Review and expert survey of allocation methods used in life cycle assessment of milk and beef

Purpose Beef and dairy production systems produce several by-products, such as fertilizers, bioenergy, hides, and pet foods, among which the environmental impacts arising from production should be allocated. The choice of allocation method therefore inevitably affects the results of life cycle assessment (LCA) for milk and beef. The aims of this study were to map out the different allocation methods used in dairy and beef LCA studies and to clarify the rationale for selecting a certain method. Methods A literature review was conducted to identify the different allocation methods used in LCA studies of milk and beef production and the products using beef by-products as a raw material. The justifications for the use of different methods in the studies were also collected. To map out the perspectives of LCA practitioners and further clarify the reasoning behind the use of certain allocation methods, a mixed method survey with quantitative questions and qualitative explanatory fields was sent to the authors included in the literature review. Results and discussion The literature review showed that the most commonly used allocation method between milk and meat was biophysical allocation, which is also the recommended method in LCA guidelines of milk production. Economic allocation was the second most common method, although the rationale for using economic allocation was weak. By-products, such as inedible body parts, were not considered in milk studies and were taken into account in only a small number of beef studies. This might be because most of the studies have cradle-to-farm gate system boundaries. According to the survey, a significantly higher share of LCA practitioners would allocate impacts also to these by-products. Conclusions The allocation is usually done between milk and meat, and other by-products are not taken into account. Since these materials are an unavoidable part of production and there are numerous uses for them, these outputs should be recognized as products and also taken into consideration in LCA studies.

Environmental Impacts of Electricity from Incineration and Gasification: How the LCA Approach Can Affect the Results

Waste-to-energy (WtE) technologies can offer sustainable solutions for waste, which can no more be reused or recycled, such as the part of municipal solid waste (MSW) that is not suitable for recycling processes. This study focused on the environmental consequences of the production of electricity from incineration and gasification of MSW. To this aim, the standardised life cycle assessment (LCA) methodology was used. A life cycle inventory, mainly composed by primary data, is provided. Starting from these data, different highly shared LCA approaches were used to calculate the potential impacts of 1 kWh provided by the two analysed WtE technologies. The different approaches concern the method of accounting for the by-products (through an economic allocation and a system expansion) and the inclusion/exclusion of environmental benefits due to the avoided landfill for the MSW. For each approach, impact-assessment results were calculated with the ReCiPe midpoint (H) method. A comparison was carried out (i) between the results obtained for the same WtE technology but calculated with different approaches and (ii) between the impact results of electricity generated by the two WtE technologies calculated with the same approach. From the study, it emerged that, according to the accounting rules, the impact results can significantly change and, for some impact categories, even lead to opposite conclusions. In the absence of category rules that harmonise the environmental assessments of WtE processes, it is therefore recommended that the development/use/reproduction/comparison of studies focused on the valorisation of waste should be carried out with caution.

Assessing the Environmental Pertinence of Cobalt Exploitation from Slag in KGHM Mines

As ore quality declines in KGHM mines after continuous exploitation, it becomes increasingly relevant to extract as much economic value as possible from the mined ore while limiting the environmental impact. The recovery of cobalt from converter slag is a possible extraction route that can increase economic output at a limited environmental and logistic cost. Life cycle assessment (LCA) is used to assess the environmental impact of copper exploitation and to compare that impact with the estimated impact of cobalt extraction in the Lubin mine. In most impact categories, Co extraction would be responsible for less than 0.2% of the impact, while increasing economic output by 3.38%. Economic allocation shows that cobalt recovery is environmentally pertinent.

Dairy Buffalo Life Cycle Assessment (LCA) Affected by a Management Choice: The Production of Wheat Crop

Life cycle assessment (LCA) was performed in dairy buffalo farms representative of Southern Italian farming systems, similar due to several characteristics, with the exception of wheat production. This work evaluated the impacts derived from this management choice, comparing farms with wheat crop (WWC) or not (NWC). In agreement with the literature, economic allocation was chosen as a useful strategy to attribute equivalents to by-products, i.e., culled animals; the same criterion was also adopted to assign pollutants to wheat grain, limited to WWC farms. Environmental impacts in terms of Global Warming Potential (GWP, kg CO2 eq), Acidification Potential (AC, g SO2 eq), Eutrophication Potential (EU, g PO43-eq), Agricultural Land Occupation (ALO, m2y) and Water Depletion (WD, m3) were estimated. The production of wheat crop significantly affected (p < 0.05) the Agricultural Land Occupation (ALO) category as WWC farms need adequate land. WWC farms could allow a significant reduction in eutrophication (EU) compared to NWC farms (p < 0.05).

Effect of Nutritional Variation and LCA Methodology on the Carbon Footprint of Milk Production From Holstein Friesian Dairy Cows

The UK livestock industry urgently needs to reduce greenhouse gas (GHG) emissions to contribute to ambitious climate change policy commitments. Achieving this requires an improved understanding of emission sources across a range of production systems to lower the burden associated with livestock products. Life cycle assessment (LCA) methods are used in this study to model milk production from two genetic merits of Holstein Friesian cows managed in two novel and two conventional UK dairy systems. Select merit cows sired by bulls with high predicted transmission for fat plus protein yield are compared with Control merit animals sired from UK average merit bulls. Cows were managed in conventional housed and grazed dairy systems with novel Byproduct and Homegrown feeding regimes. A LCA was used to quantify the effect of allocation and management of feed components on the carbon footprint of milk production. Natural variation in nutritional quality of dairy system rations was investigated to quantify uncertainty in the carbon footprint results. Novel production system data are used to assess the effect of introducing home grown legumes and co-product feeds. Control merit footprints across each of the management regimes were significantly higher (p&lt;0.001) in comparison with a high production Select merit, on average by 15%. Livestock emissions (enteric, manure management and deposition) and embedded emissions (purchased feeds, fertiliser, and pesticides) were also significantly higher from control merit cows (p&lt;0.01). Mass and economic allocation methods, and land use functional units, resulted in differences in performance ranking of the dairy systems, with larger footprints resulting from mass allocation. Pairwise comparisons showed GHG's from the systems to be significantly different in total and source category emissions, with significant differences in mean embedded emissions found between most management systems (p&lt;0.05). Monte Carlo simulated system footprints considering the effect of variation in feed digestibility and crude protein also differed significantly from system footprints using standard methods (p &lt; 0.001). Dairy system carbon footprint results should be expressed using multiple units and where possible calculations should incorporate variation in diet digestibility and crude protein content.

Effects of Accelerated Carbonation Testing and by-Product Allocation on the CO2-Sequestration-to-Emission Ratios of Fly Ash-Based Binder Systems

Carbonation of cementitious binders implies gradual capture of CO2 and significant compensation for the abundant cement-related CO2 emissions. Therefore, one should always look at the CO2-sequestration-to-emission ratio (CO2SP/EM). Here, this was done for High-Volume Fly Ash (HVFA) mortar (versus two commercial cement mortars). Regarding their CO2 sequestration potential, effects of accelerated testing (at 1–10% CO2) on as such estimated natural carbonation degrees and rates were studied. Production related CO2 emissions were evaluated using life cycle assessment with no/economic allocation for fly ash. Natural carbonation rates estimated from accelerated tests significantly underestimate actual natural carbonation rates (with 29–59% for HVFA mortar) while corresponding carbonation degrees are significantly overestimated (67–74% as opposed to the actual 58% for HVFA mortar). It is advised to stick with the more time-consuming natural tests. Even then, CO2SP/EM values can vary considerably depending on whether economic allocation coefficients (Ce) were considered. This approach imposes significant portions of the CO2 emissions of coal-fired electricity production onto fly ash originating from Germany, China, UK, US and Canada. Ce values of ≥0.50% lower the potential CO2SP/EM values up to a point that it seems no longer environmentally worthwhile to aim at high-volume replacement of Portland cement/clinker by fly ash.

Modelling of different circular end-of-use scenarios for smartphones

Purpose Repairing, refurbishing and remanufacturing are three strategies of the Circular Economy (CE), aiming at closing product cycles and maintaining materials and resources in the product cycle as long as possible. This paper analyses the environmental impacts of these three circular end-of-use scenarios (repairing, refurbishing and part remanufacturing) when performed on a common, “non-circular” smartphone. The underlying data used for this paper partly have been result of the Horizon 2020 project sustainablySMART, where circular product concepts have been developed and analysed in detail. Methods To analyse the environmental impacts of different circular end-of-use scenarios of smartphones, a Life Cycle Assessment (LCA) is performed. For considering the impact of a smartphone’s first life (e.g. materials, production), an economic allocation is used. Since the goal of the study was to better understand the environmental impacts of processing routes that enable multiple life cycles of a product, allocation according to the economic value is applied instead of applying system expansion. As system expansion provides just an aggregated view of the first and second product life cycles and no decision support at the end of the first life regarding the relevant CE strategy can be given. The economic allocation is based on the ratio between the residual market value and the original price from the scenario’s input stream of smartphones of the respective end-of-use scenario. To reach comparability of the results, a second-use-time-parameter is defined for each scenario. This parameter takes into account that the second use time reaches only a certain share from the average smart phone use time. Results This study shows that through all three circular strategies, a reduction in the investigated impact categories—Global Warming Potential (GWP) and Abiotic Depletion Potential (ADP)—can be achieved. Conclusions The analysed end-of-use scenarios repairing and refurbishing show the highest potential for smartphones in terms of Circular Economy, as most of the environmental impacts can be allocated to the device production, and the impact of additional steps to perform CE-strategies (e.g. collection of discarded phones, refurbishing) is rather low.

Environmental Impacts of Beef as Corrected for the Provision of Ecosystem Services

We aimed to assess whether the environmental impacts in terms of global warming potential (GWP), acidification potential (AP), eutrophication potential (EP), and land occupation (LO) of beef can be decreased when ecosystem and cultural/provisioning services are included in the evaluation. We used four Italian production systems: Fat, with beef imported calves kept in confinement; CoCaI, with beef cows and calves kept in confinement; SpEx, with beef cows and calves kept on pasture and finishing conducted in confinement; and Pod, with Podolian cows and calves kept on pasture and finishing conducted in confinement. After the economic allocation, the GWP of system Pod decreased considerably and showed values lower than those computed for systems CoCaI and SpEx (P < 0.05 and P < 0.001, respectively). System Pod showed the lowest AP and EP as compared with all the other systems (P < 0.01). Systems Fat and CoCaI showed the smallest LO, with values lower than systems Pod (P < 0.05) and SpEx (P < 0.001). We conclude that the environmental impacts of extensive and local beef production systems in terms of GWP, AP, and EP was markedly reduced when the provision of accessory services was included in the calculation. Conversely, LO did not markedly change due to the high absolute values needed to allow pasture-based feeding. The estimation of additional positive aspects linked to the use of natural pastures, such as removal of carbon dioxide, increased biodiversity, and exploitation of feeds nonedible by humans, may allow a further reduction of LO.