Which measures really help bakeries save energy and thus money? (Photo: © Jens Brggemann/123RF.com)
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In addition to lighting, heating, and ventilation, bakeries' ovens, refrigeration, and freezing systems consume a lot of energy. An example demonstrates which measures can sustainably reduce energy consumption.
Bakeries are among the most energy-intensive craft businesses. Energy costs account for approximately 2,9 percent of production costs. Natural gas accounts for half of this energy, while electricity accounts for approximately 29 percent. Increasing automation and a growing proportion of frozen goods are causing electricity consumption to rise steadily.
"Most of the energy used in baking is for the ovens," says Sven Ellinger, technology consultant at the Potsdam Chamber of Skilled Crafts . The ovens are heated electrically, with gas, or with oil. Oven temperatures of 200 to 300 degrees Celsius are required.
Heat recovery from the baking process can save a significant amount of energy. However, this represents a five-figure investment. Nevertheless, the Grünberg bakery in Lenzen, Brandenburg, is committed to energy-efficient and environmentally conscious production . "In the future, we will use the waste heat from the baking process to heat our water," explains master baker Ulf Grünberg. " This will reduce our consumption of fossil fuels , which benefits the environment and lowers our costs ." Sven Ellinger is overseeing the project.
It's easier and cheaper to consistently use the ovens to their full capacity . This is also worthwhile, because reduced oven utilization significantly increases energy consumption. Half-filling the oven results in an increase of almost 20 percent, and approximately 50 percent if the oven is only a quarter full.
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Energy is also wasted during the heating and cooling phases. If the furnace is not loaded after the heating phase , the energy supplied to gas and oil-fired furnaces is completely converted into exhaust gas and surface losses . These losses are much greater than in "normal" furnace operation.
Therefore, significant savings can be achieved by precisely timing the oven's operation – for example, by using a timer – and loading it in a timely manner . Switching off ovens when not in use has the same effect. Additionally, the residual heat can be used for baking goods with low temperature requirements, provided production planning is appropriate.
When the burner is off, heat escapes through the flue. Automatically opening and closing dampers can reduce the cooling of the oven during periods of inactivity . The longer the periods of inactivity, the greater the potential savings from a flue damper. However, retrofitting is not possible with all oven types. If retrofitting is feasible, savings of around three percent can be achieved.
Another weak point of ovens is the doors . They are not always heat-insulated , even newer models. Therefore, when buying a new oven, you should pay attention to proper insulation of the oven doors. The additional cost will pay for itself through energy savings. Retrofitting older ovens is also possible.
A significant amount of energy is invested in steaming baked goods. In ovens without a fixed dosing system, the amount of steam is determined by the baker's experience – often quite generously. If the steam is limited to the amount necessary for the product, substantial savings can be achieved . This is because steam generation consumes 15 to 30 percent of the total energy used in the baking process.
Even when refrigerating and freezing, significant energy savings can be achieved with simple measures. For example, well-stocked refrigerators and freezers operate much more efficiently than underutilized units. The North Rhine-Westphalia Energy Agency calculates that this alone can save €150 per year . Therefore, whenever possible, goods from partially occupied rooms should be consolidated into one room.
Every time a cold storage door is opened, cold air escapes. Therefore, it's advisable to place the goods to be stored within easy reach , remove the cold items, and only take them away after closing the door. Door contact switches for the light should also be installed . If a light is on in the cold storage room, energy is used not only for illumination but also for heat dissipation.
If possible, refrigerators and freezers should be placed outdoors and protected from direct sunlight . Lowering the ambient temperature by one degree Celsius results in energy savings of approximately four percent. Furthermore, the operating times of the machines and fans, and thus energy consumption, are significantly reduced in a cooler environment. Door seals should also be checked regularly. Defective or porous door seals allow warm air to enter the refrigerator and freezer compartments.
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