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ENERGY USAGE IN THE FOOD INDUSTRYDr. Martin Okos, Dr. Nishant Rao, Sara Drecher, Mary Rode, and Jeannie Kozak October, 1998
Executive Summary A Review of Energy Use in the Food Industry The United States food and kindred products industry plays a vital role in the US economy and in foreign trade due to its large size, stability, growth, diverse products, and competitive nature. This study reviews energy use and trends in the food industry, revealing energy intensive industries and processes that have the most incentive to reduce energy costs by implementing energy efficient processing methods. The food and kindred products industry sector includes all food-related manufacturing industries in the US. The sector is identified by Standard Industrial Classification (SIC) code 20, which can be broken down into nine three-digit SIC industry groups:
201: Meat Products The food industry sector is one of the largest manufacturers in the United States, with the second highest value of shipments in 1994, compared to all industry sectors. The food industry is also growing, with value of shipments increasing from $309 billion in 1986 to $431 billion in 1994. In 1991, the typical US household devoted 15 percent of after-tax income to the purchase of food and beverage products. The food industry is significant to US Foreign Trade because exports outnumber imports. Few trading categories display this phenomenon. Exports of foods, feeds, and beverages not only outnumber imports, but, since 1991, have increased at a greater rate than imports. PROCESSING AND MARKETING TRENDS IN THE FOOD INDUSTRY Industry is dependent on energy for the processes required for food freshness and safety. Thermal processing and dehydration are the most commonly used techniques for food preservation, and require significant amounts of energy. Process heating uses approximately 29% of total energy in the food industry, while process cooling and refrigeration demands about 16% of total energy inputs. Foods that have undergone energy intensive processing have become increasingly popular in both domestic and foreign markets. Consumers spend less of their food budget on meat, eggs and dairy, and more of their food budget on higher value-added foods and cereal and bakery products. Higher value-added foods include prepared foods, nonalcoholic beverages, table spreads, and confectionery products. At least 40% of the industry shipment value is added through energy intensive manufacturing. The Bureau of the Census calculates value-added by value of industry shipments less the cost of materials, supplies, containers, fuel, electricity, and contract work. ENERGY USE IN THE FOOD INDUSTRY In 1991, the food industry consumed 7% of the total electricity used by the manufacturing sector -- 94% of which was purchased, and 6% of which was produced through co-generation by the individual food industries themselves. Electricity meets about 15% of the food industry's energy needs. Fossil fuels are also used, with natural gas being the most widely used. The following eight industries consume approximately half of the total energy used by the food industry:
The food industry uses energy for food preservation, safe and convenient packaging, and storage. Food preservation is dependent on strict temperature controls. Safe and convenient packaging is extremely important in food manufacturing and is also energy intensive. The newest packaging techniques require aseptic techniques and electro-chemical changes. Proper storage is also energy dependent. Freezing and drying are the most crucial methods of food storage. Freezing operations require a large portion of electricity used by industries. Drying procedures usually depend on fossil fuels. Older dehydration systems were designed to operate with maximum throughput, disregarding energy efficiency. Newer systems are designed with recirculating dampers and thermal energy recovery equipment to cut energy use 40%. Approximately half of all energy end-use consumption is used to change raw materials into products (process use). Process uses include process heating and cooling, refrigeration, machine drive (mechanical energy), and electro-chemical processes. Less than 8% of the energy consumed by manufacturing is for non-process uses, including facility heating, ventilation, refrigeration, lighting, facility support, onsite transportation, and conventional electricity generation. Boiler fuel represents nearly one-third of end-use consumption. This energy was transformed into another energy source. For example, boiler fuel can be used to produce steam, which can have end uses. Processing uses 78% of electricity, with 48% used for machine drive and 25% for process cooling and refrigeration. Non-process uses account for 16% of electricity use. Lighting, heating, ventilation and air-conditioning accounted for about 12 of the 16%. Distillate fuel oil is used mainly for boiler fuel (42%) and non-process uses (42%). Onsite transportation consumes the most distillate fuel oil in the non-process category. Processing consumed 9% of total distillate fuel oil, mostly by process heating. Like residual fuel oil, natural gas was mostly consumed as boiler fuel (62%). Process heating accounted for 27 of the 28% used for processing. OPPORTUNITIES TO SAVE ENERGY IN THE FOOD INDUSTRY Since the food and kindred products industry is diverse, there are many different types of operations dependent on energy. The food industry generates a significant amount of waste per year. Waste and energy use can be decreased through process optimization, operating techniques, and scheduling. Wastewater can be processed and reused. Waste can be converted to byproducts and reused or sold. Changes made to improve quality or safety often result in energy savings. For example, improving an air filter, necessary to meet health regulations, also benefits the environment, although health regulations were the motivation behind air improvement. Thus, many opportunities exist for waste and energy reduction in the food industry. Energy use in the food processing industry could be decreased significantly by 2010. Four processes that offer particularly good opportunities for improvement include:
1. Pasteurization and sterilization by cold pasteurization and electron beam
sterilization. The food products industry currently supplies fuels produced from its byproducts to other industries. The substitution of such fuels for fossil fuels can reduce hydrocarbon and carbon monoxide emissions. Although the production and use of these biomass fuels have been shown to be technologically feasible, there are varying opinions concerning the economic stability of producing and using fuels from renewable resources. The Food Industry has unique environmental concerns. Research is needed in key areas to reduce environmental damage:
Energy efficiency improvements are currently being made by food industries to be more competitive with each other. Potential economic advantages and environmental benefits exist in waste and water efficiency improvements. Energy efficiency can be achieved by improving existing plants, developing energy-efficient process technology, creating informed and reasonable energy policies, and further research in the possibilities of zero-discharge plants. Government policies can:
There are many opportunities for improving energy efficiency in the food industry through evaluation and addition of effective governmental energy policies and voluntary process analysis and improvement. Future directions for energy efficiency studies should focus on improving existing plants, developing energy-efficient process technology, improving and expanding demand side management programs, creating informed and reasonable energy policies, and further research in the possibilities of zero-discharge plants. This paper discusses many of these opportunities. 86 pp., 1998, $20.00, IE981 |
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