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Purpose The main purpose of this article is to assess the nutritional and economic efficiency of food loss and waste (FLW) along the supply of 13 food categories included in the Spanish food basket by means of the definition of a new method which combines two indexes. MethodsThe Nutrient Rich Foods index and the economic food loss and waste (EFLW) index were combined by means of linear programming to obtain the Nutritional Cost Footprint (NCF) indicator under a life cycle perspective. The functional unit used was the daily supply of food for a Spanish citizen in year 2015. Results and discussionResults showed that vegetables and cereals were the food categories most affected by the inefficiencies in the food supply chain under a nutritional perspective, being agricultural production and household consumption the main stages in which the nutritional content of food is lost or wasted. Moreover, according to the NCF index, vegetables represented 27% of total nutritional-economic wastage throughout the entire Spanish agri-food chain. They are followed by fruits, which add up to 19%. Hence, specific food waste management strategies should be established for these specific products and supply stages. Finally, the sensitivity analysis performed highlighted that results were mostly independent from the importance attributed to either nutritional or economic variables. ConclusionsThe methodology described in this study proposes an indicator quantifying the nutritional-economic cost of different food categories in the Spanish food basket. This NCF indicator makes it possible to define reduction strategies to promote the use of food waste fractions for waste-to-energy valorization approaches or the extraction of different types of pharmacological, chemical or cosmetic compounds.

Recently, important efforts have been made to define food loss management strategies. Most strategies have mainly been focused on mass and energy recovery through mixed food loss in centralised recovery models. This work aims to highlight the need to address a decentralised food loss management, in order to manage the different fractions and on each of the different stages of the food supply chain. For this purpose, an energy flow analysis is made, through the calculation of the primary energy demand of four stages and 11 food categories of the Spanish food supply chain in 2015. The energy efficiency assessment is conducted under a resource use perspective, using the energy return on investment (EROI) ratio, and a circular economy perspective, developing an Energy return on investment – Circular economy index (EROIce), based on a food waste-to-energy-to-food approach. Results suggest that the embodied energy loss consist of 17% of the total primary energy demand, and related to the food categories, the vegetarian diet appears to be the most efficient, followed by the pescetarian diet. Comparing food energy loss values with the estimated energy provided for one consumer, it is highlighted the fact that the food energy loss generated by two to three persons amounts to one person's total daily intake. Moreover, cereals is the category responsible for the highest percentage on the total food energy loss (44%); following by meat, fish and seafood and vegetables. When the results of food energy loss and embodied energy loss are related, it is observed that categories such as meat and fish and seafood have a very high primary energy demand to produce less food, besides that the parts of the food supply chain with more energy recovery potential are the beginning and the end. Finally, the EROIce analysis shows that in the categories of meat, fish and seafood and cereals, anaerobic digestion and composting is the best option for energy recovery. From the results, it is discussed the possibility to developed local digesters at the beginning and end of the food supply chain, as well as to developed double digesters installations for hydrogen recovery from cereals loss, and methane recovery from mixed food loss.

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Recent studies have identified that buildings all over the world are great contributors to energy consumption and greenhouse gas emissions. The relationship between the building industry and environmental pollution is continuously discussed. The building industry includes many phases: extraction of raw materials, manufacturing, construction, use, and demolition. Each phase consumes a large amount of energy, and subsequent emissions are released. The life cycle energy assessment (LCEA) is a simplified version of the life cycle assessment (LCA) that focuses only on the evaluation of energy inputs for different phases of the life cycle. Operational energy is the energy required for day-to-day operation processes of buildings, such as heating, cooling and ventilation systems, lighting, as well as appliances. This use phase accounts for the largest portion of energy consumption of the life cycle of conventional buildings. In addition, energy performance certification of buildings is an obligation under current European legislation, which promotes efficient energy use, so it is necessary to ensure that the energy performance of the building is upgraded to meet minimum requirements. For this purpose, this work proposes the consideration of the energy impacts and material resources used in the operation phase of a building to calculate the contribution of these energy impacts as new variables for the energy performance certification. The application of this new approach to the evaluation of university buildings has been selected as a case study. From a methodological point of view, the approach relied on the energy consumption records obtained from energy and materials audit exercises with the aid of LCA databases. Taking into practice the proposed methodology, the primary energy impact and the related emissions were assessed to simplify the decision-making process for the energy certification of buildings. From the results obtained, it was concluded that the consumption of water and other consumable items (paper) are important from energy and environmental perspectives.

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