About 30 per cent of the energy used worldwide goes into the production and processing of food from field to table. The vast majority of it comes from fossil fuels, being responsible for some 20 per cent of global greenhouse gas emissions . Primary agriculture consumes only about 20 per cent, whilst food processing including transport uses around 40 per cent and thereby significantly contributes to global energy consumption along agricultural value chains (FAO, 2011. Energy-Smart Food for People and Climate – Issue Paper).
Especially in emerging countries, the rapidly growing agro-industry faces the challenge to cover its energy needs within processing. In India for example, the installed capacity of the fruit and vegetable processing industry has been doubled between 1993 and 2006. Energy consumption of the Indian food processing industry (including the production of meat, fish, fruit, vegetables and oil, beverages, products by grain mills and dairies, and other foods such as bakery products, convenience products, cocoa products or salty snacks) requires 5,300 kilotons of oil equivalent per year.
Most energy is consumed by processes of washing and cleaning, cooking, cooling, extraction, pureeing, brewing, baking, pasteurizing, boiling, drying and dehydration. With regards to meat, fish, fruit, vegetables and edible oil, electrical energy accounts for about 50 per cent of energy consumption, especially for preservation and processing. In further segments such as beverages and other foods a high proportion of the required energy is needed for heating processes – which to a large extent is delivered by petroleum and biomass.
Broadly, the most energy intensive activities are drying, cooling, postharvest and storage, food and beverage processing. Especially in developing countries, demand for cooling is increasing rapidly, where solar powered cooling is an option.
Agricultural products can be dried open-air or unimproved, directly in the sun, with biomass or solar dryers. Open-air
or unimproved drying means that products are exposed to the sun and wind, placed in trays, on racks, or on the
ground. The advantage of drying products this way is its low cost - the farmer does not have to spend anything (or only little) on fuel or appliances. However, the dried products are often of lower quality due to contamination with dust, vermin’s and leafs, as well as varying temperature levels (incl. rainfall patterns).
Energy Consumption in the Processing of Food: