It’s been nearly a century since Carl Sandburg dubbed Chicago “Hog Butcher for the World” in a poem. Since then, the city has swapped its meatpacking industry for a green-building one.

Much of this construction involves the transformation of industrial structures into energy-efficient facilities. A prime example: the Plant, in development on the city’s South Side. There, local entrepreneur John Edel is turning a 93,500-square-foot former USDA-certified meat-processing plant into a net-zero-energy incubator for sustainable-food businesses. Edel is limiting work on the structure’s existing concrete-and-masonry envelope, built in 1925, and is taking advantage of the building’s original 4-inch-thick foam insulation. The $4.5 million project also includes the installation of energy-efficient windows, a third-floor greenhouse, and storefront glass walls on the façade.

Most of the change will occur inside, with the installation of a series of closed, concentric energy loops. With future spaces to include a brewery, bakery, commercial kitchen, and vertical farm, Edel expects the facility to require a nominal electrical load of 300 kilowatt-hours and to be fully operational within five years. The system incorporates an anaerobic digester that will use tenants’ and neighboring businesses’ food waste to keep the operation technically off-grid, although Edel says it will remain grid-tied. To power the facility, Edel says that the digester will convert waste into biogas, which will then be fed into a repurposed fighter-jet-engine turbine to convert the biogas into electricity and approximately 2.1 million Btu per hour of steam. Freestanding aquaponic systems will harvest tilapia. The systems’ oxygen will be recycled to feed kombucha cultures, and the fish will be fed by spent barley from the brewery and nitrates created by bacteria as it processes ammonia in the system. Plants growing in hydroponic beds will also absorb the nitrates.

“[The] circle of the waste becomes the energy, which becomes the food, which becomes the waste, which becomes the energy,” says Michael Newman, an architect with local firm Shed Studio, which is collaborating on the project.

That fluidity carries over to the space’s layout, Newman says. Still in construction, the interior will feature clean lines, areas for collaboration, and pieces of the former facility—including stainless steel electrical panels, floor drains, and red-brick floors—reused to reflect what Newman calls a “holistic sense of sharing.”

The project team expects to have applied for a building permit by the time you read this. However, the goal of occupancy by Spring 2012, and the launch of the digester by Summer 2012, will depend on how quickly other permits can be secured. “Anytime you do anything that’s unusual, it can take a while to get everything lined up and everybody happy with how it works,” Newman says.

Regardless, perhaps another line should be added to Sandburg’s poem?