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A few decades ago, hydroelectric projects were considered a clean source of energy. The present study aims to assess the biomass and soil carbon (C) stock in the hydroelectric catchment in India and further, its implications to mitigate GHG emissions. The estimation depicts the low 'C' stock in the reservoir's catchment in comparison to reservoirs located globally in the same eco-region which will ultimately result in lower GHG emission in the future. Moreover, estimated total carbon density of the forest species was found as 54.92 ± 18.07 MgC.ha−1 while mean SOC was 79.64 ± 19.32 MgC.ha−1. The average total 'C' stock of Tehri hydroelectric reservoir's catchment was estimated as 134.56 MgC.ha−1. Moreover, ratios (total flooded carbon/installed capacity) comprised between 4 and304 kgC/W from the other reservoirs reported globally. These ratios are higher than the Tehri reservoir (0.28 kgC/W) as flooded area of Tehri reservoir during impoundment was 52 km2. Thus, Tehri reservoir was found to emit less GHG in time to come. The present study helps the hydropower industries, policymakers, and environmentalists in designing the catchment area treatment plan to minimize the negative impact of GHG on climate change. [ABSTRACT FROM AUTHOR]

Freshwater bodies are found as significant sources of greenhouse gas to the atmosphere, but their quantitative significance is not yet clear. The rapid increase in hydropower dams and associated emissions has received much attention from hydropower industries, environmentalists, and policymakers from across the globe. The tropical/subtropical eco-regions are, particularly, considered as hotspots from greenhouse gas production point of view as the emitted gases are playing a critical role in climate change. The present paper reviews the uncertainty and limitations of greenhouse gas measurement from Chinese freshwater bodies based on available data. Literature reported that carbon dioxide emission from Chinese lakes falls in the range of 0.01–2.16 μmol m−2s−1 except for Poyang Lake. The CO 2 emission from Chinese hydropower reservoirs is estimated as 0.15–1.11, while for rivers, it is 0.44–4.12 μmol m−2s−1. The methane and nitrous oxide emissions are, however, found less than carbon dioxide emission. The CO 2 emission falls in the range of −0.17–0.54 and 1.08–1.70, respectively higher than global lakes and rivers, while the global reservoirs have emission in the range of −0.17–2.98 μmol m−2s−1. The paper also reports the challenges in the estimation and prediction of greenhouse gas emissions from hydropower reservoirs along with suggested mitigation measures. Image 10945 • GHG emissions have been limited by data availability and inconsistencies in methodological approach. • Investigate uncertainty and limitation of GHG measurement. • Literature reveals CO 2 emission from Chinese rivers is twice than lakes and four times than hydropower reservoirs. • CH 4 and N 2 O emissions are however found less than CO 2 emission. • Suggested mitigation measures to minimize the impact of GHG on climate change. [ABSTRACT FROM AUTHOR]

Abstract China is undergoing an extensive hydropower development, but the magnitude of greenhouse gas (GHG) emissions risk to reservoirs is not well known. Electricity generation from hydropower is a challenging issue when it comes to sustainable development. In this study, the data on Chinese hydropower reservoirs (n = 12) were collected from the literature and is used as in input to Greenhouse Gas Risk Assessment Tool (GRAT) to predict long-term GHG (CO 2 & CH 4) risk to the hydropower reservoirs and its associated lifecycle GHG emissions (GHG-LCA). The model predicted that till recently (i.e., year 2018) the hydropower reservoirs found under medium risk (i.e., 109 < CO 2 ≤ 628 and 3 < CH 4 ≤ 45 mg·m−2·d−1) which will reduce slowly over a period of 100 years. Out of 12 hydropower reservoirs studied, TGR presently under high risk of CH 4 (i.e., 47 mg·m−2·d−1) and medium CO 2 risk. Therefore, assessment is required to know the magnitude of CH 4 and its effect on regional climate so that mitigation measures could be taken in advance. The carbon emissions as CO 2 eq of the studied reservoirs are found as 134.69 ± 225.23 Gg yr−1, with a large share from CH 4 emission. The associated life cycle GHG emissions are also estimated as 0.06 ± 0.09 gCO 2 eq·kWh−1, which is higher than the global estimates (i.e. 0.015 gCO 2 eq·kWh−1). Graphical abstract Unlabelled Image Highlights • Electricity generation from hydropower is a challenging issue when it comes to sustainable development. • This study predict long-term GHG risk to the Chinese hydropower reservoirs and its associated life cycle emissions. • The carbon emissions as CO 2 eq of the studied reservoirs are found as 134.69 ± 225.23 Gg yr-1, with large share from CH 4 emission. • The associated life cycle GHG emissions are also estimated as 0.06±0.09 gCO 2 eq.kWh−1. [ABSTRACT FROM AUTHOR]

The identification and accurate quantification of sources or sinks of greenhouse gas (GHG) have become a key challenge for scientists and policymakers working on climate change. The creation of a hydropower reservoir, while damming a river for power generation, converts the terrestrial ecosystems into aquatic and subsequently aerobic and anaerobic decomposition of flooded terrestrial soil organic matter resulting in the emission of significant quantity of GHG to the atmosphere. Tropical/subtropical hydropower reservoirs are more significant sources of GHG compared to boreal or temperate one. This paper aims to estimate the emission factor (gCO2eq./kWh) and net GHG emission from Koteshwar hydropower reservoir in Uttarakhand, India. Further, estimated GHG are compared with those from global reservoirs located in the same eco-region so that its impact could be timely minimized/mitigated. Results have shown that emission factor and net GHG emission of Koteshwar reservoir are, respectively, estimated as 13.87 gCO2eq./kWh and 167.70 Gg C year−1 which are less than other global reservoirs located in the same eco-region. This information could be helpful for the hydropower industries to construct reservoirs in tropical eco-regions. [ABSTRACT FROM AUTHOR]

There is considerable focus on oil sands transportation fuel production. However, most studies focus on greenhouse gas emissions; there is limited work on understanding the life cycle water footprint. This study is an effort to address this gap. The main objective of this study is to develop water demand coefficients of the complete life cycle of oil sands transportation fuel production. Water demand coefficients include consumption and withdrawals, which were estimated for different oil sands unit operations pathways for production in Alberta, Canada. The pathways include three key operations, bitumen extraction, upgrading, and refining. The water consumption coefficients for the complete life cycle range from 2.08 to 4.19 barrels of water (bbl W ) per barrel of refined oil (bbl BUR ) and 2.87–5.16 bbl W /bbl BUR for water withdrawals coefficients. The lower limit for water demand coefficients is found in refined and upgraded in situ steam assisted gravity drainage recovery and the higher amount in refined and upgraded surface mining recovery. A sensitivity analysis was conducted through Monte Carlo simulations to study the uncertainty of the water demand coefficients. The water consumption coefficient for oil sands extraction at a 90% probability was found to be 0.34–2.8 bbl W /bbl B, upgrading be 0.87 bbl W /bbl U , and refining to be 1.52 bbl W /bbl R . [ABSTRACT FROM AUTHOR]

Microplastics (size <5 mm) debris are environmentally persistent pollutants that severely affect terrestrial ecosystems by promoting the loss of soil fertility, and microbiome. The adverse effect of microplastics on the terrestrial ecosystem led to changes in physic-chemical and biological characteristics of soil resulting changes in nutrient cycling, and also future climatic risks. Therefore, understanding the potential sources, composition, abundance, life cycle and transport of microplastics is a huge challenge and an important topic of global debate among scientific communities. The present review is focused to bridge the gap by illustrating the potential sources, transport and disintegration of microplastics in terrestrial ecosystems. Further, the impacts of microplastic pollutants on soil characteristics, nutrient storage and cycling are discussed. The identified scientific gaps will be useful to environmentalists, microbiologists, hydrologists, and policymakers for a better understanding of microplastic pollution and to investigate future engineering solutions. [Display omitted] • First state-of-the-art study of microplastic impacts on nutrients storage and cycling. • Microplastics have potential to alter greenhouse gas emissions in terrestrial soil. • Present study helps in mitigation strategies to reduce the climatic risk of these emerging global stressors. • Future research is needed to understand the sources, fate and climatic risks of soil microplastics. [ABSTRACT FROM AUTHOR]

Despite improvements, the residential sector is one of most energy-intensive sectors in the world and is the third largest consumer of energy across Canada, and in Alberta in particular. This study investigates opportunities to improve energy efficiency and reduce greenhouse gas emissions (GHG) in the residential sector. A case study for Alberta is conducted. Energy modeling and scenario analyses are used to project future energy savings and greenhouse gas mitigation potential in the residential sector. Seventeen energy-saving options are identified in different residential subsectors, including space heating and cooling, water heating, appliances, and lighting. The long-term impacts (i.e., from 2013 to 2050) of these technologies in terms of energy savings and greenhouse gas mitigation potential are assessed using the Long-range Energy Alternative Planning model. For the evaluated options, more than 80% of GHG mitigation is achievable with negative GHG abatement cost. A GHG abatement cost curve is developed to assess the economic performance of various options. The results of the cost curve indicate that efficient lighting, efficient furnaces, and high efficiency appliances are the three areas in which the most GHG mitigation can be achieved at the lowest cost. The results provide invaluable insights to policy makers. [ABSTRACT FROM AUTHOR]

Hydropower, which contributes to around 16% of global electricity and more than 72% of renewable electricity, is expected to play an important role in the deep decarbonization of the energy sector. However, the idea that hydropower is a carbon-neutral energy alternative on par with solar and wind is controversial. Research, mainly from limnology and climate modeling, shows that depending on the characteristics of the hydro project, it could be a significant source of GHG emissions. This aspect has been ignored in most life cycle assessment (LCA) studies, affecting the effective use of LCA results, especially in comparative assessments. This paper aims to provide a comprehensive and critical review on this topic by conducting a systematic literature review on hydropower LCA studies published since 2010. We found that there is inconsistency in how LCA is used for hydropower projects. While the emissions associated with the engineering work are well addressed, efforts to accurately estimate and model reservoir GHG emissions are constrained by limited data availability, difficulties in accurately quantifying highly variable carbon fluxes, and inconsistent modeling approaches. A huge range of emissions values is reported in the reviewed literature, from 1.5 to 3747.8 g CO 2 eq per kWh. Reservoir-based hydropower shows high variability, which is mainly dictated by reservoir-related GHG emissions. Reservoir GHG emissions could be more than 90% of the life cycle emissions, especially for hydropower in a tropical region. The regionalized aspect is a key factor to be considered in extrapolating reservoir GHG emissions. • There is inconsistency in how LCA is used for hydropower projects. • A wide range of emission intensities has been reported (1.5–3747.8 g CO 2 eq/kWh). • The high variability in the emissions is due to major differences in key reservoir characteristics. • Data limitations are the main cause for over- or underestimation of hydropower emissions. • Harmonization of data is vital to effectively conduct LCA and to generate useful results. [ABSTRACT FROM AUTHOR]

Hydrogen is a key input to industrial processes. In western Canada, there is a significant demand for hydrogen for industrial purposes, both to upgrade bitumen and as a chemical agent. The key driver for this research is the need to assess options for the energy industry to lower its carbon footprint by using hydrogen produced from renewable sources. The environmental impacts associated with hydrogen production through water electrolysis using the electricity generated from a wind power plant are evaluated in this paper. A life cycle assessment was done to determine the greenhouse gas (GHG) emissions per unit mass of produced hydrogen by considering the emissions starting from the extraction of wind energy to the production of hydrogen. An uncertainty analysis was conducted to assess the effects of variations of different input parameters on the GHG footprint of hydrogen produced from wind. The total GHG emissions of a wind-based hydrogen production plant are estimated to be 0.68 ± 0.05 kg CO 2 eq./kg H 2 , 65% of which are from the construction of the wind power system. The results are compared with those of conventional fossil fuel-based systems. The overall GHG emissions from wind-based hydrogen production are about 94% lower than those associated with hydrogen production through steam methane reforming (SMR). Natural gas-based hydrogen production emissions are mainly found in the plant operation stage. For wind-to-hydrogen systems, the manufacturing and installation of the systems have significant environmental impacts. However, the hydrogen produced from wind energy can significantly reduce the GHG footprint of the energy industry. [ABSTRACT FROM AUTHOR]

Hydrogen production via steam methane reforming (SMR) dominates the supply to refining complexes worldwide, resulting in significant greenhouse gas (GHG) emissions. There is a considerable demand for clean hydrogen pathways that are economically competitive with SMR. The development of a 563 MW integrated wind-hydrogen model with energy storage is proposed. The model utilizes real-time wind energy data to ascertain the optimal size of the electrolyser, the number of electrolyser units and the battery (energy storage) capacity that will yield a minimum hydrogen production cost, whilst functioning in a liberalized electricity market with dynamic prices. The optimal plant configuration consists of 81 units of a 3496 kW (760 Nm 3 /hr) electrolyser and 360 MWh (60 units) of battery capacity. For the minimum hydrogen production cost determined ($9.00//kg H 2 ), the wind farm accounts for 63% of this cost. Hence, if existing wind farm assets are used, such that the investment cost of building the wind-hydrogen plant does not include the wind farm costs, the hydrogen production cost is reduced to $3.37/kg H 2 . For a particular electrolyser-battery configuration, it was observed that the minimum hydrogen production cost occurs when their respective capacity factors are approximately equivalent. The benefits of energy storage are limited by the decrease in overall plant efficiency, which results from the use of the battery. For the techno-economic conditions considered in this paper, hydrogen production costs from wind powered electrolysis ($3.37 to $9.00/kg H 2 ) are uncompetitive with SMR/SMR-CCS ($1.87 to $2.60/kg H 2 ). [ABSTRACT FROM AUTHOR]

Soil organic carbon (SOC) is the largest active terrestrial carbon reservoir, which behaves both as a sink and source for atmospheric carbon. The same is maximum in the forest soil ofAbies pindrow(128 t ha−1) and minimum inPinus roxburghii(69 t ha−1). The mitigation potential is also found to be maximum in Alpine forest soil (i.e., 1.84) inAbies pindrowand minimum in the chir (i.e., 1.00) inP. Roxburghii. This indicates that alpine forest soil can hold nearly two times more SOC than chir and hence it behaves as a CO2sink. The overall average content of SOC and carbon dioxide equivalent under all land use was estimated at 91.29 t ha−1and 334.11 t ha−1, respectively. The objective of this study is to estimate the spatial variability of SOC stocks in the catchment of both the Tehri and Koteshwar hydroelectric reservoir using field investigations, laboratory measurements, and geostatistical methods. The study provides an estimation for the amount of carbon reaching to the reservoir through various sources, where it undergoes aerobic and anaerobic degradation, thereby releasing green house gases (GHGs) to the atmosphere. The information provided in this article will be useful for policy-makers and environmentalists for undertaking appropriate conservation plans to mitigate GHGs. [ABSTRACT FROM AUTHOR]

Hydrogen (H 2) can play a critical role in global greenhouse gas (GHG) mitigation. Photocatalytic water splitting using solar radiation is a promising H 2 technology. Titanium dioxide (TiO 2) and carbon nitride (g–C 3 N 4)–based photocatalysts are the most widely used photocatalytic materials because of their activity and abundance. Several attempts have been made to improve the photocatalytic performance of these materials in terms of their activity level, life span, response to visible radiation, and stability. However, the environmental impacts of these modifications are often not included in existing studies. This research, therefore, develops a cradle-to-grave life cycle assessment (LCA) framework to evaluate and compare the GHG footprints of four alternative pathways: TiO 2 nanorods and fluorine-doped carbon nitride quantum dots embedded with TiO 2 (CNF: TNR/TiO 2), g-C 3 N 4 , and g-C 3 N 4 /BiOI composite. Unlike most studies that focus only on certain stages such as laboratory-scale photocatalytic fabrication, this study includes utility-scale cell production, assembly, operation, and end of life to give a more accurate and precise environmental performance estimation. The results show that g-C 3 N 4 /BiOI has the lowest GHG footprint (0.38 kg CO 2 eq per kg of H 2) and CNF: TNR/TiO 2 has the lowest energy payback time (0.4 years). In every pathway, energy use in material extraction processes makes up the largest GHG contribution, between 83% and 89%. Sensitivity and uncertainty analyses were conducted under the impact of various input parameters on the life cycle GHG emissions of hydrogen production. Photocatalytic water splitting is highly feasible for adaptation as a mainstream hydrogen production pathway in the future. • LCA of H 2 production via photocatalytic water splitting is conducted. • GHG emissions range from 0.33 to 1.15 kg of CO 2 eq per kg of H 2 produced. • Material extraction has the largest GHG emissions; 56–67% of total emissions. • System is scaled up to produce 5 tonnes of H 2 per day. • H 2 produced has 95% less GHG emissions than steam methane reforming. [ABSTRACT FROM AUTHOR]

Western Canada is endowed with considerable reserves of deep un-mineable coal, which can be converted to syngas by means of a gasification process called underground coal gasification (UCG). The syngas can be transformed into hydrogen (H 2 ) through commercially available technologies employed in conventional fossil-fuel based H 2 production pathways. This paper presents a data-intensive model to evaluate life cycle GHG emissions in H 2 production from UCG with and without CCS. Enhanced oil recovery (EOR) was considered as a sequestration method and included in the LCA. The life cycle GHG emissions are calculated to be 0.91 and 18.00 kg-CO 2 -eq/kg-H 2 in H 2 production from UCG with and without CCS, respectively. In addition, a detailed analysis of the influence of key UCG parameters, i.e., H 2 O-to-O 2 injection ratio, ground water influx, and steam-to-carbon ratio in syngas conversion, is completed on the results. The advantage of adopting UCG–CCS technology for H 2 production is realized over the predominant steam methane reforming (SMR) process; around 15.3 million tonnes of GHG emissions can be mitigated to achieve the projected SCO production rate from the bitumen upgrading in 2022. Furthermore, the sensitivity analysis showed that the life cycle GHG emissions is sensitive to the heat exchanger efficiency and the separation efficiency of the pressure swing adsorption (PSA) unit, with increasing values of these parameters causing an increase and a decrease in the magnitude of life cycle GHG emissions, respectively. [ABSTRACT FROM AUTHOR]

Designing and fabrication of smart hybrid multifunctional materials for energy/fuel production and environmental detoxification is indeed of great significance for sustainable development. Herein, we synthesized a new well-structured S-scheme heterostructure Fe@TiO 2 /Boron Carbon nitride (FT/BCN) with high performance tetracycline degradation and selective CO 2 photo-reduction to CH 4. Under visible light irradiation, 96.3% tetracycline was degraded in 60 min using best performing FT30/BCN sample with a high 83.2% total organic carbon removal in 2 h. The tetracycline degradation rate for FT30/BCN composite catalyst was ∼7 times than bare boron carbon nitride (BCN). The impact of reaction parameters as pH, presence of interfering electrolytes, light source and water matrix was also investigated. The FT30/BCN photocatalyst shows dramatic improvement in CO 2 photoreduction as exhibited in 24.7 μmol g−1 h−1 CH 4 and 2.4 μmol g−1 h−1 CO evolutions with optimal 91.1% CH 4 selectivity. Pure BCN shows a poor 39.1% selectivity. Further, effect of alkali activation, CO 2 /H 2 O feed ratio, reducing agent and light source onto CH 4 production and selectivity was also investigated. The CH 4 evolution and selectivity was improved because of enhanced visible light absorption, high adsorption potential, charge carrier separation and high reducing power of photogenerated electrons induced by an effective S-scheme heterojunction between Fe@TiO 2 and boron carbon nitride. An S-scheme (step-scheme) charge transfer mechanism is here operative both during tetracycline removal and CO 2 reduction. The drug degradation route and photocatalytic mechanism for antibiotic removal and CO 2 reduction was also predicted. [Display omitted] • Fe@TiO 2 /Boron carbon nitride heterojunction fabricated by hydrothermal route. • High performance antibiotic removal under visible and solar light. • Photo-induced CO 2 reduction with H 2 O for highly selective CH 4 production. • Efficient S-scheme charge transfer mechanism observed between Fe@TiO 2 and BCN. • Antibiotic degradation and selective CH 4 production detailed mechanism elucidated. [ABSTRACT FROM AUTHOR]

Hydropower is one of the widely used renewable energy sources and contributing a huge share in overall electricity generation in developing countries like India. A few decades ago, hydropower reservoirs were found to be a clean source of renewable energy, but after the pre-industrial era (1990s), these reservoirs were emitting a significant amount of greenhouse gases (GHG). The GHG are contributing a huge share to the regional/global carbon budget. The current study represents the first regional review and focuses on: present scenarios of Indian hydropower, environmental issues, constraints in dam construction, identified key predictors (i.e., age, depth of reservoir) impacting GHG potential, GHG risk to reservoirs, and suggested mitigation measures to the way forward for the sustainable planning of hydropower development. The review reveals that most Indian hydropower reservoirs are coming under the low to medium GHG risk of reservoirs. Small hydropower projects (SHPs) are deliberated as a worthy alternative for the sustainable management of hydropower projects. There are still many issues associated with SHPs, which cannot be neglected completely. This study provides baseline information to the hydropower industries, policy-makers, environmentalists, and water managers to take corrective measures before impoundment of a reservoir at the regional and global scale. [Display omitted] • This is the first review summarises GHG emission from Indian Hydropower. • Indian hydropower are coming under the low to medium GHG risk of reservoirs. • Small hydro is deliberated as a worthy alternative for the sustainable management of hydropower projects. • Research is urgently needed in tropical eco-regions to know the GHG risk to reservoirs. • Proposed mitigation strategies for carbon deduction in future dam constructions. [ABSTRACT FROM AUTHOR]

Abstract: Biomass can be used for the production of fuels, and chemicals with reduced life cycle (greenhouse gas) emissions. Currently, these fuels and chemicals are produced mainly from natural gas and other fossil fuels. In Western Canada, forest residue biomass is gasified for the production of syngas which is further synthesized to produce different fuels and chemicals. Two types of gasifiers: the atmospheric pressure gasifier (commercially known as SilvaGas) and the pressurized gasifier (commercially known as RENUGAS) are considered for syngas production. The production costs of methanol, (dimethyl ether), (Fischer-Tropsch) fuels, and ammonia are $0.29/kg, $0.47/kg, $0.97/kg, and $2.09/kg, respectively, for a SilvaGas-based gasification plant with a capacity of 2000 dry tonnes/day. The cost of producing methanol, DME, F-T fuels, and ammonia in a RENUGAS-based plant are $0.45/kg, $0.69/kg, $1.53/kg, and $2.72/kg, respectively, for a plant capacity of 2000 dry tonnes/day. The minimum cost of producing methanol, DME, F-T fuels, and ammonia are $0.28/kg, $0.44/kg, $0.94/kg, and $2.06/kg at plant capacities of 3000, 3500, 4000, and 3000 dry tonnes/day, respectively, using the SilvaGas-based gasification process. Biomass-based fuels and chemicals are expensive compared to fuels and chemicals derived from fossil fuels, and carbon credits can help them become competitive. [Copyright &y& Elsevier]

Greenhouse gases (GHGs; particularly, CO 2 , CH 4 , and N 2 O) emission from wastewater treatment systems (WWTS) is one of the inevitable concerns for sustainable development. This indicator is directly linked with the carbon footprint and potential impacts of WWTS on climate change. In this view, various modeling, design, and operational tools have been introduced to mitigate the WWTS associated GHGs, at regional and global scales. In this study, authors have critically reviewed the selected potential operational control strategies for GHGs emission, particularly emitted from the operational stages of biological WWTS. The investigated operational control strategies and/or treatment configurations included intermittent aeration, varying dissolved oxygen, enhanced sludge retention time, coupled aerobic–anoxic nitrous decomposition operation, and microalgae integrated treatment process. Based on this analysis and considering the trade-off between treatment performance of WWTS and GHGs control, an integrated framework is also proposed for existing and upcoming WWTS. The findings of this study and proposed framework will play an instrumental role in mitigating the GHGs at various operational stages of WWTS. Future research works in this direction can lead to a better understanding of investigated operational GHGs emission control strategies in WWTS. • GHGs emissions control in WWTS is an inevitable sustainability concern. • Potential operational GHGs control strategies are discussed in this manuscript. • IA, DO, CANDO, microalgae assisted process, and enhanced SRT are investigated in this study. • An integrated framework for GHGs control through operational strategies is suggested. [ABSTRACT FROM AUTHOR]

Waste management and global warming are the two challenging issues of the present global scenario. Increased human population has set the platform for rapid industrialization and modern agriculture. The industries such as energy, steel, and fertilizers play a significant role in improving the social, and economic status of human beings. The industrial production of energy (that involves combustion of coal), production of steel items and diammonium ammonium fertilizer generate a huge amount of wastes such as fly ash (FA), steel slag (SS) and phosphogypsum (PG), respectively. Inappropriate dumping of any kind of waste poses a threat to the environment, therefore, scientific management of waste is required to reduce associated environmental risks. These wastes i.e. SS, FA, and PG being rich sources of oxides of calcium (CaO), silicon (SiO 2), iron (FeO), and aluminum (Al 2 O 3), etc. may affect the release of greenhouse gases from the soil. The information associated with the application of FA, SS, and PG onto the paddy fields and their impacts on methane and nitrous oxide emissions are highly fragmented and scarce. The present review extensively and critically explores the available information with respect to the effective utilization of FA, SS, and PG in paddy cultivation, their potential to mitigate greenhouse gases emission and their associated mechanisms. The fine grid assessment of these waste management provides new insight into the next level research and future policy options for industries and farmers. Image 103 • Methane and nitrous oxide are two major greenhouses emitted from rice soil. • In this study, industrial byproducts such as steel slag, phosphogypsum, and fly ash were analyzed. • Steel slag has mitigation potential up to 60% in subtropical rice. • Steel slag has negative N 2 O emission from rice soil. [ABSTRACT FROM AUTHOR]

This study developed a novel assessment framework to analyze long-term energy transition in the road transport sector in which various technology options, market shares, policy measures, costs, and greenhouse gas emissions are considered in a single framework analysis. A data-intensive model was developed with the Low Emissions Analysis Platform (LEAP) and used to analyze policy scenarios up to 2050 for Alberta, Canada, a hydrocarbon-rich province with an emission-intensive energy sector. Three key policy measures – carbon pricing, zero-emission vehicle sales mandate, and incentivization – were analyzed in nine individual and combined policy scenarios. The transition to both hydrogen fuel cell electric vehicles and battery electric vehicles was assessed for all vehicle categories. Each fuel's full energy supply chain was modelled, including resource extraction, conversion, transmission and distribution, and fuelling, allowing for final and primary energy analysis. The findings show that carbon price and zero-emission vehicle incentives do not effectively lower greenhouse gas emissions on their own; zero-emission vehicle mandates are needed to transition the sector to a low-carbon energy system. The system-wide greenhouse gas emission footprints of hydrogen and battery electric vehicles are significantly below conventional vehicles in all cases. Scenarios biased towards battery electric vehicles had the most favorable results. The greenhouse gas emission footprint of hydrogen vehicles supplied by auto-thermal reforming with 91% carbon capture was lower than for battery electric vehicles powered by a primarily natural gas-based power grid. The findings on the effectiveness of carbon prices, incentives, and vehicle mandates should be considered by government policymakers aiming to reduce greenhouse gas emissions, infrastructure planners, and other energy stakeholders. [Display omitted] • Assessment of H 2 -FCEVs and BEVs for system-wide energy and emissions. • Impact of carbon price, ZEV sales mandate, and ZEV incentives analyzed up to 2050. • Evaluation of hydrogen production technologies including SMR and ATR with CCS. • Current policies result in 38% decline in system-wide emissions in 2050. • ZEV sales mandate is the most effective in reducing system-wide energy & emissions. [ABSTRACT FROM AUTHOR]

Jurisdictions are looking into mixing hydrogen into the natural gas (NG) system to reduce greenhouse gas (GHG) emissions. Earlier studies have focused on well-to-wheel analysis of H 2 fuel cell vehicles, using high-level estimates for transportation-based emissions. There is limited research on transportation emissions of hythane, a blend of H 2 and NG used for combustion. An in-depth analysis of the pipeline transportation system was performed for hythane and includes sensitivity and uncertainty analyses. When hythane with 15% H 2 is used, transportation GHG emissions (gCO2eq/GJ) increase by 8%, combustion GHG emissions (gCO2eq/GJ) decrease by 5%, and pipeline energy capacity (GJ/hr) decreases by 11% for 50–100 million m3/d pipelines. Well-to-combustion (WTC) emissions increase by 2.0% without CCS, stay the same with a 41% CCS rate, decrease by 2.8% for the 100% CCS scenario, and decrease by 3.6% in the optimal CO 2 -free scenario. While hythane contains 15% H 2 by volume only 5% of the gas' energy comes from H 2 , limiting its GHG benefit. [Display omitted] • A model is developed to assess well-to-combustion (WTC) greenhouse gas (GHG) emissions of hythane. • A hythane blend of 15% H 2 and 85% natural gas is assessed. • Transportation GHG emissions increase by 8% and combustion GHG emissions decrease by 4%. • Without carbon capture, WTC GHG emissions increase by 2%. • Steam methane reforming of hydrogen with 90% carbon capture will reduce WTC GHG emissions by 3%. [ABSTRACT FROM AUTHOR]

[Display omitted] • Water pollution severely impacts the GHG emissions from riverine ecosystems. • GHG emissions from Riverine ecosystem follows: CO 2 > CH 4 > N 2 O. • High nutrient loading and eutrophication enhanced the GHG emissions in rivers. • Riverine CTLI values were positively correlated with CO 2 and CH 4 fluxes. Many recent studies have revealed that polluted rivers are emerging as potent emitters of greenhouse gases (GHGs). However, the scientific understanding of GHG emissions is still limited. The present review aims to provide a systematic analysis of GHG emissions from polluted rivers in various eco-regions. The analysis highlighted that high nutrient loadings such as total nitrogen (TN), organic carbon (OC), total phosphorous (TP), and the anoxic condition of rivers are the major influencing factors for CO 2 , N 2 O, and CH 4 emissions. Moreover, a strong positive correlation of trophic level index (TLI) with CH 4 and CO 2 fluxes was observed. The state-of-art suggested that based on land use and water quality, GHG fluxes from different rivers vary considerably. For instance, the reported N 2 O fluxes ranged between 0.007 and 3.721 mmol m-2d-1 for urban-impacted rivers and 0.009–0.049 mmol m-2d-1 for agricultural rivers. The CH 4 fluxes ranged between 0.001 and 458 mmol m-2d-1, 0.05–1.02 mmol m-2d-1, and 1.40–14.30 mmol m-2d-1 for urban impacted, agricultural and natural rivers, respectively. Further reported CO 2 fluxes range between 19.94 and 895 mmol m-2d-1 for urban-impacted rivers. Overall the in-depth analysis of the existing state of the art revealed that water pollution (i.e. eutrophication) enhances the GHG emissions from rivers; therefore, incorporating effective restoration measures can mitigate the intensity of GHG emissions from rivers and assist in achieving sustainable development goals (SDGs). [ABSTRACT FROM AUTHOR]

Greenhouse gas (GHG) emissions are currently at the crux of political, environmental, technological, and cultural discussions due to climate change. A drastic reduction of GHG emissions is needed in order to mitigate potentially catastrophic climate change impacts. Thus, thoroughly understanding emission sources is imperative. A disaggregated analysis of Canada’s future GHG emission projections has not yet been conducted. The objectives in this paper are to assess disaggregated GHG emissions in Canada for the years 2014, 2030, and 2050, and analyze the results through Sankey diagrams. Emissions are calculated using a bottom-up multi-regional accounting-based Long-range Energy Alternative Planning systems model. Each major economic sector in Canada is analyzed including the electricity generation, residential, commercial and institutional, industrial, transportation, and agriculture sectors. The emissions released in these sectors are traced to the resources and end-uses responsible. Results are presented for Canada and for provinces individually. GHG emissions contained in exported resources are evaluated. Results show that Canada’s business-as-usual GHG emissions will grow from 732 million tonnes in 2014 to 780 and 798 million tonnes in 2030 and 2050, respectively. Canada exports more emissions contained in resources than it emits. Per capita emissions intensity will fall by 14% between 2014 and 2050. Results are compared to climate targets and key areas of GHG mitigation potential are identified. Alberta’s oil and gas sector and Ontario’s transportation sector are the two single largest sectoral sources of emissions by 2050. This research can help policy makers, innovators, and the public better understand GHG emissions, which can lead to more effective GHG mitigation. [ABSTRACT FROM AUTHOR]

To ensure the use of water today does not damage the prospects for its use by future generations, there is need to understand long-term water demand and supply through energy production, conversion, and use. This study aims to develop an integrated framework to assess the long-term impacts of climate change scenarios on water requirements and greenhouse gas (GHG) emissions. The framework includes the integration of the Water Evaluation And Planning model (WEAP) and the Long-range Energy Alternative Planning Systems model (LEAP). As many countries are planning to move towards a cleaner electricity grid to mitigate climate change, this work attempts to present the impact of various scenarios on water demand, GHG emissions, and cost effectiveness. This is done by conducting a case study of the western Canadian province of Alberta where more than 85% of electricity is generated by fossil fuels. This paper provides a comprehensive overview of nine integrated LEAP-WEAP climate change scenarios for the years 2015–2050 by forecasting water consumption and greenhouse gas emissions from the power sector. The economic aspects of the developed scenarios are discussed in the form of a cost curve that shows the GHG saving potential, water use, and GHG mitigation costs for each scenario. For the Business-As-Usual (BAU) scenario (coal power phase out by 2030), GHG emissions and water demand will fall by 44% and 34%, respectively, in 2030. The integrated results show that the scenarios will mitigate carbon emissions but will result in higher water consumption, which will directly affect water resources in the region. Because of the high investment cost to install the considered renewable power plants in the climate change scenarios, the cost of mitigating carbon emissions in the power sector is high. Early coal-to-gas power plant conversion is the only scenario that is expected to save water (67 million m 3 ) and reduce emissions (40 million tonnes of CO 2 eq.) and be cost effective ($68/tonne of CO 2 eq.). These LEAP-WEAP model results can help create awareness among policy makers to understand the water-energy demand and supply relationship in a quantifiable way. [ABSTRACT FROM AUTHOR]

Siting a solid waste conversion facility requires an assessment of solid waste availability as well as ensuring compliance with environmental, social, and economic factors. The main idea behind this study was to develop a methodology to locate suitable locations for waste conversion facilities considering waste availability as well as environmental and social constraints. A geographic information system (GIS) spatial analysis was used to identify the most suitable areas and to screen out unsuitable lands. The analytic hierarchy process (AHP) was used for a multi-criteria evaluation of relative preferences of different environmental and social factors. A case study was conducted for Alberta, a western province in Canada, by performing a province-wide waste availability assessment. The total available waste considered in this study was 4,077,514 tonnes/year for 19 census divisions collected from 79 landfills. Finally, a location-allocation analysis was performed to determine suitable locations for 10 waste conversion facilities across the province. [ABSTRACT FROM AUTHOR]

• TEA of hydrogen production via photocatalytic water splitting was conducted. • Four earth abundant, active and stable photocatalysts were selected. • The LCOH ranges from 4.15 to 9.8 USD per kg of H 2 produced. • Capital investment and labour costs contribute the most, 75% of the total cost. • The system was scaled from lab to facility to produce 5 tonnes of H 2 per day. Photocatalytic water splitting using solar radiation is among the promising H 2 technologies. Titanium dioxide (TiO 2)- and carbon nitride (g-C 3 N 4)-based photocatalysts are the most widely used photocatalytic materials given their activity under visible light and their abundance. Several attempts have been made to improve the photocatalytic performance of these materials in terms of activity level, life span, response to visible radiation, and stability. However, the economic viability of the large-scale deployment of these modifications is not well evaluated in the existing literature. This study develops a bottom-up techno-economic assessment framework to determine the H 2 production costs in four alternative pathways: TiO 2 nanorods, fluorine-doped carbon nitride quantum dot-embedded TiO 2 (CNF: TNRs/TiO 2), g-C 3 N 4 , and g-C 3 N 4 /BiOI composite. Sensitivity and uncertainty analyses were also conducted to understand the impact of input parameters on the hydrogen production cost. The levelized costs of hydrogen (LCOH) are 4.9 - 0.70 + 0.75 , 5.7 - 0.65 + 0.45 , 5.8 - 1.15 + 0.55 , a n d 7.8 - 0.95 + 0.45 USD per kg of H 2 produced for TNRs, CNF: TNRs, g-C 3 N 4 -S, and BiOI/g-C 3 N 4 -S, respectively. In every pathway, the largest contribution is from capital investment and labour costs; together they make up around 75 % of the total cost. Material cost accounts for 13–29 % of the overall cost. The developed information can help in making investment decisions and policy formulation. [ABSTRACT FROM AUTHOR]

Many studies have calculated deterministic point estimates of well-to-combustion (WTC) emissions of transportation fuels from crude oil in an attempt to determine which crude oils have lower or higher emissions. However, there is considerable variation in the published results, resulting in uncertainty. The purpose of this study is to identify GHG emissions ranges for five conventional and two unconventional crudes by performing an uncertainty analysis using an improved version of the FUN damental E N gineering Principl E s-based Mode L for Estimation of G reen H ouse G ases (FUNNEL-GHG). Distributions for key inputs in the Monte Carlo simulation were determined based on values obtained from the literature. Eleven scenarios were developed, nine historical and two current, the former using life-long average production data from the oil fields studied and the latter using recent production data to illustrate how WTC emissions change as the fields age. The mean WTC emissions ranges for the eleven scenarios are 97.5–140 gCO 2 eq/MJ. The uncertainty in the WTC emissions ranges from ±3% to ±11%. The largest source of uncertainty in the WTC emissions is from the venting, fugitive, and flaring volumes, fluid injection rates, and refinery yields. [ABSTRACT FROM AUTHOR]

Methane is one of the critical greenhouse gases, which absorb long wavelength radiation, affects the chemistry of atmosphere and contributes to global climate change. Rice ecosystem is one of the major anthropogenic sources of methane. The anaerobic waterlogged soil in rice field provides an ideal environment to methanogens for methanogenesis. However, the rate of methanogenesis differs according to rice cultivation regions due to a number of biological, environmental and physical factors like carbon sources, pH, Eh, temperature etc. The interplay between the different conditions and factors may also convert the rice fields into sink from source temporarily. Mechanistic understanding and comprehensive evaluation of these variations and responsible factors are urgently required for designing new mitigation options and evaluation of reported option in different climatic conditions. The objective of this review paper is to develop conclusive understanding on the methane production, oxidation, and emission and methane measurement techniques from rice field along with its mitigation/abatement mechanism to explore the possible reduction techniques from rice ecosystem. [ABSTRACT FROM AUTHOR]

The conversion of lignocellulosic biomass to biofuel requires water. This study is focused on the production of hydrogenation-derived renewable diesel (HDRD) from lignocellulosic biomass. Although there has been considerable focus on the assessment of greenhouse gas (GHG) emissions, there is limited work on the assessment of the life cycle water footprint of HDRD production. This paper presents a life cycle water consumption study on lignocellulosic biomass to HDRD via pyrolysis and hydrothermal liquefaction (HTL) processes. The results of this study show that whole tree (i.e., tree chips) biomass has water requirements of 497.79 L/MJ HDRD and 376.16 L/MJ HDRD for production through fast pyrolysis and the HTL process, respectively. Forest residues (i.e., chips from branches and tops generated during logging operations) have water requirements of 338.58 L/MJ HDRD and 255.85 L/MJ HDRD for production through fast pyrolysis and the HTL process, respectively. Agricultural residues (i.e., straw from wheat, oats, and barley), which are more water efficient, have water requirements of 83.7 L/MJ HDRD and 59.1 L/MJ HDRD through fast pyrolysis and the HTL process, respectively. Differences in water use between feedstocks and conversion processes indicate that the choices of biomass feedstock and conversion pathway water efficiency are crucial factors affecting water use efficiency of HDRD production. [ABSTRACT FROM AUTHOR]

A life cycle assessment (LCA) is an extremely useful tool to assess the greenhouse gas (GHG) emissions associated with all the stages of a crude oil’s life from well-to-wheel (WTW). All of the WTW life cycle stages of crude oil consume energy and produce significant amounts of GHG emissions. The present study attempts to quantify the WTW life cycle GHG emissions for transportation fuels derived from five North American conventional crudes through the development of an LCA model called FUNNEL-GHG-CCO ( FUN damental E n gineering Principl E s-based Mode L for Estimation of G reen H ouse G ases in C onventional C rude O ils). This model estimates GHG emissions from all the life cycle stages from recovery of crude to the combustion of transportation fuels in vehicle engines. The contribution of recovery emissions in the total WTW GHG emissions ranges from 3.12% for Mars crude to 24.25% for California’s Kern County heavy oil. The transportation of crude oil and refined fuel contributes only 0.44–1.73% of the total WTW life cycle GHG emissions, depending on the transportation methods and total distance transported. The GHG emissions for refining were calculated from the amount of energy use in the refining of crude oil to produce transportation fuels. All the upstream GHG emissions were allocated to gasoline, diesel, and jet fuel. Refining GHG emissions vary from 13.66–18.70 g-CO 2 eq/MJ-gasoline, 9.71–15.33 g-CO 2 eq/MJ-diesel, and 6.38–9.92 g-CO 2 eq/MJ-jet fuel derived from Alaska North Slope and California’s Kern County heavy oil, respectively. The total WTW life cycle GHG emissions range from 97.55 g-CO 2 eq/MJ-gasoline derived from Mars crude to 127.74 g-CO 2 eq/MJ-gasoline derived from California’s Kern County heavy oil. [ABSTRACT FROM AUTHOR]

A comprehensive LCA (life cycle assessment) for transportation fuels (gasoline, diesel, and jet fuel) derived from Canada's oil sands was conducted, and all the current possible pathways from bitumen extraction to use in vehicles were explored. Authors, in earlier studies, have presented the energy consumption and GHG (greenhouse gas) emission results for individual unit operations-recovery, extraction, upgrading and refining. The LC (life cycle) inventory data for the current LCA study were obtained from theoretical model named FUNNEL-GHG-OS ( FUN damental E N gineering Principl E s- based Mode L for Estimation of G reen H ouse G ases in the O il S ands), developed from fundamental engineering principles. The impact of the cogeneration of electricity in oil sands recovery, extraction, and upgrading on the LC GHG emissions of gasoline was explored. LC WTW (well-to-wheel) GHG emissions range from 106.8 to 116 g-CO 2 equivalent/MJ of gasoline, 100.5 to 115.2 g-CO 2 equivalent/MJ of diesel, and 96.4 to 109.2 g-CO 2 equivalent/MJ of jet fuel, depending on the pathway. Combustion emissions (64.7%–70.3%) are the largest constituent of WTW emissions for gasoline production; recovery (through surface mining and steam assisted gravity drainage) forms 7.2%–16% depending on the LC production process of gasoline. [ABSTRACT FROM AUTHOR]

• Life cycle assessment of utility-scale solar energy is performed. • Upstream production and assembly are the most emission-intensive life cycle stages. • Energy use during production and plant lifetime are the most sensitive parameters. • The system shows a net energy production with a net energy ratio up to 6.6. • The life cycle GHG emissions range from 98.3 to 149.3 g CO 2 eq /kWh. Grid-connected utility-scale solar PV has emerged as a potential pathway to ensure deep decarbonization of electricity in regions with fossil fuel-dominated energy mixes. Research on utility-scale solar PV projects mainly focuses on assessing technical or economic feasibility. Environmental performance assessments of large-scale solar applications are scarce. There is limited information on the greenhouse gas (GHG) emissions and energy footprints of utility-scale solar energy systems. Earlier studies conducted on small-scale solar systems have limited application in the grid system. We developed a comprehensive bottom-up life cycle assessment model to evaluate the life cycle GHG emissions and energy profiles of utility-scale solar photovoltaic (PV) system with lithium-ion battery storage to provide a consistent electricity supply to the grid with peak load options. We conducted a case study for a fossil fuel-based energy jurisdiction, Alberta (a western province in Canada). The results of the energy assessment show that raw material extraction, production, and assembly of solar panels are the key drivers, accounting for 53% of the total consumption. Energy consumed during battery manufacturing is responsible for 28%. The system shows a net energy production with a mean net energy ratio as high as 6.6 for two-axis sun tracking orientation. The life cycle GHG emissions range from 98.3 to 149.3 g CO 2 eq /kWh with a mean value of 123.8 g CO 2 eq /kWh. The largest emissions contribution is due to the manufacturing of batteries, 54% of the total emissions. The solar PV system offers a mean energy payback time of 3.8 years (with a range of 3.3 to 4.2 years). The results are highly sensitive to the expected lifetime of the system, the panel's peak wattage, and process energy consumption at various life cycle stages. [ABSTRACT FROM AUTHOR]

The demand for hydrogen is likely to increase in the next decade to satisfy the projected growth of the bitumen upgrading industry in western Canada. This paper presents GHG (greenhouse gas) abatement costs and the GHG abatement potential in producing hydrogen from UCG (underground coal gasification) along with CCS (carbon capture and sequestration). Seven hydrogen production scenarios are considered to assess the competitiveness of implementing UCG compared to SMR (steam methane reforming). The analysis is completed through a LCA (life cycle assessment) of large-scale hydrogen production from UCG and SMR with and without CCS. Considering SMR technology without CCS as the base case, the GHG abatement costs of implementing the UCG-CCS technology is calculated to be in the range of 41–109 $CAD/tonne-CO 2 -eq depending on the transportation distance to the CCS site from the UCG-H 2 production plant. Life cycle GHG emissions are higher in UCG than in SMR. The GHG abatement costs for SMR-CCS-based scenarios are higher than for UCG-CCS-based scenarios; they range from 87 to 158 $CAD/tonne-CO 2 -eq in a similar manner to UCG-CCS. Consideration of revenues for selling the CO 2 captured for EOR (enhanced oil recovery) reduces the GHG abatement costs. An opportunity for revenue generation is realized in the UCG-CCS case. [ABSTRACT FROM AUTHOR]

A model – FUNNEL-GHG-OS ( FUN damental E N gineering Principl E s-based Mode L for Estimation of G reen H ouse G ases in the O il S ands) was developed to estimate project-specific energy consumption and greenhouse gas emissions (GHGs) in major recovery and extraction processes in the oil sands, namely surface mining and in␣situ production. This model estimates consumption of diesel (4.4–7.1 MJ/GJ of bitumen), natural gas (52.7–86.4 MJ/GJ of bitumen) and electricity (1.8–2.1 kW h/GJ of bitumen) as fuels in surface mining. The model also estimates the consumption of natural gas (123–462.7 MJ/GJ of bitumen) and electricity (1.2–3.5 kW h/GJ of bitumen) in steam assisted gravity drainage (SAGD), based on fundamental engineering principles. Cogeneration in the oil sands, with excess electricity exported to Alberta’s grid, was also explored. Natural gas consumption forms a major portion of the total energy consumption in surface mining and SAGD and thus is a main contributor to GHG emissions. Emissions in surface mining and SAGD range from 4.4 to 7.4 gCO 2 eq/MJ of bitumen and 8.0 to 34.0 gCO 2 eq/MJ of bitumen, respectively, representing a wide range of variability in oil sands projects. Depending upon the cogeneration technology and the efficiency of the process, emissions in oil sands recovery and extraction can be reduced by 16–25% in surface mining and 33–48% in SAGD. Further, a sensitivity analysis was performed to determine the effects of key parameters on the GHG emissions in surface mining and SAGD. Temperature and the consumption of warm water in surface mining and the steam-to-oil ratio (SOR) in SAGD are major parameters affecting GHG emissions. The developed model can predict the energy consumption and emissions for surface mining and SAGD for oil sands. [ABSTRACT FROM AUTHOR]

• Six alternative or low-carbon fuels are evaluated for the cement sector. • Average long-term marginal abatement costs range from −70 to 138 CAD/tCO 2 e. • Up to 21% of emissions to 2050 can be eliminated with negative abatement costs. • Energy prices are the primary factor driving scenario cost performance. Limiting global warming and the pursuit of a net-zero global society by 2050 emphasizes the need to transform the hard-to-abate industrial sectors. The cement sector is the second-largest source of global industrial emissions, accounting for 8% of worldwide greenhouse gas emissions. Fuel switching in the cement sector is a decarbonization pathway that has not been explored in detail; previous studies involving fuel switching in the sector either view it from an energy efficiency lens or focus on a single technology. In this study, a framework is developed to evaluate and directly compare six fuel switching options (including hydrogen, biomass, municipal solid waste, and natural gas) from 2020 to 2050. Capital costs, non-energy operating costs, energy costs, and carbon costs are used to calculate marginal abatement costs and emulate cost based-market decisions. The developed framework is used to conduct a case study for Canada, using the LEAP-Canada model. This study shows that cumulative energy-related greenhouse gas emissions can be reduced by up to 21% between 2020 and 2050 with negative marginal abatement costs. Multiple fuel switching decarbonization pathways were established, reducing the likelihood that locality prevents meaningful emissions reduction and suggesting that, with low-carbon fuel and electricity policies, the sector can take significant steps towards emissions reduction. The developed framework can be applied to jurisdictions around the world for decision making, as nations move towards eliminating emissions from cement production. [ABSTRACT FROM AUTHOR]

• Geospatial techniques were employed to know the carbon dynamics in tropical forest of central India. • Tropical forest of central India acts as net C sources that emits 216398.52 Mg CO 2eq in the atmosphere. • Three viable management scenarios were suggested to achieve the carbon neutrality by 2030. • The findings will be useful in strategic planning to realize the goals of NDCs. Anthropogenic land use changes in the vicinity of forest catchments are explicitly responsible for the deforestation and degradation of tropical forest thereby altering the carbon (C) balance under rising atmospheric carbon dioxide (CO 2). Thus, strategic mitigation measures are required to achieve climate neutrality by 2030. It becomes imperative to understand the impact of land cover conversion on the functioning of tropical forests and to determine the carbon dynamics. The present study examined the land cover changes (LUC) in dry tropical ecosystem of Central India during the last two decades and assessed its influence on the forest biomass, litter crop, and C stocks. Geospatial techniques coupled with ground measurements were employed in the study. The total biomass, vegetative C stocks and soil C were estimated as 64 to 338.3 Mg ha−1, 26.4 to 131.1 Mg C/ha and 24.6 to 50.2 Mg C/ha respectively. In the past decades (2000–2020), about 1851.8 ha of forest constituting 15.1% of the total area under study was lost (mainly to Agriculture) under open mixed forest, moderately mixed forest and mixed teak forest. The study demonstrated that forests of the studied region behave as a potential C source, which accounted for a net loss of 59 gigagram carbon (Gg C) equivalent to 216 Gg CO 2eq. Besides, discussed three viable scenarios of restoration to offset C emissions and to achieve C neutral landscape by 2030. The conservation and restoration of 26–85% degraded forests (open mixed forest and moderately mixed dense forests), use of agroforestry on 1/5th of existing agricultural lands, or implementation of regenerative agricultural practices in 30% of the area will compensate for net losses, while attaining C neutrality. Further, the finding of this study helps to understand the climatic extremes as per the commitments of Paris Agreement, 2015 and Glasgow Pact, 2021. [ABSTRACT FROM AUTHOR]

The purpose of this research is to evaluate the greenhouse gas reduction potential and associated costs of integrating renewable energy technologies into Canada's oil sands. There is very limited analysis in the literature focused on the integration of renewable technology options in oil sands processes. This research addresses the gap by developing a novel framework that applies market penetration and bottom-up energy modeling techniques. A total of 27 long-term scenarios across oil sands extraction, upgrading, and electricity generation were investigated. The results show that up to 84 million tonnes of greenhouse gas emissions abatement (2.3% of oil sands GHG emissions) at a marginal greenhouse gas abatement cost of $1.3/tCO 2 e is available under a $30/tonne carbon incentive. Scenarios with no carbon incentive resulted in 69 million tonnes less greenhouse gas emissions abatement and a marginal greenhouse gas abatement cost increase of $36/tCO 2 e. Nuclear-based scenarios mitigated the largest amount of greenhouse gases and had the lowest marginal abatement costs. Geothermal energy, bioenergy, and hydropower were cost effective in certain scenarios but had limited greenhouse gas emission reduction potential. Wind and solar technologies failed to displace existing processes in the scenarios considered. The results from this study may be of value to government policy makers and industry representatives aiming to reduce greenhouse gases. • A novel framework applying market penetration and bottom-up energy modeling. • Renewable and low-carbon energy supply options for the Canadian oil sands industry. • Up to 3.7% of GHG emissions between 2019 and 2050 could be mitigated at -$6/tCO 2 e. • Nuclear energy technologies provided most of the GHG emission abatement potential. • Removing a $50 per tonne carbon price reduced GHG abatement by 89%. [ABSTRACT FROM AUTHOR]

• A novel energy-environmental model for penetration of oil sands cogeneration. • Interactions between industry cogeneration and provincial grid system considered. • 2% of oil sands greenhouse gas emissions could be mitigated by 2050. • The marginal abatement cost is $15 per tonne of carbon abated. • 92% of emission mitigation came from the steam-assisted gravity drainage sector. The purpose of this research is to evaluate greenhouse gas emission reduction opportunities from cogenerated electricity in oil sands production. A novel combined market penetration and bottom-up energy system modelling framework was developed to assess the long-range potential and marginal costs of cogenerated electricity in the oil sands. Feasible scenarios for incorporating cogeneration into the in situ, surface mining, and upgrading subsectors were developed along with four additional scenarios incorporating electricity-based technologies to improve in situ plant efficiencies. These scenarios were evaluated under three different carbon pricing policies; twenty-one scenarios in total covering the time period 2019 to 2050. The use of cogeneration in the oil sands for new production during this period was determined through market penetration modelling and the results were compared to a reference scenario of limited cogeneration growth. It was found that there is potential to provide 76 million tonnes of greenhouse gas abatement (2% of cumulative projected oil sands emissions) at a marginal cost of $15 per tonne of carbon abated compared to the reference scenario. The incorporation of electrical equipment, specifically well-pad boilers, well-pad compressors, additional steam compressors, and steam superheaters, resulted in additional costs that outweighed the benefits. A $50 per tonne of carbon dioxide equivalent carbon price (within the current Alberta emission reduction regulation) resulted in a 2% increase in forecasted greenhouse gas abatement potential and a $1.4/tonne of carbon dioxide equivalent decrease in marginal abatement costs compared to no carbon pricing. This research provides quantification of the greenhouse gas emission abatement potential and marginal abatement costs of cogeneration technologies to allow industry stakeholders and policymakers to compare these technology options to others when considering long-term greenhouse gas emission reduction. [ABSTRACT FROM AUTHOR]

The industrial sector, accounting for 30% of global greenhouse gas (GHG) emissions, is among the key drivers of human-induced climate change impacts. Given this volume of emissions, the sector could play a critical role in mitigating climate change. Canada is among the top 10 global GHG emitters and its industrial sector is responsible for more than 39% of national emissions. GHG emissions from the sector increased by almost 32% between 1990 and 2017 and are expected to almost double by 2050 if no measures are taken. This paper aims to evaluate how different technical and economic factors have contributed to the increasing GHG emission trends in Canada's industrial sector between 1990 and 2014. The Logarithmic Mean Divisia Index was developed and implemented as the decomposition method. Results from the analysis suggest that activity level is the biggest contributor to the increase in industrial GHG emissions between 1990 and 2014, which ranged from 5 Mt CO 2 eq in 1994 to 57 Mt CO 2 eq in 2014 compared to the 1990 baseline. Increased shares of low carbon-intensive industries and fuel switching contribute to GHG emission mitigation from the sector. The structural change is responsible for GHG reductions of 1.1 and 23.4 Mt CO 2 eq in 2000 and 2014, respectively. The impacts from fuel mixs and increased shares of low-carbon fuel ranged from −1 Mt CO 2 eq in 1994 to 16 Mt CO 2 eq in 2011. Despite improvements in process-energy-intensity (i.e., the energy consumed per unit of product) in several industries, changes in economic energy intensity (energy consumed per unit of economic output) have resulted in increased GHG emissions. These changes are mainly driven by changes in the process-energy intensity of the oil sands mining sector, the largest contributor to industrial GHG emissions in Canada. Image 107490 • Historical GHG emissions trends from Canada's industrial sector were analyzed. • GHG emissions decomposition analysis was done for the years 1990–2014. • The impacts of driving factors on increasing GHG emission trends were examined. • Activity level was found to be the main driver of GHG emissions. • Fuel switching and electricity decarbonization mitigate industrial GHGs. [ABSTRACT FROM AUTHOR]

The article discusses a study conducted in India to determine the carbon and water footprints of rice, wheat, and corn cultivation across different regions, highlighting the highest water footprint for rice farming and the highest carbon footprint for rice cultivation in South India.

Carbon capture and utilization (CCU) and carbon dioxide removal (CDR) technologies have the potential to significantly contribute to GHG reduction. Numerous studies have evaluated the CO 2 reduction effects and economics of CCUs and CDRs; however, uncertainties in these evaluations due to various regional characterizations and future technological transitions are of high importance. In this study, four synthetic fuels (fuels produced from captured CO 2 and H 2), methanol, methane, gasoline, and diesel, were evaluated by life cycle assessment (LCA) and techno-economic assessment (TEA). Five representative countries with different regional characteristics were selected for the study. A bottom-up integrated LCA/TEA approach was used, involving detailed process simulations to avoid uncertainties and to evaluate future technological transitions based on direct air capture (DAC) and renewable energy. The overarching objective of this study was to provide a transparent framework with a common dataset generation methodology to determine the countries that have the advantages/disadvantages in synthetic fuel production and sale, considering the local operational parameters and large-scale introduction of DAC/renewable energy. Such multiple synthetic fuel analyses across various jurisdictions have not been conducted in previous studies. The results showed that the highest and lowest CO 2 reductions were achieved by diesel (average 6.33 kg-CO 2 ·kg−1) and methanol (average 3.43 kg-CO 2 ·kg−1), respectively, whereas the highest and lowest product costs were of gasoline (average 2.96 USD·kg−1) and methanol (average 0.82 USD·kg−1), respectively. The technological transition using DAC and renewable energy showed average CO 2 emission reductions of 47% (methanol), 99% (methane), 545% (gasoline), and 621% (diesel). Moreover, in the future, the lowest CO 2 emission reduction costs are expected in Germany for methanol and diesel, Australia for methane, and Canada for gasoline. These findings can contribute to improving international collaboration to promote CCU and CDR technologies. • Carbon capture and utilization (CCU) and CO 2 removal (CDR) technologies were evaluated for four representative synthetic fuels. • CO 2 reductions and costs were analyzed for different CCU pathways, scenarios, and countries. • Diesel fuel was found to be the most effective CCU pathway in terms of cost and potential. • Germany and Canada have economical advantage for CCU production, while U.S, has in potential. • Detailed process modeling was combined with cost and GHG emission estimation for multiple jurisdictions. [ABSTRACT FROM AUTHOR]

The main purpose of this study is to develop a bottom-up life cycle assessment model to evaluate the greenhouse gas (GHG) emissions associated with the Canadian oil sands supply to China. Two pathways were considered. In pathway I, extracted bitumen is sent to Edmonton for upgrading and pipelined to the Westridge terminal near Vancouver, then shipped to a port in China. In pathway II, extracted bitumen is mixed with diluent, directly pipelined to the Westridge terminal, and shipped to China. The results from both the pipeline and the shipping models suggest that pathway I has better GHG emissions than pathway II on a per-barrel basis. GHG emissions are 2.4–3.5 times lower in pipelining synthetic crude oil (SCO) to Westridge than in pipelining dilbit, without and with a diluent return. The emissions range from 826 − 401 + 701 g CO 2 eq/bbl for SCO, 1819 − 719 + 1172 for dilbit without diluent return, and 2684 − 1065 + 1374 g CO 2 eq/bbl for dilbit with a diluent return. Shipping SCO has 15% fewer emissions than shipping dilbit. The shipping emissions are due to fuel use in the main engine. The emissions for shipping are 5536 − 914 + 966 g CO 2 /bbl for dilbit and 4034 − 822 + 899 g CO 2 /bbl for SCO. • GHG emission performances of Canadian oil sands supply to China were identified. • Pipeline GHG emissions range from 826 − 401 + 701 to 1819 − 719 + 1172 g CO 2 eq/bbl. • Shipping synthetic crude oil has 15% fewer GHG emissions than shipping dilbit. • Shipping GHG emissions ranges from 4034 − 822 + 899 to 5536 − 914 + 966 g CO 2 /bbl. • The synthetic crude oil supply pathway has a higher GHG performance than the dilbit. [ABSTRACT FROM AUTHOR]

To reduce the greenhouse gas (GHG) emission from rice and wheat cultivation several mitigation options have been suggested. However, economic impact of these technologies has been poorly documented. In the present study economic analysis of some emerging GHG mitigation technologies for rice-wheat system of the Indo-Gangetic Plains has been carried out. The experiment consisted of six combinations of wheat- rice crop rotation using eight treatments, including conventionally tilled wheat (CTW), zero tilled wheat (ZTW), transplanted puddled rice (TPR), dry direct seeded rice (DSR), intermittent wetting and drying (IWD), application of rice straw (RS) with ZTW and use of neem oil-coated urea (NOCU) in TPR and ZTW. Cost of various inputs and income from grain and straw were used for computing the benefit to cost (B : C) ratio in the different treatments. ZTW showed higher yield and B : C ratio compared to CTW along with reduction in fuel consumption during tillage operation. In spite of lower yield under DSR and IWD, saving of water, labour and energy in these treatments lowered the cost of cultivation and enhanced B : C ratio similar to TPR. Application of rice straw and NOCU also showed positive impact on crop yield. B : C ratio of rice-wheat system ranged from 1.62 to 1.86 in the first year and from 1.86 to 2.16 in the second year. B : C ratio was significantly higher in all the treatments in the experimented rice-wheat system compared to conventional system, i.e. CTW-TPR. The ZTW + RR - DSR (WR5) showed highest B : C ratiofollowed by ZTW + DSR (WR4) in both the seasons. [ABSTRACT FROM AUTHOR]

Thorium fission is a large yet relatively unexplored renewable energy source and could help feed increasing energy demands. An analysis was performed on the feasibility of replacing the uranium in Canada’s nuclear reactors with thorium. Thorium only exists as a fertile isotope, and so an external fissile source such as 235 U, 233 U, or 239 Pu is required to stimulate the fission process. A uranium plant and a similar thorium-fuelled plant were compared over a 40 year operational life based on a comprehensive economic analysis. The results from the economic analysis were used to estimate the greenhouse gas (GHG) abatement cost compared to the coal and natural gas-based power. The economic analysis determined that a thorium plant is more financially lucrative in Canada than a uranium plant. An abatement cost assessment in relation to gas-fired and coal-fired power plants demonstrated that nuclear power offers a cost savings per tonne of CO 2 equivalent greenhouse gas (GHG) when compared to both fossil fuel alternatives. From the values determined for a plant potentially fuelled on thorium, the abatement cost when compared to the coal-fired and gas-fired plants is −$10.4/tonne-CO 2 eq and −$15.7/tonne-CO 2 eq, respectively. [ABSTRACT FROM AUTHOR]

• Bottom-up life cycle assessment models were developed for battery storage systems. • Life cycle greenhouse gas (GHG) emissions of five battery storage systems were evaluated. • Four different stationary applications of batteries were examined. • The Li-ion has the highest net energy ratio (NER) and lowest GHGs in all applications. Electro-chemical batteries are widely used in portable devices and transportation, but they can also be used in the electricity grid for various applications. The assessment of the environmental impacts of electro-chemical storage systems for stationary use has received little attention. In this study, data-intensive, bottom-up life cycle assessment models were developed to assess the life cycle net energy ratios (NERs) and greenhouse gas (GHG) emissions of utility-scale stationary applications of five electro-chemical energy storage systems: sodium-sulfur, lithium-ion, valve-regulated lead-acid, nickel–cadmium, and vanadium redox flow. Four stationary application scenarios were considered: bulk energy storage, transmission and distribution (T&D) investment deferral, frequency regulation, and support of voltage regulation. The Li-ion storage system has the highest NER and lowest GHG emissions in every scenario. The life cycle GHG emissions range from 715 to 784 kg-CO 2 eq for sodium-sulfur, 625–659 kg-CO 2 eq for lithium-ion, 749–803 kg-CO 2 eq for valve-regulated lead-acid, 742–806 kg-CO 2 eq for nickel–cadmium, and 800–963 kg-CO 2 eq for vanadium redox flow per MWh of electricity delivered, depending on the application scenario. The results are highly influenced by the operation phase that involves charging the batteries. Lithium-ion and sodium-sulfur storage systems are the most suitable for all the application scenarios because of their longer cycle lives and higher energy densities. [ABSTRACT FROM AUTHOR]