Which commercial building sector uses more energy per square foot than all but one other and is more than twice as energy-intensive as office buildings and schools? Grocery stores, second only to food service.
With utility costs rising—and already a significant percentage of the famously thin profit margin on food sales—stores must get serious about energy efficiency, particularly if they care to keep prices low for value-conscious customers.
Now, imagine slashing the energy use of a new or existing store in half, while achieving a better customer environment. How could this be done? Rocky Mountain Institute’s whole-system approach, reaping multiple benefits from single design moves, works particularly well when a retailer is willing to push the boundaries.
In 2010, building on years of experience with several other grocery chains and related industries, RMI worked closely with Texas grocery retailer H-E-B to inform a dramatically efficient design being used for a store that is to begin construction this year in a brownfield redevelopment area at Austin’s former airport site. The plan is expected to reap 50 percent energy savings. RMI studied H-E-B’s efficiency opportunity areas in energy, water and waste, and then held a workshop to innovate breakthrough strategies for designing efficient new stores and retrofitting existing ones.
Illustration by Lisa Haney
RMI often uses innovation workshops, engaging many disciplines within a client’s organization (including design, engineering, and operations staff) as well as an RMI team of experts in various disciplines, to turn complex challenges into integrative design solutions. The goal is not just to solve the problem, but to transform how the client designs and runs all its facilities, and to help shift the underlying strategy and culture, so the change is durable and creates competitive pressure for emulation.
Bill Reynolds, architect and group vice president-facility alliance for H-E-B, said that not only is the new Austin store on track to meet its 50 percent energy savings goal, but the RMI charrette was a catalyst for H-E-B to incorporate progressively better efficiency strategies in other new and existing stores.
“The tipping point was the [RMI] charrette,” Reynolds said, using the architectural term for an intensive, roundtable, transdisciplinary design workshop with ambitious deliverables.
To understand the energy savings H-E-B will achieve, let’s look at where grocery store operations use energy. Of all utility costs (including truck fuel, landfill fees, water, gas, and electricity), store electricity is by far the biggest expense. Breaking this down into end uses of electricity, the biggest chunk goes to refrigeration, then refrigerated-case anti-sweat devices and other equipment, heating ventilation and air conditioning, and then lighting.
How is H-E-B’s new store design, located at Austin’s Robert Mueller Airport Redevelopment site, going to use 50 percent less energy than this capable firm’s standard design of new stores, as well as efficient water and waste use? These integrative design moves are key:
- An airlock store design with vestibules (so trucks can deliver goods without making a big hole in the back of the building) and enhanced insulation.
- A lighting scheme that allows daylight to provide all of the ambient light when possible, eliminates glare, highlights product, enhances merchandising, and dims night lighting to comfortable levels inside while providing adequate lighting outside with LEDs (this can be enhanced by light-colored pavement that also reflects heat during the day).
- A highly efficient refrigeration and air conditioning system, with chillers and cooling towers, combined with a radiant slab that can heat or cool.
- Landscape and drainage strategies that eliminate irrigation and provide unique Texas character to the site.
- Indoor water use efficiency, including high-performance domestic fixtures, and such kitchen improvements as using portable pressure washers and eliminating seafood display ice.
- Reclaiming condensate for cooling towers.
- Aggressively composting and recycling remaining waste streams. Already H-E-B recovers over 50 percent of its waste, but the company’s sights are now set much higher.
Not only do these efficiency gains save energy and resources, they can also improve the indoor environment. Natural daylight and better electric lighting design improve the shopping experience—and studies show that shoppers spend more time in well-daylit stores. Well-designed nighttime lighting can reduce glare and eyestrain, while nontoxic finishes (eliminating vinyl floors and off-gassing paints for instance) improve indoor air quality.
The store is being touted as the “most sustainable” store H-E-B has ever built.
“RMI was the catalyst that spurred the green design,” said Charlie Wernette, H-E-B’s director of engineering. Next, H-E-B will implement these whole-system efficiency strategies across its existing store portfolio.
Given the grocery sector’s energy intensity, the implications can be even greater, with these steps serving as a model for other retailers. H-E-B’s execution of RMI’s Reinventing Fire principles are a critical example of making the ideas real. Buildings use 42 percent of the nation’s energy, costing more than Medicare—and most of that is wasted through inefficiency. Reinventing Fire shows that scalable efficiency solutions can transform our buildings from energy hogs to more comfortable, livable, healthful, and workable spaces that help usher in an efficient, secure, renewable energy era.
These steps are how RMI design recommendations would reduce typical store electricity demand:
- High-efficiency refrigeration systems—saves up to 18 percent of the store’s total electricity use.
- Skylights, and high-efficiency interior and exterior lighting—saves 12 percent.
- HVAC efficiency: chilled water, efficient fans and ductwork, desiccant dehumidifier—saves 10 percent.
- Radiant heating and cooling—saves 6 percent.
- Superinsulated walls, tight construction—saves 3 percent.
- Greatly reduced infiltration at entrances (vestibules)—saves 3 percent.
Potential water savings and waste recovery, though smaller in total expenditures, are even more dramatic on a percentage basis. Water efficiency could reduce consumption by 80 percent:
- Xeriscaping—saves 28 percent.
- Low-flow restroom fixtures and sink aerators—save 23 percent.
- Rooftop rainwater capture and use—saves 11 percent.
- Kitchen improvements such as portable pressure washers and pre-rinse spray valves—save 5 percent.
- Reclaiming HVAC condensate—saves 3 percent.