Low Environmental Burden Research Articles

Pioneering precision in markerless strain development for Synechococcus sp. PCC 7002

Marine cyanobacteria such as Picosynechococcus sp. (formerly called Synechococcus sp.) PCC 7002 are promising chassis for photosynthetic production of commodity chemicals with low environmental burdens. Genetic engineering of cyanobacteria conventionally employs antibiotic resistance markers. However, limited availability of antibiotic-resistant markers is a problem for highly multigenic strain engineering. Although several markerless genetic manipulation methods have been developed for PCC 7002, they often lack versatility due to the requirement of gene disruption in the host strain. To achieve markerless transformation in Synechococcus sp. with no requirements for the host strain, this study developed a method in which temporarily introduces a mutated phenylalanyl-tRNA synthetase gene (pheS) into the genome for counter selection. Amino acid substitutions in the PheS that cause high susceptibility of PCC 7002 to the phenylalanine analog p-chlorophenylalanine were examined, and the combination of T261A and A303G was determined as the most suitable mutation. The mutated PheS-based selection was utilized for the markerless knockout of the nblA gene in PCC 7002. In addition, the genetic construct containing the lldD and lldP genes from Escherichia coli was introduced into the ldhA gene site using the counter selection strategy, resulting in a markerless recombinant strain. The repeatability of this method was demonstrated by the double markerless knockin recombinant strain, suggesting it will be a powerful tool for multigenic strain engineering of cyanobacteria.

Environmental footprints in divergent cuisines: a case study of eight Chinese culinary traditions

The sustainable dietary transitions must account for the varied culinary traditions and regional food cultures to ensure a balanced and culturally sensitive approach. This study aims to explore the impact of regional preferences on culinary culture and examine ways to achieve environmentally friendly dietary transitions in China by considering the differences in the environmental burdens of various cuisines. We investigate the eight Chinese culinary traditions and depict their respective popularity in China at the city level via POI characterization based on ArcGIS. Water, carbon, and ecological footprints are selected to investigate the environmental performance of each type of cuisine. Results show that the eight cuisines vary significantly in spreads of influence and environmental performances. Chuan cuisine is the most widely disseminated cuisine with a relatively low environmental burden. The remaining seven cuisines have limited spreads of influence and are mainly distributed in small cultural regions and the surrounding areas. Hui Cuisine, Zhe Cuisine, and Min Cuisine have the worst environmental performances. This study reveals the significant impact of regional cuisines on the environmental footprint of diets and highlights the necessity of considering this impact when promoting dietary transition, especially in culturally diverse countries.

Assessing the environmental footprint of alternative green biorefinery protein extraction techniques from grasses and legumes

The significant grasslands of Europe and its member states represents a significant feedstock opportunity for circular bioeconomy development. The development of green biorefineries (GBR), to supply protein for the feed industry from grass, could help many European member states to address significant deficits in protein availability and reduce imports. The current study assesses the environmental footprint of alternative GBR protein extraction techniques from grasses and legumes using life cycle assessment. The focus is on comparing feedstock and technology pathways that could displace soya bean imports. The study finds that leaf protein concentrate (LPC) produced from grass had an improved environmental performance when compared to soya bean meal (SBM), across the assessed feedstock (perennial ryegrass or grass-clover mixtures) and technology pathways (one-stage maceration versus multi-stage maceration). For example, in the case of Climate Change the emission intensity for LPC was 57–85 % lower per tonne of crude protein (CP) compared with SBM. Acidification burdens were 54–88 % lower, and Eutrophication: Freshwater burdens were 74–89 % lower. Some scenarios of GBR produced LPC with a larger Energy Resources: Non-Renewable burden than SBM, though this could be mitigated with higher renewable energy (biogas and wind energy) integration within the scenario. Grass-clover scenarios generally achieved a lower intensity of emissions compared to ryegrass scenarios, particularly in the category of Climate Change, where feedstock cultivation represented a significant contributor to impacts. Overall, GBR can produce high quality protein with a lower environmental burden than SBM, but choice of feedstock and system design are critical factors for overall environmental performance.

Are Peruvians moving toward healthier diets with lower environmental burden? Household consumption trends for the period 2008–2021

AbstractPeru is one of the most diverse countries in the world in terms of food production, but also suffers a wide range of food security challenges, including malnutrition, the impact of natural hazards, and rising food prices. People living in poverty conditions are the main victims of these problems, which trigger undernutrition, obesity, and diet‐related non‐transmittable diseases. Despite these challenges, Peru lacks historical food intake data. Therefore, in the current study, we assess the diet quality evolution in the period 2008–2021 based on apparent household purchases extracted from the National Household Survey. The results reveal significant variations in the consumption of certain food items and groups, and the consequences of these changes are discussed in environmental and human health terms. The consumption of lower environmental impact animal protein, such as chicken, eggs, and marine fish, has increased by 37%, 69%, and 29%, respectively; whereas the consumption of high environmental impact foods, such as beef and other red meat, has decreased. Moreover, consumption of less processed carbohydrate sources (e.g., legumes, fruits, and vegetables) has risen, while refined sugar and sugar‐sweetened beverages have decreased significantly (almost 45%). Regional differences were also visible; hence, cities on the Northern coast and the Amazon basin had similar consumption habits, whereas Central/Southern coastal and Andean cities had closer consumption patterns. On average, this improvement was reflected in the increase in calories (9.9%) and macronutrient intake (up to 15%), but at the socioeconomic level, food inequality persists, with consumption of many food groups below minimum thresholds in lower socioeconomic strata. This article met the requirements for a gold/gold JIE data openness badge described at http://jie.click/badges.

Solutions for decarbonising urban bus transport: a life cycle case study in Saudi Arabia

With heavy reliance on fossil fuels, countries like Saudi Arabia face challenges in reducing carbon emissions from urban bus transportation. Herein, we address the gaps in evaluating proton-exchange membrane fuel cell buses and develop a globally relevant life-cycle assessment model using Saudi Arabia as a case study. We consider various bus propulsion technologies, including fuel cell buses powered by grey and blue hydrogen, battery electric buses, and diesel engines, and include the shipping phase, air conditioning load, and refuelling infrastructure. The assessment illustrates fuel cell buses using blue hydrogen can reduce emissions by 53.6% compared to diesel buses, despite a 19.5% increase in energy use from carbon capture and storage systems. Battery electric buses are affected by the energy mix and battery manufacturing, so only cut emissions by 16.9%. Sensitivity analysis shows climate benefits depend on energy sources and efficiencies of carbon capture and hydrogen production. By 2030, grey and blue hydrogen-powered fuel cell buses and battery electric buses are projected to reduce carbon emissions by 19.3%, 33.4%, and 51% respectively, compared to their 2022 levels. Fully renewable-powered battery electric buses potentially achieve up to 89.6% reduction. However, fuel cell buses consistently exhibit lower environmental burdens compared to battery electric buses.

Closing the Loop between Waste-to-Energy Technologies: A Holistic Assessment Based on Multiple Criteria

This paper puts forward a generic methodological framework to holistically assess WtE technologies based on the PROMETHEE approach. In addition to environmental and economic aspects, the method focuses on large-scale applicability and social preference, thus adopting economic, environmental, social, and technological criteria. Three data sources are selected, namely the scientific literature, a public survey, and an experts’ opinion survey, which is a novel combination with the aim to cover public consensus, technological applicability, and to provide alternative data sources for the economic and environmental criteria, thus enriching the methodology with the input of location specific data. The demonstration of the applicability of the proposed methodology is realized at a national level for the case of Greece. Anaerobic Digestion is shown to be the most preferable choice, recognized for its cost-effectiveness and lower environmental burden to other WtE technologies (i.e., gasification, pyrolysis, incineration). When all criteria are evaluated with equal weights, anaerobic digestion greatly outperforms incineration (net flow 0.833 versus 0.1667), while incineration only becomes the most preferred choice if the social criterion is in high focus (i.e., over 63% weight).

Product Ecodesign: An Application of Bio-Based Materials in the Personal Care Packaging Industry

AbstractThe increasing amount of plastic materials produced and their persistence in the natural environment after the use stage makes them highly critical from the environmental viewpoint and human health and much efforts are being made to find valid alternatives worldwide. This is particularly true for the packaging industry where the use of plastics is more intense and products often have a very short useful life. Ecodesign is a recognized approach capable of proposing effective solutions to reduce the impact of plastic materials, including their replacement with alternative ones. In this view, bioplastics have been recognized as a new generation of materials characterized by a potential lower environmental burden, along their life cycle, including the end-of-life phase. The same cannot yet be said for their technological and production performance, both at an industrial level and the use phase, especially for durable products.This article refers to the personal care industry and aims at exploring, in the Circular Economy framework, the Ecodesign of a personal care plastic dispenser. In this specific sector, the use of bio-based materials is still very limited and in an early stage, differently, from other industries (e.g. agri-food) where, instead, the applications are much more widespread. In particular, a material substitution solution drew on bio-based materials has been adopted in respect of conventional polypropylene and polyethylene. The technological performances of such bio-based materials have been evaluated through laboratory, production and use tests; the results obtained highlight that they are reaching levels comparable to conventional plastics. The regulatory, environmental and economic implications of their potential use at an industrial level are also discussed.

Strategies for Sustainable Fuel Production Via Photoelectrochemical Synthesis

Developing sustainable energy is highly imperative for humankind owing to the drastic rise in world population and the proportional rise in energy demand at the expense of energy consumption. Various efforts have been made to explore, generate, store, and utilize renewable energy to replace fossil fuels. Among them, solar energy is considered an alternative to fossil fuels because it is inexhaustible, clean, cost-effective, and versatile. Interestingly, this prime source provides massive energy that is high enough (1.9 × 108 TWh/yr) to counterattack global energy consumption (1.3 × 105 TWh/yr).Photoelectrochemistry has been considered a promising route to harness this incredible energy by producing sustainable energy fuels and carriers such as hydrogen, hydrocarbon, and ammonia. PEC systems have the great advantages of simple process steps and very low environmental burdens. However, this technology must overcome many challenges regarding commercial applications, particularly in fabricating electrode materials for PEC water splitting.One of the most important challenges to overcome this problem is discovering efficient catalysts for implementing photoelectrochemical (PEC) fuel production. A critical requirement for outstanding catalysts is an ability to boost the kinetics of a chemical reaction and durability against electrochemical and photo-induced degradation. Moreover, the charge-separation and transfer mechanism are the two paramount properties to consider while designing photoelectrodes. Briefly, the semiconductor materials to be used in PEC water splitting must possess a conduction band potential more negative than the reduction edge of hydrogen and a valence band potential positive to actuate water oxidation. In practice, the photocurrent density and solar-to-hydrogen (STH) efficiency of the n-type semiconductors are far behind the theoretical values.To address this critical and long-standing technical barrier, I have focused on an intense search for efficient, durable, and inexpensive alternative catalysts with moderate band gap, efficient charge excitation-separation property, and high solar energy conversion efficiency for photoelectrochemical systems of water splitting, hydrocarbon conversion, and ammonia production. Keywords : Photoelectrochemistry, Sustainable Energy, Water Splitting, Ammonia synthesis, Urea synthesis, Hydrocarbon

Assessing the environmental impacts of beef production chains integrating grazing and landless systems

Livestock production systems contribute significantly to environmental impacts at the global level, and meat consumption is projected to increase with the population. There is a need to reduce the impact of food production, including that from beef systems. Different production systems, ranging from traditional grazing to landless systems, coexist within the beef sector. Among these, mixed systems have emerged as a promising alternative. These mixed systems typically involve adult cattle in grazing systems alongside fattening calves in landless systems, potentially achieving higher productivity while reducing the overall environmental impacts. The first step towards proposing mitigation strategies involves identifying the impacts of the sector. This study aimed to estimate the main environmental impacts of four types of mixed beef systems based on the origin of the calves that are raised, fattened, and slaughtered. Using life cycle assessment, the study evaluated the environmental impacts from the cradle to the slaughterhouse gate, expressed per kilogram of carcass weight. The four systems assessed include suckler cow farms that fatten their own offspring (beef single farm, BSF), a system in which calves raised on a suckler farm are fattened on a different farm (beef fattening unit, BFU), and systems in which dairy calves are fattened on growing units, with calves either from Spain (dairy national, DN) or from farms located abroad (dairy abroad, DA). Primary data were obtained from representative surveys of farmers and slaughterhouses, and allocation between co-products was performed according to the updated guidelines of Environmental Product Declarations and the Product Category Rules for meat. Seven environmental impact categories were assessed: climate change, marine eutrophication, freshwater eutrophication, stratospheric ozone depletion, terrestrial acidification, photochemical ozone formation on ecosystems, and photochemical ozone formation on human health. The results indicate that meat production from BSF and BFU has greater environmental impacts than that from DN and DA systems, primarily due to the lower environmental burden allocated to dairy calves, whereas the contribution of slaughterhouse activities to the environmental impacts was minimal. This study highlights the importance of mitigating the environmental impacts associated with feed production, enteric fermentation, and manure management in beef systems. Future studies should consider potential environmental benefits of grazing animals such as carbon sequestration and biodiversity promotion.

Strength, porosity and life cycle analysis of geopolymer and hybrid cement mortars for sustainable construction

Owing to the application of industrial wastes, geopolymers are generally regarded as a sustainable alternative to traditional construction materials. However, their lack of adoption on the industrial scale demands detailed investigations. This study conducts a comparative analysis of the compressive strength of different geopolymer and hybrid cement mortars with varying proportions of sodium hydroxide (from 5 to 25 wt%) and ordinary Portland cement (OPC) (from 15 to 35 wt%), respectively. The porosity of all designed mixtures was also analyzed using X-ray computed tomography (XCT) and water absorption tests. ReCiPe 2016 Midpoint (H) method was used for the Life cycle analysis of the geopolymer and hybrid cement mortars. Multi-criteria decision making (MCDM) approach was used to assess the sustainability potential of the designed mixtures based on compressive strength, porosity and overall environmental impact. Experimental results revealed that the increase in sodium hydroxide in geopolymer mortars up to 15 wt% offered its maximum compressive strength. Superior compressive strength was obtained at 35 wt% of OPC in hybrid cement mortars due to the formation of more C-S-H, C-A-S-H and N-A-S-H gels which fill up the voids and pores. Analysis of the macro and micro-porosity revealed that hybrid cement mortars yield denser structure than geopolymer mortars. Life cycle analysis based on 8 distinct impact categories showed that hybrid cement mortars outperform the geopolymers in all impact categories except ‘mineral resource scarcity’. However, the overall environmental impact assessment using the ‘coefficient of performance’ depicts that hybrid cement mortars offer a significantly lower environmental burden than geopolymers. MCDM analysis shows that hybrid cement mortar with 5 wt% of sodium hydroxide and 35 wt% of OPC is the best choice for construction applications. This idea of sustainable hybrid cement mortar will be helpful for the construction industry to limit the environmental impact without compromising their structural performance.

Full-scale partial nitritation and anammox (PN/A) application in removing nitrogen from industrial wastewater: Performance and life cycle assessment

Anaerobic ammonium oxidation (anammox) is an innovative nitrogen removal process that is widely used in wastewater treatment due to its energy-saving potential and ability to reduce carbon emissions. However, research on the application of anammox in full-scale industrial wastewater treatment plants (WWTPs) is limited, and its environmental impacts are yet to be fully understood. This study evaluates the performance and environmental burdens of one-stage partial nitritation and anammox (PN/A) in a full-scale WWTP treating coal chemical wastewater, with different demonstration periods. Compared with conventional nitrification–denitrification, the energy footprint and carbon footprint of the PN/A process were significantly lower and effluent quality was improved. Based on the four-quadrant clustering method, the overall performance of the studied WWTP achieved the greatest synergy during the stable operation period. Life cycle assessment has shown that the PN/A process significantly reduces the system’s contribution to environmental indicators. According to the sensitivity analysis, the fluctuations in energy consumption and chemical usage have significant environmental impacts, with differential sensitivity in the environmental impacts of two demonstration periods. Therefore, considering the specific situation of the WWTPs, optimizing the parameters/indicators most sensitive to environmental impact is essential to reducing environmental loads. Importantly, this work demonstrated that PN/A can improve the operational performance of full-scale industrial WWTPs with lower environmental burdens, providing valuable guidance for the development of sustainable wastewater treatment processes.

Biorefineries as a driver for sustainability: Key aspects, actual development and future prospects

The overexploitation of resources, the increase of the world population and the trend of consumption based on “use and throw away” is causing an increasing pressure on waste management. In this sense, it is necessary to promote sustainable practices in the valorization of waste streams as a strategy for the co-production of bioproducts and bioenergy. This approach can lead to more sustainable production chains, as lower environmental burdens are expected. However, even if a promising cascade production technology could be used, the technical and economic feasibility of biorefineries remains a challenge. This report aims to provide various insights on how to assess biorefineries from a sustainability perspective, including also available standards and guidelines that enable reliable, accurate and transparent sustainability assessments. It also shows where to focus for the inclusion of biorefineries in the value chain, for communicate/visualize their potential, and for the promotion of bio-based products from recovered resources. The outcomes and main conclusions of this report could be summarized as the importance and the need of assessing biorefinery scenarios under a sustainable perspective to have an increased market potential, considering the main aspects available on the international guidelines, certification schemes and voluntary standards.

Effect of industrial waste-based precursors on the fresh, hardened and environmental performance of construction and demolition wastes-based geopolymers

The main goal of this study is to evaluate the effects of incorporation of the industrial wastes into Construction and Demolition Waste (CDW)-based geopolymer mixtures. To do this, a series of CDW-based geopolymer paste mixtures were produced and blast furnace slag (BFS), fly ash (FA), and silica fume (SF) were used to partially replace the CDW-based materials at the substitution rate of 10 and 20 % by weight. Flow table, buildability, vane shear, ram extruder and compressive tests were performed to assess some engineering performances of produced mixtures. Besides that, life cycle assessment analysis was conducted to reveal both the environmental impact of CDW-based mixtures and effects of industrial wastes. The results demonstrated that the geopolymer mixture with higher flowability and longer open time can be obtained by the incorporation of industrial waste precursors. Among them, FA incorporation resulted in the highest improvement in flowability while more decrement in shear yield stress was obtained from the SF-incorporated mixtures. Substitution of CDW-based precursors with industrial wastes provided higher compressive strength test results. Although 100% CDW-based geopolymer paste had lower environmental burden, the mixture using FA, BFS and SF followed very closely behind it. The transportation-related impacts were the most determinative factor for the differences between the environmental performance of geopolymer mixtures containing and non-containing industrial waste-based precursors. Overall, the main sources of environmental burdens of CDW-based geopolymer systems were the alkaline activators, electricity, and transportation. Results showed that industrial waste-based precursor can be successfully used in CDW-based geopolymer matrix to adjust engineering properties without endangering the environmental burden of the mixture.

Constructing of a stable Ti3C2 MXenes nano-traps with ultrahigh and selectively uranyl encapsulation capability by polyethyleneimine intercalation

Seawater and salt lake naturally deposited abundant unconventionality uranium resource and can be harvest for long-term sustainability of nuclear power. However, recovering it from other more plentiful metal ions postulates high affinity and selectivity to dispose an enormous volume of water. Herein, we propose an effective strategy to regulate uranyl extraction capacity and selectivity via chemistry intercalation. We reported the PEI-Ti3C2 exhibited ultrahigh uranyl loading capability (qmax = 580 mg/g at 28 ℃ and 1370 mg/g at 40 ℃), high removal efficiency and remarkable sequestration selectivity (Uinitial = 1.02 ppm, ∼ 82.90 % ∼99.19 % capture efficiency and ∼3.17 × 104 ∼ 6.15 × 105 KdU value), despite the presence of a large concentration of Na+, K+, Ca2+, Mg2+ coexisting ions. Surprisingly, at 103-folds VO43−, the capture efficiency can still reached 89.17 % with 4.12 × 104 KdU value. PEI-Ti3C2 MXenes demonstrated trustworthiness stability after five successive adsorption–desorption cycles accompanied by 89.57 % average elution and soaking in the actual seawater for 35 days. Natural uranium spiked-seawater tests displayed the nano-traps reached ∼2.03 ∼ 26.37 mg/g adsorption capacity after 24 h contact in 0.503–10.064 ppm solution. FTIR and XPS analysis elucidated that the chelation of pyridine and pyrrolidine with uranyl is the main uptake mechanism, which showed a higher affinity than the surface oxygen terminal. The state-of-the-art of intercalation functionalization with its simplicity, low environmental burden and large-scale synthesis is expected to provide new insights into the development of highly efficient MXenes based uranium adsorption materials.

Value-added utilization of phosphogypsum industrial by-products in producing green Ultra-High performance Concrete: Detailed reaction kinetics and microstructure evolution mechanism

This paper presents an effective method for producing green ultra-high-performance concrete containing phosphogypsum aggregates to meet the demand for a sustainable environment. More exactly, the low field nuclear magnetic technology (LF-NMR), nanoindentation, and Backscattering images (BSEM) are used to clarify the hydration process and microstructure evolution of phosphogypsum-based ultra-high performance concrete (PG-UHPC). The results indicate that the mechanical performance of PG-UHPC decreases slightly as phosphogypsum aggregate content increases, but it is still capable of meeting the requirements of applications. Moreover, the introduction of phosphogypsum aggregate in UHPC accelerates water migration and directly affects its hydration degree. Lastly, a reasonable sulfur content can limit the degradation of interfacial transition zone and reduce the risk of matrix cracking in PG-UHPC. To conclude, advanced composite building materials with low environmental burden are prepared as a reference for the development of green ultra-high-performance concrete.

Conservation and intervention in MC2020

AbstractThis paper introduces the conservation and intervention provisions included in the latest edition of the fib Model Code for Concrete Structures (MC2020). This is the first international code which addresses life‐cycle management issues for both new and existing concrete structures. Accordingly, the contents relating to conservation (maintenance and interventions) have been extensively enhanced compared with the provisions included in the previous MC2010, with these now including monitoring. Much of the contents on interventions are newly‐added provisions in MC2020. A new chapter (19) is introduced to show the available materials/systems and the properties necessary for these materials. The necessary properties required to make successful interventions also include consideration of the long‐term performance of materials/systems and compatibility with the substrate concrete. All the processes for interventions, including intervention strategies, selection of intervention methods, survey for interventions, design of interventions and execution of interventions are explained in chapter (38) on conservation and a new chapter (37) on execution of interventions. Selection of intervention methods should be made according to the intervention strategies and the causes and extent of deterioration/damage. In the future the issues of repairability and the standardization of intervention methods are expected to have greater importance. Repairability is the ability to physically repair a structure or structural element which has deteriorated or been damaged by the effects of the considered actions, thus restoring its functionality, but while incurring acceptably low economic cost, environmental burdens and societal disruption.

Life Cycle Assessment of Pilot-Scale Bio-Refining of Invasive Japanese Knotweed Alien Plant towards Bio-Based Bioactive Compounds

Japanese knotweed is an invasive alien plant species with characteristic rapid expansion in Europe and North America and resistance to extermination. It displaces autochthonous biodiversity and causes major damage to infrastructure, thus causing global ecological and economic damage. The Japanese knotweed plant is usually eradicated using various chemical, biological, or mechanical techniques, which at a large scale include heavy equipment, usually followed by incineration. Therefore, excavation is preferred to eradication techniques, and as a biomass waste recovery method due to the extraction of high-value biocompounds. This is supported by the fact that the Japanese knotweed possesses various bioactive compounds with beneficial effects on human health. Its rhizome bark extract produces strong and stable antioxidant activity over time, as well as apoptotic, antibacterial, and other beneficial activities. In this work, an environmental impact assessment, including greenhouse gas footprint, acidification, eutrophication, and ecotoxicity for extraction route of the Japanese knotweed rhizome bark, is performed. A comparative case study between the lab-based and proposed pilot-scale production of active added-value extract was evaluated. The results show the pilot-scale production exhibits lower environmental burdens, mainly due to greater electricity requirements for the lab-scale alternative.

Compressed air energy storage (CAES): current status, geomechanical aspects and future opportunities

Abstract A compressed air energy storage (CAES) facility provides value by supporting the reliability of the energy grid through its ability to repeatedly store and dispatch energy on demand. Two main advantages of CAES are its ability to provide grid-scale energy storage and its utilization of compressed air, which yields a low environmental burden, being neither toxic nor flammable. The focus of this review paper is to deliver a general overview of current CAES technology (diabatic, adiabatic and isothermal CAES), storage requirements, site selection and design constraints. We discuss underground storage options suitable for CAES, including submerged bladders, underground mines, salt caverns, porous aquifers, depleted reservoirs, cased wellbores and surface pressure vessels. A geomechanical perspective is provided regarding the pressure limits for these options. The impacts of cyclic injection and withdrawal of compressed air, and the importance of caprock assessments with porous rock CAES, are also discussed. In addition, we provide an overview of the large-scale CAES facilities that are currently active or under development and a cost comparison of the diabatic, adiabatic and isothermal CAES options. Lastly, we outline major challenges and future opportunities for CAES and the top priorities for research, industry and stakeholders.

Environmental Assessment of Solar Cell Materials

Abstract In today’s world, fossil fuels, including coal, oil, and gas, are the primary energy sources from which electricity is obtained. As they are exhaustible and their exploitation has a negative impact on the natural environment, they should be, at least partially, replaced by renewable energy sources. The implementation of this goal depends on a number of factors, including social and political, the existence of investment support programmes, and the need to lower electricity prices and ensuring energy security. One of these sources is solar energy. Each year, the Earth receives around 1 · 1018 kWh of solar energy, which is more than 1000 times the current global energy demand. This is therefore a vast source of energy that can be tapped to satisfy human energy requirements. The use of solar energy releases no CO2, SO2, or NO2 gases, and does not contribute to global warming. Photovoltaics is one of the technologies that makes it possible to generate electricity in an environmentally friendly manner. By using the energy of solar radiation, a photovoltaic cell converts energy without emitting harmful substances to the atmosphere, noise, and waste. Photovoltaics is the cleanest technology among all the technologies that use renewable energy. Considering the shorter and shorter times needed to generate energy equal to that required by the module production process, during its lifetime it will produce much more electricity than was used to produce it. This results in a reduction in greenhouse gas emissions. For example, during its lifetime, a 200 Wp module prevents the emission of over four tonnes (Mg = 106 g) of carbon dioxide. Although the technologies for the production of photovoltaic cells and modules entail a lower environmental burden compared to other sources of electricity, it is necessary to remember about the risks associated with the use of chemicals at the stage of module production, which threatens their release to groundwater or air, and the need to recycle modules after their disassembly. Also, the energy consumption in the production phase of PV systems significantly worsens the ecological balance. This article presents an analysis of the impact of the materials and technologies used on the result of the environmental analysis of PV installations. In the article a detailed energy balance analysis of the EPBT value has been carried out. The values of greenhouse gas emissions throughout the life cycle of the solar module were determined. Methods of limiting the impact of photovoltaic technologies on the natural environment were indicated.

Exploitation of waste perlite products in lime-based mortars and grouts

Perlite is an amorphous mineral, coming from volcanic deposits and mainly consists of alumino-siliceous compounds. Perlite mining presents a low environmental burden, while during the last 60 years less than the 1% of the worldwide reserves have been exploited. During its industrial process, a significant number of secondary products derives and remain unexploited, inducing the environmental burden. The study focuses on exploiting two secondary products coming from the elaboration of perlite (named after D1S, D1C), in the Hellenic plant. These products have been used as pozzolans in the production of mortars and grouts. During the experimental part, nine mixtures where manufactured and tested, including five mortars and four grouts, where natural pozzolan was substituted by D1S and D1C. The fresh state properties of all mixtures were recorded, as well as their hardened ones, including shrinkage deformations, porosity, apparent specific gravity, water absorption coefficient due to capillary action, dynamic modulus of elasticity, flexure and compressive strength. From the correlation of the results, it was asserted that the partial or even total substitution of natural pozzolan by perlite secondary products, can positively influence the physical and mechanical properties of the composites. D1S seem to be an alternative pozzolanic material leading in mortars and grouts of enhanced properties. It maybe therefore concluded that the exploitation of perlite secondary products in the construction sector is feasible, leading to the development of effective, low-cost and environmentally friendly products for specific applications.