The U.S. Department of Energy has published the evaluation report from a GATEWAY demonstration at the parking structure of the U.S. Department of Labor (DOL) headquarters in Washington, DC. LED luminaires were substituted for the incumbent high-pressure sodium (HPS) luminaires and evaluated for relative light quantity and performance.

The demonstration results show energy savings of 52% from the initial conversion of HPS to the LED product. These savings were increased to 88% by using occupancy-sensor controls that were ultimately set to reduce power to 10% of high-state operation after a time delay of 2.5 minutes. This adjustment was made after it was determined that the factory-default 10-minute delay setting was much longer than necessary.
 
Because of the relatively high cost of the LED luminaires at their time of purchase for this project (2010), the simple payback periods were 6.5 years and 4.9 years for retrofit and new-construction scenarios, respectively. Staff at DOL Headquarters reported high satisfaction with the operation of the LED product.
 
Download the report, or learn more about the DOE GATEWAY demonstration program.