California shopping mall cuts lighting costs by 77% using sensors and high-efficiency LEDs — and the project will pay for itself in less than 4 years.
By Brad Dockser
Many industries and service providers have embraced energy efficiency. Hotels, for example, are encouraging guests to use fewer towels and, as they build or remodel they are switching to LED lighting. Banks are going paperless, utilities and other services are encouraging auto-payments, and grocery stores reward customers who bring their own shopping bags.
No wonder. Energy consumed by retail locations is often the second-highest expense, exceeded only by labor, according to the National Retail Federation, adding that retailers continue to face tight operating margins which, in turn, is driving a renewed emphasis on controlling costs wherever possible. In addition, carbon emissions linked to electricity needed to run those stores can make up 80% or more of chain stores’ carbon footprint. So a good, solid energy management strategy is more compelling than ever.
Five years ago, the federal government announced the Better Buildings Initiative, setting a national goal of cutting energy consumption in commercial buildings by 20% by 2020. If met, it would reduce energy bills of American businesses by $40 billion a year. Retailers themselves use about 20% of the energy consumed by all commercial businesses, and they are the fastest-growing commercial category of energy users, according to the U.S. Department of Energy. That’s why their potential for savings is so high.
A retail center, located in Southern California, for example, was constructed in 1987 and comprises five separate buildings. The site measures 346,320 square feet — of which 60% is parking. Its energy consumption was huge — way out of proportion to its size and use. The owners hired a global energy solutions provider to develop the right approach for an energy strategy and put into place solutions that would cut energy use drastically.
Lighting this big property was an expensive proposition and an opportunity to create major savings. The existing 113 lighting fixtures in the parking garage were a combination of metal halide poles, wall packs and flood fixtures. They were not controlled by any dimmers or sensors and ran continuously throughout the night, throughout the year. LED fixtures were installed to replace the existing metal halide lamps. The power required to run the fixtures decreased from 25.5 kW to 5.8 kW while ensuring optimal light levels at the parking lot surface were maintained.
Photocells were installed on the new LED fixtures to turn lights on and off in response to natural daylight levels. This maximized energy savings by limiting fixture use when sufficient ambient light exists.
Billing and consumption analyses were completed pre- and post-installation on the lighting and sensors to measure and verify the impact of the solution. Local utility rebates accounted for nearly 13% of the total project cost.
Owners and operators of the shopping mall were very pleased with the results. The new LED fixtures reduced wattage and the demand of the exterior light fixtures by 77%. The installed lighting and daylight and occupancy sensors save about 91,393 kWh annually and, overall, the solution resulted in a 79% reduction in the annual parking lot electricity consumption. Annualized energy savings are equivalent to 65 metric tons of greenhouse gases reduced or 13 cars removed from the road.
This $76,635 investment at the shopping mall will reduce energy costs by more than 77% and will pay for itself in less than 4 years.
— Bradford H. Dockser is the CEO and co-founder of Green Generation Solutions, LLC (GreenGen), a global energy solutions provider. Services include high efficiency lighting retrofits, HVAC optimization, building commissioning, building envelope assessments, procurement, CHP system development, “smart building” systems and data analytics. GreenGen has offices in Washington, D.C., London and Tokyo. Email the author at [email protected].