That’s good news for companies building new bakeries, but most manufacturers operate plants that are 10-plus years old. For them, declining prices for systems that can be retrofitted are an option for lowering energy costs.
“Heat recovery in the past has not been economical, but technologies that have been used in Europe for some time are changing that,” says Carr. “Oven-stack heat recovery is becoming more common, and off-the-shelf equipment is readily available.”
Thermal-oil ovens come with more up-front costs, but the payback over time can be significant. Superior heat transfer and precise heat control through a liquid medium compared to air makes thermal-oil ovens from Heuft OEL 20-30 percent more energy efficient than a conventional oven, according to the company.
Similar savings are achieved by coating the inside of ovens with a thin film that reflects heat back toward the product. Nanoscale particles in solution provide the insulating effect. AMF Bakery Systems is applying a NASA-developed film to ovens and marketing it as Emisshield nano-emissive technology.
But most equipment suppliers are energy-efficiency laggards, bakers say. In an IBIE presentation by three large bakers participating in DOE’s Energy Star program, the consensus was that most vendors have failed to improve on designs that are decades old.
Anthony Turano, director-administration at Turano Baking Co. in Berwyn, Ill., suggests some are actually moving in the opposite direction, engineering ovens that consume more energy. “They give you more burners,” he said, “but how does that help me?”
Turano and Northeast Foods were among five baking companies at IBIE that received Energy Star awards after documenting 10 percent energy reductions. At both companies, the reductions were realized at older facilities, where replacing inherently inefficient machinery, lighting and other equipment provide easy targets for improvement. Northeast achieved the goal at a legacy plant in Baltimore, but a five-year-old facility in Clayton, N.C., isn’t an Energy Star contender, despite lower energy use per unit of production. Efficiency was part of the design, making an additional 10 percent reduction difficult to attain.
Clayton can operate off the grid with three 1,000 KVA diesel generators that received a 50 percent subsidiary from the local utility. The back-up power, along with beefed up insulation that helps the refrigeration system to function while drawing 28 percent less electricity than a conventional freezer, is viewed favorably by McDonald’s, the plant’s primary customer.
“The modern customer wants their suppliers to be sustainable and do the right thing,” Dennis Colliton, Northeast’s vice president-engineering, maintains. He cited two benefits of sustainable practices: “It saves you money and makes your customer base happier.”
Back-up generators are becoming a common feature of large bakeries, Carr notes. Bypass connections for incoming water is another new wrinkle: A break in a water main miles away can create contamination issues and shut down a plant. By installing a bypass, water tankers can be trucked in to serve as a source of potable water.
Monitoring water use as well as energy consumption tipped Northeast Foods to a problem at one of its 12 bakeries. After an investigation, a broken underground pipe was pinpointed as the source of the problem, resulting in repairs before serious structural damage occurred.
Direct store delivery puts industrial bakers into the transportation business. Colliton, Turano and Jim McKeown, Bimbo Bakeries USA’s director-environmental/energy affairs, described their organizations’ experiments with compressed natural gas, propane and other alternatives to diesel fuel. Northeast has 25 CNG tractors. Performance isn’t an issue: “Our drivers tell us they have the same power as diesel,” Colliton says.
Efficiency programs can’t yield the dramatic improvements in uptime and throughput that advanced controls can deliver. On the other hand, they typically involve continuous improvement initiatives that require little or no capital. Regardless if managers invest in artificial intelligence or energy-reduction drives, the likely outcome is a more profitable plant.