Cumulative energy demand as predictor for the environmental burden of commodity production

Room Temperature Sensing of Volatile Organic Compounds Using Hybrid Layered SnO Mesoflowers and Laser-Induced Graphitic Carbon Devices

In this work, we demonstrate chemiresistive volatile organic compound (VOC) sensors prepared by drop-cast assembly of layered tin monoxide mesoflowers (SnO-MFs) on additively produced laser-induced graphene-like carbon (LIG). The SnO-MFs were synthesized below 100 °C at ambient pressure and offer a low fabrication energy alternative route to typical furnace-prepared metal-oxide materials. The additive dropcast assembly of room-temperature operating metal oxide active material allows the substitution of LIG for metal current collectors and glass for alumina, reducing the environmental footprint of the sensor. The sensors can detect methanol (150-4000 ppm) at room temperature and humidity (∼18 °C, ∼55% RH), with response and recovery times (150 ppm methanol) of t 90,resp ≈ 50 ± 10 s and t 90,rec ≈ 5 ± 0.5 s, respectively. The sensors demonstrated a limit of detection (170 ± 40 ppm) below 8 h worker safety exposure levels (200 ppm) and stable DC resistance responses ΔR/R = 9 ± 2% to 710 ppm of methanol for over 21 days in ambient laboratory conditions, n = 4. First-principles density functional theory simulations were used to elucidate the interactions of VOC species on the SnO surfaces. LIG-SnO hybrid sensors thus present a resource-efficient route to develop chemiresistive sensors for low-power applications, although with cross-selectivity to other alcohol species.

Life cycle analysis of the wastewater treatment system in Zabol Industrial Town: Environmental impacts, energy demand, and greenhouse gas emissions

Use of effective environmental remediation facilities represents a crucial strategy for water reclamation and addressing the challenges of water scarcity. The objective of this study was to assess the wastewater treatment system (WWTS) in Zabol Industrial Town using the life cycle assessment method. Primary data, collected annually for a functional unit of 1 m3 of wastewater treatment, were subjected to analysis using the ReCiPe, Cumulative Energy Demand, and Intergovernmental Panel on Climate Change (IPCC) methods. Human carcinogenic toxicity (50%), freshwater ecotoxicity (13%), and marine ecotoxicity (10%) were the primary environmental impacts due to the WWTS performance. The discharge of heavy metals during sludge generation, coupled with the consumption of natural gas and oil, especially for electricity production, were pivotal factors contributing to the environmental burdens observed. Furthermore, chemical oxygen demand (COD) (56.34%), electricity consumption (>15.47%), and total phosphorous (>4.49%) significantly threatened human health and ecosystem categories, while fossil fuel consumption had the greatest impact on resources. Nonrenewable fossil fuels, namely, natural gas (47.2%) and oil (38.27%), played a predominant role in the energy provision of the system. The IPCC analysis depicted the emissions of CO2 (86.77%) and CH4 (12.16%) stemming from the process of electricity generation. Based on the outcomes of the sensitivity analysis, implementing a 10% increase in COD yielded an increment in all impacts within the range of 1.40% to 6.83%. Given Iran's geographic location and the unique climatic conditions in Zabul, use of solar and wind energy to energize the WWTS can substantially alleviate its environmental burdens. This study presents a comprehensive framework for evaluating the environmental impact, energy consumption, and carbon footprint of a WWTS. Integr Environ Assess Manag 2024;20:1747-1758. © 2024 SETAC.

Assessing the environmental impacts of copper cathode production based on life cycle assessment

The demand for copper is growing considerably in parallel with economic and technological development. The rate increase in copper consumption in Iran increases pressure on the numerous unexploited mines in southeast Iran and causes the environmental crisis alongside the northern Levar wind in this area. Given this, this study systematically explored the environmental impacts of a one-ton copper cathode processing operation from a cradle-to-gate perspective, using life cycle assessment (LCA). Moreover, the release of greenhouse gases and the energy consumption during the copper cathode production were also assessed. The results indicated that sulfuric acid use in the smelting and extraction stages, metal leaching from tailings, and CO2 dominated more than 50% of contributions to freshwater and marine ecotoxicity, human toxicity, and global warming. The energy analysis revealed 88.92% of crude oil use especially for the electrowinning stage, which should be promoted technologically. For global warming, the indirect CO2 emission from electricity consumption using fossil fuels was the main contributor (94.56%). Therefore, shifting from conventional energy systems to renewable energy systems could alleviate the overall environmental impact. For a 0.57-ton sulfuric acid effluent per one ton of copper cathode production, its treatment and reuse in the process is recommended. Summing up, the results of this study provide the environmental hot spots for copper cathode production for further investigation. Integr Environ Assess Manag 2024;20:1180-1190. © 2023 SETAC.

Compiling life cycle inventories for wastewater-derived products

With the paradigm shift in wastewater management from pollutant removal to resource recovery, more wastewater-derived products are emerging from different recovery pathways. It is becoming increasingly important to understand the potential environmental impacts of these products through life cycle assessment (LCA). This study aims to compile life cycle inventories of wastewater-derived products from the perspective of the product end users (e.g., agricultural sector, packaging industry), and to explore the challenges of their compilation. Using inventories from wastewater resource recovery LCA literature, we compiled an attributional inventory (88 sets) and a consequential inventory (33 sets) of three categories of wastewater-derived products - phosphorus compounds, nitrogen compounds, and biopolymers. The two inventories differ by the choices of system boundary, how foreground systems are being modelled, and how co-products are being handled. We found that while there is a large body of literature related to wastewater resource recovery LCA, very few studies (29 out of 174 for the three categories of products) are suitable for end users to successfully compile inventories of derived products. The inventories were assessed by the technology readiness level assessment, the data quality assessment, and the cumulative energy demand indicator. The inventories can be used directly by end users or served as "screening" inventories for end users to prioritize data collection effort. The identified challenges of inventory compilation include diverse recovery settings, the absence of baseline scenarios, the multifunctional nature of wastewater treatment plants, the lack of inventory transparency and completeness, and low technology readiness level for some recovery pathways. While established or emerging approaches exist to address most of these challenges for end users, wastewater resource recovery LCA practitioners can enhance their assessments to be more end-user-oriented. This can be achieved by including baseline non-recovery scenarios, disclosing detailed life cycle inventory by system components, and assessing a wide variety of operating scenarios. Addressing some of these compilation challenges would enhance the comprehensiveness and quality of wastewater-derived product inventories.

A Comprehensive Study from Cradle-to-Grave on the Environmental Profile of Malted Legumes

Three representative pulses from the Latium region of Italy (namely, Solco Dritto chickpeas, SDC, Gradoli Purgatory beans, GPB, and Onano lentils, OL) underwent malting to reduce their anti-nutrient content, such as phytic acid and flatulence-inducing oligosaccharides. This initiative targets the current low per capita consumption of pulses. Employing Life Cycle Analysis, their environmental impact was assessed, revealing an overall carbon footprint of 2.8 or 3.0 kg CO2e per kg of malted (M) and decorticated (D) SDCs or GPBs and OLs, respectively. The Overall Weighted Sustainability scores (OWSS) complying with the Product Environmental Footprint method ranged from 298 ± 30 to 410 ± 40 or 731 ± 113 µPt/kg for malted and decorticated SDCs, OLs, or GPBs, indicating an increase from 13% to 17% compared to untreated dry seeds. Land use impact (LU) was a dominant factor, contributing 31% or 42% to the OWSS for MDSDCs or MDOLs, respectively. In MDGPBs, LU constituted 18% of the OWSS, but it was overshadowed by the impact of water use arising from bean irrigation, accounting for approximately 52% of the OWSS. This underscores the agricultural phase's pivotal role in evaluating environmental impact. The climate change impact category (CC) was the second-largest contributor, ranging from 28% (MDSDCs) to 22% (MDOLs), and ranking as the third contributor with 12% of the OWSS for MDGPBs. Mitigation should prioritize the primary impact from the agricultural phase, emphasizing land and water utilization. Selecting drought-tolerant bean varieties could significantly reduce OWSSs. To mitigate climate change impact, actions include optimizing electricity consumption during malting, transitioning to photovoltaic electricity, upgrading transport vehicles, and optimizing pulse cooking with energy-efficient appliances. These efforts, aligning with sustainability goals, may encourage the use of malted and decorticated pulses in gluten-free, low fat, α-oligosaccharide, and phytate-specific food products for celiac, diabetic, and hyperlipidemic patients. Overall, this comprehensive approach addresses environmental concerns, supports sustainable practices, and fosters innovation in pulse utilization for improved dietary choices.

Removal of toilet paper fibers from residential wastewater: a life cycle assessment

Toilet paper has been reported as one of the major insoluble pollutant components in the influent of wastewater treatment plants. Toilet paper fibers contribute to a large production of sewage sludge, resulting in a high treatment cost and high energy consumption. To find energy-efficient, cost-effective, and environment-friendly technologies for fiber removal and resource recovery from wastewater, a life-cycle assessment (LCA) was performed to analyze the wastewater treatment processes, including a sieving process for removing and recovering suspended solids before the biodegradation units. Based on the LCA results, it was estimated that the sieve screening process saved 8.57% of energy consumption. The construction phase of sieving consumed 1.31% energy cost compared with the operation phase. Environmental impact analysis showed that sieving reduced the impacts of climate change, human toxicity, fossil depletion, and particulate matter formation, which reduced the total normalized environmental impacts by 9.46%. The life-cycle analysis of the removal of toilet paper fibers from wastewater revealed the need to use more efficient methods to enhance the recovery of cellulose fibers.

Energy Self-Sufficiency Urban Module (ESSUM): GIS-LCA-based multi-criteria methodology to analyze the urban potential of solar energy generation and its environmental implications

The concentration of the population in cities has turned them into sources of environmental pollution, however, cities have a great potential for generating clean energy through renewable sources such as a responsible use of solar energy that reaches its rooftops. This work proposes a methodology to estimate the level of energy self-sufficiency in urban areas, particularly in a district of the city of Zaragoza (Spain). First, the Energy Self-Sufficiency Urban Module concept (ESSUM) is defined, then the self-sufficiency capacity of the city or district is determined using Geographical Information Systems (GIS), Light Detection and Ranging (LiDAR) point clouds and cadastral data. Secondly, the environmental implications of the implementation of these modules in the rooftops of the city using the LCA methodology are calculated. The results obtained show that total self-sufficiency of Domestic Hot Water (DHW) can be achieved using 21 % of available rooftop area, meanwhile the rest of rooftop area, dedicated to photovoltaic (PV), can reach 20 % of electricity self-sufficiency, supposing a final balance of a reduction in CO₂ emissions of 12,695.4 t CO_2eq/y and energy savings of 372,468.5 GJ/y. This corresponds to a scenario where full self-sufficiency of DHW was prioritized, with the remaining roof area dedicated to PV installation. In addition, other scenarios have been analyzed, such as the implementation of the energy systems separately.

Analyzing the relationship between product waste footprints and environmental damage - A life cycle analysis of 1,400+ products

A major problem for the circular economy is monitoring improvements in environmental sustainability. Measuring how much waste reduction efforts contribute to the decrease of environmental impact is difficult, because knowledge on whether life cycle waste amounts correlate with environmental damage is limited. In this article, product waste footprints are used to explore structural similarities and differences in associations with environmental damage. Using the waste flows linked to the production system of 1487 reference products from the Ecoinvent database, we found significant regression equations with R² of 0.75-0.89 between product waste footprints and potential impact on ecosystem diversity, human health and resource availability using log-transformed variables. For each 1 % increase in solid waste, potential impact on the environment increased by 0.75-0.84 %. This strong association between pre-consumer waste and environmental damage is particularly important for advocating for circular economy efforts at the point of consumption, where life cycle waste is invisible to consumers.

Environmental trade-offs for using low-noise pavements: Life cycle assessment with noise considerations

Noise mitigation is the main advantage of semi-dense asphalt (SDA) pavements compared to traditional pavements such as stone-mastic asphalt (SMA), but noise is not quantitatively considered in traditional life cycle assessment (LCA). This article performs a comprehensive LCA for SMA and SDA including noise considerations. State-of-the-art sound emission and acoustical ageing models were used to determine the road traffic noise. The latest Swiss dose-response curves and current noise exposure data were used to evaluate health impacts due to noise. Additionally, traditional LCA is also included for assessing the greenhouse gas emissions, non-renewable cumulative energy demand and health impacts of non-noise processes. The results show that SDA causes around 70 % higher greenhouse gases and energy demand than SMA, primarily due to its shorter service life. However, the noise impacts in disability adjusted life years (DALYs) are higher by two to three orders of magnitude than non-noise processes, and the use of SDA can reduce 40 % of the total DALYs. It is shown that road traffic noise plays a significant role in the LCA of pavements. The trade-off between greenhouse gas and energy related impacts, on the one hand, and health effects, on the other hand, requires critical consideration by decision makers when promoting low-noise pavements.

Coupling phytoremediation of Pb-contaminated soil and biomass energy production: A comparative Life Cycle Assessment

Phytoremediation is an in-situ remediation technology based on the ability of plants to fix pollutants from the soil. In this sense, plants such as Festuca arundinacea are a promising for heavy metal removal in contaminated soils. The present work studies phytoremediation for Pb removal from a contaminated soil located in Spain using F. arundinacea by applying the Life Cycle Assessment (LCA) approach. Two different options for biomass management were assessed: direct disposal in a security landfill (case 1A) and energy recovery (case 1B). For the latter option, cogeneration was simulated using SuperPro Designer 9.5. In addition, traditional treatments such as soil washing (case 2) and excavation + landfill (case 3) were evaluated in terms of environmental impacts by LCA. The former was simulated using SuperPro Designer 9.5, whereas data from literature were used for the latter to perform the LCA. Results showed that biomass disposal in a landfill was the most important contributor to the overall impact in case 1A. In contrast, biomass conditioning and cogeneration were the main steps responsible for environmental impacts in case 1B. Comparing cases 1A and 1B, the energy recovery from biomass was superior to direct landfill disposal, reducing the environmental impacts in most of the studied categories. Regarding the rest of the treatments, chemical production and soil disposal presented the most critical environmental burdens in cases 2 and 3, respectively. Finally, the comparison between the studied cases revealed that phytoextraction + energy recovery was the most environmentally friendly option for the studied conditions, reducing impacts by 30-100%.

Synthesis design using mass related metrics, environmental metrics, and health metrics

The efforts to integrate environmental aspects, health aspects as well as safety aspects into chemical production has led to the development of measurable and thus objectifying metrics. The application of these metrics is considered to be most promising, especially during the earliest phases of synthesis design. However, the operability in daily work suffers from the lack of available data, or a large variety of data, and the complexity of data processing. If a life cycle assessment is not practical in the early development phase, environmental factor and process mass intensity can give a quick and reliable overview. I will show that this often says the same in advance as a subsequently prepared life cycle assessment. Readers will realise that, based on preparative descriptions, they can quickly determine these metrics for individual syntheses or extensive synthesis sequences applying the available software support. Environmental relevance in terms of persistence, bioaccumulation and toxicity (PBT) can be presented using a modification of the European ranking method ‘DART’ (Decision Analysis by Ranking Techniques). Based on corresponding PBT data, readers can determine a hazard score between 0 and 1 for any substance using the spreadsheet file provided, with which the mass of (potentially emitted) substances can be weighted. Occupational health can be represented using a modification of the recognized ‘Stoffenmanager’. Both concepts are presented and spreadsheet files are offered. This article is based on a presentation which was given at the Green Chemistry Postgraduate Summer School in Venice, 6th–10th July 2020.

Environmental and energy performances of the Italian municipal solid waste incineration system in a life cycle perspective

The environmental and energy performances of the Italian municipal solid waste incineration (MSWI) system was investigated by a life cycle assessment approach. On average the 39 MSWIs operating in Italy in 2018 treated about 6,000,000 Mg of residual municipal solid waste (RMSW) recovering on average from 448 kWh Mg^-1 RMSW to 762 kWh Mg^-1 RMSW of electricity and from 732 kWh Mg^-1 RMSW to 1102 kWh Mg^-1 RMSW of heat. The average quantity of CO₂eq Mg^-1 RMSW emitted ranged from about 800 up to about 1000 depending on the size and on the energy recovery scheme of the facility. Avoided impacts (i.e., negative values) were detected for the kg PM_2,5eq Mg^-1 RMSW and for human health (disability-adjusted life year Mg^-1 RMSW). The determination of the hybrid primary energy index (MJ Mg^-1 RMSW) indicated that mainly large size facilities and those operating according to a power and heat energy recovery scheme are effectively able to replace other primary energies by the exploitation of the lower heating values of the RMSW.

Potential Energy Savings from Circular Economy Scenarios Based on Construction and Agri-Food Waste in Italy

In this study, our aim was to explore the potential energy savings obtainable from the recycling of 1 tonne of Construction and Demolition Waste (C&DW) generated in the Metropolitan City of Naples. The main fraction composing the functional unit are mixed C&DW, soil and stones, concrete, iron, steel and aluminium. The results evidence that the recycling option for the C&DW is better than landfilling as well as that the production of recycled aggregates is environmentally sustainable since the induced energy and environmental impacts are lower than the avoided energy and environmental impacts in the life cycle of recycled aggregates. This LCA study shows that the transition to the Circular Economy offers many opportunities for improving the energy and environmental performances of the construction sector in the life cycle of construction materials by means of internal recycling strategies (recycling C&DW into recycled aggregates, recycled steel, iron and aluminum) as well as external recycling by using input of other sectors (agri-food by-products) for the manufacturing of construction materials. In this way, the C&D sector also contributes to realizing the energy and bioeconomy transition by disentangling itself from fossil fuel dependence.

Can decontamination and reuse of N95 respirators during COVID-19 pandemic provide energy, environmental, and economic benefits?

The widespread COVID-19 pandemic led to a shortage in the supply of N95 respirators in the United States until May 2021. In this study, we address the energy, environmental, and economic benefits of the decontamination-and-reuse of the N95 masks. Two popular decontamination methods, including dry heat and vapor hydrogen peroxide (VHP), are investigated in this study for their effective pathogen inactivation and favorable performance in preserving filtration efficiency and structural integrity of respirators. Two multiple reuse cases, under which the N95 masks are disinfected and used five times with the dry heat method and 20 times using the VHP method, are considered and compared with a single-use case. Compared to the single-use case, the dry heat-based multiple-use case reduces carbon footprint by 50% and cumulative energy demand (CED) by 17%, while the VHP-based case decreases carbon footprint by 67% and CED by 58%. The dry-heat-based and VHP-based multiple reuse cases also present environmental benefits in most of the other impact categories, primarily due to substituting new N95 respirators with decontaminated ones. Decontaminating and reusing respirators costs 77% and 89% less than the case of single-use and disposal. The sensitivity analysis results show that the geographical variation in the power grid and the times of respirator use are the most influential factors for carbon footprint and CED, respectively. The result also reaffirms the energy, environmental, and economic favorability of the decontamination and reuse of N95 respirators.

Environmental sustainability assessment of biodiesel production from Jatropha curcas L. seeds oil in Pakistan

According to IPCC Annual Report (AR-5), environmental impact assessment of any product prototype is recommended before its large-scale commercialization; however, no environmental profile analysis of any biodiesel prototype has been conducted in Pakistan. Therefore, objective of this study was to conduct a comprehensive life cycle assessment (LCA), water footprint and cumulative energy demand (CED) of biodiesel production from Jatropha curcas L. (JC) seeds oil in Pakistan. A cradle-to-gate LCA approach was applied for 400 liter (L) JC biodiesel produced in Pakistan. JC biodiesel production chain was divided into three stages i.e., 1). cultivation of JC crop 2). crude oil extraction from JC seeds and 3). crude oil conversion to biodiesel. Primary data for all the stages were acquired through questionnaire surveys, field visits and measurements in the field. Potential environmental impacts were calculated in SimaPro v.9.2 software using Eco-indicator 99 methodology. Results showed that crude oil extraction stage accounted for highest emissions (77%) to the overall environmental impact categories evaluated, followed by oil conversion stage (21%) and JC cultivation stage (02%), respectively. The three stages of JC biodiesel production chain are major contributor to ecotoxicity with a contribution of 57% to this impact category. Higher contribution to ecotoxicity was due to agrochemicals used in the JC cultivation. Similarly, fossil fuels impact category was responsible for 38% of overall environmental impacts. In addition, water footprint of JC biodiesel production chain was 2632.54 m³/reference unit. Cumulative energy required for 400L JC biodiesel production chain was 46745.70 MJ in Pakistan. Fossil diesel consumption, synthetic fertilizers use and purchased electricity were major hotspot sources to environmental burdens caused by JC biodiesel production in Pakistan. By performing sensitivity analysis at 20% reduction of the baseline values of fossil diesel used, synthetic fertilizers and purchased electricity, a marked decrease in environmental footprint was observed. It is highly recommended that use of renewable energy instead of fossil energy would provide environmental benefits such as lower greenhouse gases and other toxic emissions as compared to conventional petroleum fuels. It is also recommended that JC as a biofuel plant, has been reported to have many desired characteristics such as quick growth, easy cultivation, drought resistance, pest and insect resistance, and mainly great oil content in JC seeds (27–40%). Therefore, JC plant is highly recommended to Billion Tree Afforestation Project (BTAP) for plantation on wasteland because it has multipurpose benefits.

Environmental Impacts Associated with Intensive Production in Pig Farms in Mexico through Life Cycle Assessment

In this research, environmental impacts associated with the intensive production of pigs on a farm in Mexico were determined through the application of life cycle assessment methodology. The research was focused on the following stages of the product system: (i) pig rearing and growth phases; (ii) production operations in the pig-house; (iii) the supply of feed. The life cycle inventory database was mainly made up of data collected in field visits to local farms. The functional unit was defined as one finished swine weighing 124 kg. The results for the selected impact categories of carbon, water, and energy footprints were 538.62 kg CO2eq, 21.34 m3, and 1773.79 MJ, respectively. The greatest impact was generated in the final stages of pig fattening, mainly due to the large quantity of feed supplied. The impacts caused by operation of the pig farm were less significant, their contribution in all cases was less than a third of the total quantified values. The energy conversion of pig slurry improves the environmental performance of the product system by reducing the carbon footprint.

Energy balance of torrefied microalgal biomass with production upscale approached by life cycle assessment

Torrefaction is a thermochemical process used to convert the biomass into solid fuel. In this study, torrefaction increased the raw microalgal biomass' energy content from 20.22 MJ⋅kg^-1 to 27.93 MJ⋅kg^-1. To determine if more energy is produced than energy consumption from torrefaction, this study identified the energy balance of torrefied microalgal biomass production based on a life cycle approach. The energy analysis showed that, among all processes, torrefaction had the least amount of energy demand. The experimental setup, defined as scenario A, revealed that the principal source of energy demand, about 85%, was consumed on the microalgal growth using a photobioreactor system. A sensitivity analysis was also performed to determine the varying energy demand for torrefied microalgal biomass production. The different types of cultivation methods and various production scales were considered in scenarios B to D. Scenario D, which represented the commercial production-scale, the energy demand drastically decreased by 59.46% as compared to the experimental setup (scenario A). The open-pond cultivation system resulted in the least energy requirement, regardless of the production scale (scenarios B and C) among all the given scenarios. Unlike scenarios A and D, scenarios B and C identified the drying process to consume a high amount of energy. All the scenarios have shown an energy demand deficit. Therefore, efforts to decrease the energy demand on the upstream processes are needed to make the torrefied microalgal biomass a viable alternative energy source.

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.

Life cycle-based, energy-related analysis for waste management strategies: a case study of two impact indicators in Pyongyang

Municipal solid waste (MSW) is regarded to be an important source of greenhouse gas emissions, which could result in a significant impact on climate change. This study conducted analyses of both cumulative energy demand (CED) and carbon footprint (CF) indicators per reference flow (RF) and identified the relationship between both the indicators, and additionally, it made some recommendations for MSW management strategies in Pyongyang, DPR Korea, based on life cycle thinking. This present study suggested using a hybrid CED indicator and the energy-related CF indicator for the analysis of the existing MSW management system, while applying system expansion for crediting the recycled materials, the energy recovery, and the compost/fertilizer. The result showed that the CED indicator in the MSW management system accounted for - 9,569.8 MJ/RF of primary energy savings in total, corresponding to the avoided emissions of - 1,522.89 kg CO₂eq/RF. The recycling and composting of waste presented energy savings due to the recycled materials and the avoided production of mineral fertilizers replaced with the compost, respectively. In addition, the incineration had some potential for energy recovery from waste, and it could result in crediting energy further, while the landfill should be improved in a more sustainable way of making use of the landfill gas and/or replacing the landfill with incineration with energy recovery. The results also indicated that the CED indicator was closely related to the CF indicator, valued as global warming potential, throughout the MSW management options/processes, and both the indicators could serve as an appropriate proxy of the environmental impacts on a life cycle phase.

Performance and Sustainability Tradeoffs of Oxidized Carbon Nanotubes as a Cathodic Material in Lithium-Oxygen Batteries

Climate change mitigation efforts will require a portfolio of solutions, including improvements to energy storage technologies in electric vehicles and renewable energy sources, such as the high-energy-density lithium-oxygen battery (LOB). However, if LOB technology will contribute to addressing climate change, improvements to LOB performance must not come at the cost of disproportionate increases in global warming potential (GWP) or cumulative energy demand (CED) over their lifecycle. Here, oxygen-functionalized multi-walled carbon nanotube (O-MWCNT) cathodes were produced and assessed for their initial discharge capacities and cyclability. Contrary to previous findings, the discharge capacity of O-MWCNT cathodes increased with the ratio of carbonyl/carboxyl moieties, outperforming pristine MWCNTs. However, increased oxygen concentrations decreased LOB cyclability, while high-temperature annealing increased both discharge capacity and cyclability. Improved performance resulting from MWCNT post-processing came at the cost of increased GWP and CED, which in some cases was disproportionately higher than the level of improved performance. Based on the findings presented here, there is a need to simultaneously advance research in improving LOB performance while minimizing or mitigating the environmental impacts of LOB production.

Economic and Environmental Assessment of Catalytic and Thermal Pyrolysis Routes for Fuel Production from Lignocellulosic Biomass

Meeting the transport needs of a growing world population makes it imperative to develop renewable and sustainable routes to production of liquid fuels. With a market-driven economic structure and pressing environmental issues, it is essential that these new routes provide environmental benefits while being economically viable. Conversion of second-generation lignocellulosic biomass resources to fuels via pyrolysis represents an important technological route. In this article, we report comparative assessment of the economic and lifecycle environmental aspects for catalytic and thermal pyrolysis. The goal of this assessment is two-fold: one is to understand the potential of this conversion route via the catalytic and thermal processes and second is to provide feedback for further development of catalysts for various stages of this conversion. The complete assessment is interdisciplinary in nature and connects the laboratory experiments with contextual sustainability assessment. Three catalytic and one thermal pyrolysis processes are analyzed using this assessment approach. Subject to the model choices and data inputs, the results, which consider quality of the oil product, show that biofuels produced using catalytic and thermal routes are rather expensive compared to gasoline. But at the same time, they provide significant greenhouse gas emission savings and can lead to lower CO2 abatement costs compared to the first-generation ethanol that is used currently. With one of the product scenarios of hydrotreated (HT) oil, the abatements costs are estimated to be 51% of those associated with first-generation ethanol. Additional product scenarios with developments in catalysts show potential to further reduce abatement costs significantly to below 100 EUR per metric tonne of CO2 equivalents. Using scenario analysis, the results help us to understand specific areas for development of novel catalysts. At the same time, the results demonstrate the trade-offs associated with the variety and complexity of technical factors associated with the pyrolysis routes. The study highlights the challenges and the promises of catalytic and thermal pyrolysis for production of high-quality biofuels produced via a sustainable production route.

Environmental and Economic Sustainability of Electric Vehicles: Life Cycle Assessment and Life Cycle Costing Evaluation of Electricity Sources

The electro-mobility of vehicles could solve the negative effects of road transport, by decreasing greenhouse gas emissions. However, some electric vehicles also have a negative impact on the environment related to the nature of electricity used. This paper aims to evaluate the electricity sources for electric vehicles using a Life Cycle Thinking approach. Life cycle assessment, using several midpoints and endpoint methods, highlighted that the most damaging sources were lignite and diesel, while hydropower, wind, and biomass were the most sustainable ones. Cumulative energy demand showed that biomass used the least energy (0.034 MJ eq.), but originates from 100% non-renewable sources. Lignite, which also comes from 100% non-renewable sources, used the most energy (17.791 MJ eq.). The lowest carbon footprints were for wind, biomass, and photovoltaic (<0.1 kg CO2 eq). Municipal waste incineration and natural gas had a medium impact, while lignite, coal, peat, and diesel had a high impact (>1.0 kg CO2 eq.). Considering life cycle costing, photovoltaic electricity generation was the most expensive (0.2107 USD/kWh) while natural gas the cheapest (0.0661 USD/kWh). Therefore, this study presents an integrated approach that may offer a valid tool for decision-makers, giving them the possibility to choose the electricity sources for electric vehicles.

On Reduced Consumption of Fossil Fuels in 2020 and Its Consequences in Global Environment and Exergy Demand

As the world grapples with the COVID-19 pandemic, there has been a sudden and abrupt change in global energy landscape. Traditional fossil fuels that serve as the linchpin of modern civilization have found their consumption has rapidly fallen across most categories due to strict lockdown and stringent measures that have been adopted to suppress the disease. These changes consequently steered various environmental benefits across the world in recent time. The present article is an attempt to investigate these environmental benefits and reversals that have been materialized in this unfolding situation due to reduced consumption of fossil fuels. The life cycle assessment tool was used hereby to evaluate nine environmental impacts and one energy based impact. These impacts include ozone formation (terrestrial ecosystems), terrestrial acidification, freshwater eutrophication, marine eutrophication, terrestrial ecotoxicity, freshwater ecotoxicity, marine ecotoxicity, land use, mineral resources scarcity, and cumulative exergy demand. Outcomes from the study demonstrate that COVID-19 has delivered impressive changes in global environment and life cycle exergy demand, with about 11–25% curtailment in all the above-mentioned impacts in 2020 in comparison to their corresponding readings in 2019.

Economic Energy Efficiency of Food Production Systems

The current global population growth forecast carries with it a global increase in demand for food. In order to meet this demand, it is necessary to increase production, which requires an increase in energy consumption. However, forecasted energy production growth is insufficient and traditional sources of energy are limited; hence, it is necessary to strive for greater energy efficiency in food production systems. The study aimed to compare the economic energy efficiency of food production systems in selected countries and identify the sources of diversification in this field. As a measure of energy efficiency, the indicators of the energy intensity of food production were used in this study. To calculate these indicators, a method based on input-output life-cycle assessment assumptions was used, which enables researchers to obtain fully comparable results between countries. The study showed that despite an increase in energy consumption in the food production systems of the analyzed countries by an average of 27%, from 19.3 EJ to 24.5 EJ, from 2000 to 2014, their energy intensity decreased, on average, by more than 18%, from 8.5 MJ/USD to 6.9 MJ/USD. This means that energy efficiency improvements are possible even under conditions of increased energy consumption, which in turn, means that food production can increase significantly. In the case of developed countries, the main inefficiencies are found in agricultural production, while in developing countries, they are observed in the food industry. Decision-makers should also pay attention to the high level of energy intensity that results from the supply of inputs to agriculture and the food industry because there is great potential for the improvement of energy efficiency in this field, especially because energy consumption associated with supply constitutes a major part of total consumption in the food production systems of developed countries.

Screening Life Cycle Assessment of Tall Oil-Based Polyols Suitable for Rigid Polyurethane Foams

A screening Life Cycle Assessment (LCA) of tall oil-based bio-polyols suitable for rigid polyurethane (PU) foams has been carried out. The goal was to identify the hot-spots and data gaps. The system under investigation is three different tall oil fatty acids (TOFA)-based bio-polyol synthesis with a cradle-to-gate approach, from the production of raw materials to the synthesis of TOFA based bio-polyols at a pilot-scale reactor. The synthesis steps that give the most significant environmental footprint hot-spots were identified. The results showed the bio-based feedstock was the main environmental hot-spot in the bio-polyol production process. Future research directions have been highlighted.

Same-plant trends in capacity factor and heat rate for US power plants, 2001–2018

This note uses electricity generator level 2001–2018 US capacity, generation, and heat input data to evaluate trends in same-plant capacity factor (how much plants run) and heat rate (how efficiently plants run) as plants age. Based on compound annual growth rates for capacity factor and, for thermal plants, heat rate, and based on the subset of US plants that have been operating since 2010 or earlier, same-plant capacity factors increased slightly, and heat rates decreased slightly, between 2001–2018 (weighted average based on 2018 plant capacity). Trends vary by region, fuel, and plant age. Notably, US natural gas-fired power plants tended to run more, and more efficiently, as they aged, while coal-fired power plants tended to run less, and less efficiently. Potential drivers include relative plant age, policy, financial competitiveness, and an anticipated tendency for plant operators to react to the effects of equipment aging with maintenance, repair, replacement, and optimization. These observations can inform committed emissions-based research, which requires making assumptions about how plant operational characteristics change (or do not) as they age.

Guiding the design space for nanotechnology to advance sustainable crop production

The globally recognized need to advance more sustainable agriculture and food systems has motivated the emergence of transdisciplinary solutions, which include methodologies that utilize the properties of materials at the nanoscale to address extensive and inefficient resource use. Despite the promising prospects of these nanoscale materials, the potential for large-scale applications directly to the environment and to crops necessitates precautionary measures to avoid unintended consequences. Further, the effects of using engineered nanomaterials (ENMs) in agricultural practices cascade throughout their life cycle and include effects from upstream-embodied resources and emissions from ENM production as well as their potential downstream environmental implications. Building on decades-long research in ENM synthesis, biological and environmental interactions, fate, transport and transformation, there is the opportunity to inform the sustainable design of nano-enabled agrochemicals. Here we perform a screening-level analysis that considers the system-wide benefits and costs for opportunities in which ENMs can advance the sustainability of crop-based agriculture. These include their on-farm use as (1) soil amendments to offset nitrogen fertilizer inputs, (2) seed coatings to increase germination rates and (3) foliar sprays to enhance yields. In each analysis, the nano-enabled alternatives are compared against the current practice on the basis of performance and embodied energy. In addition to identifying the ENM compositions and application approaches with the greatest potential to sustainably advance crop production, we present a holistic, prospective, systems-based approach that promotes emerging alternatives that have net performance and environmental benefits.

Environmental Life Cycle Assessment of Rapeseed and Rapeseed Oil Produced in Northern Europe: A Latvian Case Study

There is a major international effort to improve the availability of data for life cycle assessment (LCA), as these assessments have become one of the main pillars driving European policy with respect to the sustainable use of resources. However, there is still a lack of data even for Europe. This study presents a cradle-to-farm gate assessment, or LCA, of winter and spring rapeseed produced in the northern European country of Latvia. The LCA model is based on an in-depth and up-to-date agricultural practice used in the region and covers the time span of 2008–2016. An LCA of rapeseed oil produced by cold pressing was carried out. The environmental impact assessment was calculated with the ReCiPe impact assessment method version 1.03, a hierarchical (H) perspective, along with the cumulative energy demand method v1.11. Cultivation of winter rapeseed has a lower environmental impact than cultivation of spring rapeseed due to higher agricultural inputs and higher yield. The greatest impact is on human health. Mineral fertilizers (production and application) and agricultural machinery are responsible for the greatest environmental impact. The results for the mill stage of rapeseed oil demonstrated that the choice of the allocation method has a significant impact on the environmental performance results.

Influence of metal speciation on soil ecotoxicity impacts in life cycle assessment

It is unknown whether metallic elements remain important contributors to terrestrial ecotoxicity impact scores in life cycle assessment (LCA) when solid- and liquid-phase speciation are considered in environmental fate, exposure and effects. Here, a new speciation-based method for calculating comparative toxicity potentials (CTP) of 23 metallic elements in soils was compared with two other widely used methods which do not consider speciation (i.e., IMPACT, 2002+ and ReCiPe 2008) for nearly 13,000 life cycles of unit processes taken from different sectors. Differences in impact scores between method were driven either by differences in characterization models (ReCiPe 2008) or both by differences in characterization models and substance coverage (IMPACT, 2002+). Strong correlations (r > 0.98) and seemingly constant shifts in impact scores were found for those processes where one or few substances (usually metals) contributed most to total impact and there were large differences in CTPs between methods for these substances. Weaker correlations but often better agreement in impact scores were found for those processes where organic substances were dominant contributors to total impact. Our results suggest that metals are expected to remain important contributors to soil ecotoxicity impacts in LCA when speciation is considered.

Energetic and Economic Analyses for Agricultural Management Models: The Calabria PGI Clementine Case Study

Farming systems need to be planned to provide suitable levels of economic profitability and, at the same time, ensure an effective energy use, in order to perform environmentally friendly production strategies. The herein present work aims to assess the efficiency of energy use and economic impacts of the main farming methods (conventional, organic and integrated) of Clementine’s crops in Calabria (South Italy), through a combined use of Life Cycle Energy Assessment (LCEA) approach and economic analysis. For this purpose, data were collected from clementine producers by using face-to-face interviews. The results revealed that average energy consumption in the organic farming systems was 72,739 MJ, lower than conventional and integrated systems equal to 95,848 MJ and 94,060 MJ, respectively. This is mainly due to the ban of chemicals. Economic analysis showed that organic farms were more profitable compared with the other farming methods, because of the greater selling price and the EU economic support, reaching an average net profit of 4255 € ha−1 against 3134 € ha−1 of integrated farms and 2788 € ha−1 of conventional ones. The economic efficiency of energy from clementine production was 0.058 € MJ−1 in the organic farming, higher compared to the other two farming systems equal to 0.033 € MJ−1 on average.

Discrete-Point Analysis of the Energy Demand of Primary versus Secondary Metal Production

The metal industry consumes large amounts of energy and contributes significantly, up to 10%, to global greenhouse gas (GHG) emissions. Recycling is commonly included among the most viable options for mitigating the climate forcing of metal production by replacing primary production. However, the recycling rates of metals are still incomplete and, in particular, do not exist for most specialty metals. Our empirical analysis of 48 metals shows that their recycling is mainly impeded by their low concentrations. In many cases, the metal concentration in end-of-life products is lower than that in natural ores. This phenomenon inevitably raises the question of the extent to which recycling can be conducted without losing its mitigating effects on climate change. We answer this question for two example metals, tantalum and copper, within the scope of Germany, a leader in recycling. For tantalum, the results show that a further increase in the end-of-life recycling rate (EOL-RR) could contribute to minimizing the overall energy consumption and GHG emissions, despite its low concentrations in end-of-life products. The energy requirements for recycling copper from end-of-life products already reach the magnitude of those for primary production. A further increase in EOL-RR must be examined in detail to ensure mitigating effects on climate change.

Techno-economic and environmental sustainability of biomass waste conversion based on thermocatalytic reforming

The development and design of innovative biomass waste to energy conversion processes is a key issue to pursue the implementation of circular economy and to endorse a sustainable management of agricultural land. Assessing the environmental and economic sustainability of such processes is of paramount importance to prevent the trade-off of their impacts. The present study focused on a novel biomass waste to energy conversion process based on thermocatalytic reforming (TCR). Two different agricultural waste substrates (olive wood pruning and digestate) were selected as reference cases for conversion to energy and valuable material fractions. Mass and energy balances allowed the calculation of environmental and economic indexes considering alternative scenarios for the final use of the energy and of the products obtained from the TCR conversion (i.e. syngas, bio-oil and bio-char). A sensitivity analysis was carried out to assess the robustness of results. The overall performances of the TCR process resulted strongly related to the characteristics of the biomass waste and to the possible use of the product fractions obtained in the TCR process. The use of bio-char for soil amendment, allowed by the high quality of bio-char obtained from the TCR, was a key point to improve the expected environmental and economic sustainability of the conversion process.

Handling uncertainties inherited in life cycle inventory and life cycle impact assessment method for improved life cycle assessment of wastewater sludge treatment

Life cycle assessment (LCA) has been used to evaluate environmental impacts of products or processes including wastewater treatment. Uncertainty has not received adequate attention in LCA studies. Uncertainty inherited in LCA steps such as the life cycle inventory (LCI) or the life cycle impact assessment (LCIA) method use is unavoidable, but it affects LCA outcomes and associated decision-making. The objective of this paper was to show the impact of uncertainty from LCI and LCIA method on LCA outcomes by using a case study base approach on wastewater sludge treatment processes. A qualitative analysis included setting criteria about what data to be included in LCI, characterization of data, differentiating between major and minor contributors in LCI modeling, evaluation of data quality indicators, setting achievable alternative scenarios, and selecting proper LCIA method were used, in addition to quantitative analysis included assigning most appropriate values for data gaps and proper distribution, and conducting probabilistic analysis to evaluate overall uncertainty. This research used a full-scale wastewater treatment plant in Missouri, USA for case study in which multiple hearth incineration (MHI) is the existing process, while fluid bed incineration (FBI) and anaerobic digestion (AD) were proposed as the alternatives. Using ReCipe method, the study revealed that variation in LCA results of MHI is 63.4% for a single end-point score of 57.9 mPt. On the two alternative processes, it is 54.6% probable that FBI would have more environmental impact than AD. The case study showed that the proposed steps were able to address issues of data uncertainty. Due to differences in characterization, normalization, and weighting factors, different LCIA methods may point out different conclusions and need to be addressed in evaluation.

Environmental impact assessment model for substitution of hazardous substances by using life cycle approach

Regulations that are indirectly driving the substitution of hazardous chemicals, such as the EU REACH regulation, necessitate improvements in chemical alternatives assessment frameworks. In those frameworks, life cycle thinking lacks some important aspects such as systematic and quantitative occupational safety methods and risks from intermediate chemicals that are not released to the environment under normal operating conditions. Concerns of companies about regulatory drivers regarding substances of very high concern often lead to inadequate evaluation of the baseline situation; an issue also overlooked by the frameworks. Moreover, life cycle assessment is optional for assessors with limited resources, such as small and medium enterprises. However, the success of substitution should not be evaluated without life cycle concerns. An environmental impact assessment model has been suggested to overcome these shortcomings of the chemical alternatives assessment frameworks. The model was applied to a case study of primed metal sheet production, where the company was driven to substitute reprotoxic 2-methoxypropanol used in their formulations. The results show that the proposed model is promising for solving the mentioned shortcomings, informing the assessor about substances of very high concern along the life cycle, and it has the potential to be further improved with the help of supporting software and databases. Particularly, in the occupational safety area that concerns risks of accidents at work, improvements to the EU occupational health database can drastically increase the accuracy of the assessments. Besides, the development of methodologies for the quantification of the impacts of reprotoxic, bioaccumulative and endocrine disruptor substances is necessary.

Environmental Assessment of Energy Scenarios for a Low-Carbon Electrical Network in Chile

Nowadays, establishing clean energy sources is an undeniable need for all territories to reconcile energy and competitiveness objectives with those of security and sustainability. This article shows the main advantages of implementing clean energy sources in the long-term Chilean electrical network. The clean energy considered in this work is based on Renewable Energy (Conventional and Non-Conventional) with the backup of gas or nuclear. Thus, four scenarios are proposed and were simulated for the year 2050, the year assumed for the decommissioning of all coal plants in the country. These scenarios contemplate a high or low penetration of Renewable Energy. Additionally, a reference and realistic scenario for the year 2018 has also been considered to compare to the clean scenarios proposed. The results obtained coincide with the goals of reducing environmental impacts such as global warming emissions and fossil fuel dependence. However, the backup that was chosen for supporting the intermittence of renewable energy may have an important role in the main system considering the expected growth of energy demands in the near future.

Energy Sustainability Analysis (ESA) of Energy-Producing Processes: A Case Study on Distributed H2 Production

In the sustainability context, the performance of energy-producing technologies, using different energy sources, needs to be scored and compared. The selective criterion of a higher level of useful energy to feed an ever-increasing demand of energy to satisfy a wide range of endo- and exosomatic human needs seems adequate. In fact, surplus energy is able to cover energy services only after compensating for the energy expenses incurred to build and to run the technology itself. This paper proposes an energy sustainability analysis (ESA) methodology based on the internal and external energy use of a given technology, considering the entire energy trajectory from energy sources to useful energy. ESA analysis is conducted at two levels: (i) short-term, by the use of the energy sustainability index (ESI), which is the first step to establish whether the energy produced is able to cover the direct energy expenses needed to run the technology and (ii) long-term, by which all the indirect energy-quotas are considered, i.e., all the additional energy requirements of the technology, including the energy amortization quota necessary for the replacement of the technology at the end of its operative life. The long-term level of analysis is conducted by the evaluation of two indicators: the energy return per unit of energy invested (EROI) over the operative life and the energy payback-time (EPT), as the minimum lapse at which all energy expenditures for the production of materials and their construction can be repaid to society. The ESA methodology has been applied to the case study of H2 production at small-scale (10–15 kWH2) comparing three different technologies: (i) steam-methane reforming (SMR), (ii) solar-powered water electrolysis (SPWE), and (iii) two-stage anaerobic digestion (TSAD) in order to score the technologies from an energy sustainability perspective.

Life cycle assessment (LCA) of food waste treatment in Hong Kong: On-site fermentation methodology

"Smart Food Waste Recycling Bin" (S-FRB) systems have recently been developed to facilitate the transformation of food waste into an end-product suitable for use as an energy resource following circular economy principles. This decentralized waste decomposition system utilizes fermentative microorganisms for the treatment of organic food waste and has emerged as a possible solution for coping with both landfill capacity and greenhouse gas emissions issues. This paper utilizes Life Cycle Assessment (LCA) to determine the environmental impacts associated with this S-FRB technology and identify environmental hotspots to reduce these impacts. In this paper, we have conducted an on-site pilot-scale study for 2 months at a canteen located at the City University of Hong Kong, which resulted in a 90% reduction in the mass of food waste treated in the S-FRB system. Based on this pilot-scale study hypothetical scenarios were developed to determine potential environmental impacts potential scaled-up deployments of the S-FRB instrument based on varied assumptions. Examination of the LCAs of these different scenarios demonstrated the potential for further reduction in CO₂ equivalent emissions during food waste treatment. Cumulative Energy Demand (CED) and Energy Return on Investment (EROI) were also investigated to understand the energy balance energy of the S-FRB technology. Finally, using current waste treatment methods in Hong Kong as a benchmark, the environmental impacts of the S-FRB are compared with the conventional food waste treatment approaches such as landfilling and organic waste treatment facilities (OWTF).

Streamlined Life Cycle Assessment of an Innovative Bio-Based Material in Construction: A Case Study of a Phase Change Material Panel

Research Highlights: This is the first study that analyzes the environmental performance of wood-based phase change material (PCM) panels. Background and Objectives: Life cycle assessment (LCA) is a powerful environmental management tool. However, a full LCA, especially during the early design phase of a product, is far too time and data intensive for industrial companies to conduct during their production and consumption processes. Therefore, there is an increasing demand for simpler methods to demonstrate a company’s resource efficiency potential without being data or time intensive. The goal of this study is to investigate the suitability of streamlined LCA (SLCA) tools and methods used in the building material industry, and to assess their robustness in the case study of a wood-based PCM panel. Materials and Methods: The Bilan Produit tool was selected as the SLCA tool and a matrix LCA was selected as the most commonly used SLCA method. A specific case study of a wood-based PCM panel was selected with a focus on its application in building construction in the province of Québec. Results: As a semi-quantitative LCA method, the matrix LCA provided a quick screening of the product life cycle and its hotspot stages, i.e., life cycle stages with high impact. However, the results of the full LCA and SLCA tools were quantitative and based on scientific databases. The use of the PCM panel and heating energy had the highest environmental impacts as compared to other inputs. The results of the full LCA and SLCA also identified energy consumption as a hotspot. Insufficient material or processes in the SLCA databases was one of the reasons for the difference between the results of the SLCA and full LCA. Conclusions: The examined SLCA methods provided proper explanations for the bio-based material in construction, but several limitations still exist, and the methods should be improved to make them more robust when implemented in such a specific sector.

Effectiveness of municipal solid waste incinerators in replacing other fuels. A primary energy balance approach for the EU28

The latest European Union legislation introduced the possibility of considering high efficiency incineration of waste as a recovery operation, that is, to use waste as a means of producing energy and hence able to replace other fuels. This possibility has been further investigated by expanding the boundaries for the mass and energy balance of municipal solid waste incinerators operating in the EU28. An energetic analysis based on a hybrid primary energy (MJ Mg^-1) approach was performed also using the cumulative energy demand index. Average results showed a net hybrid primary energy >0 for those municipal solid waste incinerators recovering only electricity, indicating that no primary energies can be replaced. For those operating in combined heat and power mode, an average hybrid primary energy ranging from about -200 MJ Mg^-1 to about -4800 MJ Mg^-1 was detected for large-size municipal solid waste incineration facilities (>200,000 Mg y^-1). The value of hybrid primary energy for medium and small facilities ranged from about +3000 MJ Mg^-1 to -4000 MJ Mg^-1. Furthermore, in some operating conditions landfill had a lower hybrid primary energy than those of small-size municipal solid waste incinerators. To some degree, these results are not in agreement with the classification of municipal solid waste incinerators based on the energy efficiency formula, particularly for those recovering only electrical energy.

Energy use and carbon footprint of the tomato production in heated multi-tunnel greenhouses in Almeria within an exporting agri-food system context

Almeria (Spain) is one of the most important agricultural centers of vegetable cultivation in Europe. The search for technological innovation has led to the introduction of climate control systems in greenhouses in Almeria to improve productivity during the cold season. Up to now, no studies have analyzed the energy behavior of introducing this technology in this specific region. The objective of the present study is therefore to analyze the energy use and carbon footprint (CF) of the tomato production in heated multi-tunnel greenhouses in Almeria from a life cycle perspective (cradle to regional distribution center approach). The results obtained show that the introduction of heating systems in multi-tunnel greenhouses in Almeria allowed for an increase in the annual productivity per hectare and kilogram below the increment in cumulative energy demand (CED). The on-farm CED and CF were estimated at, respectively, 13.4 MJ and 0.92 kg CO₂-eq kg^-1 of gross production. The impacts were thus 3.3 and 2.75 times higher than those of the unheated crop. The use of energy and infrastructure (86.1%), fertilizers, and infrastructure (66.9%) were the main hotspots of the heated and unheated tomato crops. With regard to the marketed output and the supply chain, the CF and CED of heated tomatoes were 2.07 kg CO₂-eq and 29.30 MJ kg^-1, with a non-renewable EROI (energy return on investment) (0.030:1) that was 48% lower than the one obtained with unheated tomatoes. On-farm production (64.1%), transport, and packing (65.9%) were, respectively, the main hotspots in the heated and unheated tomato agri-food systems. The production of heated tomatoes in Almeria may continue to be a better energy option than locally producing the crop in heated greenhouses in northern Europe, as long as other options related to the seasonal local production and changing diets are not taken into account.

Cumulative energy demand and global warming potential of a building-integrated solar thermal system with/without phase change material

Building-integrated solar thermal (BIST) systems are a specific type of solar thermal systems which are integrated into the building and they participate in building functionality. The present article is about the life-cycle assessment of different options of a BIST system (Mediterranean climatic conditions: Ajaccio, France). The environmental profile of the studied configurations is assessed by means of CED (cumulative energy demand), GWP (global warming potential) and EPBT (energy payback time). The proposed configurations (for the collector) include: i) a system without PCM (phase change material) using only rock wool as insulation and ii) a system with PCM (myristic acid) and rock wool. Concerning life-cycle results based on CED and GWP 100a (scenario without recycling), the configuration without PCM shows 0.67 MJ_prim/kWh and 0.06 kg CO_2.eq/kWh while the configuration with PCM presents 0.74 MJ_prim/kWh and 0.08 kg CO_2.eq/kWh. Regarding EPBT, if the inputs for pumping/auxiliary heating are not taken into account, both configurations (with/without PCM) have almost the same EPBT (about 1.3 years). On the other hand, if the inputs for pumping/auxiliary heating are considered, EPBT is lower for the system with PCM. In addition, scenarios with recycling have been examined and the results demonstrate that recycling considerably improves the environmental profile of the studied configurations.

Portfolio Optimization of Nanomaterial Use in Clean Energy Technologies

While engineered nanomaterials (ENMs) are increasingly incorporated in diverse applications, risks of ENM adoption remain difficult to predict and mitigate proactively. Current decision-making tools do not adequately account for ENM uncertainties including varying functional forms, unique environmental behavior, economic costs, unknown supply and demand, and upstream emissions. The complexity of the ENM system necessitates a novel approach: in this study, the adaptation of an investment portfolio optimization model is demonstrated for optimization of ENM use in renewable energy technologies. Where a traditional investment portfolio optimization model maximizes return on investment through optimal selection of stock, ENM portfolio optimization maximizes the performance of energy technology systems by optimizing selective use of ENMs. Cumulative impacts of multiple ENM material portfolios are evaluated in two case studies: organic photovoltaic cells (OPVs) for renewable energy and lithium-ion batteries (LIBs) for electric vehicles. Results indicate ENM adoption is dependent on overall performance and variance of the material, resource use, environmental impact, and economic trade-offs. From a sustainability perspective, improved clean energy applications can help extend product lifespans, reduce fossil energy consumption, and substitute ENMs for scarce incumbent materials.

Municipal solid waste system analysis through energy consumption and return approach

Inappropriate waste management and poor resource efficiency are two of the biggest problems which European Union is trying to solve through Landfill Directive, Waste Framework Directive and Circular Economy Package by increasing recycling and reuse and reducing waste disposal. In order to meet set goals, new European Union member states must quickly change national legislature and implement appropriate solutions. In the circumstances of strong EU resource and energy dependence, decision makers need to analyse which of the considered waste management systems leads to higher overall benefits ie. which is more sustainable. The main problem in this kind of analysis is a wide range of possible technologies and the difference in inputs and outputs. Sustainability of these systems is analysed through single-score LCA based assessment, using primary energy used to produce materials and energy vectors as a common measure. To ensure reliable results, interoperability between different data sources and material flows of waste and its components are monitored. Tracking external and internal material, and energy flows enable modelling of mutual interactions between different facilities. Resulting PERI, primary energy return based index, is used for comparison of different waste management scenarios. Results show that time and legislation dependent changes have great influence on decision making related to waste management and interconnected systems.