Walgreens Plans a Net-Zero Store
The company says it would be the first net-zero retail store in the country
If you were thinking the nation’s first net-zero energyProducing as much energy on an annual basis as one consumes on site, usually with renewable energy sources such as photovoltaics or small-scale wind turbines. retail store might turn out to be something trendy, like an Apple store or a Starbucks, brace yourself. Those honors will apparently go to Walgreens, the national drugstore chain.
The company has announced that as far as it can tell its retail store in Evanston, Illinois, will be the first retail outlet in the U.S. to generate as much energy as it uses over the course of a year, thus meeting the “net-zero energy” test. Evanston is on the western shore of Lake Michigan just north of Chicago and not far from Walgreens headquarters in Deerfield.
"We've done some exhaustive research as you can imagine to find another retailer that has done this and we haven't been able to find one," says Jamie Meyers, Walgreens' manager of sustainability. "That's not to say there isn't one out there but we're fairly confident that if anyone had done this they would have spoken up about it because it's a pretty difficult task particularly for a retailer."
An existing Walgreens store is being torn down to make room for the net-zero building at the corner of Chicago Avenue and Keeney Street. Its proximity to company headquarters will make it convenient for Walgreens engineers to stop by and measure building performance over the year.
Meyers says the 13,968-sq. ft. drug store should be open for business by November. Walgreens won't disclose how much the building will cost, but admits it will cost more than a typical outlet.
Rooftop PV, wind turbines and LED lighting
Walgreens estimates the building will actually be on the plus side of the energy ledger, generating 256,000 kWh of electricity a year while using 200,000 kWh.
Like any net-zero building, the new drugstore will get to net-zero performance with a combination of lower than average energy consumption and renewable energy systems.
Here are the details:
- Roughly 850 rooftop photovoltaic(PV) Generation of electricity directly from sunlight. A photovoltaic cell has no moving parts; electrons are energized by sunlight and result in current flow. panels, with a total generating capacity of 225 kW.
- Two vertical-axis wind turbines, with a capacity of 6 kW.
- A ground-source heat pumpHome heating and cooling system that relies on the mass of the earth as the heat source and heat sink. Temperatures underground are relatively constant. Using a ground-source heat pump, heat from fluid circulated through an underground loop is transferred to and/or from the home through a heat exchanger. The energy performance of ground-source heat pumps is usually better than that of air-source heat pumps; ground-source heat pumps also perform better over a wider range of above-ground temperatures. using eight 550-foot deep wells below the store as its earth link.
- LED lighting.
- Carbon dioxide refrigeration equipment.
Not a typical net-zero strategy
Because of the cost of renewable energy systems and the space required to deploy them, residential net-zero projects tend to be super-insulated buildings with very low heating, cooling and electrical loads. Wall R-values of 40 and roofs insulated to R-60 aren't uncommon.
"I can tell you we're nowhere near that," says Meyers. "We found through the energy model that once you get to a certain point it's a case of diminishing returns."
Designers did cut energy consumption in a variety of ways, but the nature of a retail store is completely different than a house where only a few people live. The whole point is to get people in and out of the building to shop, not button the building up tightly to reduce heating and cooling demands. Doors are opened and closed many times a day.
Meyers says the building has typical block and brick walls and an insulated metal deck roof. Although air sealing and insulation levels are relatively modest, the project makes up for it with its oversized renewable energy package. The rated 225 kW capacity of the PV panels is 20 times as much as a typical net-zero energy house.
Suppliers for the project include Trane, Cree lighting, Acuity Lighting, CalStar Products, Cooper Lighting, Geothermal International, and SoCore Energy. Energy modeling was done by Cyclone Energy Group of Chicago and the Energy Center of Wisconsin.
In addition to shooting for net-zero performance, Walgreens wants the building to win LEED’s top tier platinum rating and will enter it in the International Living Future Institute’s Living Building Challenge. The company also is partnered with the U.S. Department of Energy's Better Buildings Challenge and committed to cut energy consumption by 20% by 2020.
The net-zero project is far from Walgreens’ first foray into energy efficient design. The company says 150 of its stores have solar power, two have been LEED-gold certified, and 400 have charging stations for electric vehicles.
"We want, as a company, to help people get, stay and live well," Meyers says, "and part of living well is minimizing our impact on the environment, and so we have an opportunity with having 8,000 locations to have an impact. It's important to us."
If you have a Facebook account, you can read more about the project here.
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