Total Energy Requirements of the Household Preparation and Storage of Foods

摘要

The total energy requirements of the household storage and preparation of foods in New Zealand are discussed. Data from published sources were used to estimate the direct energy requirements. Overall, the direct energy requirements of the household preparation and storage of foods in New Zealand were estimated to be just over 13PJ/yr. Cooking accounted for 32% of the direct energy required. The ancillary services to cooking and food preparation such as refrigeration, dishwashing, lighting and HVAC accounted for 68% of the direct energy requirements. On October 1980 costing, this direct energy was estimated to cost about $120,000,000 per annum. The indirect energy requirements were estimated by using published cost data in conjunction with data from the University of Canterbury's Energy Analysis of the New Zealand economy. On an amortised basis, the indirect energy embodied in kitchen equipment, buildings and materials such as dishwashing detergent and oven bags was estimated to be abut 2.5 PJ/yr. This represents only 16% of the total energy requirements. A methodology was developed to estimate energy intensities (MJ/kg), from published data, so as to characterise the energy requirements of this step of the food chain. There was quite a large variation demonstrated in the direct energy intensities for cooking processes: Baking (25.57 MJ/kg), Roasting (10.63 J/kg), Grilling (6.30 MJ/kg), Steaming (4.39 MJ/kg), Boiling (2.92 MJ/kg), Frying-Heating (1.77 MJ/kg) and Deep Frying (1.62 MJ/kg). The energy intensities for the ancillary services and the indirect energy requirements were generally much lower (approx. 1 - 4 MJ/kg) and demonstrated less variation. It was estimated that in terms of the minimum practical energy use concept, housekeeping energy conservation methods could save about 20%. In the long term, it was estimated that another 25% could be saved by appliance development and modification. (ERA citation 08:041389)