A loss of power can happen to any bakery for any number of reasons. Sometimes it’s a minor blip, a flicker of lights that’s an annoyance more than anything. And sometimes there’s a natural disaster that takes out electricity for an entire region. Between those two extremes is the ever-common hour or two lost because of a bad thunderstorm. Regardless of the reason or duration of an outage, it’s a good idea to have a contingency plan in place to get the bakery back up and running as quickly as possible.

“Typically, there are three main short-term concerns,” said Greg Carr, senior director of project planning, The Austin Co. “Bakers need to maintain their IT systems and lighting and empty the ovens.”

It’s important that bakers know the points of highest risk for products and safety in their process. It’s also beneficial to understand the different types of back-up power they have at their disposal and the strategies for optimal performance.

Balance of powers

When the power goes out in a bakery, there are several options to keep the facility operating in some capacity.

“The obvious choice to get a baking facility back up and running as quickly as possible is to have it fully backed by a generator system,” said Tim Gause, electrical design engineer, A M King. “In such power distribution schemes, the generator control system senses a loss of utility power and kicks in very quickly, which essentially eliminates any loss of operation if the system is automatic and not manual.”

To remain fully operational during a power failure, a properly sized generator and fuel supply will be the best choice for a baker, whether that generator system is permanent or a rental. A rental can be cost-friendly, but it requires a connection point for the generator on the outside of the building and a location to park it, said Barry Rogers, project executive, The Austin Co.

“It’s important to have a contract with a generator supplier to ensure availability at short notice, typically 24 hours,” he said. “Similar arrangements are necessary for fuel supply to the generator.”

However, with extended periods of downtime due to natural disasters there’s more to overcome than just keeping the bakery operating.

“There are challenges in trucking finished product away from the bakery and receiving all of the ingredients required, as well as challenges in staffing because employees may not be able to get to the plant or home from the plant,” Mr. Rogers explained.

A permanent stand-by generator sized to run an entire facility may seem like an obvious choice, but it may be cost-prohibitive, leading some companies to search for other alternatives. Smaller generators and uninterrupted power sources (UPS) will keep the most essential parts of the bakery operating to prevent product loss or safety issues.

The first step is identifying highest risk areas and equipping only those places with back-up systems rather than the entire facility.

“For instance, we have equipped our high-volume cracker ovens with UPS systems,” said Craig Zavilla, technical services manager, Pepperidge Farm, Norwalk, Conn. “If the power goes out, there could be 250 feet of product in that oven that will burn. That presents both a loss and a fire hazard.”

By putting a UPS system on the oven band, the plant can remove the product from the oven in a power outage, possibly preventing a fire.

The bakery also might need back-up power on computer-driven systems or freezers and refrigerators to protect ingredients and frozen finished product. Bakers might also consider alternative sources of energy such as solar and wind power to supplement a generator.

In some communities, it’s also possible for a facility to be connected to two independent electrical services fed from different substations, said Mr. Rogers.

“This will ensure continued power if the electrical failure is limited to a single substation, which is typical other than for a regional issue, such as a hurricane, that would cause area-wide outages,” he said.

This actually works in the case of Mr. Zavilla’s Pepperidge Farm facility in Richmond, Utah.

“We are connected to two separate grids on a power system,” he said. “If one grid goes down, there will be a momentary loss of power, but the other one will pick it up.”

Optimizing energy use

If a back-up power source isn’t going to power the entire facility, it’s important to have a strategy to optimize it.

“It becomes about utilizing what you have in the most effective way,” Mr. Gause said. “That means implementing a design that automatically and temporarily drops off the freezer during a loss of power. This would allow the generator to back current production line activity. Once complete, production lines could come off the generator, and the freezer could go back on.”

This strategy keeps production moving without jeopardizing frozen products.

It’s also vital to know the limits of the product that’s running. Fermented doughs compared to chemically leavened products are going to react differently.

“After about 45 minutes, chemically leavened dough products will begin to deteriorate to the point they may no longer be able to make saleable product,” said Scott Hughes, engineer, InLine Engineers. “Fermented dough products are a bit more forgiving and can tolerate a bit more time prior to being run off as scrap.”

Despite its forgiving nature, fermented dough can cause issues when stuck in an oven. Even if the oven isn’t running, the temperatures inside the baking chamber are still high enough to combust any product inside. This may result in a major fire hazard, so it’s important the oven has some kind of back-up power to empty in case of an outage. If the product inside the ovens is a fermented dough, like crackers, Mr. Hughes explained that alcohol fumes could be present in the baking chamber.

“If the oven is not evacuated of product residue, the restart of combustion air fans or even exhaust fans could possibly lead to an explosion,” he said.

For freezers and refrigerators holding finished products or ingredients, the solution is simple: Keep the doors closed. Despite not having power, the chambers will retain their temperatures for a while if that cold air is trapped inside.