Savings in Energy Systems
A decade ago, retail cost cutting technologies revolved largely around supply chain management. But as the recession continues to squeeze businesses, products that help cut costs in non-merchandise areas are becoming more meaningful. For c-stores, these include technologies that monitor or reduce the channel’s massive utility load.
On a per-square-foot basis, c-stores use more energy resources than any other retail channel (not counting restaurants). Hence, every area from car washes to restrooms and beer caves is being scrutinized for efficiency.
Energy saving solutions applied range from cost effective LED lights and heat-free cooler doors to headquarters-monitored energy management systems that control multiple equipment units. In addition to saving energy, many technologies recoup their cost within two years. Improvements can focus on a single department or on an entire store or chain.
The impetus to monitor and conserve resources is not being driven by tree huggers, said Mike Lawhe, president of Fort Worth, Texas-based Paragon Solutions, a c-store design consultancy who worked with Green Valley Grocery to create a “green” store. Energy management follows a direct path to a retailer’s bottom line.
“People are not doing these things simply because they are a good idea,” he said. “It’s about getting a good ROI and becoming more competitive. Money saved is just sitting there.”
C-stores’ interest in energy management began in earnest about five years ago, spurred by more affordable technologies and increased awareness of the category. Historically, retailers’ interpretation of energy monitoring was limited to expensive solar panels and wind turbines.
Erik Peterson, director of store engineering for Kwik Trip Inc., said energy management has allowed the company to pinpoint and reduce high consumption areas. Based in LaCrosse, Wis., Kwik Trip has received either gold or silver LEED certification for six stores and installed energy efficient solutions in other locations.
“Building controllers with energy management have taught us how we use buildings and equipment and have given us tools to make informed decisions and identify company-wide savings opportunities. We learned how we operate our stores and how we use power. The biggest surprise was how much savings we could generate by making operational changes.”
Costs, scopes of projects and return-on-investment (ROI) can vary tremendously from chain to chain and region to region, as can a retailer’s timeframe for change. The following is a look at some of the energy saving and “green” projects enacted by Green Valley, Kwik Trip and Susser Holdings Corp.’s Stripes chain.
Susser Holdings Corp.
Corpus Christi, Texas-based Stripes has spent four years testing and implementing different technologies in its 540-plus locations across Texas, Oklahoma and eastern New Mexico. A transition from private to public ownership, coupled with a stepped up new store schedule, has prompted the $2.4 billion chain to be more accountable for its spending.
“We started looking at the entire envelope,” said Michael Choate, director of construction at the chain. “While the whole site is important, smaller components can have a huge impact on reduction.” Today, energy savings on a new store averages 248,000 kwh.
-- In all new and renovated stores (over 40 locations in all to date) energy control systems operate and control HVAC, lighting and refrigeration from headquarters. Technologies are supplied by Site Controls, Current Energy and TCS Basys Systems Inc., and sensors in cooler and freezer doors set off alarms if the case temperature falls below a set point. Overall, refrigeration accounts for 25 percent of energy consumption.
-- Stripes has switched from an R22 Freon refrigerant to a more environmentally friendly R4 10 Freon for all stores.
-- A Tier 1 HVAC system (11.2 rating) has been replaced by a Tier 2 (11.8) unit. The dual compressor system runs each compressor 50 percent of the time, and sensors monitor and maintain discharge air temperature. Also, an alarm alerts headquarters to any irregularities, and the system has been installed in new and renovated stores, as well as locations undergoing HVAC overhauls.
-- Many Stripes stores are in hot climates so installation of a white, heat reflective Duro-Last membrane ripping roof system ensures the roof temperature never rises more than 5 degrees above the ambient temperature. This improves interior HVAC efficiency. The new material was installed in 50 new stores, and is also being used in the 10 to 15 roof replacements conducted annually.
-- At 10 stores (new ones plus locations designated for lighting upgrades) LED lighting from LSI has been installed in fuel areas’ 54- by 120-foot canopies. Locations that dispense truck diesel have larger canopies. Average annual savings per store is $1,300, said Choate. Carbon emissions have been reduced by over 15,000 (the equivalent of 22 cars), and Stripes hopes to install LED lighting in parking lots and other areas.
-- Stripes owns its locations, and its energy company rebates average $1,100 to $1,200 per store per year.
Kwik Trip Inc.
In addition to building seven stores that are LEED certified or have gold or silver status, Kwik Trip implemented “green” initiatives in its renovated locations. Kwik Trip operates 371 stores across Wisconsin, Minnesota and Iowa, and all use various energy saving products. The locations are between 2,500 and 5,200 square feet, although its travel centers are larger.
-- LEED certified buildings are 16.2 percent more energy efficient than standard stores and use 40 percent less water, said Todd Bornholdt, communications center manager at Kwik Trip. The stores feature water-conserving sinks and toilets, but most savings is generated by car washes during the “spot free” rinse cycle. The cycle uses water that has been put through a reverse osmosis process, and two gallons of tap water are needed to create one gallon of RO water. The extra gallon, which is usually wasted, is recaptured and used in subsequent wash cycles. Per year, the company saves 4.8 million gallons.
-- In 366 stores an energy management system reduces peak electrical consumption. Daytime energy use is billed according to the highest amount consumed throughout any 15-minute period during the utility's peak time of day. At Kwik Trip, 37 percent of the energy bill is based on this peak demand. With the building management systems, defrost cycles, for example, can be scheduled to ensure that no two units defrost at the same time. Other equipment can be controlled (based on the instantaneous peak demand) so that units are not operating simultaneously. Also, coolers are sub cooled at night when energy is less costly, reducing consumption during periods when rates are higher.
-- T 12 florescent lights were replaced with more efficient T 8 lighting in 125 locations. LED lights, which generate less heat, are being used in refrigerator and freezer cases. The company is saving 9,500 kwh per year, per store, on coolers (average 20 doors) and 2,700 kwh on freezers (four doors). In most stores, units have alarms that go off if a walk-in door is open more than 30 minutes.
-- ECM motors, which emit 65 percent less heat and use 60 percent less energy, are currently being installed in refrigeration units at all locations .
-- Historically, stores were heated by refrigeration waste heat recovery and a duct heater that would periodically emit one large heat blast. These 50 kw units are now comprised of three heat units that go on and off in stages according to need and power consumption peaks.
-- Fuel canopies at new stores incorporate LED lights and have 26 fueling positions. Those with truck canopies have an additional six.
-- Fifty stores use LED lighting in beer caves and the refrigeration unit is tied to a rack system that controls all refrigeration units. By using compressors of various sizes that run at different frequencies, each area’s cooling is timed according to need. In the past, systems were independent of each other and used more energy.
-- Hot water heaters automatically shut off at night when the food preparation area is not in use.
Green Valley Grocery
Green Valley Grocery decided to create a “green” store in its home town of Las Vegas. The 41-store chain wanted to achieve ROI within two years. Working with Paragon Solutions, Green Valley realized its goal. The 3,500-square-foot store opened in 2009. Since then, some of its “green” concepts have been installed in remodeled locations, said Paragon’s Lawshe.
-- A Purclean Water Reclamation System cost $22,000 and saves $12,424 annually (based on 80 percent reclaim). It reduces water usage by 1.8 million gallons. Because most water is reclaimed, Green Valley was able to bypass a $24,000 water impact fee usually levied by the city. “The savings was immediate,” said Lawshe.
-- An Anthony International ESP System cost $3,300 and saves $2,400 annually (payback in 1.3 years) and cuts energy use by 16,475 annual kwh. LED lights in cooler doors contribute to savings. Coolers, which cost only slightly more than traditional systems, also emit less heat.
-- LSI Exterior LED Lighting cost $9,000 and saves $7,506 per year (payback in 1.2 years). Energy use was reduced by 68.5 percent.
-- LSI Interior LED Lighting cost $12,000 and saves $2,365 annually. Energy consumption declined by 39.13 percent.
-- During daylight hours, stores can use natural light. When the light level drops below a certain level, a twin lamp system turns on half the lights. When it gets dark, remaining lights go on. Lighting levels vary by area. For example, lighting in the soda aisle is brighter than at the coffee counter.
-- An SSDI energy management system turns on lights, equipment timers and other devises based on peak load times. The system cost approximately $5,000 and monthly savings is about $400, allowing the system to pay for itself in a year.
-- New stores use vinyl insulated roofing. The surface reflects rather than absorbs heat.
Green Valley and other convenience store operators say they are nowhere near done with implementing energy saving strategies. In addition to conducting ongoing research of new technologies, they continue to look at business areas where money can be saved.
“Over the next six to 12 months, we have been challenged to look at the latest technologies as well as things in our stores that consume energy,” said Stripes’ Choate. “We are working towards specing components that give us a greater reduction in kilowatt hours and save thousands of dollars based on the locations we have.”