Energy use accounts for at least 15% of total operational costs of a food and beverage business. Becoming more energy efficient is critical to becoming profitable and competitive.
Additional benefits can be delivered through energy efficiency improvements, including lower water and chemical costs, increased plant productivity and improved product quality.
The food and beverage sector presents many opportunities to reduce energy demand. Some examples of opportunities are outlined below.
Metering and monitoring
To help benchmark current energy use, it’s recommended that metering and monitoring capabilities are installed at the process level. This will help operators to:
- understand how energy is used in different processes
- develop accurate modelling of energy and material flows
- identify and evaluate the most cost-effective ways to reduce energy waste.
See the Metering and monitoring guide for more information.
Operating temperatures and pressure settings
Food and beverage manufacturing plants have a variety of equipment operating at different temperatures and pressures. Ensuring this runs at optimal conditions saves significant amounts of energy.
Cooled storerooms are often kept at lower temperatures than required due to concerns about potential equipment failure. However, overcooling a storeroom wastes energy and raises the probability of equipment failure by increasing the load on the refrigeration plant.
The temperature should always be set to meet product storage requirements.
Other opportunities to explore:
- Operate air compressors at the lowest required pressure settings.
- Operate extraction fans only when equipment is in use.
- Provide make-up air close to the equipment.
- Ensure that the make-up air inlet is closed when equipment is not in use.
Preventive maintenance programs can detect potentially developing problems, such as heat leaks, leaks in air compressors, seal leaks in chiller rooms and fridges, and bearings running hot.
Allocate a budget and implement a preventive maintenance program to delegate responsibility for specific equipment. For example, assigning responsibility for lubrication and identification of leaks in air compressors can prevent unnecessary and costly stoppages.
Most food and beverage processing plants have energy overheads that lead to heat being lost even when the plant is not operating. To address this:
- implement and maintain good ‘control engineering’ to ensure equipment automatically switches off or shifts to low-power mode when not in use
- fix or replace fault-prone equipment so that it can be turned on and off regularly without the risk of not restarting properly
- identify and insulate equipment that continues to lose or gain heat when useful services are not being delivered.
Minimising heat gain into refrigerated systems reduces the energy needed to maintain temperatures in these areas.
Some options to consider:
- Position refrigeration units as far from cooking/boiler equipment as possible.
- Maintain cool-room efficiency by checking door seals and refrigerant levels.
- Ensure cool-rooms are well insulated, with no thermal bridging through metal frames.
- Insulate pipe-work, locating refrigeration heat exchangers away from heat sources, such as radiators, and minimising the temperature of supply air.
See the Refrigeration guide for more information.
In cooling processes, efficiency declines as the temperature difference over which a chiller operates increases. Staged cooling can improve efficiency by a variety of methods, including the use of:
- residual stored cold product that has to be warmed
- multi-stage chillers rather than single-stage'
Boilers and ovens
Heat loss from boiler systems can be minimised by insulating boiler valves, steam and condensate return pipes and storage units.
Many commercial ovens are either poorly insulated or have metal joints that form a thermal bridge allowing heat loss. By increasing insulation around these ovens to an R value of at least 2.5 and reducing thermal bridging, radiated heat can be reduced by up to 75%.
See the Process heat and steam guide for more information.
Pasteurisation is widely used to reduce or eliminate microbiological contamination and extend storage life. Energy modelling can estimate the efficiency of heating in pasteurisation. Using heat for pasteurisation can approach zero net energy if very efficient heat recovery is utilised.
High standards of process hygiene and monitoring can avoid or reduce the need for pasteurisation.
Alternatives to pasteurisation include:
- microfiltration of beverages and other liquids
- ultraviolet (UV) treatment as a non-heating option for sterilising containers
- ultrasonics, which has a similar effect to irradiation in disrupting the DNA chains of bacteria.
These alternative methods are more efficient where products are heat sensitive, or where heat recovery is not practical.
Heat and steam creation alternatives
Using heat to evaporate water involves large amounts of energy. Several methods provide heat for evaporation much more efficiently, such as:
- depressurisation using waste heat
- ambient temperature air or water
- microwave ovens.
Where heat is used, efficient heat recovery (including the latent heat of water vapour) is critical.
Using steam traps to collect condensed water and return it to the boiler, for example, saves water and also boiler heating requirements. The returned condensate is much hotter than feedwater and may not require treatment.
Heat pump systems can also efficiently recover heat for use in other processes and can be designed for steam production.
The principle benefit of electric heat pumps over other heating technologies is their efficiency, i.e. they can produce more units of heat output than they consume in electrical energy.
See the Waste heat recovery guide for more information.
Solar water heating
Solar water heating is well suited to pre-heating boiler feed water for many food and beverage processing plants. Feed water can be heated in solar panels to 80ºC before the boiler. Solar cooling systems are also good options for cooling and commercial refrigeration demands.
Food waste-to-energy plant
Most food waste has potential for reuse as an energy or nutrient source. Organic waste can be used as compost and liquid fertiliser, or in the generation of renewable energy through anaerobic digesters.
Anaerobic digestion occurs when microorganisms break down organic material in the absence of oxygen, producing biogas (methane) and a rich fertiliser. When this biogas is captured, it can reduce methane emissions from manure decomposition by up to 95%.
Anaerobic digestion and biogas recovery is best suited to large food processing plants with high-strength wastewater, such as dairy processing plants or breweries.
Supply chain collaboration is key to determining the lowest cost options to improve energy efficiency and reduce greenhouse gas emissions.
For instance, the Australian Industry Group and Sustainability Victoria developed a pilot study with businesses from two supply chains to identify the carbon reduction opportunities for two basic food products—a can of peaches and a tub of ice cream.
The study demonstrated substantial opportunities for carbon reduction that arise from supply chain co-operation, life-cycle management and changes to product design.
Renewable energy for process heat
The food and beverage sector is one of the largest users of process heat in Australia. In 2019, the Australian Renewable Energy Agency (ARENA) commissioned the Renewable Energy Options for Industrial Process Heat report which outlines opportunities for industrial users to switch to renewable energy alternatives to provide process heat.
The report shows that shifting to renewable energy to generate process heat is possible for industrial sites over the short, medium and long-term using numerous technologies and approaches. These include:
- solar thermal.
In the food and beverage sector, all renewable energy options are worth consideration.
Bioenergy dominates the current use of renewable energy in the sector given the large use of biomass. In any situation where a waste or low-cost biomass resource is available, it is likely to offer a positive return on investment.
Many businesses in the sector have installed on-site rooftop solar PV systems. Solar thermal and geothermal options are worth considering, with economic performance depending on the resource at the site plus the temperature for the required heat.
The 4 cornerstones of the fourth industrial revolution are uncovering new pathways to manufacturing for the food and beverage industry.
- Networking of intelligent manufacturing systems.
- Coordination of manufacturing and logistics.
- Virtualisation and integration along the supply chain.
- Exponential technologies.
In order to embrace Industry 4.0, facilities need more types of reliable and accurate data. Acquiring data is made easier with new and advanced sensor technologies. Examples include:
- smart pressure sensors
- point level switches
- radar level sensors.
Bringing sensor process data together using the Internet of Things (IoT) helps drive smarter and faster business decisions.
Sensor technologies can also help trace contamination and eliminate sources of error. There are many varieties of intelligent identification systems which enable better traceability. For instance, radio frequency identification (RFID) labelling tracks crops right from harvesting to trace the origins of the cargo.
Another emerging technology is intelligent labelling. The combination of wireless labelling, software applications and cloud platforms lets consumers scan product labels with smart phones to ensure the product’s authenticity or to obtain information on ratings and customer loyalty programs.
See the Industry 4.0 guide for more information.
Choice Energy Food and beverage companies benefitting from improving their energy procurement, demand side management and solar installation.
Foodprocessing.com.au Energy efficiency and sustainability improvements at food and beverage manufacturers.
Green Industries SA South Australian food and wine producers exploring resource and energy efficiency and waste management.
Winery Energy Saver Toolkit Energy gains made through tank insulation, air compressor efficiency, cogeneration and solar.
Abattoirs and meat processing case studies Government of Victoria
Energy Savings Measurement Guide Australian Government
Food and beverage industry capability statements Australian Government
Food processing and storage case studies Sustainability Victoria
Industrial refrigeration NSW Government
Publications and links to industry resources Food South Australia
Renewable Energy Options for Industrial Process Heat Australian Renewable Energy Agency
Winery Energy Saver Toolkit South Australian Wine Industry Association