Total Cumulative Energy Demand Research Articles

Environmental Impact Assessment of Organic Wheat Cracker Value Chains with and without Nettle Powder as a Natural Additive: A Case of Sweden

Due to the growing global population and consequent increased demand for food, the global production of cereal crops has increased. Wheat is one of the most important food crops in the world, as its products, e.g., bread and crackers, have served as important sources of nutrition for many years. However, the environmental impacts of wheat-derived food products are not frequently explored. This study presents an environmental impact assessment of organic wheat crackers within the context of Swedish winter wheat production using both primary and literature-based data. A cradle-to-consumer gate life cycle analysis (LCA) approach using the functional unit (FU) of 1 kg of crackers was applied while considering two cracker value chains: (i) without additives and (ii) using nettle powder as a natural additive. Four environmental impact categories—cumulative energy demand (CED), climate change impact (GWP), acidification, and eutrophication—were explored, with a particular focus on CED and GWP. The analysis results indicated that the total CED values were about 13 MJ/FU and 14 MJ/FU for crackers without and with the additive, respectively. Similarly, the total GWP values were 379 g CO2 eq/FU and 464 g CO2 eq/FU, respectively. The post-harvest processing and handling stage was an environmental hot spot in both cases. The introduction of the nettle additive has increased the quantified values of all four of the investigated impact categories. These insights will enable food processors and policy makers to communicate the environmental impacts and make informed decisions to improve the sustainability of wheat crackers. This paper contributes to a database of the environmental impacts of wheat products, specifically LCA data of organic wheat crackers and the LCA method for further LCA studies of snacks and other wheat products with plant-based functional additives.

Life Cycle Assessment of Dried Organic Apple Value Chains Considering Conventional and Heat-Pump-Assisted Drying Processes: The Case of Sweden

The increasing population pressure and demand for quality food, and the significant burden of agriculture on the environment, impede the sustainable development of the food sector. Understanding the environmental performance of different agricultural technologies and food value chains and identifying improvement opportunities play important roles in the sustainable development of this sector. This article presents the results of an environmental impact assessment of organic dried apples produced and supplied in Sweden, which was conducted using primary and literature-based data. A “cradle-to-consumer gate” life cycle analysis (LCA) method with a functional unit (FU) of 1 ton of fresh organic apples at the farm stage was used while considering conventional drying and heat-pump (HP)-assisted apple-drying techniques. The main environmental impact categories investigated were cumulative energy demand (CED), climate change impact (GWP), acidification potential (AP), and eutrophication potential (EP). The results indicate that the total CED values were 7.29 GJ and 5.12 GJ per FU for the conventional drying and HP-assisted drying methods, respectively, i.e., a reduction of about 30%. Similarly, the GWP values were 130 kg CO2 eq and 120 kg CO2 eq per FU, respectively. These findings highlight the importance of improving energy use and process efficiency to increase the sustainability of dried organic apple value chains.

Environmental sustainability assessment of softwood and hardwood seedlings production in forest nurseries: A case study from Pakistan.

This article describes the environmental impacts of producing a single seedling in forest nurseries of selected districts (i.e., Haripur, Abbottabad, and Mansehra) of Hazara Division of Khyber Pakhtunkhwa, Pakistan using the life cycle assessment (LCA) approach. This study was based on the cradle-to-gate approach which begins with the pre-nursery stage and progresses toward the main nursery before transplanting seedlings into the plantation site. Data or life cycle inventory (LCI) of seedling production were collected through questionnaire surveys and personal meetings with forest nurseries managers and workers regarding consumption of different inputs such as electricity, diesel, fertilizers, herbicides, and polyethylene bags, organic manure, and water consumption. The SimaPro software version 8.5 and the CML2000 v2.05 environmental model was applied to perform life cycle impact assessment (LCIA) for a single seedling production in forest nurseries in the study area. In line with the objectives of the study, primary data regarding inputs and outputs of the nurseries were collected from 35 nurseries in the study area by using a random questionnaire method. In addition, secondary data were taken from online databases such as Eco-invent v.3.2 CORRIM and peer-reviewed published literature. For this study, a functional unit of a single seedling was considered. Production weighted average data were modeled in the latest environmental modeling software i.e., SimaPro v.8.5 for ten US-EPA most wanted environmental impacts, such as global warming potential (GWP), abiotic depletion (AD), eutrophication potential (EP), acidification potential (AP), freshwater aquatic eco-toxicity (FAE), marine water eco-toxicity (MWE), terrestrial eco-toxicity (TE), ozone layer depletion (OLD), photochemical oxidation (PO), and human toxicity (HT). The results showed that the highest environmental impact posed by a single seedling was marine aquatic eco-toxicity (11.31360 kg 1,4-DB eq), followed by global warming potential (0.02945 kg CO2 eq) and (0.01227 kg 1,4-DB eq) human toxicity. The primary reason for these environmental burdens was the use of synthetic fertilizers in forest nurseries and the consumption of fossil fuels in nursery mechanization and transportation activities. The total cumulative energy demand for a single seedling was (0.800 MJ) with more than 90% contribution from fossil fuel energy resources such as petrol and diesel. It is therefore highly recommended to use renewable energy resources and organic fertilizers instead of chemical fertilizers in forest nurseries to avoid and minimize greenhouse gas emissions (GHS) and other toxic emissions in the study area.

Environmental sustainability assessment of wooden furniture produced in Pakistan.

Life cycle assessment was carried out for a conventional wooden furniture set produced in Mardan division of the Khyber Pakhtunkhwa province of Pakistan during 2018-19. Primary data regarding inputs and outputs were collected through questionnaire surveys from 100 conventional wooden furniture set manufacturers, 50 in district Mardan and 50 in district Swabi. In the present study, cradle-to-gate life cycle assessment approach was applied for a functional unit of one conventional wooden furniture set. Production weighted average data were modelled in the environmental impacts modelling software i.e., SimaPro v.8.5. The results showed that textile used in sofa set, wood preservative for polishing and preventing insects attack and petrol used in generator had the highest contribution to all the environmental impact categories evaluated. Total cumulative energy demand for wooden furniture set manufactured was 30,005 MJ with most of the energy acquired from non-renewable fossil fuel resources.

Investigations on the performance of xanthan gum as a foam stabilizer and assessment of economic and environmental impacts of foam concrete production

The properties of foam concrete are greatly influenced by the quality of the foam used. The stability of the foam is a vital property that needs dire attention when selecting surfactant. This paper evaluates the role of Xanthan gum (XG) as an additive in the performance improvement of foam produced with two different surfactants, viz., Hingot (Natural surfactant) and Nonylphenol ethoxylate (NPE) (Synthetic surfactant). Different characteristics of foam and surfactant, such as initial foam density, foam drainage, foam bubble microstructure, surface tension, and viscosity of surfactants, are experimentally evaluated. Addition of XG results in a 10-fold increment in viscosity for both Hingot and NPE surfactant solutions. The above enhancement in viscosity results in a substantial reduction in bubble size and an increment in lamella thickness. Further, the reduced surface tension of Hingot surfactant also contributes to a significant reduction in the rate of bubble coalescence. Having studied the surfactant and foam behaviour, the next phase comprises studies on the influence of XG on consistency, setting behaviour, compressive strength, and thermal conductivity of foam concrete with two different densities, viz., 1000 kg/m3 and 1500 kg/m3. Results show that the addition of XG results in a reduction in consistency and an increase in demoulding time of foam concrete. Besides improvement in foam performance, a substantial increase in compressive strength and reduction in thermal conductivity of FC is also observed due to XG addition, indicating that foam bubble microstructure has a significant impact. The last phase involves the life cycle assessment (LCA) of the FC produced with the aforementioned surfactants, which is the first of its kind study that considers the impact of surfactants across various environmental categories. Results of the LCA analysis show that the total cumulative energy demand of preparation of 1 kg of Hingot solution is less than that of 1 kg of NPE surfactant solution. The environmental impact analysis also favours Hingot as a sustainable and economical alternative to NPE surfactant. Results of LCA analysis of FC indicate that foam concrete with 1000 kg/m3 performs better than AAC block and conventional clay brick. Furthermore, the studies highlighted that there is more scope for improving the performance of LCA of FC through using various mineral admixtures as replacement for cement.

Environmental Impact Analysis to Achieve Sustainability for Artisan Chocolate Products Supply Chain

Small-scale artisan chocolate producers target environmentally conscious consumers and must work with their supply chain partners to measure and improve their environmental impacts. This research evaluates the environmental impact along the supply chain of artisan dark chocolate products in Indonesia and creates an action plan to reduce environmental impact. The Life Cycle Assessment (LCA) methodology was used. The analysis considers cocoa production from the farm level to the processing of cocoa beans into bars in three stages for 1 kg of dark chocolate: the farm maintenance and harvesting stage; post-harvesting stage; and processing stage. At the farm maintenance and harvesting stage, the significant contributions are 72.5% of total abiotic depletion (AD), 47.2% of total global warming (GW), 80.2% of total eutrophication (EU). The significant contributions at the post-harvesting are 31.2% of total AD, 51.8% of total GW, 83% of total EU, 26.4% of total ozone layer depletion (ODP), 20.1% of total cumulative energy demand (CED) and non-renewable fossil (NRF), and 36.9% of total CED renewable biomass (RB). And at the processing stage, the significant contributions are 20.5% of total AD, 15% of total GW, 4% of total ODP, 13.1% of total acidification (AC), 12% of total EU, 10% of total fossil resource scarcity (FRS), and 1.6% of total CED NRF. Changes to the farm maintenance and harvesting stages contributed the most to environmental impact reduction by improving waste utilization and the treatment and selection of environmentally friendly materials.

Environmental, Energy, and Water Footprints of Marble Tile Production Chain in a Life Cycle Perspective

The marble industry is growing in Pakistan, and Khyber Pakhtunkhwa province is the largest producer of marble tiles in Pakistan. Marble production consumes a considerable amount of water during its life cycle stages and impacts various environmental compartments, such as air, water, and soil; therefore, this study aimed to quantify the environmental impacts, water footprint, and cumulative energy demand of one-tonne marble tile manufactured in a small industrial estate Mardan (SIEM), Pakistan, and provide recommendations to improve its environmental impact profile. The study covers water consumption, energy use, and associated environmental impacts of raw materials and processes through different stages of the marble life-cycle during 2017–2018. The cradle-to-gate (extraction to factory gate or store house) life cycle assessment approach was followed in this study. The functional unit for the current study was one tonne of finished marble tile produced. Primary data from the field surveys and secondary data were modeled using the water scarcity index (WSI), CML 2000 v.2.05 methodology, and the cumulative energy demand indicator present by default in SimaPro v.8.3 software. The total water footprint required for one tonne of finished marble tile was 3.62 cubic meters per tonne (m3/t), with electricity consumed at processing units contributing to environmental burdens the most. Similarly, electricity consumed (at processing units and during polishing) and transportation of finished marble tile to the local market were responsible for global warming potential (388 kg CO2 eq/tonne tile), human toxicity (84.34 kg 1,4-DB-eq/tonne), freshwater aquatic ecotoxicity (94.97kg 1,4-DB eq/tonne) and abiotic depletion (7.1 × 10−5 kg Sb eq/tonne). The results of our study follow other marble tile LCA studies conducted globally (such as in Turkey and Italy), which also reported a high contribution to GWP, AP, EP, and HT due to electricity and fossil fuels consumption. The total cumulative energy demand (CED) was calculated as 5863.40 MJ (Mega Joule), with most energy usage associated with non-renewable fossil fuel sources. The results indicated that reducing electricity (using standard automatic machinery) and waste materials, especially paper and plastic wastes, can reduce environmental impacts. Most of the surveyed industrial units did not have wastewater treatment and recycling plants, and wastewater directly flows to nearby freshwater bodies and terrestrial ecosystems. These wastewaters should be adequately treated before being discharged into freshwater aquatic bodies. Environmental impacts must be improved by using the latest automatic machinery, reducing waste materials generation, reducing the distance between processing units and the market, and installing wastewater recycling plants.

Economic and embodied energy analysis of integrated circuit manufacturing processes

Integrated circuits (ICs) are the fundamental microelectronic building blocks of typical information and communication technology (ICT) devices such as laptops and smartphone. With the emergence of faster and cheaper low-power ICs for the growing ICT market, there is a limited information on their manufacturing energy and economic impacts owing to the lack of recurrent upgradation of proprietary IC manufacturing process data. Economic and life cycle energy assessments (LCAs) of IC manufacturing and assembly processes were conducted using the latest bill of materials (BOM) manufacturing data in a state-of-the-art IC manufacturing cost software tool developed by IC Knowledge, LLC. IC manufacturing cost was estimated to be $1.00-$5.00/cm2; the high-end cost represents the most advanced 3D NAND IC technology with the Wafer Level Chip Scale Package cost of $4/cm2. Total cumulative energy demand (CED) estimates of IC manufacturing using the OpenLCA software ranged from 9 to 38 MJ/cm2 or 56–235 BJ/month with the largest share (~ 75%) from on-site energy. The IC manufacturing CED is projected to increase with the progress in IC technology node, which has increased by more than two times for technology node evolution from 110 to 14 nm. Furthermore, the representative detailed BOM data were considered to reduce the CED uncertainties of the estimated standard deviation of 35%− 42%.

Assessing China’s potential for reducing primary copper demand and associated environmental impacts in the context of energy transition and “Zero waste” policies

To conserve resources and enhance the environmental performance, China has launched the “Zero waste” concept, focused on reutilization of solid waste and recovery of materials, including copper. Although several studies have assessed the copper demand and recycling, there is a lack of understanding on how different waste management options would potentially reduce primary copper demand and associated environmental impacts in China in the context of energy transition. This study addresses this gap in view of a transition to low-carbon energy system and the optimization of copper waste management combining MFA and LCA approaches. Six types of waste streams (C&DW, ELV, WEEE, IEW, MSW, ICW) are investigated in relation to various “Zero waste” strategies including reduction, reuse (repair, remanufacturing or refurbishment), recycling and transition from informal to formal waste management. Under present Chinese policies, reuse and recycling of copper containing products will lead to a somewhat lower dependency on primary copper in 2100 (11187Gg), as well as lower total GHG emissions (64869 Gg CO2-eq.) and cumulative energy demand (1.18x10^12 MJ). Maximizing such “Zero waste” options may lead to a further reduction, resulting in 65% potential reduction of primary copper demand, around 55% potential reduction of total GHG emissions and total cumulative energy demand in 2100. Several policy actions are proposed to provide insights into future waste management in China as well as some of the challenges involved.

Environmental impacts, water footprint and cumulative energy demand of match industry in Pakistan.

A comprehensive life cycle assessment (LCA) was conducted for the matchsticks industry in the Khyber Pakhtunkhwa province of Pakistan to quantify environmental footprint, water footprint, cumulative energy use, and to identify improvement opportunities in the matchsticks manufacturing process. One carton of matchsticks was used as reference unit for this study. Foreground data was collected from the matchsticks industry through questionnaire surveys, personal meetings, and field measurements. The collected data was transformed into potential environmental impacts through the Centre for Environment Studies (CML) 2000 v.2.05 method present by default in the SimaPro v.9.1 software. Water footprint was calculated using methodology developed by Hoekstra et al., 2012 (water scarcity index) V1.02 and cumulative energy demand by SimaPro v.9.1 software. The results showed that transport of primary material (wood logs), sawn wood for matchsticks, red phosphorous, acrylic varnish, and kerosene fuel oil contributed to the overall environmental impacts. Transport of primary materials and sawn timber for matchsticks contributed significantly to abiotic depletion, global warming, eutrophication potential, ozone depletion, corrosion, human toxicity, and aquatic ecotoxicity effects. The total water footprint for manufacturing one carton of matchsticks was 0.265332 m3, whereas the total cumulative energy demand was 715.860 Mega Joules (MJ), mainly sourced from non-renewable fossil fuels (708.979 MJ). Scenario analysis was also conducted for 20% and 30% reduction in the primary material distance covered by trucks and revealed that reducing direct material transport distances could diminish environmental impacts and energy consumption. Therefore, environmental footprint could be minimized through diverting matchsticks industries freight from indigenous routes to high mobility highways and by promoting industrial forestry close to industrial zones in Pakistan. Many industries did not have emissions control systems, exceeding the permissible limit for emissions established by the National Environmental Quality Standards (NEQS) of Pakistan. Thus, installation of emissions control system could also diminish emissions from match industry in Pakistan.

Applying data envelopment analysis (DEA) to improve energy efficiency of apple fruit, focusing on cumulative energy demand

Analysis of energy consumption provides useful information for planners and policymakers to improve the efficiency of energy consumption. Given the energy crisis which caused by the consumption of non-renewable resources in agriculture sector, a lot of attempts have been made to reduce the energy consumption of inputs as much as possible. The goal of this study is to evaluate the energy efficiency and determine the optimal pattern of input consumption and improve the efficiency in apple orchards. Based on the simple random sampling method and Cochran equation, sample size was determined as 30. Based on the results, inputs energy and output were obtained as 73092 and 59537 MJ ha-1, respectively and electricity was identified as major contributor to total energy consumption with the share of 37.91% (277707 MJ ha-1). Energy efficiency (ER), energy productivity (EP) and specific energy (SE) were determined as 0.82, 0.43 kg MJ-1 and 2.36 MJ kg-1, respectively. Results showed that the total amount of cumulative energy demand is 32159.92 MJ tonne-1 for five environmental impact categories, of which non-renewable fossil resources had highest contribution to total cumulative energy demand (98%). Based on data envelopment analysis (DEA) results and using constant returns to scale (CRS), 9233 MJ ha-1 of energy could be saved, means that applying DEA can mitigate energy consumption up to 12.6% in apple orchards. Also after optimization of energy flow in orchards, energy ratio and energy productivity were improved as 12.76% and 14%, respectively.

Bamboo grid versus polyvinyl chloride as packing material in cooling tower: Energy efficiency and environmental impact assessment

As an abundant and fast-growing biomass, bamboo can be used as construction materials owing to its desirable physical and mechanical properties, environmentally friendly features, and alternative to replace toxic and hazardous wastes in industrial processing. In this study, grid material made from bamboo (termed ‘bamboo grid’) was developed and compared to commercially used polyvinyl chloride (PVC) as packing material in cooling towers; PVC packing has drawbacks such as fouling, deposit buildup, low durability, and is harmful to environments. The cooling capacity, energy efficiency and environmental impact of bamboo grid packing were evaluated via life cycle assessment (LCA), particularly the cumulative energy demand (CED) and the Building for Environmental and Economic Sustainability (BEES). Although the thermal performance of the PVC packing was found higher than that of the bamboo grid packing, the bamboo grid packing showed improved resistance characteristic, recording a total saving of 529.2 tons of standard coal during a six-month field test in a real thermal power generation plant. LCA results revealed that the utilization of bamboo-grid packing to replace PVC packing in cooling towers reduced total CED from 3420 MJ to 561 MJ per functional unit, achieving 6 times reduction. A desirable reduction ranging from 1.5 to 10.5 times was also recorded for the BEES indices. This LCA comparison analysis confirmed the improvement of energy efficiency and reduction of environmental impact by using the bamboo grid to replace PVC as packing material in cooling towers. The major environmental impact (BEES) indices (e.g., the total Global warming potential, Acidification, Eutrophication and Smog) were reduced by 1.5–10.5 times via the use of bamboo grid. The results demonstrate that bamboo grid packing is a good alternative to replace existing grid packing materials such as concrete and PVC that are harmful to human health and environments.

Prospects of solar systems in production chain of sunflower oil using cold press method with concentrating energy and life cycle assessment

The aim of this study is determination of exergoenvironmental efficiency for using solar technologies in sunflower oil production in Iran. Accordingly, the applications of photovoltaic and photovoltaic/thermal systems were evaluated for both agricultural and industrial phases of sunflower oil production. Energy results reveal that 1 ton of sunflower oil consumes and produces about 180,354 and 39,400 MJ energy, respectively. About 86% of total energy consumption belongs to agricultural phase and electricity with 32%, has the highest share of total energy consumption. IMPACT 2002+ method and cumulative energy demand of life cycle assessment are applied to 3 defined scenarios including Present, photovoltaic and photovoltaic/thermal. Results indicate that total amounts of climate change in Present scenarios is 24537.53 kg CO2 eq. . The highest share of human health (90%), ecosystem quality (90%) and climate change (50%) in all scenarios belongs to direct emissions. Results also illustrates that total cumulative energy demand of Present, photovoltaic and photovoltaic/thermal scenarios are about 177,538, 99,054 and 132,158 MJ 1TSO−1, respectively. Furthermore, the most contribution of non-renewable resources and fossil fuels belongs to electricity (37%), nitrogen (52%) and photovoltaic/thermal panels (39%) in Present, photovoltaic and photovoltaic/thermal scenarios, respectively. Finally the photovoltaic scenario is the best environmental-friendly scenario.

Development of an integrated tool based on life cycle assessment, Levelized energy, and life cycle cost analysis to choose sustainable Facade Integrated Photovoltaic Systems

Facade Integrated Photovoltaic Systems (FIPS) is considered the most promising strategy to utilize solar power in various buildings and enhance its energy efficiency in recent years. The sustainability performance of FIPS needs to be evaluated. Hence, this study aims to analyze and compare the life cycle impacts of FIPS using energy analysis, life cycle assessment (LCA), and life cycle costing (LCC), from cradle-to-grave to identify the most sustainable alternative. Three types of PV facades using cadmium telluride (CdTe), dye sensitizes (DSS), and Perovskite modules were investigated to determine the best and worst economic and environmental options. Life cycle impact assessment was performed through cumulative energy demand (CED), ReCiPe, greenhouse gas (GHG) emission rate, and the energy payback time (EPBT). The ReCiPe results indicated that Perovskite and CdTe façades created the lowest and highest environmental burdens, regardless of their lifespan. The module fabrication, along with panel manufacturing, was the major contributor to the environmental impacts. Furthermore, the total CED for the CdTe facade was 1975.6 MJ per m2, which was significantly higher than that for perovskite (587.1 MJ) and DSS (1177.4 MJ) facades. Besides, the EPBT of DSS, CdTe, and Perovskite facades was 1.57, 1.21, and 0.6 years, respectively. Moreover, the economic analysis, including LCC and the Levelized cost of electricity (LCOE) of the DSS façade was estimated at 204 $ and 0.12 $/kWh, which indicated the lowest quantity among other facades. Hierarchical adaptive weighting (HAW) was utilized as a multi-criteria decision-making (MCDM) tool which assists to combine the suggested various criteria in environmental (e.g., GHG emission rate, ReCiPe, CED), economic (e.g., LCC and LCOE), and energy (EPBT) aspects to a sustainability index. Therefore, the analysis results indicated that the Perovskite façade was the most sustainable options for building. However, the integrated LCC-LCA- HAW implies that choosing an option depends on the policy maker’s approach.

Cradle-to-gate environmental impacts of sulfur-based solid-state lithium batteries for electric vehicle applications

In this study, we investigate the cradle-to-gate environmental impacts of a pre-production sulfur-based solid-state lithium pyrite battery suitable for electric vehicle applications. We apply process-based attributional life cycle assessment methodology, utilizing laboratory data, literature, U.S. patents, and US-EI 2.2 life cycle inventory database to estimate the materials and energy required for the battery and its anticipated manufacturing and assembly processes. We estimate a mass of 440 kg and a specific capacity of 182 Wh kg−1 for a battery with 80 kWh energy capacity and 100 kW power, capable of powering a full-size battery electric vehicle with a 200-mile range. The estimated cumulative energy demand (CED) and global warming potential for a 100-year time horizon (GWP100) are 3300 MJ kWh−1 and 199 kg CO2 eq. kWh−1, respectively. The combination of direct and upstream energy associated with clean dry-room operation accounts for the biggest share of the total CED (75%) and GWP100 (73%), followed by the cathode paste (10% and 6%, respectively). The energy demand and environmental impacts of the clean dry-room and cathode paste present opportunities to improve production processes and reduce costs. CED and GWP100 impacts associated with battery production are lower than well-to-wheel energy consumption and emissions for a vehicle with the same size and range. The pyrite battery delivers higher specific capacity than the current Li-ion battery chemistries while its CED and GWP100 environmental impacts are comparable.

Environmental life cycle assessment of seafood production: A case study of trawler catches in Tunisia

The Gulf of Gabes is one of the most productive fishery areas in the southern Mediterranean Sea. It is archetypal of an ecosystem in which the effects of fisheries are most pronounced. Demersal trawling is the main fishing activity in the Gulf of Gabes. Life Cycle Assessment (LCA) was applied to assess the environmental performance landing 1t of seafood with wooden demersal trawlers in the Gulf of Gabes. Impact categories included in the study were abiotic depletion potential (ADP), acidification potential (AP), eutrophication potential (EP), global warming potential (GWP), ozone depletion potential (ODP), photochemical oxidant formation potential (POFP), human toxicity potential (HTP), marine eco-toxicity potential (METP), terrestrial eco-toxicity potential (TETP), land occupation potential (LOP), and total cumulative energy demand (TCED). Demersal trawlers were classified based on their impact intensity. Results showed that 70% of the vessels had relatively low impacts. Impact intensity was proportional to the amount of fuel consumed to land 1t of seafood. Ships that fished less had the highest impacts per ton, due to lower fishing effort and catch per unit effort. This is likely to typify vessels that target highly valuable species such as shrimp. Onboard vessel activities contributed most to different environmental impacts (AP, EP, GWP and POFP), related to the high energy use of this fishery. Several impacts (ADP, ODP, METP, LOP and TCED) were associated mainly with fuel and lubricating oil production. Therefore, improvements must focus on minimizing fuel consumption. LCA is a valuable tool for assessing how to increase environmental sustainability of demersal trawling and it can help stakeholders identify the main operational issues that require improvement.

Rearing performances and environmental assessment of sea cage farming in Tunisia using life cycle assessment (LCA) combined with PCA and HCPC

The present study aims to understand the influence of rearing practices and the contributions of production phases of fish farming to their environmental impacts and determine which practices and technical characteristics can best improve the farms’ environmental performance. Another objective is to identify the influence of variability in farming practices on the environmental performances of sea cage aquaculture farms of sea bass and sea bream in Tunisia by using principal component analysis (PCA) and hierarchical clustering on principal components (HCPC) methods and then combining the classification with life cycle assessment (LCA). The approach consisted of three major steps: (i) of the 24 aquaculture farms in Tunisia, 18 were selected which follow intensive rearing practices in sea cages of European sea bass (Dicentrarchus labrax) and gilthead sea bream (Sparus aurata) and then a typology was developed to classify the studied farms into rearing practice groups using HCPC; (ii) LCA was performed on each aquaculture farm and (iii) mean impacts and contributions of production phases were calculated for each group of farms. Impact categories included acidification, eutrophication, global warming, land occupation, total cumulative energy demand and net primary production use. Results revealed high correlation between rearing practices and impacts. The feed-conversion ratio (FCR), water column depth under the cages and cage size had the greatest influence on impact intensity. Rearing practices and fish feed were the greatest contributors to the impacts studied due to the production of fish meal and oil and the low efficiency of feed use, which generated large amounts of nitrogen and phosphorus emissions. It is necessary to optimise the diet formulation and to follow better feeding strategies to lower the FCR and improve farm performance. Water column depth greatly influenced the farms’ environmental performance due to the increase in waste dispersion at deeper depths, while shallow depths resulted in accumulation of organic matter and degradation of water quality. Cage size influences environmental performances of aquaculture farms. Thus, from an environmental viewpoint, decision makers should grant licences for farms in deeper water with larger cages and encourage them to improve their FCRs. This study is the first attempt to combine the HCPC method and the LCA framework to study the environmental performance of aquacultural activity. The typology developed captures the variability among farms because it considers several farm characteristics in the classification. The LCA demonstrated that technical parameters in need of improvement are related to the technical expertise of farm managers and workers and to the location of the farm.

Environmental performance evaluation of a grid-independent solar photovoltaic power generation (SPPG) plant

This paper presents the environmental analysis of a solar photovoltaic power generation (SPPG) plant model, proposed for small off-grid communities. The analysis carefully considers both the life cycle energy- and the emission-related impacts of the plant's components, such as the PV array and the balance of system (BOS). Results reveal that a proposed 54.15 kW SPPG plant has global warming potential (GWP) ranging from 72,445 to 75,085 kg CO2−eq. The results further show that the battery system accounts for ∼85–90% of the plant's GWP impact. The battery also accounts for ∼68–75% of the total cumulative energy demand (CED) of 7.01–10.36 × 106 MJ. The energy payback times (EPT) for the PV-only range from 2.12 to 4.39 years, while a relatively higher value of 9.41–10.36 years was obtained for the PV and the BOS. The net energy ratio (NER) values of 4.56–9.43 and 2.24–2.52 were obtained for the PV-only and the PV with BOS, respectively, for a lifetime of 20 years. The NERs obtained for a lifetime of 25 years were 5.7–11.79 and 2.41–2.66, while the values obtained for a 30-year lifetime range from 6.83 to 14.15 and 2.54 to 2.78. These results have been obtained under different solar irradiation levels, lifetimes and performance ratios (PRs) of 1450–2200 kWh/m2/yr, 20–30 years and 60–80%. The research outputs demonstrate that the battery system has the highest life cycle energy and emissions impact because of its relatively shorter lifespan and the replacements over the system's lifetime. However, a sensitivity analysis reveals that the impact of the battery reduces as the lifespan increases. In addition, the GWP and the EPTs increases as the PRs are decreased, while the NERs are reduced. The significance of the study is that it reveals the effect of solar irradiation, lifetimes, PRs and the battery lifespan on the SPPG plant's environmental performance, which can be a basis for understanding solar PV life cycle impact for different locations around the world.

Seaweed as innovative feedstock for energy and feed – Evaluating the impacts through a Life Cycle Assessment

Offshore cultivation of seaweed provides an innovative feedstock for biobased products supporting blue growth in northern Europe. This paper analyzes two alternative exploitation pathways: energy and protein production. The first pathway is based on anaerobic digestion of seaweed which is converted into biogas, for production of electricity and heat, and digestate, used as fertilizer; the second pathway uses seaweed hydrolysate as a substrate for cultivation of heterotrophic microalgae. As a result the seaweed sugars are consumed while new proteins are produced enhancing the total output. We performed a comparative Life Cycle Assessment of five scenarios identifying the critical features affecting resource efficiency and environmental performance of the systems with the aim of providing decision support for the design of future industrial scale production processes. The results show that all scenarios provide environmental benefits in terms of mitigation of climate change, with biogas production from dried Laminaria digitata being the most favorable scenario, quantified as −18.7*102 kg CO2 eq./ha. This scenario presents also the lowest consumption of total cumulative energy demand, 1.7*104 MJ/ha, and even resulting in a net reduction of the fossil energy fraction, −1.9*104 MJ/ha compared to a situation without seaweed cultivation. All scenarios provide mitigation of marine eutrophication thanks to bioextraction of nitrogen and phosphorus during seaweed growth. The material consumption for seeded lines has 2–20 times higher impact on human toxicity (cancer) than the reduction achieved by energy and protein substitution. However, minor changes in cultivation design, i.e. use of stones instead of iron as ballast to weight the seeded lines, dramatically reduces human toxicity (cancer). Externalities from the use of digestate as fertilizer affect human toxicity (non-cancer) due to transfer of arsenic from aquatic environment to agricultural soil. However concentration of heavy metals in digestate does not exceed the limit established by Danish regulation. The assessment identifies seaweed productivity as the key parameter to further improve the performance of the production systems which are a promising service provider of environmental restoration and climate change mitigation.

Environmental assessment of seabass (Dicentrarchus labrax) and seabream (Sparus aurata) farming from a life cycle perspective: A case study of a Tunisian aquaculture farm

Life Cycle Assessment (LCA) was applied to assess potential environmental impacts generated by production of 1ton of European seabass (Dicentrarchus labrax) and gilthead seabream (Sparus aurata) on a sea-cage aquaculture farm in Tunisia. The studied farm produces 2100tons of fish per year. Impact categories included in the current study were acidification, eutrophication, global warming, land occupation, total cumulative energy demand and Net Primary Production Use (NPPuse). In addition, a refinement of “sea use” impact category was proposed to assess impacts of aquaculture on the area of sea required and seabed degradation. Calculations were performed using the software SimaPro® 8.0, and the database ecoinvent 3.0 was used for background data. Uncertainty analysis was performed using Monte-Carlo simulations. Results of this study indicate that seabass rearing has lower mean impact than seabream rearing for all the impact categories considered. However, no significant differences were observed in all the impact categories except the global warming. Fish feed is the main contributor to most of the impacts studied, which is directly related to production of fish meal and oil as feed ingredients and the large amounts of nitrogen and phosphorus released into the environment. Management decisions aiming to optimize production and use of fish feed may have a positive impact on the environmental performance of the farm. It is essential to optimize diet formulation and to follow better feeding strategies and farming practices (e.g. stock management, feed distribution, accurate ration calculation) to lower feed-conversion ratios and consequently improve the environmental performance of aquaculture farms. LCA is a valuable tool for assessing decisions for improving environmental sustainability of aquaculture because it performs overall impact assessment and helps identify main areas for improvement.