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The pulp and paper industry, which provides cellulose pulp and paper, bio-based energy and chemicals, is one of the largest energy consumers, greenhouse gases (GHG) and pollutant emitters among manufacturing industries. Although the environmental impact of the pulp and paper industry has been extensively studied, life cycle assessment (LCA) results have not yet reached a consensus. By means of a systematic review and meta-analysis, this article contributes to the quantification and harmonization of the life cycle environmental impacts of pulp making and paper making systems. Based on the screening of 45 cases of paper making and 18 cases of pulp making, we found that 1 t of paper results in about 950 kg carbon dioxide (CO 2 ) equivalent (CO 2 -eq) GHG emissions on average. However, there are distinct differences between countries and pulp and paper categories. The dominant factor influencing GHG emissions is energy use. In paper making, the pulp making process is responsible for 62% of energy use, 45% of GHG emissions, 48% of acidification potential, and 49% of eutrophication potential. The kg CO 2 -eq emissions of three different types of pulp were as follows: Kraft, 508 kg CO 2 -eq/t; chemi-mechanical, 513 kg CO 2 -eq/t; and recycled pulp, 408 kg CO 2 -eq/t. Excluding emissions from electricity and steam production, the convergence of carbon emissions is observed within the same categories of pulp. Straw-based pulp caused far more environmental impact than any other type because of the intensive inputs in agricultural activities as well as in the pulp making process. This research highlighted the inconsistencies in functional units, system boundaries, and methodologies and carbon neutrality assumptions in different LCA studies of pulp and paper making. Future studies should focus on the environmental impact of straw-based pulp making, system boundary unification, and calculation of biogenic carbon emissions. [ABSTRACT FROM AUTHOR]

Pulp and paper industry is one of the eight critical industries for controlling carbon emissions in China. As the paper productions increase, the pulp and paper industry may fail in achieving the emission reduction target due to the rapid growth of greenhouse gas emissions. The study uses life cycle assessment to evaluate the greenhouse gas emissions of China's papermaking industry chain in order to propose emission reduction targets and find ways to achieve the emission reduction targets for China's papermaking industry. Considering the net carbon absorption of plant raw materials and the extensive paper industrial chain, this study obtained that the greenhouse gas emission of major paper types under corresponding pathways ranges from 1.96 t CO 2 eq/t paper to 6.55 t CO 2 eq/t paper. Plant carbon sink can reduce greenhouse gas emissions by 14.3%–42.9% under virgin fiber-based pathways. This study found that the greenhouse gas emissions caused by terminal products of 814 papermaking enterprises counted in China were 282.23 Mt CO 2 eq in 2015, accounting for 10.23% of the total greenhouse gas emissions of manufacturing industries and construction. To achieve the emission reduction target by 2050, emissions of the pulp and paper industry in China have been investigated from the perspective of three ideal energy structures. The research findings show that the emission reduction target of Intended Nationally Determined Contribution will be achieved in 30 years if the energy structure of the pulp and paper industry is adjusted only based on the optimal 450 scenario. In terms of other energy structures, the pulp and paper industry should assume afforestation areas ranged from 5900 km2 to 223,000 km2 at least to make up for the greenhouse gas emissions beyond allowance, which accounts for 0.85%–32.16% of the existing areas of plantation forestry in China. • Statistics in this work reveal the problem of excess capacity in China's pulp and paper industry. • GHG emission of paper products in different pathways range from 1.95 to 6.52 t CO 2 eq/t paper. • Energy supply mode transition is conductive to green development of pulp and paper industry. • Pulp and paper enterprises should assume afforestation areas to achieve emission reduction targets. [ABSTRACT FROM AUTHOR]

This paper develops a framework for a financial, economic, and stakeholder analysis of a residential rooftop solar net-metering program. The empirical focus of the paper is the net-metering program in Ontario, Canada, but the methodology is applicable to evaluating other public programs. The results highlight that without the Federal Government's subsidy for the initial investment cost, net-metered solar systems are not financially viable for representative households. Moreover, the stakeholder analysis reveals that for each additional net-metered system installed in Ontario, non-net-metered households experience financial losses of six times the benefits to the net-metered households. The net losses to the Federal Government of Canada and the Canadian economy are five and nine times the benefit to the net-metered households, respectively. The only stakeholder who benefits marginally is the Government of Ontario. In terms of environmental benefits, our estimate of the cost of greenhouse gas abatement by residential net-metered solar is 325 CAD per ton of CO 2 , which is significantly higher than the current (65 CAD in 2023) and future (170 CAD by 2030) national carbon price set by the Government of Canada. [ABSTRACT FROM AUTHOR]

Negative emission technologies driven by nature with less energy input, lower costs, and long carbon storage capacities are essential for meeting ambitious global carbon mitigation goals. This paper evaluates the carbon sequestration potential of bivalve shellfish farming because its sequestration process is driven by nature, and it is cost-effective and energy efficient. The carbon in shells and the carbon that enters sediments via bio-deposition are long-lived forms of carbon. Using China as a case study, a preliminary estimation suggests that the carbon sequestration efficiency and intensity of cultivated shellfishes are much higher than those of artificial forests. In China, approximately 6.23 Mt CO 2 -eq a−1 was fixed via net carbon sequestration during shellfish growth from 2015 to 2019. In addition, the farmed shellfishes provided 0.37 Mt of harvested protein, and approximately 37.39 Mt CO2-eq a-1 were reduced compared to the same amount of protein provided by beef, and thus, shellfish farming has the win-win benefits of carbon sequestration and high-quality food provision. More importantly, a total of 5.64 Gt CO 2 -eq, accounting for 17.63% of the total emissions in 2020, can be potentially sequestrated at the global scale under the world's largest farming area scenario. • A Negative Emission Technology via shellfish farming was introduced. • Carbon sequestration function and efficiency of shellfish farming were investigated. • Carbon sequestration potential for bivalve shellfish farming was evaluated globally. • Life cycle GHG emissions of shellfish farming in China was assessed. [ABSTRACT FROM AUTHOR]

Energy scarcity and environmental pollution from biogenic residues and wastes are major challenges in the 21st century, which can be converted to useful renewable energy and reduce environmental threats. In Bangladesh, a tremendous amount of biogenic residues is generated which remains largely underutilized. Mono-digestion, which is a common practice in Bangladesh for biogenic residue processing, resulted in low biogas yield. However, Bangladesh has a vast source of biogenic residues which can be utilized through anaerobic co-digestion to increase biogas production. In this paper, a desk study and comprehensive review has been conducted in finding potentiality of biogenic residues in biogas production from available biogenic residues in Bangladesh. Research studies on co-digestion of biogenic residues were reviewed critically, and their practices and benefits on energy production and impact on the environment were stipulated in this study. The study shows that co-digestion of biogenic residues in appropriate ratio increases the biogas production, improves digested quality and reduces GHG emissions. [Display omitted] • Biogas production potential from agricultural and livestock sectors were analyzed. • State of art co-digestion options of animal dung as main feedstock was reviewed. • Co-digestion of crop residues and animal dung lessened environmental burden. • Digestate can be used as bio fertilizer or converted into other forms of fuels. [ABSTRACT FROM AUTHOR]

In addressing the detrimental impacts of greenhouse gas emissions and decarbonization targets, the imperative shift towards electrification in the transportation sector is underscored, with additional advantages arising from shared features. Nevertheless, technological progress, particularly in the realm of connected and autonomous features, brings forth notable benefits but also introduces challenges related to safety, cost, and implementation. The convergence of connectivity, autonomy, shared mobility, and electric propulsion leads to the concept of shared autonomous electric vehicles. In practical integration scenarios several concerns encompassing the transportation network, power network, and user satisfaction. This paper conducts a thorough analysis of various aspects of shared autonomous electric vehicles, rigorously evaluating the feasibility of their integration within a coupled power and transportation network. The analysis highlights allocation, routing, charging, battery swapping, social-economic considerations, and modelling as pivotal areas warranting focused research attention in the realm of shared autonomous electric vehicles. • Comprehensive review of shared autonomous electric vehicle (SAEV). • SAEV features and comparative literature. • Independent study on power network and transport network. • Integration challenges of SAEV in the coupled power and transportation network (CPTN). • Future research direction and research recommendation for the perspective of green energy and mobility. [ABSTRACT FROM AUTHOR]

The carbon emissions associated with the built environment represent the dominant fraction of the total carbon footprint of society. As a result of the intense debate over how to address climate change, Life-Cycle Carbon Emissions Assessment and carbon footprint standards such as the PAS2050, ISO/TS 14067, and the GHG Protocol, are receiving increased attention. However, carbon emission calculations often vary in terms of boundaries, scope, units of greenhouse gas emissions, and methodologies. There is not an internationally accepted method for measuring, reporting, and verifying GHG emissions from existing buildings in a consistent and comparable way. In support of developing a standardized approach, this paper reviews current methodologies for carbon footprint accounting and outlines the inconsistencies of most life-cycle carbon assessments studies. The paper also aims to present the cutting-edge knowledge about emissions resulting from buildings during their life-cycle. The conclusion of this research, after a comprehensive literature review and critical analysis, is that there is a need for a clear, accessible and consistent method to assess the carbon emissions from buildings. The findings in this paper can also support and facilitate the discussion of the meaningful targets required to reduce carbon emissions. [ABSTRACT FROM AUTHOR]

Carbon dioxide emissions from burning fossil fuels are believed to be the main factor for alarming rise in global temperatures. Conference of Parties 21 held at Paris in the year 2015 strictly warned and asked the nations to reduce their greenhouse gas emission level. This makes the nations to adopt renewable energy technology to substitute burning fossil fuels. Solar energy due to its accessibility and affordability leads the renewable energy application race. Even though Photovoltaic (PV) technology is mature but the effect of temperature on its efficiency is considerable, which opens up new front of research where combination of PV and thermal absorber is focussed to harness thermal energy which otherwise negatively affect the PV electrical efficiency. In the proposed study starting from the effect temperature on PV electrical efficiency, construction of Photovoltaic-Thermal (PV/T) module, historical development of PV/T, about different types of PV/T's developed around the globe along with performance of developed PV/T's, effect of operating parameters and methods of thermodynamic management are reviewed and presented. The study emphasised on the use of nano fluid and phase change material to harness maximum thermal energy from the system, also includes an insight into commercially available PV/T modules across the globe. This paper presents enviro-economic evaluation of PV/T systems developed by various researchers and also enumerated thermodynamic methods for evaluating system efficiency, which includes both energy and exergy analysis. This paper also provides the necessary information about the requirement of future research in PV/T. [ABSTRACT FROM AUTHOR]

The production of cement depletes natural resources, consumes high energy and emits huge amounts of green house gases. It accounts for almost 7% of the global carbon dioxide emissions, as the production of one ton of ordinary Portland cement releases approximately one ton of carbon dioxide. Due to the severe environmental pollution and health hazards associated with the cement and construction industries, they are under the strict scrutiny from the governments and environmentalists. Rice husk is an agricultural waste, whose natural degradation is restricted due to the irregular abrasive surface and high siliceous composition. It is not appropriate to be used as a feed for animals due to the low nutritional values. If dumped as landfill, they can take a lot of area and become a major challenge to the environment. If they are disposed by burning, the ashes can spread to the surrounding areas, create pollution and destroy the natural beauty. One of the possible solutions for the disposal of rice husk is to convert them into rice husk ash and incorporate them into cement based materials. The partial inclusion of rice husk ash (RHA) for cement is found to be durable, environmental friendly and economically viable. This paper presents an overview of some of the published results on the successful utilization of rice husk ash as a supplementary cementitious material and the properties of such concrete at fresh and hardened stages. Studies indicate that there is a promising future for the use of rice husk ash in normal, high strength and self compacting concrete as it shows high strength, low shrinkage and permeability, high resistance to carbonation, chloride, sulfate and acidic environments. The summery and discussions provided in this paper should provide new information and knowledge on the applications of greener and sustainable rice husk ash concrete. [ABSTRACT FROM AUTHOR]

The world is moving towards the reduction of dependency on fossil fuels. Various innovations are undergoing to make the use of sources of renewable energy like wind, solar, tidal etc. Among these sources, solar energy is available in enormous quantity and best option that may be used for space heating and generation of electric energy. For drying agricultural and non-agricultural products, solar energy can be used directly or indirectly. But in open sun drying the products are affected by external calamities such as rain, insects and animals. To overcome the shortcomings of open sun drying various greenhouse solar dryer had been proposed so far. Some of recent researches have been discussed in the paper. This paper provides the data of already developed greenhouses so the reader can develop new and modified the greenhouse structure. To accomplish this, various researches of recent years have been studied and presented in this review. [ABSTRACT FROM AUTHOR]

Several factors such as climate change, increment in fuel cost and digital technology era have lead to transformation of conventional grid into smart grid. Existing microgrid can be integrated with smart grid characteristics by various topologies, including cogeneration system where both electricity and thermal energy from single source of fuel can be produced. Cogeneration system has better efficiency, lower costs and able to reduce greenhouse gas emissions compared to singular conventional methods. This paper presents a comprehensive review of cogeneration system, covering the principle operation and types of prime movers available for use in power plant, building and industrial plant. Prime movers such as gas turbine, steam turbine, micro turbine, reciprocate engine and fuel cell are compared in terms of size (kW), efficiency and principal operation. This review also describes the hierarchical control system for cogeneration system; classified into three types, which are local, centralized and decentralized. This study tries to find the most suitable control strategy for certain cogeneration system by referring to the related standards available. A number of cogeneration applications in commercial buildings, including hospital, airport, shopping complex and hotel, are presented to show the effectiveness of the cogeneration system. Overall, this paper presents comparison between each prime mover technology, factors that influence the selection of prime movers, challenges and prospects of cogeneration system. [ABSTRACT FROM AUTHOR]

Research on greenhouse gas (GHG) emissions in the building sector has concentrated on the use phase of buildings, and more recently embodied emissions from construction materials. Much less research has focused on reducing GHG emissions from onsite fuel use during construction, in part because predicting and measuring fuel use is complex and lacks guidance to help modelers focus on key factors that drive variability in results. This paper addresses that challenge by examining the state-of-the-art in onsite fuel use accounting with a focus on earthworks, one of the largest drivers of onsite fuel consumption. It provides a comprehensive summary of the existing literature, describes and quantifies the ways in which factors influence fuel use, and fills several gaps identified during the review process by drawing from research in related fields. The result is a new taxonomy for categorizing fifteen factors which influence fuel use, including equipment factors (e.g., engine specifications, attachment selection), operational factors (e.g., operator skill, fleet configuration), and site factors (e.g., soil type, excavation depth). Drawing on earthwork productivity and productivity/fuel use in related fields (e.g., freight hauling, military equipment) to augment the construction emissions literature, most notably to investigate the influence of weather on earthwork GHG emissions. Across case studies, soil type, attachment selection, engine specifications, weather and hauling conditions arise as the most influential factors. Finally, this work presents recommendations for structured fuel use data collection to improve the consistency of future data collection and reporting, along with subsequent fuel use modelling and optimization efforts. [Display omitted] • A comprehensive review of how fifteen factors influence earthwork fuel use. • Presenting a taxonomy for categorizing factors affecting earthwork fuel use. • Preliminary analysis of weather's impact on earthwork fuel use. • Presenting a framework for earthwork fuel use data collection. [ABSTRACT FROM AUTHOR]

The critical transmission hubs in global supply chain networks have great potential to reduce carbon emissions, yet this has not received much attention from existing studies. This research combines the structural path betweenness, an extended structural path analysis, and a multi-level modularity optimization algorithm to identify key transmission sectors, paths, and carbon communities in a global supply chain network using the environmentally extended multi-regional input-output analysis. The results show that (1) China's metal industry, power industry, and non-metallic industry are the most crucial transmission centers, and some sectors, such as the paper industry and textile industry in China, are also key transmission hubs, yet they are ignored by traditional accounting methods. From a national viewpoint, China is the most key transmission hub, and its high betweenness is mainly caused by domestic demand. Meanwhile, the CO 2 emissions transferred by China to satisfy foreign demand are mainly related to the US, ROW (especially the Asia-Pacific region), and Japan. (2) The transmitted carbon emission is mainly concentrated in the first four production layers, accounting for 69.46 % of the total. (3) The global carbon emission network can be divided into 20 carbon communities. And the largest communities are mainly led by mainland China. Most of the communities contain various national sectors, which offer evidence for international cooperation strategies. The results offer policymakers a new perspective on mitigating environmental stress. [Display omitted] • Critical sectors having higher betweenness are identified from a global level. • Key supply chain paths causing the high betweenness are identified. • Some critical carbon communities in the global carbon emission network are detected. • An extended structural path betweenness is proposed to find key supply chain path. [ABSTRACT FROM AUTHOR]

Energy model, a systematic data-intensive multi-objective framework replicating the energy sector of the country or globe, constitutes of energy resource supply, energy consumption sector-by-sector, energy transformation technologies, greenhouse gas emission and energy pricing. Considering the atypical weather pattern yearly and geographical diversity, the challenges and benefits of designing an energy model have been summarized. The paper has documented the tremendous jeopardy of drastic climate change, energy crisis on the global economy, requirement for transition to low carbon economy and rural electrification which have been impetus for the evolution of legitimate energy model. Special emphasis has been provided on the types of energy models that have been developed and practiced throughout the world followed by a comparative analysis of a few. The requirement to configure a unique energy model in India followed by certain recommendations has been proposed in this paper. [ABSTRACT FROM AUTHOR]

Bangladesh is a hugely populated country in South Asia. The country produces its electricity mainly from natural gas followed by liquid fuels. Although the installed electricity generation capacity of the country has been increased to 12,261 MW, there is scarcity of electricity in the hot summer season which is a barrier to industrial development as well as socio-economic development. Combustion of fossil fuels releases greenhouse gases (GHGs) into the atmosphere which causes global warming. Bangladesh can be badly affected by greenhouse effect and global warming. These problems can be mitigated by incorporating renewable energy sources (e.g., solar, wind, hydro, biomass, etc.) to the country's electricity generation. Renewable energy resources are considered as clean and can serve the electricity demand in the remote areas where grid connection is not possible. The potential of solar energy and biomass is enormous in Bangladesh and people have already started to harness energy from these sources. The government and the policy makers should come forward to encourage the people of rural areas as well as urban areas to use renewable based electricity. The government of Bangladesh has set up a plan to generate 5% of the country's total electricity from renewable sources within 2015 and 10% within 2020. However, within 2015 the country has been able to generate only 3.5% of the total electricity from renewable sources. This paper presents a thorough review of the current status and future potentials of renewable energy sector in Bangladesh. In this paper the updated information is provided for the overall renewable energy sector of the country. [ABSTRACT FROM AUTHOR]

This paper provides a critical review on the current status and potential of biomass utilization in ferrous metallurgical processes, i.e., the blast furnace (BF) – basic oxygen furnace (BOF) route, the direct reduction (DR) – electric arc furnace (EAF) route, the scrap – EAF route and the other routes. In the BF-BOF route, biomass can be used as a fuel for iron ore sintering, or as a raw material for the production of bio-coke, and utilized for blast furnace injection. In the DR-EAF route, direct reduction iron can be produced form iron ore and biomass pellet. In the scrap – EAF route, biomass can be utilized in EAF through a cogeneration system. In addition, biomass can be utilized in magnetic separation of refractory low-grade iron ore, in reuse of iron and steel slag, or as an adsorbent for pollutant control, etc. The challenges and outlook of biomass utilization in metallurgical industry are also discussed in this paper. [ABSTRACT FROM AUTHOR]

Natural gas hydrate (NGH) is a source of energy that has attracted significant interest for the secure and effective extraction of CH 4 gas from permafrost and marine regions. CH 4 gas can be produced and greenhouse gases (GHG) sequestrated by injecting flue gas into NGH, minimizing environmental threats. This paper provides a complete summary of the advancement of CH 4 recovery from NGH by CO 2 replacement. The CH 4 –CO 2 exchange mechanisms are examined in different types of hydrates concerning their cage structure and formation in geological layers. The gas composition of CO 2 injected with H 2 , N 2 , and air, thermodynamic pressure and temperature, hydrate and water saturations, and concentration of CO 2 are factors influencing the efficiency of the CH 4 –CO 2 exchange. The structural integrity of the sedimentary film throughout the exchange process is evaluated, and the evaluation indicates that the hydrate formed by CO 2 gas is stronger than the layer formed by CH 4 gas and that the mechanical integrity of the reservoirs can be maintained after the exchange process. The replacement effect of CH 4 –CO 2 combined with depressurization, thermal stimulation, and other factors is discussed. Restrictions and further studies of the CH 4 –CO 2 exchange process are also analyzed in light of current findings. This article offers information for future NGH extraction and CO 2 storage applications by providing an overview of recent advances in CH 4 –CO 2 replacement. • Mechanism of CH 4 –CO 2 replacement comprises CH 4 extraction and CO 2 sequestration. • Using different compositions of N 2 and H 2 gases with CO 2 enhances CH 4 –CO 2 exchange. • Combination of thermal stimulation with CO 2 exchange improves CH 4 recovery rate. • Mechanical properties of CH 4 –CO 2 hydrates maintain the mechanical integrity of rock. [ABSTRACT FROM AUTHOR]

Solar energy offers over 2,945,926 TWh/year of global Concentrating Solar Power (CSP) potential, that can be used to substitute fossil fuels in power generation and mitigate 2.1 GtCO 2 of greenhouse gas (GHG) emission to support Sustainable Development Goals (SDGs) set by the United Nations (UN). Thermal energy storage (TES) is required in CSP plants to improve dispatchability, reliability, efficiency, and economy. Of all TES options, the latent heat thermal energy storage (LHTES) together with phase change materials (PCMs) exhibit the highest potential in terms of efficiency and economy. PCM properties thus become the ultimate decider of CSP performance. This paper reviews over 200 of published articles and websites to describe the history, identify the technologies, economics, and current trends of PCM as LHTES material for CSP plants. A list of 163 PCM candidates suitable for LHTES systems in low-temperature (T < 220 °C), medium-temperature (220 °C < T < 420 °C), and high-temperature (T > 420 °C) applications is presented for the first time. Research gaps are identified to determine the future directions. • CSP shows remarkable potential in global electricity generation. • Intermittency of solar has made the requirement of a TES for CSP system. • We evaluate the advantages of LHTES for storing thermal energy. • LHTES shows 5–14 times the energy density of SHTES allowing for more compact storage and lower inventory requirements. • Selection of a compatible PCM is crucial for operating the LHTES at desired performance level. [ABSTRACT FROM AUTHOR]

Anaerobic digestion (AD) is a viable technique to address food waste (FW) problems by converting FW into sustainable energy. Despite the advantages of the AD process, large-scale AD plants like in Germany and the USA have not been developed in Australia. Therefore, this paper aims to study the technological, economic, and environmental feasibility of sustainable energy production from household FW in Australia. In addition, this paper discusses the different waste to energy (WtE) technologies along with the operational parameters as well as the challenges in developing a biogas plant. The energy and economic potential analysis of the AD process indicates that the processing of 10% FW from Australian states and territories can generate 1.22 GWh to 35.4 GWh electricity which can subsequently earn AUD 0.54 million to AUD 15.7 million revenue per year. The greenhouse gas (GHG) emissions analysis indicates that conversion of the 10% of Australian FW has the potential to lower GHG emissions by 639,852 tonnes per annum. Hence, it can be said that FW plays a vital role as a promising source of sustainable energy and is capable of benefiting the country's economy significantly and reducing GHG emissions. • FW is a potential source of sustainable energy. • AD is a useful waste to energy process for producing clean energy. • Conversion of FW into energy can significantly lower GHG emissions. [ABSTRACT FROM AUTHOR]

Carbon nanomaterials have huge potential in the field of energy and environmental applications. However, a wide range of greener and environment friendly synthesis methods utilizing natural, renewable, cheaper waste materials has to be developed. This will lead to the reduction of green house gases, exploitation of toxic materials and helps in the development of sustainable technologies. In this review, the details progress made in the last ten years concerning the synthesis of new one dimensional (carbon nanotubes CNT, carbon nanofiber) and two dimensional (graphene) carbon based materials using natural precursors and waste materials is summarized. The aim of this review paper is to provide a comprehensive scientific progress of synthesis of graphene and carbon nanotubes using natural precursor and waste materials for the future perspective. This paper also concludes with a brief discussion on the impact of natural precursor for the graphene and CNTs for environment, its toxicological effects and its future prospects in this rapidly emerging field. Natural precursors and waste carbon containing products are emerging as a new class of materials that have efficiency to produce graphene and CNTs. The various synthesis processes of graphene, CNTs and carbon dots has been reported using several natural hydrocarbon precursors (turpentine oil, eucalyptus oil, palm oil, neem oil, sunflower oil, castor oil, biodiesel, tea-tree extract, honey, milk, sugar, butter, egg etc.). Also, some research groups have used foods wastes (cookie and chocolate), vegetation wastes (woods, leaf, grass, fruit wastes), animal/bird/insect wastes (bone and cow dung, dog feces, chicken feather) and agro waste (sugarcane bagasse) for the synthesis of graphene and CNTs. Research on natural hydrocarbon precursors and wastage materials has increased in recent years as they promise to produce better and high quality of graphene and CNTs in large quantities. The fascinating aspect of this research area is that it guides the use of natural hydrocarbons to explore the possibilities of improving graphene stability and robustness suitable for different type of applications. [ABSTRACT FROM AUTHOR]

The transport sector, which heavily depends on oil-derived liquid products such as gasoline and diesel, globally occupies the 3rd place when total energy consumption and greenhouse gas (GHG) emissions are considered (after the industry and the building sectors). This consumption level is predicted to increase by 60% by 2030 mainly because of population growth, industrialization and exposure to better living standards. Biodiesel is one of the sustainable sources of energy for meeting increasing global transport energy demand and reducing GHG emissions significantly. The use of non-edible plant oils is very significant because it can be grown in harsh and marginal lands which require less maintenance, less soil fertility and less water as opposed to arable lands for growing edible vegetable oils. However, it is noted that the 2nd generation feedstocks can also be grown in arable lands, but this is not a general practice and is not recommended. The 2nd generation biodiesel can be considered as a promising alternative because of its feedstocks, such as non-edible vegetable oils, animal fats and waste cooking oils are cheaper in most of the countries in the world than the 1st generation feedstocks which are produced from edible-vegetable oils (food crops). Furthermore, the price of biodiesel depends on the cost of feedstocks which makes up 70–95% of the total production costs. However, extraction of non-edible oils as well as conversion process of oil into biodiesel should be well scrutinized. This paper extensively reviews on the selection of 2nd generation biodiesel feedstocks, oil extraction as well as biodiesel conversion techniques with the aim to identify the most appropriate and cost-effective feedstocks, identify the most suitable oil extraction technique and most efficient technology for producing of the 2nd generation biodiesel which will substitute the current dependence on the fossil fuel worldwide. This paper will contribute to greater understanding of the recent development and prospects of 2nd generation biodiesel as a sustainable transport fuel. [ABSTRACT FROM AUTHOR]

In recent years, many countries put an emphasis on the development and deployment of renewable energy to cope with the global environmental crisis such as depletion of fossil energy, climate convention to control emissions of greenhouse gases. Among the various new and renewable energy sources, the Korean government selected wind power energy as one of the core areas for R&D investments. In this paper, we evaluate the economic value of the investment in wind power energy R&D in Korea and optimal deployment timing of wind power technology by using the real option approach. The real option model adopted in this paper assumes that a decision maker has a compound option to abandon, deployment, or continue the R&D. As a result by using empirical data of Korea, it is found that there exists a considerable amount of positive economic value of investments in wind power energy R&D. [ABSTRACT FROM AUTHOR]

Taiwan, located in a subtropical area, is a high energy-importing nation with approximately 98% of our energy supplied by imported fuels since 2000. In this regard, renewable electricity systems from its richness of solar radiation and strong monsoon are thus becoming attractive due to the energy, economic, and environmental policies for pursuing clean electricity supply, sustainable development and greenhouse gases emission mitigation in Taiwan. The objective of this paper was to present an analysis of profitable promotion and innovative measures for renewable electricity in Taiwan because the photovoltaic (PV) power and wind power systems have rapidly increased the total installed capacity from 2.7 MW in 2000 to 1006.2 MW in 2013. The description in the paper was thus summarized on an analysis of renewable electricity supply since 2000 and its future goals up to 2030, and then centered on the new promotion legislation (i.e., Renewable Energy Development Act) in the measures of feed-in tariff (FIT) and tax/subsidy incentives. Current subsidiary and innovative programs to promote the development of renewable electricity technologies, including roof-type PV power, off-shore wind power and biogas-to-power, were also described. Due to its innovation promotion for renewable energy exploitation in recent years, Pingtung County, located in the southernmost of Taiwan, was introduced as a case study. Finally, some recommendations for promote renewable electricity development were addressed in the paper. [ABSTRACT FROM AUTHOR]

Malaysia, as a developing country and a member of the Association of Southeast Asian Nations (ASEAN), is looking into inexhaustible and repeatable alternative energy sources such as solar, wind, mini-hydro and biomass. The estimated GDP at 2010 is $15,385 per capita and the economic and industrial growth of the country implies that energy demand is growing very fast. In addition, the growing prices of fossil fuels, and greenhouse gas (GHG) emissions, make inevitable renewable energy solutions for the country. Geographically, Malaysia is located in a region of tropical and humid climate which provides easy access to a variety of renewable energy sources. The government of Malaysia has initiated renewable energy policies to encourage industries and individuals to employ renewable-energy-powered systems in power applications. This paper first gives a brief overview of the current status of renewable energy in Malaysia. Then it provides the energy policies, specifically the renewable energy policies in Malaysia, in Section 2 . The renewable energy programs are reviewed in Section 3. The building energy efficiency program with green aspect is provided in Section 4. Lastly, the conclusion and forecasts of this paper are given in Section 5. [ABSTRACT FROM AUTHOR]

Global energy demand is lowering its growth, but it is still expected to increase by 30% between now and 2040. To decrease greenhouse gas emissions a shift to more sustainable renewable energy sources is fundamental. Among the renewable energy sources, biomasses already have the largest share in Europe and their future demand for biorefinery plants will increase at global level. This study provides a comprehensive and exportable categorization of the residual biomasses (RB) from different supply sectors. Thanks to the individual descriptive and quantitative parameters introduced in the paper, an estimate of the theoretical and techno-economic potential is presented for a well-industrialized, agricultural-oriented and environmentally advanced European Region. Results are presented as recoverable biogas or biomethane, considering also the seasonal availability. In a relatively small region like Emilia Romagna (Italy), 106 different types of residual biomasses belonging to 6 main groups have been characterized. Over half of the total residues come from the agro-industrial and food businesses (58) followed by the agricultural sector (33). The estimate reveals a theoretical potential of 3544 ± 291 Gg/year of total solids for thermochemical valorisation and 3460 ± 639 Gg/year of total solids suitable for biological treatment. In terms of unused potential, the quantities decrease respectively to 2120 ± 298 and 915 ± 167 Gg/year. The estimates indicate stable results over the years from 2014 to 2016. The seasonal availability shows two evident peaks from August to October, while a significant shortage is present from April to June for the residues suitable for thermochemical valorisation. The theoretical potential that can be obtained from the Region's residues corresponds to about 1.8–2.3 million TOE/year, corresponding to 13–17% of the total regional consumption. Unused residues contribute to 0.9–1.2 million TOE/year. Image 1 • A fully comprehensive and exportable categorization of the RBs is developed. • 106 residual biomasses have been identified and estimated in Emilia Romagna Region. • About 1.5 Mg/year/capita of total solids is produced in the Region. • The theoretical RB potential covers the 13–17% of the regional energy consumption. • The unused RB potential decrease to 7–9% of the annual regional energy consumption. [ABSTRACT FROM AUTHOR]

In recent decades, freshwater reserves have been under high threats, generated mainly by anthropogenic causes such as rapid population growth and climate change. Currently, one of the technologies that has been used to meet the freshwater global demand is seawater desalination. However, this solution has two major drawbacks. First, the discharge of reject brines with a high concentration of pollutants and nitrates, causing environmental problems such as eutrophication processes. Second, desalination systems, both membrane and thermal technologies, have a high energy consumption that is supplied with fossil fuels, contributing to the emission of greenhouse gas. Recently, to solve both problems, the zero —or minimal— liquid discharge strategy has emerged. This alternative for brine management is based on recovery of more than 90% of the freshwater fraction and salts, which can be revalued. Currently, there are some zero liquid discharge desalination plants that incorporate renewables to supply the necessary energy, making desalination a totally sustainable and environmentally-friendly process. Zero liquid discharge desalination plants powered by renewables already exist, although in an immature stage. This paper analyzes and discusses the potential of combining different renewables with the most developed and efficient desalination technologies. In addition, the most important plants and solutions currently installed on a real scale, mostly the result of different research projects, are described and compared. [Display omitted] • Water scarcity is a global problem that has promoted policies included in SDG 6. • Over 21,123 desalination plants produce 142 million m3/day of freshwater. • Reject brine and GHG emission reductions are crucial for sustainable desalination. • MLD and ZLD combined with RES are a strategy to solve desalination's negative impact. • The newest ZLD-desalination plants powered by RES are discussed. [ABSTRACT FROM AUTHOR]

Depletion of fossil fuel reservoirs, greenhouse gas emissions' impact on global warming, and rising energy costs are pushing the data center sector to reduce energy use. This paper reviews strategies for improving the energy performance of air-cooled systems in datacom facilities and enhancing temperature and flow distribution in white space by analyzing different airflow delivery architectures (hard floor and raised floor designs), eliminating cold and hot air mixing by incorporating cold/hot aisle containment or exhaust chimneys, and potential energy savings achievable by utilizing evaporative cooling systems. It was found that the optimal ventilation system is hard-floor architecture with locally-ducted supply and return air. Hard floor is less complicated than raised floor design, and overhead supply air can minimize hot spots at the top of racks. Airflow management strategies including cold and hot aisle formation, aisle containment, and exhaust chimneys can reduce annual cooling energy usage by 10–50% in conjunction with air-side and water-side economizers, minimize hot spots, and enhance thermal performance during cooling system failure. Hot-Aisle Containment or exhaust chimneys provide better thermal and energy performance than open and/or cold-aisle containment, but they require new ducting in traditional data centers. Depending on the climate and geographical location, evaporative cooling can reduce annual cooling energy usage by 20–70% and lead to Power Usage Effectiveness as low as 1.06. Evaporative coolers are more suitable for dry climates, but this limitation can be ameliorated by incorporating desiccant wheels and thermal energy storage. [Display omitted] • A hard-floor layout with locally ducted supply and return air is optimal. • Aisle containment can lower annual cooling load factor by 40–50% and PUE by 16%. • Evaporative cooling can lower cooling energy by 20–70% and PUE to as low as 1.06. • Hot-Water cooling and desiccant-assisted EC can reduce demand by 95%, cooling energy by 84%. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive taxonomy and assessment of existing and emerging space cooling technologies in Europe. The study aims to categorize 32 alternative space cooling technologies based on eight scouting parameters (physical energy form, basic working/operating principle, refrigerant or heat transfer medium, phase of the working fluid, specific physical process/device, type of space cooling technology, fuel type and technology readiness level) and evaluate their key characteristics and development trends. The increasing demand for space cooling in Europe necessitates a thorough understanding of these technologies and their potential for energy efficiency. The majority of space cooling demand in Europe is currently met by conventional vapour compression systems, while a small portion is covered by thermally-driven heat pumps. The study reveals that several alternative space cooling technologies show promise for energy-efficient cooling but are not yet competitive with vapour compression systems in terms of efficiency and cost in the short-term and medium-term. However, technologies such as membrane heat pumps, thermionic systems, thermotunnel systems, and evaporative liquid desiccant systems demonstrate cost-competitiveness and energy efficiency in specific applications. The findings highlight the need for further research and development to improve the efficiency, costs, and market competitiveness of alternative space cooling technologies. The study also emphasizes the importance of policy support and the urgency to reduce greenhouse gas emissions, which can drive the adoption and advancement of sustainable cooling solutions. • The study provides a taxonomy of 32 space cooling technologies in the EU • Eight scouting parameters are discussed to categorize the space cooling technologies • Most of the alternative technologies have potential but can't compete in efficiency and cost • Only ten of the alternative cooling technologies have a TRL between 5 and 9 • Membrane heat pumps, thermionic systems, thermotunnel systems, and evaporative liquid desiccant systems are cost-competitive and energy-efficient in certain applications. [ABSTRACT FROM AUTHOR]

The wastewater sector accounts for up to 7 and 10% of anthropogenic CH 4 and N 2 O emissions, respectively. Nowadays wastewater treatment plants are going through a paradigm shift to approach a net-zero carbon condition. Numerous ongoing measures have taken place to identify the sources of greenhouse gases and minimize the carbon footprint. This paper systematically reviews all known practices leading towards net-zero carbon wastewater treatment. The greenhouse gas emissions from the wastewater sector are identified and carbon footprint quantification tools, such as reliable models and emission factors are compared. The direct process emissions can contribute to over 60% of the carbon footprint in wastewater treatment plants, while around 30% of the carbon footprint is due to energy-related indirect emissions. Therefore, greenhouse gas mitigation via process optimization and energy usage in wastewater treatment plants are comprehensively described. The implantation of novel nitrogen removal processes can reduce both greenhouse gas emissions and energy consumption. Other techniques such as source separation systems can potentially allow mitigation of N 2 O emissions by 60% while avoiding energy-intensive nitrogen fertilizer production. Nutrient recovery methods are another approach which offer negative value for the net carbon footprint. Recovering N 2 O for energy production is a promising method which can lead to both direct and indirect carbon footprint reductions. Ultimately, to achieve full decarbonization any remaining emissions need to be offset, including carbon footprint of chemicals usage and transportation. [Display omitted] • Wastewater sector is going through a paradigm shift towards decarbonization • GHG emission hotspots are identified and emission factors are reviewed • WWTPs may be responsible for approximately 5% of total GHG emissions • Direct emissions can contribute to >60% of the carbon footprint in WWTPs • Process modifications and energy optimization play key roles towards net-zero WWTPs [ABSTRACT FROM AUTHOR]

Net-zero emission and self-sustaining carbon-neutral have been widely encouraged and intensively explored in wastewater treatment, as the wastewater industry accounts for approximately 1.6% of global greenhouse gas (GHG) emissions. However, how to achieve net-zero GHG emission in wastewater treatment from a biological standpoint is still lacking. In this paper, the status of GHG (i.e. nitrous oxide (N 2 O), methane (CH 4) and carbon dioxide (CO 2)) production and emission in wastewater treatment was comprehensively reviewed. Generally, N 2 O emission contributes the majority of the total GHG emissions from wastewater treatment, and the dissolved N 2 O and CH 4 in the effluent should be paid more attention for the further GHG mitigation. Based on the newly identified microbial communities capable of nitrogen removal with less GHG emissions, several alternative integration systems for GHG mitigation were discussed. Coupling denitrifying anaerobic methane oxidation with anammox process shows high nitrogen removal performance and low GHG emissions, which is regarded as a more promising integration system for GHG mitigation. Moreover, the novel strategies to manage N 2 O and CH 4 as energy sources were also demonstrated, aiming to offset certain carbon footprint in wastewater treatment and thus attain net-zero GHG emission. In addition, future challenges and perspectives of above integration systems and strategies were discussed to facilitate the development of environmentally sustainable wastewater treatment. Finally, a prospective hybrid system integrating emission reduction and energy recovery was proposed as an example for achieving net-zero GHG emission from wastewater treatment. [Display omitted] • Status on GHG production and emission in each treatment unit is quantified. • Autotrophic microorganisms play important roles in mitigating GHG emission. • CH 4 is more feasible than N 2 O for energy recovery from mainstream wastewater. • Net-zero GHG emission integrates both emission reduction and energy recovery. [ABSTRACT FROM AUTHOR]

Increased renewable electricity reduced electricity prices but the costs of consumer-funded support schemes were added to utility bills. Previous studies compared these two components to understand the impacts on consumers. This paper constructs a framework for the electricity sector and provides a new angle to examine the impacts of renewable support schemes on consumers and the sector, respectively. Any negative gain to consumers was offset by the positive gain received by renewable generators (and suppliers), leaving the sector unaffected. In contrast, the increase in renewable electricity brought positive gain to the sector as a whole through reduced fossil fuels imports and greenhouse gas (GHG) emissions. We examine the structural change in the generation mix from 2006 to 2020 in the UK and suggest that wind generation replaced coal-fired generation rather than gas-fired generation on the longer horizon. Therefore, using coal-related coefficients and a contribution share of 38.6% for renewable subsidies, we suggest that wind generation supported by the RO scheme brought positive net gain to the sector, exceeding £800 million per annum in 2018–19 and 2019–20. Therefore, the discrepancy in payoffs from the perspective of consumers and the sector imposed a difficult challenge for policymakers, as criticism would be raised if the analysis was done on consumers only. • Renewable support schemes brought net gain to the electricity sector. • The first type of net gain was avoided costs from fewer imports of fossil fuels. • The second type of net gain was avoided costs from reduced GHG emissions. • Wind replaced coal rather than gas in the generation mix in the long term. • The net gain to the electricity sector exceeded £800 million per annum between 2018 and 2020. [ABSTRACT FROM AUTHOR]

The building construction has a significant impact on sustainability worldwide. However, industrialised building systems (IBS) might reduce these impacts compared to traditional building systems (TBS). Previous literature reviews have analysed IBS's sustainability, based primarily on environmental aspects and through qualitative indicators, disregarding a detailed quantitative comparison between both technologies and nor considering economic and social sustainability indicators. To fill this gap, this paper aims to evaluate vis-à-vis IBS's sustainability in relation to TBS, based on the quantitative and qualitative indicators studied in the literature. Thus, an exhaustive bibliographic review of IBS and TBS case studies was conducted. In total, 67 scientific papers were selected (papers, book chapters and reports), containing 86 case studies. Major findings indicated that IBS are more sustainable in almost all studied values – except construction costs. Nevertheless, this advantage depends on material design, prefabrication levels, transportation, work management and each author's methodological approaches. These factors are discussed to explain the reasons for IBS′ sustainability. Furthermore, main conclusions indicate that sustainability assessments have been unbalanced in literature, with few analyses of economic and social performance, and some indicators have been poorly studied (e.g., water and acidification potential), so their results are not yet representative. Similarly, reusability, prefabrication levels and the social indicators of IBS were insufficiently analysed in the reviewed case studies. Finally, the current review highlights IBS sustainability indicators that have been less studied in order to motivate new investigations in the broader field, exposing the IBS sustainability outlook and other research gaps. • Comparison of IBS and SCT sustainability based on 86 case studies worldwide. • IBS prove to be more sustainable than SCT based on sustainability indicators. • The energy consumption and GHG emissions of IBS are widely studied, lacking other relevant indicators. • Less-studied IBS sustainability indicators are revealed to motivate new investigations in the broader field. • Reusability, as well as timber and steel construction materials, are less studied. [ABSTRACT FROM AUTHOR]

Abstract: The combined cooling, heating and power (CCHP) system – a typical representative of the decentralized energy system – has been increasingly attracting attention in academia and industries in recent years, thanks to its distinctive advantages of high system and economic efficiency, and less greenhouse gas (GHG) emissions. In this paper, the state of the art of CCHP research is surveyed. First, the development and working scheme of the CCHP system will be presented. Some analyses of the advantages of this system and a brief introduction of the related components are then given in the first part. In the second part of this paper, we elaborately introduce the prime mover and thermally activated facilities. Recent research progress on the management, control, system optimization and sizing will be summarized in the third part. The development of the CCHP system in representative countries and the development barriers will be discussed in the last part. [Copyright &y& Elsevier]

Abstract: Renewable energy represents an area of tremendous opportunity for India. Energy is considered a prime agent in the generation of wealth and a significant factor in economic development. Energy is also essential for improving the quality of life. Development of conventional forms of energy for meeting the growing energy needs of society at a reasonable cost is the responsibility of the Government. Limited fossil resources and associated environmental problems have emphasized the need for new sustainable energy supply options. India depends heavily on coal and oil for meeting its energy demand which contributes to smog, acid rain and greenhouse gases’ emission. Last 25 years has been a period of intense activities related to research, development, production and distribution of energy in India. Though major energy sources for electrical power are coal and natural gas, development and promotion of non-conventional sources of energy such as solar, wind and bio-energy, are also getting sustained attention. The use of electricity has grown since it can be used in variety of applications as well as it can be easily transmitted, the uses of renewable energy like wind and solar is rising. Wind energy is a clean, eco-friendly, renewable resource and is nonpolluting. The gross wind power potential is estimated at around 48,561MW in the country; a capacity of 14,989.89MW up to 31st August 2011 has so far been added through wind, which places India in the fifth position globally. This paper discusses the ways in which India has already supported the growth of renewable energy technologies i.e. wind energy and its potential to expand their contribution to world growth in a way that is consistent with world''s developmental and environmental goals. The paper presents current status, major achievements and future aspects of wind energy in India. [Copyright &y& Elsevier]

Abstract Tidal current turbine, as an effective technical means to contribute to all around the world achieving targets for reducing greenhouse gas emissions and the production of renewable energy, has obtained great concern. It was established that more than 94 TWh per year could be generated in the developable sea area. Many types of tidal current turbine structures and control methods have been proposed, however, the possible increase in power generation must consider parameters such as reliability, cost, and complexity of the control system. The paper presents a review on configuration and control methods of tidal current turbines. The configuration and control methods of tidal current turbines are classified, described and compared, especially for horizontal axis tidal current turbines. Horizontal axis tidal current turbine is more widely used, due to high energy conversion efficiency. Different configuration and corresponding control methods have their advantages and disadvantages, which affect efficiency, maintenance requirements, and the cost of electricity from tidal current. Highlights • The configuration of the main tidal current turbines is detailed. • The structure of horizontal axis tidal current turbine is described. • The control methods of horizontal axis tidal current turbine are illustrated. [ABSTRACT FROM AUTHOR]

Abstract As investments and policies that promote renewable energy (RE) projects in electricity systems are most often grounded on the goal of reducing emissions of greenhouse gases, and actual investment and policy decisions are shaped by the estimates of the accrued emissions savings, it is crucial that these estimates are as accurate as possible. In this paper we compare different econometric models that estimate the amount of carbon abated due to RE in terms of their results and their inherent methodological benefits and drawbacks. Specifically, we use the British, French and Spanish grids as case studies for the application of a selection of econometric models and compare the resulting CO2 abatement estimates. We find that, across the three markets, estimates can vary substantially across the different models – this can lead to an over or underestimation of the emissions abated by RE. Overall, our results highlight the need for choosing econometric specifications that lead to results that are congruent with the operational framework of the examined power systems. Highlights • We compare three econometric models to estimate marginal emissions factors (MEF) in power systems. • Focus on CO2 reductions due to renewable electricity generation – wind and solar. • We use the British, French and Spanish grids as case studies. • In each country MEF estimates vary substantially according to the model that is used. [ABSTRACT FROM AUTHOR]

Abstract Increasing the adoption of energy efficient technologies by households is one of the formulated strategies to reduce greenhouse gas emissions. This paper presents a systematic review of agent-based modelling studies on the adoption of energy efficiency by households. It starts with an overview of barriers for adoption, of energy efficiency policies, energy efficiency model types. Afterwards, an analysis is given of technologies modelled, policies simulated, decision-making theories included, and the use of empirical data. An overview is presented of how technologies, barriers and policies relate in the models. Furthermore, the core policy recommendations from existing models are presented. The analysis shows that the reviewed studies predominantly focus on a subset of barriers – a lack of capital, a lack of information, high upfront cost, ignorance, inertia and other priorities. So far, agent-based models have focused on how subsidies, technology bans and information campaigns influence energy efficiency adoption. There is ample opportunity for future agent-based modelling research on energy efficiency adoption policy by studying other residential technologies, other barriers, and other policies that fit the agent-based modelling paradigm well. Highlights • An overview of barriers to and policies for energy efficiency adoption is presented. • Accounting and agent-based models explore effects of energy efficiency policies. • 23 ABMs on energy efficient technology adoption by households are reviewed. • ABMs focus on subsidies, technology bans and information campaigns as policies. • ABMs focus on lack of information, upfront cost/capital, and behavioural barriers. [ABSTRACT FROM AUTHOR]

Abstract: Promoting sustainable consumption and production patterns is a key challenge for the future, in order to use the Earth resources efficiently, to reduce the greenhouse gas emissions, and to decouple the economic growth from the environmental degradation. New or customized methods have to be applied to support decisions makers in the choice of environmental-friendly products, and to select policy priorities and sustainable strategies. A modified input–output model can aid to analyse the relationships among economic growth, energy consumptions and pollutants, in order to assess the energy and environmental impacts due to the actual production and consumption patterns. The following paper introduces an energy and environmental extended input–output model and combines it with the Life Cycle Assessment (LCA) methodology. The authors apply this model to the Italian context in order to assess the energy and environmental impacts related to the consumptions of the Italian households in the period 1999–2006 and to identify the economic sectors involving the highest impacts. The paper represents one of the first Italian studies aimed at identifying those national economic sectors and final goods and services to be assumed prior in the definition of sustainable production and consumption strategies. Results show that about the 70% of the total energy, needed to meet the household final demand of products, is consumed by the productive sectors. In particular tertiary, “electricity, gas and vapour”, road transports and “food and beverage” sectors are the most contributors, accounting for about 75%. Further, the environmental impact analysis associated to Italian households consumptions is carried out, starting from three different data sources The results point out that, to include emissions arising both from energy and non-energy sources, in the assessment of environmental impacts is of paramount importance to obtain reliable simulations of the link between households consumptions and energy and environmental performances. [Copyright &y& Elsevier]

Abstract: Due to the vast growth of development in the infrastructure and investment in energy, the electricity consumption in the GCC countries had increased at a fast rate; 12.4% from 2005 to 2009 (3.15%, annually). This rate is much larger than the world average, which is 2.2% for the same period, or USA (0.5%). In 2005, the average Watt per person in the GCC countries was 1149 which is much higher than the world average (297W per person) or the European Union (700W/person) – but less than USA (1460W/person). The GCC countries need to increase its electrical capacity by 60,000MW, which represents 80% of the current installed capacity, to meet demand in 2015. This means that there is a need to build 50 more gas fired power generator plant turbine (each rated 1400MW). The GCC countries have realized that depending on gas will not be the solution due to shortage of resource or environmental impact, particularly the GHG emissions. Therefore, they thought back of using renewable energy resources – after lifting it over in 1990s. They also thought of diversity in electricity production where nuclear energy comes to the picture. The power capacity in GCC countries is at around 75,000MW, a projected 9.5% growth in annual demand will require more electricity and energy projects; expected to invest USD 200 billion to 250 billion in between 14 and 20 energy projects by 2020. The paper lists the major renewable energy projects (mainly solar and wind) in each of the six GCC countries. The total capacity of these projects exceeds 600MW. Among these projects is the establishment of the first zero emission house (Green house) in the middle east (7kW solar, wind and fuel cell) constructed in Bapco residence town (Awali) in Bahrain and therefore, been highlighted more in this paper. Moreover, nearly all GCC countries are planning to construct PV plants with large capacity. Also, several projects in Building Integrated Photovoltaic and Building Integrated Wind Turbines are established in GCC countries. The projects made in the GCC countries allow researchers and investors to size the cost of kWh from thermal, PV and wind energy more precisely. For example, it was found that the cost of kWh from large grid connected solar thermal plant (20MW) – with cost of USD 72.5 million and energy – is US ¢ 12/kWh (assuming a life time of 40 years and a discount rate of 4%) while, the cost issue of kWh from PV Electricity (in the GCC countries) is ranging from US ¢ 27 (for ground mount) to US ¢ 35 (for roof mount) as it was deduced from two actually installed project PV in UAE – a GCC country member. Meanwhile, the cost of 1kWh from wind electricity in the GCC countries may be from US ¢10 (large turbine ≈2MW at 80m height with good wind speed) to US ¢ 15 (for large turbine ≈2MW at 80m height with modest wind speed) while the cost of kWh from grid connected Wind farm plant (20MW) – with a cost of USD 38.6 million and energy – is US ¢ 6.7/kWh to US ¢ 8.8/kWh, depending on the location of wind farm. This makes it very challengeable for investor, government (Feed-in-Tariff) and citizens because each citizen in GCC countries pays only (US cent 1 for each kWh, for consumption less than 3000kWh, or even nothing for citizens-like in Qatar). [Copyright &y& Elsevier]

Abstract: To overcome the negative impacts on the environment and other problems associated with fossil fuels have forced many countries to inquire into and change to environmental friendly alternatives that are renewable to sustain the increasing energy demand. Solar energy is one of the best renewable energy sources with least negative impacts on the environment. Different countries have formulated solar energy policies to reducing dependence on fossil fuel and increasing domestic energy production by solar energy. This paper discusses a review about the different solar energy policies implemented on the different countries of the world. According to the 2010 BP Statistical Energy Survey, the world cumulative installed solar energy capacity was 22928.9MW in 2009, a change of 46.9% compared to 2008. Also this paper discussed the existing successful solar energy policies of few selected countries. Based on literatures, it has been found that FIT, RPS and incentives are the most beneficial energy policies implemented by many countries around the world. These policies provide significant motivation and interest for the development and use of renewable energy technologies. Also the status of solar energy policy for Malaysia is investigated and compared with that of the successful countries in the world. [Copyright &y& Elsevier]

Abstract Anaerobic digestion of organic wastes produces valuable biogas. The main constituents of biogas, methane (CH 4) and carbon dioxide (CO 2), although being greenhouse gases (GHGs) are versatile feedstock for production of valuable fuels and chemicals. This paper provided an overview on conversion technologies to produce syngas and methanol from CH 4 and CO 2. Two conversion routes are considered: (1) reforming of methane which is used to produce syngas from biogas and (2) CO 2 hydrogenation which directly converts CO 2 to methanol. An overview of the most significant factors to attain high conversion efficiency in both conversion processes is presented. The effect of operating parameters (including reaction temperature, gas hourly space velocity (GHSV), reduction temperature, etc.), catalyst preparation method and use of promoters in catalyst on conversion efficiency and product yield is reviewed and discussed. An overview on techno-economic analysis of biogas constituent conversion is presented based on the available literature. This survey of literature indicates that despite the high potential of biogas constituents to be converted to value added products, many problems in terms of technology maturity and economic feasibility need to be addressed before the process could be exploited at industrial scale. Issues such as catalyst deactivation, biogas purification and H 2 S removal from biogas need to be obviated. With further improvement of the process and also with the involvement of policy makers and private sectors, the conversion technologies can help to mitigate the GHG release and the products obtained from the conversion can be used as sources of renewable fuel and energy. Graphical abstract fx1 Highlights • The utilization of biogas as feed source for syngas and methanol production is discussed. • In order to achieve desired efficiency of conversion, some parameters must be chosen wisely. • Several methods to improve the catalytic conversion are suggested. [ABSTRACT FROM AUTHOR]

Abstract: With the increasing negative effects of fossil fuel combustion on the environment in addition to limited stock of fossil fuel have forced many countries to inquire into and change to environmentally friendly alternatives that are renewable to sustain the increasing energy demand. Energy policy plays a vital role to mitigate the impacts of global warming and crisis of energy availability. This paper explores the wind energy industry from the point of view of the wind energy policy. It is noticed that energy policy could help increasing wind power generation as well as stimulating the energy industry. It may be stated that without specific energy policy, a country would not be able to solve the acute problems like reducing greenhouse gases (GHGs) emission, scarcity of energy, etc. This paper discussed the existing successful energy policies for few selected countries. Based on literatures, it has been found that FIT, RPS, incentives, pricing law and Quota system are the most useful energy policies practiced by many countries around the world. Then, status of wind energy policy for Malaysia was investigated and compared with few selected countries around the world. [Copyright &y& Elsevier]

Abstract: Domestic biogas programs are often justified on the basis of the private benefits and costs accruing to the individual households, in terms of providing a superior cooking fuel, improved indoor air quality and saving of time spent on collecting firewood. This paper contends, however, that the economic surpluses from domestic biogas programs are realized beyond such narrowly defined project boundaries. The paper maintains that economic value addition from the consumptive use of the biogas for cooking and the non-consumptive and indirect value derived from the biogas plant providing feedstock for other processes and other such benefits as greenhouse gas mitigation (positive externalities) need to be accounted for. The process approach adopted by this paper would enable an integrated view of the value chain and consequently, a mechanism to reallocate costs and to distribute such surpluses. [Copyright &y& Elsevier]

Taiwan is a high energy-importing nation with more than 95% of its energy supplied by imported fuels. Environmental pollution and greenhouse gas emissions are becoming significant environmental issues. In this regard, renewable energy like waste-to-energy are thus becoming attractive due to the energy policy for the sustainable development and environmental pollution mitigation in Taiwan. The objective of this paper is to present an updated overview of energy utilization from mass agrowastes in industries. The description is thus centered on new/revised promotion legislation/regulations especially concerning the agrowaste-to-energy in the measures of environmental protection and economic/financial incentives. The Statute for Renewable Energy Development is being enacted to further enhance and promote the green energy utilization, which is also addressed in the paper. Finally, we present the biomass energy utilization of three mass agrowastes (i.e. bagasse and rice husk from mills, and piggery wastes from swine farms) in progress. [Copyright &y& Elsevier]

Meeting the Paris Agreement will most likely require the combination of CO 2 capture and biomass in the industrial sector, resulting in net negative emissions. CO 2 capture within the industry has been extensively investigated. However, biomass options have been poorly explored, with literature alluding to technical and economic barriers. In addition, a lack of consistency among studies makes comparing the performance of CO 2 capture and/or biomass use between studies and sectors difficult. These inconsistencies include differences in methodology, system boundaries, level of integration, costs, greenhouse gas intensity of feedstock and energy carriers, and capital cost estimations. Therefore, an integrated evaluation of the techno-economic performance regarding CO 2 capture and biomass use was performed for five energy-intensive industrial sub-sectors. Harmonization results indicate that CO 2 mitigation potentials vary for each sub-sector, resulting in reductions of 1.4–2.7 t CO 2 /t steel (77%–149%), 0.7 t CO 2 /t cement (92%), 0.2 t CO 2 /t crude oil (68%), 1.9 t CO 2 /t pulp (1663%–2548%), and 34.9 t CO 2 /t H 2 (313%). Negative emissions can be reached in the steel, paper and H 2 sectors. Novel bio-based production routes might enable net negative emissions in the cement and (petro)chemical sectors as well. All the above-mentioned potentials can be reached for 100 €/t CO 2 or less. Implementing mitigation options could reduce industrial CO 2 emissions by 10 Gt CO 2 /y by 2050, easily meeting the targets of the 2 °C scenario by the International Energy Agency (1.8 Gt CO 2 /y reduction) for the industrial sector and even the Beyond 2 °C scenario (4.2 Gt CO 2 /y reduction). • Literature review on CO 2 mitigation in steel, cement, chemical, H 2 and paper sectors. • Introduction harmonized methodology to allow comparison between industrial sectors. • All investigated sectors have large reduction potentials for <100 €/t CO 2 avoided. • Negative emissions possible in iron/steel, H 2 and paper sectors. • Potential CO 2 emission reduction of 10 Gt/yr in 2050, easily meeting climate target. [ABSTRACT FROM AUTHOR]

With global population growth, the security of food, energy and water is becoming more challenging. Both anaerobic digestion (AD) and composting are waste management methods that are plausible approaches to address this challenge by reusing organic waste and generating value-added products. In this paper, recent research on AD and composting is summarized, and differences in the technical, economic, and environmental aspects of AD and composting, and their potential to improve the sustainability of waste management, are examined. Recent research on AD has focused on process enhancement and valorization of end products, while composting research has emphasized ways to shorten composting period and reduce odor and greenhouse gas (GHG) emissions. Strategies to enhance AD and composting processes are similar, but the operational parameters that affect microbial activity, including inoculation, aeration, temperature, moisture, C/N ratio, and pH, can differ. AD can be economically more advantageous than composting, depending on plant scale and valorization of end products, while composting is more profitable at smaller scales (e.g. < 20,000 t). Therefore, AD may be favored for centralized treatment, such as for food waste or sewage sludge; whereas, composting may be preferred for decentralized treatment, such as for on-farm animal manure. Environmentally, AD is favorable in terms of lower GHG emissions due to production of biogas as a renewable energy source. In composting, no single aeration scheme or additive has been found to be effective in reducing odor and GHG emissions simultaneously. Further research on AD and composting should be conducted to improve precision control and optimization, process design, product value, pollution control, and economic and environmental analyses, and more information needs to be provided to decision makers. [ABSTRACT FROM AUTHOR]

The sustainable practice in the palm oil industry, which provides the global most demanded edible oil has a long way to be well developed. One of the most challenging problems is the management of palm oil mill effluent (POME). The current most applied treatment method of POME is anaerobic ponding system, which is not environmental friendly. This is because a large amount of the generated greenhouse gases is not captured, but escaped into the atmosphere. It is so critical to encourage the sustainable practice of closed anaerobic digestion system in the palm oil industry for utilizing POME to generate renewable biogas. For this, theoretical and technological studies of improving biogas production by POME anaerobic digestion are essential as the supporting research. Therefore, this paper will firstly discuss the influential factors of anaerobic digestion on the biogas production, then review the strategies which had been applied to improve the biogas production of POME anaerobic digestion. A lot of efforts have been made to emphasize on the co-digestion and biomass retention improvement within the digester. Other studied strategies include the POME pretreatment, additives supplementation, and bioreactor modification. By operating the anaerobic digester successfully, these applied strategies had positive response to the biogas production. However, the effectiveness of these strategies cannot be compared directly with each other, due to the different operating conditions. Overall, the studied strategies seem to be insufficient and lack of breakthrough. [ABSTRACT FROM AUTHOR]

The EU is aiming to increase the utilisation of renewable energy to 20% of the total energy consumption by 2020. For Finland, the target is 38%. Renewable energy sources are assumed to reduce greenhouse gas emissions when compared to fossil fuels. Yet not all environmental impacts of renewable energy use are thoroughly assessed, and there are no comprehensive assessments on the impacts and risks of renewable energy production that would take into account all possible environmental impacts. We applied qualitative expert knowledge to attain information on the impacts and risks of renewable energy in Finland. According to the expert panel, the overall impacts of renewable energy by 2020 are not significant. However, we found some hot spot areas, i.e. areas of the most concern related to particulate matter formation during regional wood combustion, climate impacts of forest energy, biodiversity impacts connected to several renewable energy sources, and eutrophication caused by utilisation of agricultural energy sources. There are currently no reliable and generally accepted methods to estimate the biodiversity impacts of renewable energy production, thus, this topic would require further studies. The climate change impacts of forest based energy sources are relatively well studied, but the results of these studies are highly variable because of different assumptions on spatial and time scale. A qualitative impact assessment framework, as described in this paper, can be used to assess the environmental impacts of renewable energy production and is a potential option to attain information on the renewable energy impacts as long as reliable and comparable quantitative datasets are not available. These kinds of qualitative assessments can also be applied to detect the areas that need further studies. [ABSTRACT FROM AUTHOR]

China is the top CO 2 emitter with enormous regional variation in economic development, resource endowment, and consumption patterns, which leads to great variations in regional CO 2 emissions and embodied CO 2 transfer among provinces. Analyzing the mechanisms responsible for carbon footprint (CF) and embodied CO 2 transfer among provinces via trade could help policy makers allocate emission responsibilities and reduction targets. Based on a multi-regional input–output model, this paper investigates the CFs and embodied CO 2 transfer in/among 30 provinces of China in 2007 and 2010, and analyzes emissions from different perspectives. Results indicate that China's CF grew from 5230 Mt in 2007 to 6922 Mt in 2010, with an annual growth rate of 9.8%. The provinces with the large CFs and per capita CF were mainly those locate in eastern, developed regions along the coast and several highly populated ones. CO 2 emissions due to capital formation contributes the most to the CFs and the increment in this period, and this was followed by urban consumption. Significant embodied CO 2 transfer were observed to drift from the developing and energy-abundant provinces like Hebei and Inner Mongolia, to the developed coastal provinces. Total embodied CO 2 transfer account for 43.9% of the national CF in 2007, and decreased to 41.0% in 2010. In order to control CO 2 emissions and make reduction allocations for provinces, interprovincial embodied CO 2 transfer and practical capacities need to be taken into account. [ABSTRACT FROM AUTHOR]

Among other things, the European Union climate and energy legislation package seeks to achieve a renewable energy contribution of 20% to total energy consumption by the year 2020. In addition, it also seeks to improve energy efficiency and to reduce the 2005 total primary energy consumption by 20% in that same year. In 2013, the residential sector of Spain consumed 15.0 Mtoe of final energy, representing 19% of total energy consumption. This sector has great potential for savings and energetic improvement due to the multitude of possible actions that can be taken to improve it. This paper presents a methodology for evaluating the final energy consumption, primary energy consumption, and contribution by renewable energy of the residential sector decomposed by energy source in any Autonomous Community and in Spain as a whole. The method is applied to the Autonomous Community of La Rioja and to Spain between 1991 and 2013. The results show a complete energy analysis of the Riojan and Spanish residential sectors, ultimately obtaining the key energy indicators to demonstrate the advances toward compliance with European goals for 2020, adapted to the residential sector. The results themselves serve as a control tool for energy planning. [ABSTRACT FROM AUTHOR]