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China's energy dependents on coal due to the abundance and low cost of coal. Coal provides a secure and stable energy source in China. Over-dependence on coal results in the emission of Hazardous Trace Elements (HTEs) including selenium (Se), mercury (Hg), lead (Pb), arsenic (As), etc., from Coal-Fired Power Plants (CFPPs), which are the major toxic air pollutants causing widespread concern. For this reason, it is essential to provide a succinct analysis of the main HTEs emission control techniques while concurrently identifying the research prospects framework and specifying future research directions. The study herein reviews various techniques applied in China for the selected HTEs emission control, including the technical, institutional, policy, and regulatory aspects. The specific areas covered in this study include health effects, future coal production and consumption, the current situation of HTEs in Chinese coal, the chemistry of selected HTEs, control techniques, policies, and action plans safeguarding the emission control. The review emphasizes the fact that China must establish and promote efficient and clean ways to utilize coal in order to realize sustainable development. The principal conclusion is that cleaning coal technologies and fuel substitution should be great potential HTEs control technologies in China. Future research should focus on the simultaneous removal of HTEs, PM, SOx, and NOx in the complex flue gas. Image, graphical abstract [ABSTRACT FROM AUTHOR]

We compare sustainably managed with unmanaged forests in terms of their contribution to climate change mitigation based on published data. For sustainably managed forests, accounting of carbon (C) storage based on ecosystem biomass and products as required by the United Nations Framework Convention on Climate Change is not sufficient to quantify their contribution to climate change mitigation. The ultimate value of biomass is its use for biomaterials and bioenergy. Taking Germany as an example, we show that the average removals of wood from managed forests are higher than stated by official reports, ranging between 56 and 86 mill. m3 year−1 due to the unrecorded harvest of firewood. We find that removals from one hectare can substitute 0.87 m3 ha−1 year−1 of diesel, or 7.4 MWh ha−1 year−1, taking into account the unrecorded firewood, the use of fuel for harvesting and processing, and the efficiency of energy conversion. Energy substitution ranges between 1.9 and 2.2 t CO2 equiv. ha−1 year−1 depending on the type of fossil fuel production. Including bioenergy and carbon storage, the total mitigation effect of managed forest ranges between 3.2 and 3.5 t CO2 equiv. ha−1 year−1. This is more than previously reported because of the full accounting of bioenergy. Unmanaged nature conservation forests contribute via C storage only about 0.37 t CO2 equiv. ha−1 year−1 to climate change mitigation. There is no fossil fuel substitution. Therefore, taking forests out of management reduces climate change mitigation benefits substantially. There should be a mitigation cost for taking forest out of management in Central Europe. Since the energy sector is rewarded for the climate benefits of bioenergy, and not the forest sector, we propose that a CO2 tax is used to award the contribution of forest management to fossil fuel substitution and climate change mitigation. This would stimulate the production of wood for products and energy substitution. [ABSTRACT FROM AUTHOR]

Highly efficient and stable supported non-noble metal catalysts to realize the real-time evolution of hydrogen for the promising substitution of fossil fuels are urgently desired but are still greatly challenging to achieve. In this work, a highly dispersed ultrafine CoNi nanoalloy has been successfully enclosed within a hierarchically porous carbon which exhibits a unique core–shell metal@carbon structure through an in situ carbonized reduction approach by using bimetallic CoNi-MOF-74 as a self-sacrificed template. Note that the all-around interactions between the nanoalloy and carbon within such a unique hierarchically porous core–shell can effectively stabilize and activate the CoNi nanoalloy, meanwhile facilitating the fast mass transfer of substrate molecules. We found that the Co/Ni ratio of the original precursors of MOF-74 and the pyrolysis temperature can significantly meditate the catalytic performance of the derived composite catalysts. In particular, the synthesized catalyst, 10%-CoNi/HPC-400, showed the best catalytic activity and good stability for hydrogen evolution with a turnover frequency value (TOF) of 27.22 min−1 at 323 K, which is higher than most reported non-noble metal catalysts and even some noble metal catalysts. The outstanding catalytic performance and durability of the composite catalysts were attributed to the synergic effect of the well-dispersed CoNi alloy and the unique hierarchical core–shell structure, which demonstrated the huge potential for AB hydrolysis in hydrogen storage applications. [ABSTRACT FROM AUTHOR]

In the present work, dual fuel operation of a diesel engine has been experimentally investigated using biodiesel and hydrogen as the test fuels. Jatropha Curcas biodiesel is used as the pilot fuel, which is directly injected in the combustion chamber using conventional diesel injector. The main fuel (hydrogen) is injected in the intake manifold using a hydrogen injector and electronic control unit. In dual fuel mode, engine operations are studied at varying engine loads at the maximum pilot fuel substitution conditions. The engine performance parameters such as maximum pilot fuel substitution, brake thermal efficiency and brake specific energy consumption are investigated. On emission side, oxides of nitrogen, hydrocarbon, carbon monoxide and smoke emissions are analysed. Based on the results, it is found that biodiesel-hydrogen dual fuel engine could utilize up to 80.7% and 24.5% hydrogen (by energy share) at low and high loads respectively along with improved brake thermal efficiency. Furthermore, hydrocarbon, carbon monoxide and smoke emissions are significantly reduced compared to single fuel diesel engine operation. Exhaust gas recirculation (EGR) has also been studied with biodiesel-hydrogen dual fuel engine operations. It is found that EGR could improve the utilization of hydrogen in dual fuel engine, especially at the high loads. The effect of EGR is also found to reduce high nitrogen oxide emissions from the dual fuel engine and brake thermal efficiency is not significantly affected. • Biodiesel-H 2 dual fuel operation of the diesel engine has been experimentally studied. • Performance features with maximum pilot fuel substitution and emissions are analysed. • Biodiesel showed better pilot fuel substitution at low load and low emission. • It was possible to significantly reduce NO x emissions at high load using EGR. [ABSTRACT FROM AUTHOR]

This paper describes the reversible operation of a highly efficient microtubular solid oxide cell (SOC) with a nickelate-based oxygen electrode. The fuel cell was composed of a microtubular support of nickel and yttria stabilized zirconia (Ni-YSZ), an YSZ dense electrolyte, and a double oxygen electrode formed by a first composite layer of praseodymium nickelate (PNO) and gadolinium-doped ceria (CGO) and a second one of PNO. A good performance of the cell was obtained at temperatures up to 800 °C for both fuel cell (SOFC) and electrolysis (SOEC) operation modes, specially promising in electrolysis mode. The current density in SOEC mode at 800 °C is about −980 mA cm−2 at 1.2V with 50% steam. Current density versus voltage curves (j-V) present a linear behavior in the electrolysis mode, with a specific cell area resistance (ASR) of 0.32 Ω cm−2. Durability experiments were carried out switching the voltage from 0.7V to 1.2V. No apparent degradation was observed in fuel cell mode and SOEC mode up to a period of about 100 h. However, after this period especially in electrolysis mode there is an accumulated degradation associated to nickel coarsening, as confirmed by SEM and EIS experiments. Those results confirm that nickelate based oxygen electrodes are excellent candidates for reversible SOCs. • PNO-CGO composite electrode enhances the stability of SOC cells. • Highest electrolysis performance for a microtubular cell was achieved. • Switching to fuel cell mode partially recovers the degradation in electrolysis. [ABSTRACT FROM AUTHOR]

Recent developments have rendered the Dual Fuel (DF) engines an attractive alternative solution for achieving cost-efficient compliance to environmental regulations. The present study focuses on the safety investigation of a marine DF engine in order to identify potential safety implications. This investigation is based on an integrated engine model, which was developed in GT-ISE™ software and is capable of predicting both the engine steady-state behaviour and transient response. The model includes the engine thermodynamic simulation module as well as the engine control system functional module; the latter is responsible for implementing the ordered load changes and the operating mode switching. The developed model is first validated against available published data and subsequently used to simulate several test cases with fuel changes, from gas to diesel and diesel to gas with rapid and with delayed wastegate valve operation. The derived simulation results are used to investigate the potential safety implications that can arise during the engine operation. The results demonstrate that the engine–turbocharger matching as well as the wastegate control are critical parameters for ensuring the compressor surge free operation during gas to diesel modes transition. Abbreviations: 0D: zero-dimensional; 1D: one-dimensional; BMEP: brake mean effective pressure; CO2: carbon dioxide; DF: dual fuel; D/G: diesel generator; DTG: diesel to gas fuel modes switching; ECA: emission control area; ECS: engine control system; EEDI: energy efficiency design index; GTD: gas to diesel modes switching; HFO: heavy fuel oil; IMO: International Maritime Organization; LFO: light fuel oil; LNG: liquefied natural gas; MCR: maximum continuous rating; NOx: nitrogen oxides; PHA: preliminary hazard analysis; PI: proportional–integral; SOx: sulphur oxides; TC: turbocharger; WG: wastegate; λ: air–fuel equivalence ratio [ABSTRACT FROM AUTHOR]

The ability to switch fuels for oxidation in response to changes in macronutrient composition of diet (metabolic flexibility) may be informative of individuals' susceptibility to weight gain. Seventy-nine healthy, weight-stable participants underwent 24-h assessments of energy expenditure and respiratory quotient (RQ) in a whole-room calorimeter during energy balance (EBL) (50% carbohydrate, 30% fat) and then during 24-h fasting and three 200% overfeeding diets in a crossover design. Metabolic flexibility was defined as the change in 24-h RQ from EBL during fasting and standard overfeeding (STOF) (50% carbohydrate, 30% fat), high-fat overfeeding (HFOF) (60% fat, 20% carbohydrate), and high-carbohydrate overfeeding (HCOF) (75% carbohydrate, 5% fat) diets. Free-living weight change was assessed after 6 and 12 months. Compared with EBL, RQ decreased on average by 9% during fasting and by 4% during HFOF but increased by 4% during STOF and by 8% during HCOF. A smaller decrease in RQ, reflecting a smaller increase in lipid oxidation rate, during HFOF but not during the other diets predicted greater weight gain at both 6 and 12 months. An impaired metabolic flexibility to acute HFOF can identify individuals prone to weight gain, indicating that an individual's capacity to oxidize dietary fat is a metabolic determinant of weight change. [ABSTRACT FROM AUTHOR]

Substitution of fossil gaseous fuels with biomass-based gases is of interest to the iron and steel industry due to its role in the mitigation of anthropogenic CO 2 emissions. In switching from fossil fuels to biomass-based gases, a systems analysis of the full value chain from biomass supply to the production and supply of final gas products becomes crucial. This study uses process and heat integration methods in combination with a supply chain evaluation to analyse full value chains of biomass-based gases for fossil gas replacement within the iron and steel industry. The study is carried out as a specific case study in order to understand the implications of utilizing bio-syngas/bio-SNG as heating fuels in iron- and steel-making, and to provide insights into the most sensitive parameters involved in fuel switching. The results show a significant cost difference in the fuel production of the two gas products owing to higher capital and biomass use in the bio-SNG value chain option. When tested for sensitivity, biomass price, transportation distance, and capital costs show the most impact on fuel production costs across all options studied. Trade-offs associated with process integration, plant localisation, feedstock availability and supply were found to varying extents. • Options to replace natural gas with biomass-based gases in iron and steel industry. • Integrated gas production at the steel plant has the lowest overall costs. • Supply of gas becomes cost-competitive with biomass supply at longer distances. • Trade-offs across key factors are observed to varying extents. [ABSTRACT FROM AUTHOR]

Due to increasing concern of the Indonesian government towards the ever increasing national level of carbon emissions and the increasing demand of oil, in 2014 the Indonesian National Energy Council released the National Energy Policy which set the target of an increased renewable energy portion to become 23% of the total national energy consumption while setting a limit to oil consumption to be at most 25%. As the road transportation sector consumes more than 60% of the national oil consumption, measures targeting this sector will be important in fulfilling the target. A model has been set up to evaluate the impact of the measures on oil consumption via two main avenues: the substitution of oil based fuels with alternative fuels (e.g. biofuel, compressed natural gas/CNG), the reduction of oil consumption via vehicle retirement and the acceleration of fuel economy improvement for vehicles. Results have shown that it is important that policies consider the presence of older vehicles in the population since there is presently no vehicle retirement policy or penalty for older vehicles resulting in a large number of old vehicles still being operational. Thus, introduction of new vehicles will have a limited effect on the average fuel efficiency. Implementation of a vehicle retirement policy to reduce the amount of older vehicles is shown to be very effective in stemming the increase of oil consumption. In regards to fuel substitution, oil substitution with ethanol is most impactful, as most motor vehicles in Indonesia rely on gasoline including the rapidly increasing motorcycle population. While oil consumption is also reduced by biodiesel substitution, impact is more limited due to a smaller diesel vehicle population with a lower annual increase of vehicle population. In addition, financial, social and regulatory barriers exist that impend implementation of alternative fuels and vehicle limitation schemes. We also evaluated possible barriers and avenues that can further promote these measures to meet the national energy policy target. • The impact of fuel substitution of Indonesian road transportation energy was simulated. • The avenues in order to meet the national energy policy target were evaluated. • Fuel substitution with ethanol is the most impactful for the Indonesian transportation energy sector. • Oil consumption can be also reduced by biodiesel substitution. • Regulatory barriers exist in the implementation of alternative fuels and vehicle limitation schemes. [ABSTRACT FROM AUTHOR]

Aim: An emerging framework for tropical ecosystems states that fire activity is either "fuel build‐up limited" or "fuel moisture limited", that is, as you move up along rainfall gradients, the major control on fire occurrence switches from being the amount of fuel, to the moisture content of the fuel. Here we used remotely sensed datasets to assess whether interannual variability of burned area is better explained by annual rainfall totals driving fuel build‐up, or by dry season rainfall driving fuel moisture. Location: Pantropical savannas and grasslands. Time period: 2002–2016. Methods: We explored the response of annual burned area to interannual variability in rainfall. We compared several linear models to understand how fuel moisture and fuel build‐up effect (accumulated rainfall during 6 and 24 months prior to the end of the burning season, respectively) determine the interannual variability of burned area and explore if tree cover, dry season duration and human activity modified these relationships. Results: Fuel and moisture controls on fire occurrence in tropical savannas varied across continents. Only 24% of South American savannas were fuel build‐up limited against 61% of Australian savannas and 47% of African savannas. On average, South America switched from fuel limited to moisture limited at 500 mm/year, Africa at 800 mm/year and Australia at 1,000 mm/year of mean annual rainfall. Main conclusions: In 42% of tropical savannas (accounting for 41% of current area burned) increased drought and higher temperatures will not increase fire, but there are savannas, particularly in South America, that are likely to become more flammable with increasing temperatures. These findings highlight that we cannot transfer knowledge of fire responses to global change across ecosystems/regions—local solutions to local fire management issues are required, and different tropical savanna regions may show contrasting responses to the same drivers of global change. [ABSTRACT FROM AUTHOR]

Since the electric grid does not store electrical energy, the demand for electric power must be matched by the production almost instantaneously. The supply-demand balance imposes a severe constraint on the penetration of renewable energy sources – especially wind and solar – in the power production markets of all nations, because solar irradiance and wind energy are not available at all hours of the day and exhibit daily and seasonal variabilities. Using the hourly data of the electric power demand in the Electric Reliability Council of Texas, we calculate the implications of this constraint on the substitution of fossil fuel power plants with renewable energy sources. When the market penetration of renewables increases and the utilization of solar and wind energy sources expands to approximately 25%–30% of the annual electricity production, significant energy storage capacity is needed. Simulations of the entire electric grid are performed to determine the power ratings of the renewable sources and the necessary storage capacity to substitute part or all of the fossil fuel power capacity in Texas with renewable energy sources. • The production of electricity from renewables does not match the demand. • At renewable penetrations greater than 25–30% energy storage is necessary. • Energy storage becomes a limitation to the further development of renewables. • Less storage is needed for the substitution of coal with wind and solar energy. • Significant storage is required for the substitution of all fossil fuel plants. [ABSTRACT FROM AUTHOR]

Straw is an important livestock bedding material facing increasing demand for alternative uses in Europe and is often transported long distances from arable to livestock regions. Alternative bedding materials cultivated directly on livestock farms could potentially avoid this transport and competition for use. For the first time, we applied consequential life cycle assessment (LCA) to account for the direct and indirect implications of miscanthus bedding production on livestock farms, considering displacement of fodder or livestock, and substitution of fossil fuels with straw in electricity generation. We modelled the effect of substituting straw with 'home‐grown' miscanthus bedding across seven beef and sheep farms. The consequences of displacing grass forage (or animal) production with home‐grown miscanthus bedding cultivation were evaluated via three farmer decision scenarios: buy extra concentrate feed (D1), utilize remaining pasture areas more efficiently (D2) and buy grass silage (D3). Electricity generated from displaced straw (bedding) substituted either natural gas or coal electricity. Sensitivity analyses were undertaken using 34 scenario permutations to represent combinations of feed and electricity substitution, miscanthus fertilization rates and yields, and the quality of displaced pasture. Consequential LCA indicates that miscanthus bedding production could be environmentally beneficial, under scenarios involving D2 and D3. However, greenhouse gas emissions and wider environmental burdens may be increased under D1 scenarios, owing to the environmental cost of additional concentrate feed production, and possible indirect land use change, outweighing the benefits from: (a) fossil electricity substitution with straw bioelectricity; (b) reduced animal emissions via improved digestibility of concentrate feed; (c) avoided straw transport. The ratio of the yield of miscanthus to replaced grass was found to be a critical determinant of D1 environmental outcomes. We conclude that if grass forage production can be better managed, the use of miscanthus as a bedding material on livestock farms provides environmental benefits via diversion of straw to bioenergy use. [ABSTRACT FROM AUTHOR]

• The impact of automated vehicles on the broader US energy system is modeled. • Dynamic interaction of transportation with fuel cost and supply is modeled. • High travel demand may increase share of alternative fuels. • Efficiency improvements could lead to increased health-impacting emissions. Vehicle automation has the potential to drastically transform transportation, with important implications for energy and the environment. There is considerable uncertainty regarding the impact of automation on travel demand and vehicle efficiency. We utilize the MARKet ALlocation (MARKAL) energy system model to examine four previously published scenarios that consider different effects of automation on efficiency and demand. We do not replicate detailed estimation of individual mechanisms but apply key outcomes from prior studies within a broader energy system framework. Our analysis adds insights on fuel switching, upstream impacts, and air emissions. MARKAL dynamically captures interactions between transportation and non-transportation sectors, which is important given that the revolutionary shifts from automation may invalidate static assumptions. Model results suggest that increasing travel demands from automation may boost fuel use and petroleum-based fuel prices, potentially increasing the market penetration of alternative-fuel vehicles. In contrast, dramatic efficiency improvements from automation could drive fuel prices lower, greatly reducing the competitiveness of alternative-fueled vehicles. Furthermore, these shifts could yield positive or negative environmental impacts. Some automation scenarios even resulted in counterintuitive results. For example, if high levels of efficiency improvement drive out alternative-fuel vehicles, such as battery electric and hybrids, a net worsening of air quality relative to the other scenarios could result. We also found system-level dynamics to be key. For example, reductions in liquid fuel prices led to increased consumption, and the resulting increase in air pollutant emissions offset a portion of the potential air quality benefits of automation. [ABSTRACT FROM AUTHOR]

The environmental impacts and high long-term costs of poor waste disposal have pushed the industry to realize the potential of turning this problem into an economic and sustainable initiative. Anaerobic digestion and the production of biogas can provide an efficient means of meeting several objectives concerning energy, environmental, and waste management policy. Biogas contains methane (60%) and carbon dioxide (40%) as its principal constituent. Excluding methane, other gasses contained in biogas are considered as contaminants. Removal of these impurities, especially carbon dioxide, will increase the biogas quality for further use. Integrating biological processes into the bio-refinery that effectively consume carbon dioxide will become increasingly important. Such process integration could significantly improve the sustainability of the overall bio-refinery process. The biogas upgrading by utilization of carbon dioxide rather than removal of it is a suitable strategy in this direction. The present work is a critical review that summarizes state-of-the-art technologies for biogas upgrading with particular attention to the emerging biological methanation processes. It also discusses the future perspectives for overcoming the challenges associated with upgradation. While biogas offers a good substitution for fossil fuels, it still not a perfect solution for global greenhouse gas emissions and further research still needs to be conducted. [ABSTRACT FROM AUTHOR]

Industrial furnace is one of the most energy intensive processes in Europe and it has been the focus of multiple researches to address improvements in the competitiveness energy, environmental and cost performance. One of the alternatives is the reduction of fossil fuel consumption, such as natural gas, promoting its substitution by an alternative fuel (Co-firing). This paper gathers a wide evaluation of the possibilities of substitution of natural gas. A revision of the types of syngas with potential for use has been carried out, as well as the evaluation of the physical properties of the mixtures from the combustion operation point of view. Three types of syngas from biomass gasification (BSG) and three from process off-gases (POG) have been considered. The feasibility study has taken into consideration parameters such as the lower heating value, the Woobe index, adiabatic flame temperature, air preheating temperature, total flue flow and laminar flame velocity. Regardless of the type of syngas, significant increase in volumetric fuel flow occurs in all cases. This behaviour is directly related to the LHV of the syngas, so that using syngases with lower LHV than the NG will always produce an increase of the fuel flow. A weigh matrix has been obtained in order to evaluate the viability of burners use with the syngas/natural gas mixture. It has been considered a burner commonly used in ceramic sector and it has been concluded that relevant modifications are necessary in order to consider the combustion of syngas/natural gas. The modifications have been evaluated using CFD simulations to stablish the proper design of the mix zone to ensure the mixture between the air, syngas and natural gas. This evaluation has been carried out following the fuel to air ratio. • Woobe Index is the best theoretical parameter to evaluate fuel replacement. • AFT, LHV and LFV should be also taken into account in the evaluation. • Deep burner modifications should be carried out for NG substitution by syngas. • Fuel to air ratio is a proper parameter to evaluate combustion performance. • Swirl plate is required to achieve a suitable mixture between NG-SG-combustible. [ABSTRACT FROM AUTHOR]

With the increasing need to reduce greenhouse gas emission and adopt sustainability in combustion systems, injection of renewable gases into the pipeline natural gas is of great interest. Due to high specific energy density and various potential sources, hydrogen is a competitive energy carrier and a promising gaseous fuel to replace natural gas in the future. To test the end use impact of hydrogen injection into the natural gas pipeline infrastructure, the present study has been carried out to evaluate the fuel interchangeability between hydrogen and natural gas in a residential commercial oven burner. Various combustion performance characteristics were evaluated, including flashback limits, ignition performance, flame characteristics, combustion noise, burner temperature and emissions (NO, NO 2 , N 2 O, CO, UHC, NH 3). Primary air entrainment process was also investigated. Several correlations for predicting air entrainment were compared and evaluated for accuracy based on the measured fuel/air concentration results in the burner. The results indicate that 25% (by volume) hydrogen can be added to natural gas without significant impacts. Above this amount, flashback in the burner tube is the limiting factor. Hydrogen addition has minimal impact on NO X emission while expectedly decreasing CO emissions. As the amount of hydrogen increases in the fuel, the ability of the fuel to entrain primary air decreases. Image 1 • Flashback at ignition limits the amount of hydrogen that can be added to natural gas to ~25% by volume. • Hydrogen addition doesn't impact oven burner NO X emissions, but, decreases CO, as expected. • The cyclic operation of the oven leads to complex emissions behavior as a function of time. • Primary air entrainment of the mixtures is successfully predicted using Jones's correlation. [ABSTRACT FROM AUTHOR]

Forest residue biomass can be used as bioenergy feedstock, however, issues associated with its properties including low density and high moisture content constrains its valorization. Using mobile conversion technologies that can operate in remote areas and are capable of converting forest residues into high quality energy products can address the issues associated with its valorization for renewable energy production. This study evaluated environmental sustainability of using an integrated novel system of semi-mobile biomass conversion technologies (BCTs) to utilize low-value forest residue biomass as high value bioenergy products. A cradle-to-grave life cycle assessment (LCA) and resource use assessment on a unit-process level was conducted for two bio-products: nontorrefied briquettes (NTB) and torrefied briquettes (TOB). Their use for production of useful thermal energy in wood stoves for domestic heating and electricity at power plants were investigated along with their alternatives. The analyses were performed with SimaPro 8.5 using the DATASMART database. The impact assessment results showed a notable decrease in global warming (GW) impact when substituting fossil fuels with these two bio-products. Specifically, for domestic heating on an equivalent energy basis, a 50% substitution of propane with NTB and TOB showed GHG emission reductions of 46% and 41%, respectively. For electricity generation, 10% cofiring at coal power plant with NTB and TOB showed GHG emission reductions of 6% and 8%, respectively. For the TOB supply chain, a large portion of the GW impact of the came from the torrefaction process and followed by the drying process. This was due to the propane use in these processes. Comparative analysis showed that near-woods biomass conversion for TOB production instead of processing feedstock at an in-town facility with access to grid electricity found 48%–55% lower GW impact for both electricity and heat generation scenarios, respectively. Resourced footprint analysis showed that most exergy extraction from the natural environment came from the drying process for NTB supply chain. In the TOB product system, torrefaction was the major contributor. • Near-woods woody biomass briquette processing improved environmental performance. • Drying process affected GHG emissions substantially during briquette production. • Fossil fuel substitutions with briquettes decreased GHG emissions. • Burning briquettes for heating decreased the overall resource footprint. • Propane use for drying feedstock had the greatest sensitivity for GHG emissions. [ABSTRACT FROM AUTHOR]

Finding renewable alternative energy resources for fossil fuels substitution has become very vital due to the serious challenges faced by humankind at present such as environmental pollution, greenhouse gas emissions, climate change, crude oil price volatility, and fossil fuels exhaustion. Macroalgae (seaweeds) are fast-growing marine plants, providing several harvests per year without the need for arable land, fertilizer, and fresh water. Various types of ecosystems like coral reefs, mangrove forests, and rocky shores can efficiently host the seaweeds production systems. These characteristics have made them highly suitable feedstocks for third-generation bioethanol production. Iran has a huge potential in renewable energy resources owing to its unique geographical location and climatic features. The country borders with the Caspian Sea in the north and with the Persian Gulf and the Gulf of Oman in the south. Seaweeds farming can also play a key role in mitigating air pollution, increasing employment rate, sustaining fossil fuel resources, bioremediating contaminated water, and improving marine ecosystem in the Persian Gulf and the Gulf of Oman. In the present article, macroalgae diversity, cultivation, and their conversion and upgrading technologies into bioethanol in Iran are scrutinized and discussed. Finally, the potential of Bushehr (the Persian Gulf) and Chabahar (the Gulf of Oman) coastlines for macroalgae cultivation is investigated. These locations receive the annual solar radiation in the range of 1680‒1753 kWh/m2 and the photosynthetically active radiation (PAR) in the range of 2.6‒2.71 GJ/m2/year with 3051‒3311.9 h sunshine per annum. Furthermore, the nutrient-rich and calm water with relatively stable pH, salinity, and temperature make these coasts suitable for macroalgae farming. A potential yield up to 147‒153 t/ha/year can be obtained if proper native/engineered species, well-situated sites, and compatible cultivation techniques are selected. • Seaweeds can be cultivated, pretreated, saccharified, and fermented into bioethanol. • Southern coastlines of Iran provide favorable conditions for macroalgae cultivation. • Iran coastlines have 379 macroalgae species, of these 81 are brown macroalgae. • Padina (10 species) and Sargassum (25. species) have high carbohydrate content. • Macroalgae cultivation provides various socio-economic advantages for Iran. [ABSTRACT FROM AUTHOR]

• Future decarbonisation of the UK Iron and Steel sector have been evaluated. • The improvement potential of different technological interventions were assessed. • 2050 'technology roadmaps' were also developed for various alternative scenarios. • Best practice technologies will prompt short-term energy and CO 2 emissions savings. • Radical process technology innovations are likely to be available in the longer term. The opportunities and challenges to reducing industrial energy demand and carbon dioxide (CO 2) emissions in the iron & steel sector are evaluated with a focus is on the situation in the United Kingdom of Great Britain and Northern Ireland (UK), although the lessons learned are applicable across much of the industrialised world. It is the largest industrial sector in the UK in terms of energy demand and ' greenhouse gas ' (GHG) emissions, and accounts for some 26% of GHG emissions from British industry. Current Best Available Technologies (BAT) will lead to short-term energy and CO 2 emissions savings in iron & steel processing, but the prospects for the commercial exploitation of innovative technologies by mid-21st century are far more speculative. The attainment of significant falls in carbon emissions over the period to 2050 will depend critically on the adoption of a small number of key technologies [e.g., energy efficiency techniques, fuel switching towards bioenergy, and carbon capture and storage (CCS)], alongside the decarbonisation of national electricity supply. The blast furnace is the most efficient energy conversion process in the sector, but also the largest energy user and consequently a priority target for energy demand reduction. Many existing technologies could reduce a significant proportion of process energy loss, e.g., heat recovery at the coke ovens, sinter plant, and electric arc furnace, and further heat and gas recovery from the basic oxygen furnace. The uptake of key BAT technologies for hot-rolling could reduce sector primary energy by 18% and GHG emissions by 12%. Further potential may be available for blast furnace operation by optimising chemical transfer to minimise blast furnace gas (BFG) production. Nevertheless, there are a number of non-technological barriers to the take-up of such technologies going forward. Other radical process technological innovations (such as the 'electrowinning' or so-called HISARNA process) are likely to be available in the longer term. [ABSTRACT FROM AUTHOR]

• Highlights factors that affect life cycle GHG emissions of light-duty vehicles. • Provides a typology of these factors. • Performs an in-depth review of 14 popular integrated energy models. • Highlights the importance of considering certain factors for policy analysis. • Identifies potential modeling improvements regarding the representation of vehicles. Light-duty vehicles (LDVs) are responsible for more than one tenth of global energy use and CO 2 emissions and are therefore an important focus in pollution mitigation efforts. Integrated energy models (IEMs) are frequently used to explore cost-optimal climate change mitigation measures for energy supply and demand sectors, such as LDVs. Options include fuel and powertrain switching through efficiency standards, taxation, and technology mandates. This review provides an overview on how LDVs are modeled in 14 popular IEMs. We find that the representation of mitigation options can be enhanced by linking emissions and physical outputs from industry, agriculture, and energy conversion directly to the vehicle life cycle and by more carefully reflecting important factors that influence LDV life cycle emissions. This would allow for a more complete internalization of emissions in the technology mix optimization procedure of IEMs. The results highlight a range of mitigation options currently not considered in most integrated models, such as reducing embodied emissions in infrastructure and vehicle production, reducing methane leakage, or switching to less carbon intensive crude oil grades. [ABSTRACT FROM AUTHOR]

The UK is facing tremendous challenges in tackling food waste diversion from landfill. Whilst much effort has been made to prevent food waste, there is still a lack of attention and strategic approach in dealing with resource recovery and valorisation of food waste. This paper presents a systematic framework for sustainable organic waste management and valorisation in the UK through (i) review of current policy framework; (ii) analysis of resource recovery potential from food waste at national, community and organisational levels; (iii) proposition of alternative waste management strategies; and (iv) examination of challenges and opportunities with respect to economic, environment and social dimensions of sustainability of waste management strategies. The paper explores valorisation of source-segregated food waste and mixed waste from the supermarket and households into electricity and transportation fuels, through partially and completely decentralised configurations using anaerobic digestion and gasification technologies. This study demonstrates a potential for reducing the cost of electricity and greenhouse gas emissions of one supermarket store by 12% when adopting partially decentralised food waste anaerobic digestion strategy, and full substitution of fossil fuel based electricity with net surplus renewable electricity generation through complete decentralisation of mixed waste gasification. Therefore, a more integrated, circular and advanced technological approach in waste management should be undertaken as it can lead to a wider range of socio-economic and environmental advantages to the local community, highly essential in the UK. Image 1 • Valorisation of waste closer to the source promotes resource circularity. • A synergistic approach is robust in addressing challenges in waste management. • Technology and configuration determine the viability of valorisation strategies. • Decentralised waste management enhances community participation. • A supportive fiscal incentive scheme promotes uptake of waste valorisation. [ABSTRACT FROM AUTHOR]

Tanneries boost the local economic development, but lead to severe environmental pollution; hence, improving the environmental assessment of this sector is essential. In this paper, the Life Cycle Assessment method was applied to estimate impacts on the environment and human health of retanning, fatliquoring and dyeing. The analysis was performed from a "gate to gate" perspective. Moreover, sulpho chlorinated paraffin and epoxidized vegetable oil have been evaluated as alternative fatliquoring agents. The production of electricity required for the rotation of drums gives the main contribute to most of the impact categories, followed by the azo-dye production. Emissions of sulfur dioxide, nitrogen oxides, manganese, vanadium and nickel associated to power plants are the main sources of terrestrial acidification and particulate matter formation, as well as of human and marine toxicity (4.48·10−1 and 1.09·10−2 kg of 1,4-DBeq kg−1 crust leather, respectively). Nitrate loads from wastewater treatment and oxidative treatments affect heavily marine eutrophication (6.9·10−1 g N eq kg−1 crust leather). The use of epoxidized vegetable oil would affect human toxicity, ecosystem, metal and water resources depletion more than the use of sulpho chlorinated paraffin, mainly due to pesticides distribution and other cultivation practices. Phosphate and nitrate releases due to fertilization determine the high impact on the categories freshwater and marine eutrophication. Progress in increasing the conversion efficiency is demanded, but overall focus must be made on the substitution of fossil fuels with cleaner alternatives. The transition towards a circular economy is encouraged; increasing rates of reduction, reuse, recycle and recover of solid waste and tannery effluents are recommended. Agricultural practices with a reduced consumption of phytosanitary products and mineral fertilizers, alternative to conventional farming, would strongly contribute to increase the sustainability of epoxidized vegetable oil as alternative fatliquoring agent. Image 1 • Tanneries boost local economy but lead to severe environmental pollution. • Electricity production affects heavily human toxicity, environment and resources. • Energy conversion efficiency and replacement of fossil fuels have to be increased. • Reuse, recycle and recover of solid waste and tannery effluents are recommended. • Impact of vegetable fatliquoring agents is mainly due to pesticides and fertilizers. [ABSTRACT FROM AUTHOR]

The effect of natural gas compositions on the thermodynamic performance characteristics of the single-shaft gas turbine cycle is analyzed in this study. The fuel characteristics are signified by H/C ratio and heating value, then the system are analyzed, and the full off-design analysis is performed by using TIT, TET, and power control. As the heating value of natural gas decreases, power output increases due to the increased mass flow passing through the turbine for all control methods. Additionally, regardless of the control method, the compressor surge margin is reduced and the turbine blade temperature is raised, making the gas turbine operation extremely vulnerable. Most parameters are sensitively affected by the HC ratio of fuel with TIT control. When the power control is used, gas turbine efficiency is reduced due to the increased operation of the compressor. The results are expressed by polynomial equations relative to each design value. In terms of the performance curves of the gas turbine cycle, the trends of most parameters accord with high H/C ratio and low heating value. [ABSTRACT FROM AUTHOR]

[Display omitted] • Untapped carbon-free residual energy amounts to 70% of Ontario's heating demand. • Harvesting variable resources requires real time fuel switching and thermal storage. • MTN temperature modulation presents an approach to balancing the electrical grid. • ICE-Harvest systems can offset 72% of the heating demand with up to 58% GHG savings. In this article, the Integrated Community Energy and Harvesting System is introduced, a grid modernization solution for cold climates that incites a paradigm shift in virtual power plant design and operation. The focus is on system-wide GHG reductions by using variable temperature micro-thermal networks and prioritizing the harvesting of existing residual (waste) energy resources in communities, such as high-grade heat from decentralized fossil-fuel marginal generators, low-grade heat from cooling processes and curtailed carbon-free electricity. The novel strategy enables rapid fuel switching between residual energy resources, changing the micro-thermal network temperature between 20 and 70 °C on the scale of an hour, which provides valuable electrical demand response while maximizing the use of existing underutilized energy resources. Thermal storage is shown to have a critical role in both storing residual energy for later use, daily and seasonally, and enabling electrical demand response by rapidly changing the micro-thermal network temperature. The quantity of residual energy sources identified highlights that, as much as, 50% of all building heating loads could be met by energy currently rejected to the atmosphere. To illustrate the ICE-Harvest system's effectiveness, a detailed case study is conducted on a typical integrated community and then applied to 1,000 prospective sites across a cold climate jurisdiction with a relatively low-carbon grid. It is shown that cooling process heat recovery, an energy source which is already located at buildings, can provide 24% of the prospective sites' heating load when powered by carbon free, otherwise curtailed electricity. The results demonstrate that mass deployment of ICE-Harvest systems has the potential to provide 72% of the heating demand of these building clusters from residual energy sources, corresponding to an over 58% reduction in GHG emissions. [ABSTRACT FROM AUTHOR]

Air to water electric heat pumps are one technological solution to achieve energy defossilisation goals for heating of residential building stock. Nevertheless, they may not necessarily be the only solution for all residential building stock. A case in point is where extensive fabric refurbishment is impracticable or where electric heat pumps are installed where low ambient temperatures prevail and/or high water delivery temperatures must be utilised. For such instances, hybrid (gas and electric) heat pumps offer an alternative option by facilitating fuel source switching between electricity and gas, when ambient temperatures are low or high water supply temperatures are required. In the current study, the effectiveness of an air-to-water electric heat pump and hybrid heat pump are examined for different building retrofit scenarios for a residential dwelling located in Ireland. This is achieved by means of a sensitivity study of a validated building simulation model, incorporating both heat pump systems, subject to different building retrofit scenarios. Relative to a conventional oil-fired boiler, for a deep building retrofit scenario, the hybrid and electric heat pumps achieve primary energy reduction of 128 kWh/ m 2 /year (72%) and of 123 kWh/ m 2 /year (70%), respectively. Considering the associated carbon footprints, the reductions were found to be 29.7 g C O 2 e / m 2 /year (74%) for the hybrid heat pump, and 27.6 g C O 2 e / m 2 /year (68%) for the electric heat pump. Finally, the deployment of either an electric heat pump or hybrid heat pump for deep building fabric retrofit achieves approximately half of the heating system capital cost return within 20 years. • Analysis of a hybrid gas-electric heat pump system in a residential building. • Benchmarked against, oil boiler, gas boiler and electric heat pump. • Integrated validated simulation model utilised for retrofit options analysis. • Electric and hybrid heat pumps with deep retrofit are the most economically attractive options. • Electric heat pump and hybrid heat pump systems with deep retrofit exhibit the lowest C O 2 emissions. [ABSTRACT FROM AUTHOR]

In view of the current geopolitical situation, the EU and its Member States are accelerating efforts to reduce their dependency on fossil fuel imports, while simultaneously tackling the climate crisis. With heating in buildings accounting for a large share of the energy consumption in the EU, policies to phase-out fossil fuels for heating and to switch to renewables are key elements. In the context of the proposed actions to phase-out fossil fuels at EU level, this article provides a systematic analysis of current and planned phase-out regulations for fossil fuel boilers in the EU Member States. The paper quantifies the share of energy consumption for heating that is addressed by such regulations and finds that the current regulations only address about 10% of the total fossil energy consumption for heating in the EU. The share increases to almost 30% when considering the planned regulations, reflecting the fact that large energy consumers such as Germany and the Netherlands have announced such regulations. The analysis shows that several Member States with high energy consumption for heating have neither implemented nor announced plans to introduce phase-out regulations for fossil fuel heating. The study concludes that immediate policy action is needed both at EU and at Member State levels. At EU level, the proposed introduction of an end-date for stand-alone fossil fuel boilers needs to be substantiated and implemented into the legislative framework. At the national level, phase-out regulations for fossil fuel boilers need to be expanded both in quantity and scope. [Display omitted] • Systematic analysis of phase-out regulations for fossil fuel boilers in the EU. • Only 10% of the EU fossil energy used for heating is covered by phase-out regulations. • Including planned regulations, the share of heating energy covered by phase-out regulations increases to almost 30%. • Comparison of different approaches for implementing regulations for phasing out fossil fuel boilers. [ABSTRACT FROM AUTHOR]

We perform spatially resolved measurements of light scattering of soot in atmospheric pressure counterflow diffusion flames to complement previously reported data on soot pyrometry, temperature and gaseous species up to three-ring polycyclic aromatic hydrocarbons (PAHs). We compare two flames: a baseline ethylene flame and a toluene-seeded flame in which an aliquot of ethylene in the feed stream is replaced with 3500 ppm of pre-vaporized toluene. The goal is twofold: directly adding an aromatic fuel to bypass the formation of the first aromatic ring, widely regarded as the main bottleneck to soot formation from aliphatic fuels, and assessing the impact of a common component of surrogates of transportation fuels on soot formation. The composition of the fuel and oxidizer streams are adjusted to ensure invariance of the temperature-time history, thereby decoupling the chemical effects of the fuel substitution from other factors. The doping approach enables the comparison of very similar flames with respect to combustion products, radicals and critical precursors to aromatic formation (C2–C5 species), in addition to the temperature-time history. Doping with toluene boosts the aromatic content and soot volume fraction relative to the baseline ethylene flame, but, surprisingly, the soot number density and nucleation rate are affected modestly. As a result, the observed difference in volume fraction in the toluene-doped flame is reflective of larger initial particles at the onset of soot nucleation. The nucleation rate when soot first appears near the flame is of the same order as the dimerization rate of single-ring aromatics, in contrast with the expectation that the dimerization of larger PAHs initiates the process. Even though in and of itself nucleation contributes modestly to the overall soot loading, nucleation conditions the overall soot loading by affecting the size of the initial particle, which ultimately affects subsequent growth. [ABSTRACT FROM AUTHOR]

• Water hyacinth biodiesel is used as injected fuel for hydrogen run a dual fuel diesel engine. • Maximum liquid fuel substitution of 85% is obtained at 240 bar and 100% load. • Maximum brake thermal efficiency of 28.11 % is obtained at 240 bar and 100% load. • Parametric optimization revealed the operating setting as 83.61% engine load and 242 bar FIP. • Desirability-based optimized results were 26.5% BTE, 80.47% LFR, and 191.19 ppm NO x. Hydrogen is one of the most promising green fuels. The present study explores the potential of novel water hyacinth biodiesel as pilot fuel as well as investigates the influence of the injection pressure of pilot fuel on the performance of hydrogen running a dual-fuel diesel engine. For experimentation, a 4.8 kW research test engine was considered. Three fuel injection pressure (FIP) of the pilot fuel, namely 220 bar, 240 bar, and 260 bar were considered at a ratio of compression as 17.5 and standard injection timing of 23° before Top Dead Centre (bTDC) for different loading conditions were considered. The peak brake thermal efficiency (BTE) under dual fuel mode (DFM) was observed as 26.77%, 28.11%, and 27.21% for FIP of the pilot fuel of 220 bar, 240 bar, and 260 bar, respectively in comparison to 25.11% for biodiesel mode at 100% load. The maximum drop in carbon monoxide (CO) and hydrocarbon (HC) emissions was found to be 15.48%, and 35.7%, respectively for the FIP of the pilot fuel of 240 bar under DFM in comparison to biodiesel mode. The fall in Oxides of Nitrogen (NO X) emission under DFM was found to be 23.66% for the FIP of the pilot fuel of 220 bar under DFM compared to biodiesel mode. Based on the performance and emission analysis, the optimum FIP of the pilot fuel is found to be 240 bar. For the same FIP, the maximum liquid fuel replacement of 85% was obtained. The experimental study's data were evaluated using analysis of variance (ANOVA) to create models in the form of mathematical expressions for each outcome. The desirability approach was employed to optimize the operating settings for maximum performance while emitting the least amount of emission. According to the desirability-based optimization research, ideal operating conditions were 83.61% engine load and 242 bar FIP, resulting in engine performance of 26.5% of BTE, 80.47% of LFR, and 51.82 bar peak cylinder pressure. The emission levels were 191.19 ppm of NO X , 106.41 ppm of HC, and 130.95 ppm of CO at this setting. A model validation test found that the model-predicted values were within 6% of the observed values. [ABSTRACT FROM AUTHOR]

The necessity for advancement in the field of energy storage devices is inevitable due to the forthcoming exhaustion in the availability of primitive hydrocarbon deposits. Benign and ecological renewable sources can opt as the perfect substitution for fossil fuels as a remedy for sustainability, which can be stored to meet the overflowing energy demand. Even a single spark in the development of energy storage devices can be viewed as an explosion in the execution of future energy concerns. This review is a token of recent progress in the arena of two-dimensional material-based supercapacitors for energy storage applications, manuscript starts with the need for energy storage devices in the anticipation of upcoming energy catastrophe. A brief introduction to the capacitors along with their classification under various parameters and their peaks and valleys in storing energy are included in the review. The chief attention of the appraisal stands on the capacitors employing the pseudo mechanism but those based on electrochemical double layer and faradaic mechanism are also included along with performance evaluation. The role of various 2D materials including graphene, molybdenum-based TMDs, tungsten-based TMDs, MXene, two-dimensional metal-oxides and phosphides in enhancing the charge storage performance are scrutinized in the review. • Investigated the underlaying concepts of supercapacitors supported by pictorial illustrations. • The impact of graphene-based compounds, TMDCs, and MXene on the performance of supercapacitors are scrutinized. • Dissected the upshot of two-dimensional metal-oxides and metal-phosphides on the augmentation of SPR activity. • An integrated overview of various two-dimensional materials in altering the electrochemical behaviour is presented. • Analyzed challenges on commercialisation of supercapacitors and the latitudes of future investigation. [ABSTRACT FROM AUTHOR]

To reduce vessel emissions, various green technologies have been proposed, such as switching fuel oil, using scrubbers, and implementing shore side electricity (SSE). Based on the management and operation conditions of ports and shipping companies, three impact factors are extracted: (1) the different availability of green technologies on shore and on board, (2) the time-of-use electricity tariff, and (3) the incentives. Considering them raises a problem of how to best leverage green technologies in reducing emissions while meeting the economic needs of ports and shipping companies. To address the problem, this paper first proposes a mixed-integer programming model to optimize the berth allocation and quay crane assignment, the sailing speed of vessels and the usage time of each green technology to minimize the penalty cost to the port and the vessel cost to the shipping companies. Then, a decomposition for the proposed model is conducted by the frame of the Partial Optimization Metaheuristic Under Special Intensification Conditions (POPMUSIC), and the Nested Non-dominated Sorting Genetic Algorithm II (N-NSGA-II) is applied to solve each decomposed sub-model. Numerical experiments are performed to demonstrate the applicability and effectiveness of the proposed model and solution approach. Different Pareto solutions are provided, based on which trade-offs between different objectives are dissected and managerial suggestions are outlined. • Proposes a novel optimization model for berth allocation and quay crane assignment. • Considers the adoption of different green technologies. • Develops integrative algorithms to tackle well-defined problem instances. • Finds optimal solutions for quayside operations and provides managerial insights. [ABSTRACT FROM AUTHOR]

The main goal of this paper is to present a vision for the future of aviation. Developing such a vision is always a complex matter, but in times of environmental emergencies and unjustifiable wars it becomes even more difficult. One of the main reasons of this paper is to show that there is still room for advancing clean technology developments and to demonstrate that the aviation sector is ready for embarking on new challenge. Green and environmentally sustainable aviation, in our opinion, can be achieved with continuous improvements along multiple parallel paths, ramp up of SAF (Sustainable Aviation Fuel) production, and of course, breakthrough technologies. The latter will require a significant amount of research, testing and probably mistakes need to be made before reaching the level of transportation efficiency and mission safety obtained with traditional propulsion, but these drawbacks should only encourage scientists, engineers, politicians and visionaries to strongly pursue the objectives of a new eco-aviation. Aviation decarbonization requires a strategy change from near term improvements in aircraft fuel efficiency to long term (from neutral to zero carbon emissions) fuel switching. The successful introduction of long-term solutions requires transdisciplinary research into technological, operational and economy fields. New technologies should probably be introduced into smaller aircraft segments first then migrate into the larger segments as the technologies mature. We should expect a first electric and hydrogen fuel cell commuter aircraft entry into service by the end of this decade, with hydrogen combustion-powered narrow bodies around 2040. In 2019, aviation accounted for approximately 2.3% of global greenhouse gas emissions, with global commercial fleet CO 2 emissions totaling 0.918 Gigatonnes. Narrowbody and widebody aircraft produce over 95% of the industry's greenhouse gas emissions, therefore, while the introduction of new technologies on smaller aircraft will be important for the development of sustainable solutions, they will have minimal impact on the overall carbon footprint until they make their way onto larger platforms. However, carbon-free fueled (electric, hydrogen) aircraft will require significant infrastructure investments to develop the novel transportation network and the re-fueling procedures that will be required to support their use. Therefore, their success will require the coordinated combined efforts of the entire industry (airlines, airports, air navigation service providers, manufacturers) and significant government support. This paper tries to summarize the most important aspects for a vision on sustainable green aviation and to indicate a possible roadmap for reaching this goal. [ABSTRACT FROM AUTHOR]

Mode switching operations between fuel cell (FC) and water electrolysis (WE) modes are indispensable to unitized regenerative FCs. Complicated electrochemical reactions and product transformations occur in the cell during mode switching. Thus, identifying dynamic behaviors during this procedure can improve cell durability and system design. In this study, the dynamic behaviors of cell voltage and electrochemical reaction during the switch from the FC mode to the WE mode are experimentally investigated. Reactant switching time significantly affects the electrochemical reactions. The water pumped into the cell in the FC mode reduces the cell voltage to a negative value and results in a hydrogen evolution reaction at the oxygen electrode side. Before FC mode voltage rapid decrease caused by supplied water, current transition could efficiently avoided the hydrogen evolution reaction at oxygen side. Ensuring that the moment water reaches the channels is close to the moment of current transition can improve the stability of unitized regenerative FCs. • The dynamic response of voltage during mode switching is investigated. • Two-phase flow in oxygen side channels is observed during mode switching. • Hydrogen evolution reaction occurs at oxygen electrode side during mode switching. • Short time interval between reactant and current switching promotes stable operation. [ABSTRACT FROM AUTHOR]

It is well established that hibernating mammals rely predominantly on lipid stores to fuel metabolism throughout the hibernation season. However, it is unclear if other endogenous fuels contribute to the rapid, ~400-fold increase in metabolic rate during the early phase of arousal from torpor. To investigate this issue, we used cavity ring-down spectroscopy, a technique that provides a real-time indication of fuel use by measuring the ratio of 13 C to 12C in the exhaled CO2 of arousing 13-lined ground squirrels (Ictidomys tridecemlineatus). We used infrared thermography to simultaneously measure ventilation and surface temperature change in various body regions, and we interpreted these data in light of changing plasma metabolite abundances at multiple stages of arousal from torpor. We found that hibernating squirrels use a combination of lipids and, likely, carbohydrates to fuel the initial ~60 min of arousal before switching to predominantly lipid oxidation. This fuel switch coincided with times of maximal rates of ventilation and rewarming of different body surface regions, including brown adipose tissue. Infrared thermography revealed zonal rewarming, whereby the brown adipose tissue region was the first to warm, followed by the thoracic and head regions and, finally, the posterior half of the body. Consistent with the results from cavity ring-down spectroscopy, plasma metabolite dynamics during early arousal suggested a large reliance on fatty acids, with a contribution from carbohydrates and glycerol. Because of their high oxidative flux rates and efficient O2 use, carbohydrates might be an advantageous metabolic fuel during the early phase of arousal, when metabolic demands are high but ventilation rates and, thus, O2 supply are relatively low. [ABSTRACT FROM AUTHOR]

Abstract Introduction Diesel emissions have a high level of particulate matter which can cause inflammation and oxidative stress in the airways. A strategy to reduce diesel particulate matter and the associated adverse effects is the use of biodiesels and fuel additives. However, very little is known about the biological effects of these alternative emissions. The aim of this study is to compare the effect of biodiesel and triacetin/biodiesel emissions on primary human bronchial epithelial cells (pHBECs) compared to diesel emissions. Methods pHBECs were exposed to diesel, biodiesel (20%, 50% and 100% biodiesel derived from coconut oil) and triacetin/biodiesel (4% and 10% triacetin) emissions for 30 min at air-liquid interface. Cell viability (cellular metabolism, cell death, CASP3 mRNA expression and BCL2 mRNA expression), inflammation (IL-8 and IL-6 secretion), antioxidant production (HO-1 mRNA expression) and xenobiotic metabolism (CYP1a1 mRNA expression) were measured. Results Biodiesel emissions (B50) reduced cell viability, and increased oxidative stress. Triacetin/biodiesel emissions (B90) decreased cell viability and increased antioxidant production, inflammation and xenobiotic metabolism. Biodiesel emissions (B100) reduced cell viability, and increased IL-8 secretion and xenobiotic metabolism. Conclusions Biodiesel substitution in diesel fuel and triacetin substitution in biodiesel can increase the adverse effects of diesel emissions of pHBECs. Further studies of the effect of these diesel fuel alternatives on pHBECs are required. Highlights • Increasing biodiesel percentage is diesel fuel decreases particle mass and particle number in engine emissions. • Increasing triacetin percentage in biodiesel fuel increases particle number while decreasing particle mass in emissions. • The addition of biodiesel and/or triacetin to diesel may be more detrimental to pHBECs than conventional diesel emissions [ABSTRACT FROM AUTHOR]

Fuel icing of fuel/oil heat exchange systems has been a troublesome issue. In this study, a de-icing method is proposed to manage the fuel icing problem by switching the fuel flow direction of the systems. This method uses the fuel/oil heat exchanger as a passive heat source, heat and momentum of the fuel are delivered to the ice. A device named FFDSD (Fuel flow direction switching device) has been developed for this method. This device consists of two normally open and two closed type solenoid valves, and the proposed configuration consumes electrical power only when switching fuel flow directions (36 W to 0 W). A control algorithm has been developed as a countermeasure against a large amount of ice inflow that conventional methods cannot cope with. FFDSD was designed and fabricated, and the experimental test was conducted. The experimental results show that the proposed method can successfully achieve the de-icing of the fuel system within 1 s. A numerical de-icing process was attempted. Ice in fuel was numerically modeled as a fluidized quasi-solid material based on descriptions in previous studies. Numerical analysis results show a similar tendency to experimental results. The results of this study would be useful to manage fuel icing problem of heat exchange systems. [ABSTRACT FROM AUTHOR]

• China LEAP model used to assess multi-sector decarbonization strategies to 2050. • Energy, CO 2 impacts of accelerated electrification and renewables are assessed. • 2025 CO 2 peak feasible under 4 strategies, peak levels vary from 10.2 to 10.7 GtCO 2. • Faster electrification's CO 2 impact depend on pace of power sector decarbonization. • Demand-side renewable has similar CO 2 reduction impact as power decarbonization. Energy efficiency has played an important role in helping China achieve its domestic and international energy and climate change mitigation targets, but more significant near-term actions to decarbonize are needed to help China and the world meet the Paris Agreement goals. Accelerating electrification and maximizing supply-side and demand-side renewable adoption are two recent strategies being considered in China, but few bottom-up modeling studies have evaluated the potential near-term impacts of these strategies across multiple sectors. To fill this research gap, we use a bottom-up national end-use model that integrates energy supply and demand systems and conduct scenario analysis to evaluate even lower CO 2 emissions strategies and subsequent pathways for China to go beyond cost-effective efficiency and fuel switching. We find that maximizing non-conventional electric and renewable technologies can help China peak its national CO 2 emissions as early as 2025, with significant additional CO 2 emission reductions on the order of 7 Gt CO 2 annually by 2050. Beyond potential CO 2 reductions from power sector decarbonization, significant potential lies in fossil fuel displaced by renewable heat in industry. These results suggest accelerating the utilization of non-conventional electric and renewable technologies present additional CO 2 reduction opportunities for China, but new policies and strategies are needed to change technology choices in the demand sectors. Managing the pace of electrification in tandem with the pace of decarbonization of the power sector will also be crucial to achieving CO 2 reductions from the power sector in a scenario of increased electrification. [ABSTRACT FROM AUTHOR]

• Design of CO 2 -enriched greenhouses using captured CO 2 from a biogas to biomethane upgrading unit. • Economic and environmental assessment of the proposed CO 2 Utilization route. • Comparison with CO 2 geologically stored plant configurations. • CO 2 utilization route exhibits better economic performance than the CO 2 storage case. • Net greenhouse gas emission savings for the Utilization case are strongly dependent on system/boundary assumptions. Anaerobic digestion plants enable the production of power, heat and fuel. Biogas can be upgraded to biomethane fulfilling grid injection requirements by separating CH 4 from CO 2. By- product CO 2 could be geologically stored or utilized as a feedstock to produce valuable goods, enabling in both cases negative climate change impact fuel production. CO 2 utilization could as well improve plant economics, as a consequence of the profits related to the commercialization of the final products whilst allowing further emission reductions. In this paper, a techno-economic assessment of the use of the CO 2 by-product in CO 2 -enriched agricultural greenhouses for tomato production is discussed. The results of the research show that, depending on the operating mode and the design approach, the use of a greenhouse enables the recovery of 14–67% of the by-product CO 2 when the internal CO 2 concentration is kept at 1000 ppm. In addition, it is estimated that the associated heat and power demand ranges from 0.097 to 0.138 kWh th /kg of used CO 2 and 0.04–0.05 kW e /kg of used CO 2 , respectively. Revenues related to the tomato production are partially offset by the greenhouse capital investment and operating costs; however, a net profit between 16 and 19 p/kg of used CO 2 was calculated, leading to a net profit of 1.3–1.6 p/kWh of injected biomethane. These results show that CO 2 utilization is technically feasible and economically more convenient than CO 2 storage. While both geological storage and CO 2 utilization would allow negative climate change impact fuel production, the net greenhouse emission savings for the utilization configuration were found to be strongly dependent on the assumptions regarding fuel substitution for the produced biomethane. [ABSTRACT FROM AUTHOR]

In many developing countries, there is a desire to switch from traditional fuel to renewable energy. However, the supply of renewable energy is often characterized by a severe lack of reliability. This paper seeks to answer if, and to what extent, power outages inhibit switching from fuelwood to hydropower based electricity supply, and factors that determine households' willingness to pay to reduce power outages using a unique combination of mixed logit and seemingly unrelated regression models. We find that frequency, duration, timing of power outages and advance notice are important characteristics determining whether households switch to electricity. The less reliable the electricity supply is the less likely households are to switch to it. Therefore, unreliability in electricity supply maintains the current use of fuelwood, resulting in continued environmental and health problems. Hence, policymakers should work to improve reliability to speed up the desired fuel switching process. • We study households' valuation of reliability of electricity in developing country. • We conducted a choice experiment with a sample of urban households in Ethiopia. • We combined mixed logit and seemingly unrelated regression models for the analysis. • Unreliable electricity make households shy away from fully switching to electricity. • Income, age, type and price of fuels are among the determinants of households' MWTP. [ABSTRACT FROM AUTHOR]

• Newly implemented IMO regulations require a significant reduction of ship emissions. • Ship emission studies related to switching to low-sulphur fuels are thoroughly reviewed. • Refinery processes to produce low-sulphur fuels require extra energy consumption. • Scope for new regulations to be added to reduce particle number and methane slip. • Future marine fuel mix needs to be involved to meet fuel regulations and emission reduction. This study presents an overview of the context and global impacts of recent International Maritime Organization (IMO) regulations on the marine fuel oil refining industry, future marine fuel mix and ship emissions. IMO limited marine fuel sulphur content in both Sulphur Emission Control Areas (SECAs) and Nitrogen Oxide Emission Control Areas (NECAs) to 0.1% (wt. %) by 2015, and to 0.5% globally by 2020. It is anticipated that the newly implemented IMO regulations will help to mitigate negative impact of ship emissions on public health and environment. IMO regulations require significant changes to refineries to increase the production of low sulphur fuels through a shift to distillates, use of novel deep desulphurization techniques, or fuel blending. Changes to the refinery processes can bring forth increases in greenhouse gas emissions and high capital investments. Alternative fuels will need to meet the required reduction of air pollutants and greenhouse gas emissions in coastal areas. Alternative marine fuels consisting of liquefied nature gas (LNG) and biofuel may be suitable fuels to meet both targets. These two fuels are predicted to account for 50% of shipping energy demand by 2050, while the remainder will still be supplied by conventional heavy fuel oil (HFO)/marine gas oil (MGO). Switching to low sulphur fuels as a results of the new IMO regulations has led to measureable reductions in ship emissions generally. This fuel switching also resulted in changes in engine emission characteristics, especially on particulate matter chemical composition. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Greenhouse gas optimised deployment of crop based biofuels across transport sectors. • A switch to gaseous fuels increases abatement by up to a factor of five per land unit. • If gaseous fuels are not feasible, liquefied options in goods and shipping sectors are best. • Aviation biofuels optimal only when other sectors covered by renewables. • Current biofuel quota policy results in much lower abatement than optimal use. Abstract The optimal role of biofuels from energy crops for greenhouse gas (GHG) abatement in the German transport sectors is investigated under different progressive long-term scenarios, from a set arable land area corresponding to current use. The sectors included are land passenger and goods transport, shipping and aviation. The GHG abatement from the same land area can be increased by a factor of five through switching to higher yielding biofuel options. Silage maize based biomethane and wood based Synthetic Natural Gas (SNG), in either gaseous or liquefied form are the options with the highest GHG abatement potential per arable land unit, and thus markets where such fuels are an option should be prioritised. Sector fuel restrictions combined with fuel yields resulted in the land passenger sector to be the first priority for maximising GHG abatement, followed by land goods transport, shipping and finally aviation. Only when the previous sectors have been covered by renewable options do the following become relevant and thus a large transition is required before aviation biofuels or any liquid advanced biofuel become the climate optimal use of biomass. Applying admixture quotas to sub-sectors yields a lower GHG abatement than an optimal strategy. [ABSTRACT FROM AUTHOR]

Highlights • Long-chain oxymethylene ether show a soot-free combustion. • Oxymethylene ether suppress the nitrous oxide - soot trade-off in diesel engines. • Solubility of long chain oxymethylene ether in diesel fuel is limited. • Oxymethylene ether is a promising diesel substitute for dedicated engines. Abstract Oxymethylene ether (OME n) has recently drawn high attention due to its high pollutant emission reduction potential and the sustainable synthesis pathways involving carbon capture and renewable hydrogen. In this work, five blends of OME n in diesel fuel in addition to pure OME 3-5 and diesel fuel as reference were investigated in a single cylinder engine. Each OME n -Diesel blend was prepared with a different chain length, ranging from OME 1 to OME 5. The blending ratio of OME n in fossil diesel fuel was set to 35 vol%, corresponding to a ∼23.5% diesel fuel substitution on a heating value basis. We find that OME n contributes to improved oxidation conditions, resulting in a more complete combustion compared to conventional diesel fuel operation. This is reflected by reduced emissions of unburned hydrocarbons and carbon monoxide (up to 90%), higher burned mass fractions after the main combustion phase, higher indicated efficiencies (up to +3%) and lower exhaust gas temperatures (up to −70 °C). Furthermore, while pure OME n burns soot-free, a significant soot reduction was measured for the OME n -Diesel blends. Based on the findings of this work, it is concluded that from a combustion and emission point of view, the OME n chain length is of minor importance for applications where OME n is blended with diesel fuel up to a ratio of 35 vol%. Thus, the main considerations for an optimal OME n chain length range should focus on aspects like fuel properties and OME n synthesis. In this regard, a simple and efficient synthesis process (e.g. synthesis of OME 1) must be weighed up against favorable fuel properties of the synthesis product (e.g. OME 3-5). Hence, bearing in mind that OME n is not a drop-in fuel and will always demand a dedicated engine, the preference of long chain OME n over OME 1 is not straight forward and strongly depends on the application. [ABSTRACT FROM AUTHOR]

Highlights • The application of big data to energy economy modelling is a critical research gap. • Big data has the potential to reduce multiple blind spots in energy economy models. • Bottom-up hybrid models are a logical starting point for big data integration. • Moving from data scarcity to data abundance could completely transform the field. • We explore the research possibilities for revolutionising the state-of-the-art. Abstract Energy economy models are central to decision making on energy and climate issues in the 21st century, such as informing the design of deep decarbonisation strategies under the Paris Agreement. Designing policies that are aimed at achieving such radical transitions in the energy system will require ever more in-depth modelling of end-use demand, efficiency and fuel switching, as well as an increasing need for regional, sectoral, and agent disaggregation to capture technological, jurisdictional and policy detail. Building and using these models entails complex trade-offs between the level of detail, the size of the system boundary, and the available computing resources. The availability of data to characterise key energy system sectors and interactions is also a key driver of model structure and parameterisation, and there are many blind spots and design compromises that are caused by data scarcity. We may soon, however, live in a world of data abundance , potentially enabling previously impossible levels of resolution and coverage in energy economy models. But while big data concepts and platforms have already begun to be used in a number of selected energy research applications, their potential to improve or even completely revolutionise energy economy modelling has been almost completely overlooked in the existing literature. In this paper, we explore the challenges and possibilities of this emerging frontier. We identify critical gaps and opportunities for the field, as well as developing foundational concepts for guiding the future application of big data to energy economy modelling, with reference to the existing literature on decision making under uncertainty, scenario analysis and the philosophy of science. [ABSTRACT FROM AUTHOR]

This paper reviews the literature on vehicle routing problems and location routing problems with intermediate stops. We classify publications into different categories from both an application-based perspective and a methodological perspective. In addition, we analyze the papers with respect to the algorithms and benchmark instances they present. Furthermore, we provide an overview of trends in the literature and identify promising areas for further research. [ABSTRACT FROM AUTHOR]

Abstract This paper analyzes the energy selection behavior of Nepalese households, specifically the effects of socio-demographic factors on the energy mix. To overcome the limitations of prior research and to accurately model household energy selection and consumption behavior simultaneously, this study uses the multiple discrete continuous extreme value (MDCEV) model. The empirical analysis was performed on data from the Annual Household Survey (AHS) conducted by the Central Bureau of Statistics (CBS) of Nepal. The results show that lower education levels of the household and private house ownership are linked to the consumption of fuels such as firewood and kerosene, whereas ownership of information and communications technology (ICT) devices and access to renewable energy lead to a preferred selection of more modern, cleaner fuels. The results provide implications for policy measures supporting a shift towards the use of cleaner fuels such as LPG and electricity to overcome the negative effects of traditional fuels on personal health and the environment. Highlights • Lower education levels are linked to the consumption of firewood and kerosene. • House ownership is linked with traditional, dirtier fuels. • Access to ICT increases transition to cleaner fuels. • LPG shows good market potential, but electricity is still a challenge. [ABSTRACT FROM AUTHOR]

Forestry and forest industry sectors have vital roles for many regional economies. Consequently, it is important to understand how the introduction of the iron and steel industry (ISI) as a new large consumer of woody materials may affect existing feedstock markets. The use of metallurgical coal can partially or fully be substituted by refined biomass. To analyze the potential consequences of a new woody consumer on regional markets, three regions in northern Sweden and Finland are used as a case. A regional partial equilibrium model is developed, the Norrbotten County Forest Sector Model (NCFSM), and applied on three different scenarios. The purpose of the study is to analyze the intra- and inter-regional effects increased competition for woody materials may have on regional markets and on the economic well-being of the regions. The result suggest that the total welfare effect is relatively small, however, some regional welfare distributional effects are observed. Additionally, the price of roundwood will only be moderately affected if the ISI sector switch from fossil fuels to refined woody biomass. However, secondary woody materials, i.e. by-products and harvesting residues, will experience larger price shifts. [ABSTRACT FROM AUTHOR]

Abstract An important challenge facing firms and governments is the realization of sustainable development objectives. Sustainable technology, as an effective means to achieve sustainable development, has recently gained much interest from both society and academia. Prior research has investigated the effects of several factors on the adoption of sustainable technologies and provides a basic understanding of firms' sustainable technology adoption behaviours. However, the results of this research are scattered across different disciplines, making that knowledge on sustainable technology adoption fragmented. In this systematic literature review, Elsevier and Web of Science were used as databases to search articles in the field of sustainable process technology adoption. Based on criteria, i.e., document type, languages, definition of adoption and sustainable technology and analysis level, 34 out of 964 articles were selected in the review. A qualitative synthesis method was chosen because the aim of this study is to understand and explain the effect of a specific factor as well as to explain the often-contradictory evidence in different contexts, focusing on not only the convergence but also the divergence in prior studies. Based on the typology from United Nations Environmental Program of sustainable technologies, a classification of sustainable process technologies is provided: CO 2 /emission reduction, material/fuel substitution, energy/material efficiency and recycling technologies. Environmental regulations and firm characteristics are most widely studied factors influencing sustainable process technology adoption. Coercive pressure, market pressure, technology capability, internal support, adoption experience, certified systems, and cooperation are important for sustainable process technology adoption. Firm characteristics (e.g. firm size, ownership) and technology types (e.g. end-of-pipe technology vs. cleaner technology) are mostly discussed as reasons for different effects of factors in prior studies. Lastly, directions for future research are provided. [ABSTRACT FROM AUTHOR]

Dramatic fluctuations in gas compositions will affect end-users. At current stage, studies on interchangeability indices, which are commonly utilized to characterize the interchangeability of natural gas, can resolve the dilemma. However, the existing studies mainly focused on conventional atmospheric burners, and it tends not to be suitable for fully premixed appliances because of different combustion characteristics. In this paper, an experimental system of fully premixed burners was built up to verify the applicability of interchangeability combinations, and the equivalent gas was mixed by H 2 , N 2 , and i-C 4 H 10 . Five sets of double indices combinations were theoretically selected within a relative error of ±5% compared to the reference gas. The adaptability of several equivalent gas was quantified by energy efficiency indices, combustion performances, and flue gas emissions. It is found that ( W s , H i ) can be used as gas interchangeability indices for fully premixed burners better than ( W s , V 0 ), because thermal efficiency of ( W s , H i ) changed within 3%. ( W s , CP ) can only work on gas appliances equipped with low-pressure injectors. Moreover, the utilization of ( H i , S n ) and ( V 0 , S n ) would decrease the thermal efficiency by 18% and it should be avoided. This work can provide a guidance to supplement technical gaps in interchangeability studies of fully premixed appliances. [ABSTRACT FROM AUTHOR]