Ways to save
Optimise the use of existing equipment in manufacturing
Improving real-time process data monitoring and benchmarking can identify many opportunities to reduce energy demand, from optimising equipment performance, minimising heat gains and losses, optimising the conditions under which equipment operates and shutting down equipment when it is not required.
Some examples of opportunities in this area are outlined below.
Install effective metering and monitoring to improve data analysis
To help benchmark current energy use and identify new energy efficiency opportunities, it is recommended that effective energy metering and monitoring capabilities are installed at the process level. This will help companies to:
- understand how energy is used within different manufacturing processes and major pieces of equipment
- develop accurate modelling of energy and material flows
- identify and evaluate the most cost-effective ways to reduce energy waste.
National Foods installed energy-monitoring equipment at its Penrith site at a cost of $14,000. Monitoring the electrical energy use in each processing section led to the reprogramming of chillers to make them more efficient, saving 377 MWh (460 tonnes CO2-e and $30,160) per year. The monitoring equipment paid for itself in six months.
For more information
The Energy Efficiency Assessments section of EEX has further details and guidance material on how to effectively capture and analyse data.
Ensure effective shutdown procedures to minimise energy overheads
Most food and beverage processing plants have energy overheads that lead to heat being lost even when the plant is not processing any product.
To address this:
- implement and maintain good ‘control engineering’ to ensure that equipment automatically switches off or shifts to its lowest power mode when not being used, and requires response when needed again. Coca Cola Amatil’s plant in Thebarton is saving an estimated 344 GJ per annum after installing sensors to trigger automatic shutdown of conveyors when no product is being processed.
- fix or replace temperamental equipment so that it can be turned off and on regularly without the risk that it won’t restart properly
- identify and insulate equipment that continues to lose or gain heat when useful services are not being delivered.
- Pears, A. (2004) Energy Efficiency – Its Potential: Some Perspectives and Experiences, Background paper for International Energy Agency Energy Efficiency Workshop, Paris April 2004 (Opens in a new window) PDF 964 KB ↩
Optimise operating temperatures and pressures of equipment and processes
Food and beverage manufacturing plants have numerous pieces of equipment operating at different temperatures and pressures. Ensuring that all these pieces of equipment are operating at optimal conditions saves significant amounts of energy. For example:
- Cooled storerooms are often kept at lower temperatures than required due to concerns about potential equipment failure. However, overcooling a storeroom, as well as wasting energy, 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.
- Operating air compressors at the lowest settings saves energy; e.g. operating at 690 kPa (100 psi) instead of 830 kPa (120 psi) requires 10% less energy.
- Energy can be saved by reviewing air-conditioner settings and widening the temperature band when air-conditioning is not required (e.g. 20–26°C).
- Other opportunities should also be explored such as operating extraction fans only when equipment is in use, providing make-up air close to the equipment, and ensuring that the make-up air inlet is closed when equipment is not in use.
Minimise heat gain into refrigeration systems and refrigerated spaces
Minimising heat gain into refrigerated systems and spaces can reduce the energy required to maintain temperatures in these areas.
This can be done by:
- positioning refrigeration units as far away from cooking/boiler equipment as possible
- maintaining cool room efficiency by regularly checking door seals and refrigerant levels of chillers
- ensuring cool rooms are well insulated, with no thermal bridging through metal frames
- insulating pipe work and locating refrigeration heat exchangers away from heat sources, such as radiators and air-conditioning systems, and minimising the temperature of supply air.
Minimise heat loss from boiler systems, cooking equipment and pasteurisers
Heat from boiler systems, cooking equipment and pasteurisers can impact on the energy required to maintain refrigerated areas and increase requirements for air-conditioning cooling loads. 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 provide a thermal bridge allowing heat loss. By increasing average insulation around these ovens from an R value of 0.22 to an R value of 2.5 and reducing thermal bridging, radiated heat can be reduced by as much as 75%.
Maintain existing equipment
Preventative maintenance programs can help identify potential problems before they occur, 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 preventative maintenance program to delegate responsibility for maintaining specific equipment. For example, assigning responsibility for basic lubrication and identification of leaks in air compressors can prevent unnecessary and costly stoppages.
Invest in process innovation and equipment upgrade
Redesigning and improving food and beverage manufacturing processes and upgrading equipment can yield the largest energy efficiency improvements. While this may require significant resources and investment it will often yield significant savings.
The Bakers Delight case study also highlights how significant savings can be made when applying best practice design, technology and operating practices to a food manufacturing process.
Some further examples of opportunities in this area are outlined below.
Recover and reuse waste heat
There are many waste heat sources in the food and beverage industry from which useful heat can be recovered and reused, yielding significant onsite savings.
Using steam traps to collect condensed water and return it to the boiler, for example, not only saves water but also lowers boiler heating requirements as the returned condensate is much hotter than feedwater and may not require treatment.
UNEP’s Working Group for Cleaner Production, based at the University of Queensland, has identified a range of other heat recovery opportunities in the food processing sector with one to four year investment returns. ( see Table 1)
Table 1: Examples of heat recovery in the food processing industry
|Sources of waste heat||Applications for recovered heat||Industry examples|
|Hot exhaust from baking ovens||Preheat warm and humid proofing ovens||Baker: Goodman Fielders Baking, Australia|
Savings: 500 GJ for one 8-hour shift
Payback: 3.5 years
|Hot exhaust from fryer||Preheat air for dryers|
Heat water for blanchers
Preheat boiler feedwater
|Snack food processor: McCain Foods, UK|
Savings: A$443 261
Payback 3.5 years
|Surplus heat from boiler flue gases|
|Lubrication oil cooler from a rotary screw compressor||Preheat boiler feedwater||Bluebird Foods, New Zealand|
Payback period: 2 years
|Heat from gas engines used to drive kiln fans||Preheat the kiln air||Malt processor, Australia|
Savings: $70 000
Payback period: 2.5 years
|Heat from the freezer condenser||Water at 65°C for cleaning|
24 hours a day
|Chicken processor: Danpo|
Savings: 2500 MWh
Payback period: 3.2 years
|Heat from the superheater on compressor|
|Heat from compressor lubrication oil||Preheat boiler feedwater||Food processor: Jordan|
Savings: 53 t/year
Payback period: 0.6 year
|Heat from boiler blowdown|
|Condensate return||Preheat boiler feed water||Food processor: USA|
Savings: A$20 944
Payback period: 2.6 years
(Source: UNEP Working Group for Cleaner Production, 2003)
Footnotes ~ Show 2 footnotes
- EnviroWise (2002) Reducing Water Costs in Paper and Board Mills Envirowise UK (Opens in a new window) 242 KB ↩
- Pagan, R., Prasad, P., Price, N. and Kemp, E. (2004) Eco-efficiency for the Queensland Food Processing Industry UNEP Working Group for Cleaner Production in the Food Industry, Australian Industry Group (Opens in a new window) PDF 3.8 MB ↩
Purchase more energy efficient equipment and ensure it is correctly sized
Significant energy efficiency improvements can be achieved through upgrading or replacing old, equipment. Ensuring it is sized correctly for expected loads is critical however to reaping the benefits.
See the following technology pages on the EEX website:
For more information
- How to test and fix compressed air leaks
- UK Carbon Trust
Find out how to test and fix compressed air leaks to save energy.
Note, this publication is free to access, but users must register first.
- Industrial Refrigeration and Chilled Glycol and Water Applications Technology Report 2011 (Opens in a new window)
This report outlines 15 energy saving technologies available to increase the energy efficiency of an industrial refrigeration plant. Where possible, for each technology the annual energy savings, capital costs and payback periods have been estimated by considering examples.
Use lower energy alternatives to create heat/steam
Using heat to evaporate water involves large amounts of energy. A range of methods are available which provide heat for evaporation much more efficiently, such as:
- depressurisation using waste heat
- ambient temperature air or water
Where heat is used, efficient heat recovery (including the latent heat of water vapour) is critical. Heat pumps can efficiently recover heat for use in other processes.
- Around 2.3 MJ per litre is required to evaporate water and 0.33 MJ to heat it from ambient to boiling temperature ↩
Consider pasteurisation alternatives
Pasteurisation is a widely used process applied to food and beverage products to reduce or eliminate microbiological contamination and extend storage life. Energy modelling can be used to estimate the efficiency of heating in pasteurisation, so that losses can be identified and minimised. In theory, using heat for pasteurisation can approach zero net energy if very efficient heat recovery is utilised.
Using high standards of process hygiene and monitoring can avoid or reduce the need for pasteurisation.
Alternatives to pasteurisation also exist, such as:
- microfiltration, various forms of which have been successfully used to remove bacteria from beverages, achieving equivalent results to pasteurisation.
- ultraviolet (UV) treatment, which provides a non-heating option for sterilising containers;
- ultrasonics, which through the use of very high frequency sound waves can have 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 practicable.
Using staged cooling
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.
Invest in low carbon energy supply options
A wide variety of alternative energy sources are being used cost effectively in the food and beverage processing industry such as anaerobic digesters and biogas, solar thermal and photovoltaics, solar drying of grains, and fuel switching from oil or electricity to natural gas.
Some examples of opportunities in this area are outlined below.
Consider solar thermal systems for water heating
Solar water heating is well suited to pre-heating boiler feed water for a wide range of food and beverage processing plants. Boiler feed water can be heated in solar panels up to 80ºC before being fed to the boiler. Solar cooling systems are also well suited to helping food and beverage companies meet cooling and commercial refrigeration demands.
For more information
Install a food waste-to-energy plant
Most food waste has potential for reuse as an energy or nutrient source. In Australia, such organic waste can be used in horticultural and agricultural sectors as compost and liquid fertiliser, or applied 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 96%.
Anaerobic digestion and biogas recovery is best suited to large food processing plants with high-strength wastewater, such as dairy processing plants or breweries. Foster’s Australia, installed upflow anaerobic sludge blanket (UASB) units as part of the wastewater treatment process at their plant in Brisbane. Biogas is extracted from this process and burnt in boilers, contributing approximately 20% of the energy use on site and saving approximately $750,000 per year. The biogas unit cost approximately $220,000 to install in 1995 and had a payback period of less than one year.
- Environmental Entrepreneurs (2007) Dairy Strategy October 2007’ ↩
- Queensland Government. Eco-efficiency resources for the food processing industry (Opens in a new window) PDF 4 KB ↩
Explore novel use of low carbon energy solutions
Research is being undertaken into the use of low carbon energy solutions for pest control of food crops post-harvest. A significant percentage of grain production is lost after harvest1because of challenges in managing insect pests infestation of stored grain. For the last 30 years, infestation of Australian stored grain has been controlled by chemical methods as the grain is loaded into grain stores. Environmental concerns and regulations are leading to some chemicals, such as methyl bromide, being phased out.
Aeration processes offer a non-chemical alternative to prevent infestation. In areas where ambient temperature can get high, using refrigerated air can help effectively control insects. But refrigerated air has high upfront equipment costs and uses significant amounts of energy. ATO address these issues, a solar desiccant system has been designed and built at Victoria University of Technology (VUT) for cooling bulk stored grains. This has been successfully tested.
Renewable energy options can also be utilised to dry crops. For instance, A solar-assisted crop drying facility in Griffith NSW uses solar energy to dry prunes and achieves significant energy savings.
Supply chain collaboration is emerging as a new strategy for companies and their supply chains to work together to find the lowest cost options to improve energy efficiency and reduce greenhouse gas emissions.
The Australian Industry Group and Sustainability Victoria worked 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 pilot study demonstrated that substantial opportunities for carbon reduction arise from supply chain co-operation or through changes to product design. A report based on this study outlines a life-cycle methodology to help businesses develop management approaches with supply chain partners to become more energy efficient and reduce greenhouse gas emissions.