longer. This is not the case when it comes to LED lighting. We find that standards we created less than two years ago have become stale as new product offerings come out. Advancements in efficacy continue to make even lower CCT LEDs attractive. Our first standard offerings centered around what we thought were cutting-edge low 3000K LEDs, but found that customers want even lower CCTs, and now we are moving to 2700K lights. At last year’s Street and Area Lighting Conference we saw studies looking at what CCT performs best for hazard detection. We are waiting to see what conclusions result. For now, I can say that from a utility perspective I like to retrofit lights so that the customer does not notice a negative change. Lights closer in CCT to HPS have some potential benefits in the form of sky-glow reduction and customer perception.

5. Think ROI
Concerning smart-city applications, the rate of deployment of such technologies needs to make economic sense. Attending the IES SALC will give you a snapshot of where some utilities have deployed certain applications. From what I’ve seen, programmable timed dimming works, but motion sensing applications are still in their infancy. Other bolt-on applications are working, such as camera and small-cell deployment, but be aware that the more you add to your “street furniture,” the more these poles tend to look like hat racks. At some point, integrated pole designs that hide the attachments make sense.

One year ago NorthWestern Energy began a three-year statewide effort to convert 40,000 streetlights to LEDs. Rather than a simple one-for one conversion we found a much more dynamic challenge. Customers ask for additional energy savings beyond a simple conversion from HID to LED. In many locations, they demand lower street lighting temperatures, improvements to fixtures that may cause light trespass and elimination of fixtures that contribute to sky glow. With short product lifecycles, our standards engineers have to continually reevaluate our specifications to stay current. Smart-city applications continue to evolve, but the integration of such applications involves their own maintenance considerations and may have a high cost to deploy. Work with your stakeholders to make the conversion to LEDs a positive customer experience. Deploy advanced technologies at the speed of value and make the conversion to LEDs a positive story.