Diego Iribarren

Benchmarking environmental and operational parameters through eco-efficiency criteria for dairy farms

Life Cycle Assessment (LCA) is often used for the environmental evaluation of agri-food systems due to its holistic perspective. In particular, the assessment of milk production at farm level requires the evaluation of multiple dairy farms to guarantee the representativeness of the study when a regional perspective is adopted. This article shows the joint implementation of LCA and Data Envelopment Analysis (DEA) in order to avoid the formulation of an average farm, therefore preventing standard deviations associated with the use of average inventory data while attaining the characterization and benchmarking of the operational and environmental performance of dairy farms. Within this framework, 72 farms located in Galicia (NW Spain) were subject to an LCA+DEA study which led to identify those farms with an efficient operation. Furthermore, target input consumption levels were benchmarked for each inefficient farm, and the corresponding target environmental impacts were calculated so that eco-efficiency criteria were verified. Thus, average reductions of up to 38% were found for input consumption levels, leading to impact reductions above 20% for every environmental impact category. Finally, the economic savings arising from efficient farming practices were also estimated. Economic savings of up to 0.13€ per liter of raw milk were calculated, which means extra profits of up to 40% of the final raw milk price.

The link between operational efficiency and environmental impacts: A joint application of Life Cycle Assessment and Data Envelopment Analysis

Life Cycle Assessment (LCA) allows the estimation of the environmental impacts of a process or product. Those environmental impacts depend on the efficiency with which operations are carried out. In the case that LCA data are available for multiple similar installations, their respective operational performances can be benchmarked and links between operational efficiency and environmental impacts can be established. In this paper, this possibility is illustrated with a case study on LCA of mussel cultivation in rafts. For each site (raft) both its inputs consumption and mussel production are known. A separate LCA of each site has been performed and its corresponding environmental impacts have been estimated. Using Data Envelopment Analysis (DEA) on the input/output data allows computing the relative efficiency of each mussel raft and setting appropriate efficiency targets. The DEA targets represent virtual cultivation sites, which consume less input and/or produce more output. The performance of an LCA study for each of these virtual cultivation sites and the comparison between their environmental impacts are used to estimate the environmental impacts consequences of operational inefficiencies. This direct link can help to convince the managers and operators of the cultivation sites of the double dividend of reducing inputs consumption and achieve operational efficiency: lower costs and lower environmental impacts.

Further potentials in the joint implementation of life cycle assessment and data envelopment analysis

The combined application of Life Cycle Assessment and Data Envelopment Analysis has been recently proposed to provide a tool for the comprehensive assessment of the environmental and operational performance of multiple similar entities. Among the acknowledged advantages of LCA+DEA methodology, eco-efficiency verification and avoidance of average inventories are usually highlighted. However, given the novelty of LCA+DEA methods, a high number of additional potentials remain unexplored. In this sense, there are some features that are worth detailing given their wide interest to enhance LCA performance. Emphasis is laid on the improved interpretation of LCA results through the complementary use of DEA with respect to: (i) super-efficiency analysis to facilitate the selection of reference performers, (ii) inter- and intra-assessments of multiple data sets within any specific sector with benchmarking and trend analysis purposes, (iii) integration of an economic dimension in order to enrich sustainability assessments, and (iv) window analysis to evaluate environmental impact efficiency over a certain period of time. Furthermore, the capability of LCA+DEA methodology to be generally implemented in a wide range of scenarios is discussed. These further potentials are explained and demonstrated via the presentation of brief case studies based on real data sets.

Estimation of the carbon footprint of the Galician fishing activity (NW Spain).

The food production system as a whole is recognized as one of the major contributors to environmental impacts. Accordingly, food production, processing, transport and consumption account for a relevant portion of the greenhouse gas (GHG) emissions associated with any country. In this context, there is an increasing market demand for climate-relevant information regarding the global warming impact of consumer food products throughout the supply chains. This article deals with the assessment of the carbon footprint of seafood products as a key subgroup in the food sector. Galicia (NW Spain) was selected as a case study. The analysis is based on a representative set of species within the Galician fishing sector, including species obtained from coastal fishing (e.g. horse mackerel, Atlantic mackerel, European pilchard and blue whiting), offshore fishing (e.g. European hake, megrim and anglerfish), deep-sea fishing (skipjack and yellowfin tuna), extensive aquaculture (mussels) and intensive aquaculture (turbot). The carbon footprints associated with the production-related activities of each selected species were quantified following a business-to-business approach on the basis of 1year of fishing activity. These individual carbon footprints were used to calculate the carbon footprint for each of the different Galician fisheries and culture activities. Finally, the lump sum of the carbon footprints for coastal, offshore and deep-sea fishing and extensive and intensive aquaculture brought about the carbon footprint of the Galician fishing activity (i.e., capture and culture). A benchmark for quantifying and communicating emission reductions was then provided, and opportunities to reduce the GHG emissions associated with the Galician fishing activity could be prioritized.

Biomass Pyrolysis for Biochar or Energy Applications? A Life Cycle Assessment

The application of biochar as a soil amendment is a potential strategy for carbon sequestration. In this paper, a slow pyrolysis system for generating heat and biochar from lignocellulosic energy crops is simulated and its life-cycle performance compared with that of direct biomass combustion. The use of the char as biochar is also contrasted with alternative use options: cofiring in coal power plants, use as charcoal, and use as a fuel for heat generation. Additionally, the influence on the results of the long-term stability of the biochar in the soil, as well as of biochar effects on biomass yield, is evaluated. Negative greenhouse gas emissions are obtained for the biochar system, indicating a significant carbon abatement potential. However, this is achieved at the expense of lower energy efficiency and higher impacts in the other assessed categories when compared to direct biomass combustion. When comparing the different use options of the pyrolysis char, the most favorable result is obtained for char cofiring substituting fossil coal, even assuming high long-term stability of the char. Nevertheless, a high sensitivity to biomass yield increase is found for biochar systems. In this sense, biochar application to low-quality soils where high yield increases are expected would show a more favorable performance in terms of global warming.

Computation of Operational and Environmental Benchmarks Within Selected Galician Fishing Fleets

Increasing the eco‐efficiency of fishing fleets is currently a major target issue in the seafood sector. This objective has been influenced in recent years by soaring fuel prices, a fact particularly relevant to a sector whose vessels present high energy consumption rates. Efforts to minimize fuel consumption in fishing fleets result in economic benefits and also in important reductions regarding environmental impacts. In this article, we combine life cycle assessment (LCA) and data envelopment analysis (DEA) to jointly discuss the operational and environmental performances of a set of multiple, similar entities. We applied the “five‐step LCA + DEA method” to a wide range of vessels for selected Galician fisheries, including deep‐sea, offshore, and coastal fleets. The environmental consequences of operational inefficiencies were quantified and target performance values benchmarked for inefficient vessels. We assessed the potential environmental performance of target vessels to verify eco‐efficiency criteria (lower input consumption levels, lower environmental impacts). Results revealed the strong dependence of environmental impacts on one major operational input: fuel consumption. The most intensive fuel‐consuming fleets, such as deep sea trawling, were found to entail the diesel consumption levels nearest to the efficiency values. Despite the reduced environmental contributions linked to other operational inputs, such as hull material, antifouling paint, or nets, these may contribute to substantial economic savings when minimized. Finally, given that Galicia is a major fishing region, many of the conclusions and perspectives obtained in this study may be extrapolated to other fishing fleets at the international level.

Review of life-cycle approaches coupled with data envelopment analysis: launching the CFP + DEA method for energy policy making.

Life-cycle (LC) approaches play a significant role in energy policy making to determine the environmental impacts associated with the choice of energy source. Data envelopment analysis (DEA) can be combined with LC approaches to provide quantitative benchmarks that orientate the performance of energy systems towards environmental sustainability, with different implications depending on the selected LC + DEA method. The present paper examines currently available LC + DEA methods and develops a novel method combining carbon footprinting (CFP) and DEA. Thus, the CFP + DEA method is proposed, a five-step structure including data collection for multiple homogenous entities, calculation of target operating points, evaluation of current and target carbon footprints, and result interpretation. As the current context for energy policy implies an anthropocentric perspective with focus on the global warming impact of energy systems, the CFP + DEA method is foreseen to be the most consistent LC + DEA approach to provide benchmarks for energy policy making. The fact that this method relies on the definition of operating points with optimised resource intensity helps to moderate the concerns about the omission of other environmental impacts. Moreover, the CFP + DEA method benefits from CFP specifications in terms of flexibility, understanding, and reporting.

Updating the carbon footprint of the Galician fishing activity (NW Spain)

Recent life cycle assessment studies have revealed the relevance of cooling agent leakage when assessing the greenhouse gas (GHG) emissions generated by fishing vessel operations. The goal of this communication is to update the carbon footprinting of the Galician fishing activity (NW Spain) by including the GHG emissions from cooling agent leakage. Results proved the relevant role played by refrigerants regarding their contribution to the carbon footprint of fishing activities. Thus, an overall increase of 13% was found when comparing the final global carbon footprint for the Galician fishing activity with previous calculations that did not include these emissions. Nevertheless, further efforts should be made in order to provide robust data in this respect.

On the feasibility of producing hydrogen with net carbon fixation by the decomposition of vegetable and microalgal oils

The decomposition of vegetable and microalgal oils was herein analysed as a process of high interest for the production of both hydrogen and carbon, which potentially entails the advantage of attaining a negative CO2 balance through carbon fixation. The feasibility of a series of oil decarbonization systems was evaluated by means of energy and CO2 balances, which comprised not only the direct decarbonization process itself but also the cultivation and oil extraction stages. Three potential scenarios were assessed, embracing different options to meet the energy requirements of the systems. For each scenario, a wide range of case studies were evaluated, involving the use of rapeseed, sunflower, soybean, jatropha, Botryococcus braunii and Chlorella vulgaris oils as raw materials. Favourable energy and CO2 balances were found for a variety of crops in different scenarios. In particular, jatropha oil from high seed yield crops and rapeseed oil from high seed yield and high oil content crops were identified as the most promising biomass feedstocks for oil decarbonization since they led to net hydrogen production as well as to negative balances of CO2 emissions, therefore showing a carbon fixation effect. When compared to vegetable/microalgal oil transesterification to produce biodiesel, oil decomposition proved to be a more suitable alternative from a combined energy and environmental approach.

Life cycle assessment of hydrogen energy systems: a review of methodological choices

PurposeAs a first step towards a consistent framework for both individual and comparative life cycle assessment (LCA) of hydrogen energy systems, this work performs a thorough literature review on the methodological choices made in LCA studies of these energy systems. Choices affecting the LCA stages “goal and scope definition”, “life cycle inventory analysis” (LCI) and “life cycle impact assessment” (LCIA) are targeted.MethodsThis review considers 97 scientific papers published until December 2015, in which 509 original case studies of hydrogen energy systems are found. Based on the hydrogen production process, these case studies are classified into three technological categories: thermochemical, electrochemical and biological. A subdivision based on the scope of the studies is also applied, thus distinguishing case studies addressing hydrogen production only, hydrogen production and use in mobility and hydrogen production and use for power generation.Results and discussionMost of the hydrogen energy systems apply cradle/gate-to-gate boundaries, while cradle/gate-to-grave boundaries are found mainly for hydrogen use in mobility. The functional unit is usually mass- or energy-based for cradle/gate-to-gate studies and travelled distance for cradle/gate-to-grave studies. Multifunctionality is addressed mainly through system expansion and, to a lesser extent, physical allocation. Regarding LCI, scientific literature and life cycle databases are the main data sources for both background and foreground processes. Regarding LCIA, the most common impact categories evaluated are global warming and energy consumption through the IPCC and VDI methods, respectively. The remaining indicators are often evaluated using the CML family methods. The level of agreement of these trends with the available FC-HyGuide guidelines for LCA of hydrogen energy systems depends on the specific methodological aspect considered.ConclusionsThis review on LCA of hydrogen energy systems succeeded in finding relevant trends in methodological choices, especially regarding the frequent use of system expansion and secondary data under production-oriented attributional approaches. These trends are expected to facilitate methodological decision making in future LCA studies of hydrogen energy systems. Furthermore, this review may provide a basis for the definition of a methodological framework to harmonise the LCA results of hydrogen available so far in the literature.