Outdoor Lighting SSL Demonstration Project Reports Issued for Street and Walkway Lighting
Real-world demonstration projects are an important way that the U.S. Department of Energy (DOE) is helping to develop and commercialize solid-state lighting (SSL). Advertising and trade shows are examples of how manufacturers are working hard to build awareness and ultimately sales of SSL products. Most parties interested in the emergence of SSL are aware of DOE’s CALiPER program (see Round Four CALiPER article) which provides rigorous performance testing of “off the shelf” SSL products. However, knowledge of the existence and lab reports of a product are often not enough to attract potential buyers to invest in any product, let alone a new one such as SSL. Therefore, many people are left with the question: “What’s the product like in “real life?" The DOE’s website describes the demonstration program this way:
The DOE Solid-State Lighting (SSL) Technology Demonstration Gateway Program showcases high-performance LED products for general illumination in a variety of commercial and residential applications. Demonstration results provide real-life experience and data on state-of-the-art SSL product performance and cost effectiveness. These results connect DOE technology procurement efforts with large-volume purchasers and provide buyers with reliable data on product performance.
Over the past several weeks, the DOE has released reports on two demonstration projects.
Oakland, California: Neighborhood Street Lighting
Working with Pacific Northwest National Laboratories, the City of Oakland, Ruud Lighting, and Pacific Gas & Electric Company replaced the conventional high pressure sodium lighting in a residential neighborhood with Ruud’s “Beta” street light product (a typical “Cobra-head” street light).
The objectives of the project were to assess performance in the areas of energy, lighting quality, and economics as measured by the following:
- Energy:
- Lighting Quality:
- Illuminance
- Uniformity
- Correlated Color Temperature (CCT)
- Stakeholder satisfaction
- Economics:
- Simple-payback (retrofit and replacement scenarios), considering:
- Lamp life-span
- Maintenance costs
- Electrical costs
Measures of lighting performance indicated a lower overall lumen output (due to a somewhat dimmer light directly under the fixture for the LED) but improved uniformity (or lower ratios of maximum to minimum), a correlated color temperature of 1991K for high pressure sodium and 6255K for the Ruud “Beta” LED. Of 20 residents surveyed, an average of 75 percent clearly saw the LED as preferable based on overall preference, appearance, safety, and visibility. Though no test procedure or actual empirical data (given the extreme length of time the products are expected to last) is currently available to verify the manufacturer claimed lifetime of 100,000 hours for the LED versus 30,000 hours for the high pressure sodium, such a protocol is expected to be released this year by the Illuminating Engineering Society of North America.
The results showed savings of 43 watts per street light and an estimate of 178 kWh per year (per street light), or about $42 per year (per street light) based on PG&E’s rate structure. The incremental installed cost of the LED’s was $487 ($833 versus $346 for the high pressure sodium) for a payback of 14.9 years in new installations and 25.5 years in retrofits (assuming bulk purchasing and replacement). As they have exhibited thus far, SSL technology prices are expected to continue to decline in terms of cost per lumen. More information can be found on the web by clicking here.
Atlantic City, New Jersey: Commercial Walkway Lighting
Working with Ruud Lighting, the U.S. Federal Aviation Administration and Pacific Northwest National Laboratories replaced the conventional high pressure sodium path lighting at an FAA technical Center in Atlantic City, New Jersey with Ruud’s “The Edge” area light products using the standardized objectives and protocols associated with DOE’s Technology Demonstration Gateway Program.
In performing the demonstration testing it was noted that the existing high pressure sodium fixtures significantly over-lit the walkways relative to IESNA minimum illuminance guidelines for this type of space. In practice either a two bar Ruud Edge LED or a three bar product could suffice.
The existing lighting was generating an average of 3.54 foot candles versus the IESNA recommendation of at least 0.5 foot candles. Ruud’s three bar LED most closely matched the current level at an average of 3.63 foot candles. Therefore this product was used, but it should be noted that the two bar version could be expected to perform well above the IESNA recommended minimum. Correlated color temperature of the high pressure sodium lighting is rated at 1900 K while the Ruud Edge is rated at 5000K.
The high pressure sodium lighting drew 97 watts per fixture and used 425 kWh at 4,380 hours per year utilization per fixture while the three bar Ruud Edge drew 71 watts per fixture and used 311 kWh per year per fixture for a savings of 27 percent or $11.75 per year per fixture (assumed electricity rate of 10.3¢ per kWh). The cost of the high pressure sodium lamp and ballast was $150 versus $725 for the three bar Ruud Edge. Additionally, the high pressure sodium product was assumed to require a new lamp every 5.5 years and new ballast every 10 years for an annual maintenance cost of $39.24 while the Ruud Edge was assumed to have a lifetime of over 100,000 hours and zero maintenance cost. These cost and maintenance assumptions lead to a simple payback of 18 years for retrofit, or 7 years if the 30 year old high pressure sodium product is assumed to need replacement anyway. The alternate scenario of moving to the two bar Ruud Edge offers an even better economic picture with a cost of $575 and a draw of 48 watts; in this case the simple paybacks for retrofit and replacement respectively are 13 years and 3 years.
The average opinion of 58 staff which were surveyed is greater than 4 on a five point scale where 5 equates with “great improvement” in all questions posed regarding satisfaction. The only caveat being the issue of glare for which the average response was 3.85. Similarly, for nighttime security questions posed to ten security guards, the average response was over 4 on a 5 point scale. More information can be found on the web by clicking here.
