Elk Grove Retrofits HPS with American Electric Lighting® LED System for 60 to 70 Percent Energy Savings. Elk Grove, California officials hoped residents wouldn’t notice the difference after the city upgraded the high pressure sodium lighting fixtures on city streets to an LED system. The city purchased >9,800 LED luminaires from Acuity Brands’ American Electric Lighting® (AEL), to replace HPS fixtures and achieve energy savings of 60 to 70 percent. Werner expects the system to operate 20 years without maintenance compared to five to seven years for the HPS units. Combined energy and maintenance savings are estimated at $400,000 annually. The city invested $3 million to purchase the LED system and $500,000 to install it, which translates into a payback of approximately nine years.