The application of the framework is presented through a fictious example, inspired by the existing literature on school canteens (Cerutti et al. 2016; Boschini et al. 2018; Garcia-Herrero et al. 2019) and representing a realistic situation. It is assumed that a generic school canteen catering company aims at evaluating the environmental and economic consequences of an intervention aiming at the prevention of serving and plate waste during school lunch.
The current situation is including the serving of about 200,000 meals per year in the schools of a medium-sized municipality. Serving and plate waste constitutes almost 25% of the food mass, equivalent to 30 t of organic waste per year. This food waste is disposed of through a large municipal biogas facility, generating biogas for electricity and digestate. The school is charged a fee for waste collection.
In the perspective scenario, the catering company, in agreement with the municipal council, would like to implement in the school a prevention measure by reducing the amount of served food. This measure is predicted to have an effect of 30% reduction of food waste. The municipality is also planning to introduce a “food waste carbon tax” charging an extra fee for the disposal of wasted food, calculated on the embedded CO2eq emissions of food and based on the carbon emission trading system.
The specific aim of the analysis for the assessor (the catering company) is the assessment of the costs for all the engaged parties and the identification of the environmental impact related to this change.
Step 1: Phrase the question of the study and identify the audience for the result
The focus of the study is on the change in economic costs and environmental impacts for the catering company, the school, and the biogas operator, which could derive from a reduction in the amount of organic waste sent to municipal waste handling, obtained by preventing serving and plate waste. The result of the study should support the catering company and the municipality in the decision to undertake such intervention.
Step 2: Establish REFRESH situations
The REFRESH situation decision tree allows to establish if the study explores a side flow (not a deriving product) thanks to the principle “the less, the better’ applied for discarded products. The current scenario is represented by RS3 (valorization as part of waste management) since the catering company and the school just dispose of food waste and pays a fee for its collection, but the biogas producer extracts some value out of the treatment. The perspective scenario is represented by RS1 (prevention) since the reduction of the amount of food waste sent to the biogas facility would guarantee a saving in the resources needed (purchased) for the disposal of such waste.
Step 3: Footprint or intervention study?
Since the catering company will take its decision on the basis of the results of the study, an intervention modelling approach is recommended. Considering the scale of the flow (30,000 t per year), the intervention might influence the operations of the municipal biogas facility leading to some consequences in the background processes. Thus, the modelling system expansion should be considered when accounting for “additional” functions from the system, using marginal market data for processes in the background system (e.g. how electricity and digestate from that biogas plant will be substituted).
Step 4: E-LCC appropriate?
The catering company wants to assess both environmental and cost. In addition, only stakeholders directly involved in the supply chain will be considered (the food ingredient suppliers, the catering company, the school, and the biogas operator). No other stakeholders external to this chain are included, so it is recommended to select an E-LCC approach.
Step 5: FU, SB, cut-off, and handling multi-functionality
While in the goal and scope stage of an LCA study, several aspects must be included to comply with international standards; this example is focusing only on the aspects of FU, SB, cut-off, and multi-functionality. Since the aim of the study would be to assess the effects of moving from RS 3 to RS 1 (prevention), then the FU and SB should include the supply chain of the driving product (ingredient production, meal production, and consumption) and not only the food waste management chain. Specifically, the FU should be the 200,000 meals, over a time period of 1 year, in the time horizon 2018–2023. Details about the composition of the driving product and side flow should also be provided.
The inclusion of the supply chain of the driving product is also needed because food waste prevention actions might cause a reduction of produced food in the upstream processes. Such perspective would thus allow to analyse such consequences.
For the E-LCC, system boundaries should be coherent with LCA, e.g. considering the same life cycle stages. Catering costs must be fully inventoried. Market prices can be used for the production of inputs for processes (e.g. fuels and chemicals). Costs of cultivation and transport stages can be estimated using market prices of purchased food/service as a proxy or with further detail. This latter case is desirable if internal costs for suppliers are changing (e.g. because different purchasing levels by catering company could lead to different production by suppliers). The same options are also valid for downward processes related to biogas. Avoided impacts from system expansion can be estimated either through revenues from electricity and digestate or market price of identified substituted products.
Cut-off can be different for LCA and LCC. In the first case, it should exclude processes such as production of seeds and seedlings, transport of personnel, transport of fertilizers, production of equipment, buildings, and vehicles, due to their limited influence on final results. In the E-LCC, considering that worker training and hours as well as indirect costs might change, the cut-off should include also items not related to LCA flows, adopting a financial relevance criterion.
As for the multifunctionality, current systems deliver also biogas and digestate, which are replacing respectively natural gas and mineral fertilizer. In the perspective scenario, prevention of serving and plate waste would hardly have the magnitude to influence the market but could have some local consequences (e.g. municipal biogas facility operating at a reduced rate). Average market data for substitute product and to model the impact should be used in both scenarios, including also avoided costs.
Step 6: LCI data
Data collection should focus on primary data for catering and service processes and the production of biogas. Food production and transport, replaced production of fuel and fertilizer, and transport and energy production impacts could be modelled using secondary data.
Cost modelling should categorize costs by type of costs, life cycle stages, and specific cost items. Primary cost data related to catering must be used while market prices can be used as proxy of other stages (see above). Considering the nature of catering operation (e.g. potential production of meals for other services), some indirect costs should be allocated to the FU, using a specific factor, such as the share of meals/turnover of FU over the total. Contrarily, no discounting is mandatory due to the relatively short time horizon of the intervention. Depreciation of plants and machineries can be used. Since the introduction of a “food waste carbon tax” is anticipated, the external cost of embedded CO2eq emissions in wasted food should be encompassed by the inventory and the impact assessment. Finally, cost modelling should focus on the relevant actors of the supply chain that can be affected by the intervention. In the current scenario, the caterer is purchasing food (including its transport) at market prices, thus bearing all those costs. Municipal waste management company is bearing all costs and benefits related to food waste disposal. In the future scenario, agricultural producers and the transport company will likely have to cope with a reduction of revenues, and the municipal waste management company could operate at a reduced rate, so it should be considered as a cost bearer of the system.
Step 7: LCIA
Since food production is included, impact indicators suggested are GWP, water depletion, depletion of fossil resources, terrestrial and aquatic eutrophication, acidification, and land transformation. In the E-LCC, it is recommended to assess costs and their changes for the different cost bearers (cost distribution), according to the categories and details included in the model. A portfolio of total results and contributions of life cycle stages/cost bearers could be useful to present results in a combined way. A plot graph could show percentage changes of moving from RS 3 to RS 1 for different indicators, e.g. GWP and total costs. If the catering company would prefer to have a single score, weighting and sum of LCA and E-LCC scores should be carried out to avoid double counting of externalities (e.g. “food waste carbon tax”).