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As a push towards alternative and renewable resources for heat and power generation, biomass and thermally treated fuels from biomass may be viable options in the upcoming economic reality. This study the verified mass and energy balance of spruce woody biomass after low temperature pyrolysis between 250 and 550 °C. The results showed that low-temperature pyrolysis can yield high-grade biochar suitable for substitution of fossil fuels. Crucially, the net calorific value of biochar processed at 350 °C substantially exceeded that of brown coal. An economic analysis was carried out on the assumption of the current economic reality in the Czech Republic. It was shown that even if the price of the biochar slightly increased, it would still be beneficial to invest in torrefaction technology over paying carbon credits. [ABSTRACT FROM AUTHOR]

This study analyzed the particulates and gaseous emissions from 2005 to 2022 for power plants in South Korea (Utility scale: 125 MW (B-1) and 200 MW (B-2), respectively), which recently successfully converted from coal to wood pellets. The analysis showed that (1) NOx reduction was 78.9 to 90.0% (with outlet denitrification facility), (2) SOx reduction was 95.0 to 99.6% (without desulfurization facility condition), and (3) total suspended particles (TSP) reduction was 70.3 to 87.2% (with improved filtration and dust collection facility). This research confirmed the capabilities of wood pellets as a baseload power source and demonstrated their superior NOx reduction compared to coal. In the case of SOx, the desulfurization facility was discontinued at the stage of the fuel switch, so the value was affected by exogenous variable factors other than fuel. The TSP appears to be a combination of the 'fine dust' contained in the wood pellets and the performance of the filtration dust collector. The results suggest that fuel switching to wood pellets is a viable alternative to fossil fuels as an appropriate climate technology. [ABSTRACT FROM AUTHOR]

The use of hydrogen can be a potential solution to reduce high CO and unburnt HC emissions, which is one of the most critical challenges, from Reactivity Controlled Compression Ignition (RCCI) engines at low loads as it is a very clean and carbon-free fuel candidate for internal combustion engines. Therefore, the aim of this study is designed to investigate numerically the effect of the hydrogen share on combustion characteristics in a diesel research engine operated in RCCI mode. The engine is fueled with conventional diesel and iso-octane enriched with hydrogen and is operated at 20% of the maximum torque (low load) and 2400 rpm. A 40% of conventional diesel (in the case of conventional diesel mode (CDM), its share was 100%) is injected per cycle into cylinder of the engine, while varying proportions of iso-octane (60% to 12%) and hydrogen (0% to 48%) are sprayed into the air from the intake manifold. Both CDM and RCCI combustion models built by 3D scanning of the existing engine using reverse engineering to computational fluid dynamic (CFD) was simulated through ANSYS-Forte coupled with a chemical kinetics solver (Chemkin-Pro). The simulation results showed that by adding hydrogen to iso-octane in RCCI mode, the proportion of hydrogen could be increased up to 48% while improving thermal efficiency by 33.3% in comparison with 24.9% with RCCI without hydrogen addition. Therefore, the overall hydrocarbon fuel consumption per cycle was reduced by up to 47.52%. Hydrogen addition resulted in a higher concentration of OH species in the flame front, and higher pressure and temperature in the cylinder, in turn, contributed to an increase in NOx emissions considerably but led to decrease in CO/HC emissions of RCCI operation. The decrease in the emissions of CO, HC, and C2H2 of up to 64.6, 81.8, and 76.6%, respectively, was observed by using 48% of H2 in RCCI mode compared to RCCI mode without hydrogen addition. It was concluded that high CO and unburned HC emissions from RCCI combustion. This research provides promising contributions to the literature for using hydrogen in substitution of hydrocarbon fuels and reducing emissions from RCCI engines. [ABSTRACT FROM AUTHOR]

The process of making cement clinker uses a lot of energy and produces a lot of pollution. Currently, cement companies use a combination of traditional fossil fuels and alternative fuels (AF-Fuels) to lower their energy consumption and environmental footprint by improving the pyro-system. In a calciner, AF-Fuels can reach a thermal substitution rate (TSR) of up to 80–100%. However, a kiln burner can only achieve a TSR of 50–60%. High TSR values have been provided by improvements in multi-channel burners, proper AF-Fuel feeding point setups, and various AF pre-combustion methods. Significant modeling of the calciner burner and system has also improved TSRs. However, the cement industry has encountered operational problems such as kiln coating build-up, reduced flame temperatures, higher specific heat consumption, and incomplete combustion. There is growing interest in waste substitution, a promising source of AF-Fuel that needs to be integrated into the current cement plant design to solve the calciner operational problems of the cement industry. This study discusses the latest developments and different experimental and modeling studies performed on the direct burning/co-firing of AF-Fuel in the cement industry as well as the incorporation of gasification in cement manufacturing. Based on this, a technically and environmentally improved solution is proposed. The characteristics of both approaches towards pre-calciner function and optimization are critically assessed. The many in-line cement calciner integration technologies and their various configurations for the long-term problems of cement plants are discussed. This project report also focuses on the necessity of creating appropriate calciner models for forecasting calciner production based on various AF-Fuels and their feeding positions in the calciner. [ABSTRACT FROM AUTHOR]

Renewable sources play a crucial role in the decarbonisation process of the current linear economy, aimed at reaching the 2030 climate objectives and fulfilling the EU's long-term strategy of achieving carbon neutrality by 2050. All economic subjects, including households, can contribute to the Green Deal goals. The main goal of this paper is to evaluate households' consumption of energy sources for heating purposes in the Czech Republic in the period 2003–2020 and depict possible drivers of switching to biomass. For this, various data were collected, such as data published by the Czech Statistical Office, ministries, and other national authorities, as well as data from Eurostat. Concerning methods, data analysis, correlation analysis, and regression analysis were used. Different models focus on the substitution effect, rebound effect, and behaviour of different kinds of households. The results show a substitution effect connected with the consumption of coal, electricity, and biomass for heating purposes. Many households substituted coal for biomass in the observed period. On the other hand, the environmental impact of such substitution is not significant, as carbon emissions and emissions of other pollutants are stable. The substitution of fuels should be accompanied by technological change, e.g., improvement of combustion boilers. Moreover, households of pensioners are the key economic subjects with the highest impact on biomass consumption for heating purposes. Against this background we recommend policies to support households in replacing their boilers for more environmentally friendly ones. [ABSTRACT FROM AUTHOR]

With the growing production and storage of urban solid waste, there have been impacts in the environmental, social and economic spheres around the world. For this reason, the theoretical compilation of the energy recovery alternatives present for the waste is carried out, which are established as a possible mitigation of the present problems, in the same way, the use of the waste in the Doña Juana landfill is focused, where it is feasible to generate great benefits such as the gradual substitution of fossil fuels for alternative fuels, reduce damage to the environment and society. [ABSTRACT FROM AUTHOR]

The search for sustainable ideas has gained prominence in recent decades at all levels of society since it has become imperative an economic, social, and environmental development in an integrated manner. In this context, biorefineries are currently present as the technology that best covers all these parameters, as they add the benefits of waste reuse, energy cogeneration, and fossil fuel substitution. Thus, the study of the various applicable biological matrices and exploring the technical capabilities of these processes become highly attractive. Thermodynamic modeling acts in this scenario as a fundamental tool for phase behavior predictions in process modeling, design, and optimization. Thus, this work aimed to systematize, using the PRISMA statement for systematic reviews, the information published between 2010 and 2020 on phase equilibria modeling in systems related to biorefineries to organize what is already known about the subject. As a result, 236 papers were categorized in terms of the year, country, type of phase equilibria, and thermodynamic model used. Also, the phase behavior predictions of different thermodynamic models under the same process conditions were qualitatively compared, establishing PC-SAFT as the model that best represents the great diversity of interest systems for biorefineries in a wide range of conditions. [ABSTRACT FROM AUTHOR]

The aim of this paper is to analyze energy pathways for a fossil fuel rich developing country towards an energy transition considering national and international oil availability using Ecuador as a reference. An integrated assessment model has been developed to simulate energy transition scenarios considering constraints on oil availability at the national and global level. Results show that if current trends in energy demand and supply persist, energy scarcity would start around 2040 due to depletion of national oil reserves and restricted access to foreign oil. This would trigger a degrowth in economic activity in sectors with high dependency on petroleum products. Scenarios with conservative efforts might partially revert the increasing use of fossil fuels supported by policies for energy efficiency and substitution of liquid fuels with electricity mainly from renewables. However, energy shortages would still be foreseeable as well as a decay of the economy. Under a maximum efforts scenario with an optimistic availability of national oil, a moderate-sustained economic growth could be feasible. This shows that oil would still play a key role during the transition. Furthermore, ambitious policies must be implemented in the short term to smooth the effects of displacing oil as energy and income source. [ABSTRACT FROM AUTHOR]

Germán Vergara, Cambridge University Press, 2021, pp. xii + 322 As the ongoing climate crisis spearheads global concerns, energy comes to the fore both as a potential solution and a means to explain how we have got to the present situation. Germán Vergara's insightful and well-documented I Fueling Mexico i showcases how the energy transition to fossil fuels has unfolded in Mexico, paying special attention to the intricate, co-constitutive relationship between energy regimes and human agency, as well as changing social behaviour. Fueling Mexico: Energy and Environment, 1850-1950. [Extracted from the article]

This paper analyzes the changes in carbon dioxide (CO2) emissions related to energy consumption in the Polish agricultural sector between 2000 and 2019. Based on the Logarithmic Mean Divisia Index (LMDI), the changes in agricultural CO2 emissions are viewed in the context of changes in six factors, i.e., CO2 emission intensity, substitution of fossil fuels, penetration of renewable energies, energy intensity, labor productivity and number of employees. The analysis demonstrated that total energy consumption declined over the study period; this was related to a reduction in the intake of energy derived from solid fossil fuels (−1.05%), crude oil (−1.01%), electricity (−4.89%), and heat (−1.37%), and to an increased consumption of natural gas (5.78%) and biofuels (0.82%). Furthermore, it follows from the analysis that changes in CO2 emissions witnessed in that period were consistent with changes in energy consumption levels; this resulted from a negligible transformation of the energy mix (largely determined by fossil fuels). Generally, CO2 emissions declined over the study period at a rate comparable (−0.9%) to that of the reduction in energy consumption (−1.03%). In light of the LMDI method, the reduction in CO2 emissions from fuel consumption in the Polish agricultural sector was mainly driven by a reduction in energy intensity and in employment. Conversely, rapid growth in labor productivity was the key factor in increasing carbon dioxide emissions. Compared to these impacts, changes in other factors (i.e., emission intensity, energy mix and penetration of renewable energies) had an extremely small or marginal effect on the variation in CO2 emissions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Singapore kept its stale policy while targeting a zero-waste Circular Economy plan. • In 2019, Shanghai enhanced household waste segregation and recycling at the source. • Differences were assessed in strategy, environmental, economic and social perspectives. • New policies and digitalisation improved waste management in Shanghai in 2019. • Digitalisation, market reshaping and COVID-19 triggered challenges and opportunities. Due to rapid economic development and urbanisation, emerging megacities with dense populations have witnessed a significant increase in waste generation. Megacities face challenges in developing sustainable waste management systems. Considerable heterogeneity exists across megacities in management strategies. The two selected emerging megacities, Singapore (a city-state) and Shanghai, have similar developmental characteristics, but their waste management modes differ strikingly. This study assessed the two modes in terms of management strategies, environmental effects, economic costs, and social outcomes. Environmental footprint analysis and cost quantification were employed for the assessment based on public data. The research results would permit a deeper understanding of the long-term sustainability of each mode while considering the feasibility of implementation across different contexts. It was found that the waste management system in Singapore had a relatively lower environmental impact than Shanghai before Shanghai's new waste segregation and recycling policy in 2019. However, when the effect of fossil fuel substitution is taken into account, the environmental burden in Shanghai can be lowered more substantially than the one in Singapore. Although Shanghai had more economic burden for the waste segregation at source, it tended to implement the circular economy principles (e.g., reduce, reuse, and recycling) better and improve its sense of community significantly. Based on the practical experiences from the two representative megacities, suggestions for better waste management practices were provided for Singapore, Shanghai, and other emerging megacities with similar circumstances. In addition, challenges and opportunities related to household waste segregation and recycling were identified to guide future practices in emerging megacities. [ABSTRACT FROM AUTHOR]

The Five-Year Plan (FYP) effectively guides China's short- to medium-term development goals, but limited data hinder research on long-term CO 2 performance within the FYP framework. This study compiles sectoral CO 2 emissions from detailed fuels in 1981–2021, employing the input–output model and structural decomposition technique to examine their performance and driving forces. Our results show that the growth rates of national emissions increased continuously from the 6th to the 11th FYP (1981–2011), gradually declined thereafter (2011−2020), but rose significantly in 2021. Urban household emissions per capita fell by 40%, while rural household emissions rose by 209%. The mix effect (or substitution effect) drove households to increase their use of oil and natural gas, reducing reliance on coal. Coal was the primary emissions source in industrial sectors, specifically in manufacturing and utilities. Elevated coal- and oil-related emissions were primarily due to the level effect, whereas the mix effect drove natural gas-related emissions. Manufacturing and construction were major sources of embodied emissions. Emissions intensity had modest mitigation effects, and the input structure effect was relatively low. Our results underscore the need for China to expedite the substitution of fossil fuels with non-fossil energy sources to achieve its low-carbon goals outlined in the 14th FYP. • We examine China's sector-specific CO 2 emissions from fuels during 1981–2021. • China's CO 2 emissions rates have gradually declined since the 12th Five-Year Plan. • Households are increasing oil and gas, reducing their reliance on coal. • Manufacturing and utilities are the primary direct coal emitters. • Manufacturing and construction are the primary sources of embodied emissions. [ABSTRACT FROM AUTHOR]

Crustacean waste has great potential as fossil fuel substitution and efficient desulfurization to reduce pollutant emissions, but high moisture and poor quality restrict broad-scale utilization. This study used microwave radiation on crayfish shell to investigate the combustion characteristics and desulfurization effect in different atmospheres/pulse microwave cycle. Meanwhile, the structure evolution mechanism and molecular reaction pathways were revealed. The results show that crayfish shell derived fuel has a pleasurable combustion performance and sulfur fixation ability after microwave radiation in flue gas. The heat release of derived fuel increased by 29.9 % after five microwave cycle in flue gas, and activation energy decreased by 3.7 %. By contrast, the heat release increased by 17.4 % after five microwave cycle in inert gas, and activation energy increased by 39.3 %. Subsequently, the effect of microwave cycle times in flue gas on crayfish shell combustion and desulfurization performance was studied. The results show that the heat release of derived fuel gradually increases with microwave cycle. After seven microwave cycle, the derived fuel heat release and SO 2 removal efficiency increased by 34.9 % and 44.4 %, respectively. The results establish the foundation for expanding the utilization pathway of crustacean waste and realizing the low-carbon energy transition. [Display omitted] • Prepared crayfish shell derived fuel use microwave radiation in flue and inert gas. • The effect mechanism of pore structure on combustion performance was elucidated. • Proposed the two reaction pathways of functional groups under microwave radiation. • Microwave radiation in flue gas increased exotherm by 35 % and reduced SO 2 by 44 %. • Crayfish shell derived fuel sync realized the fuel substitution and SO 2 reduction. [ABSTRACT FROM AUTHOR]

Biomass energy is the most likely new energy source to replace fossil fuels. This study presents a prediction method for biomass energy supply-demand and changes in supply-demand patterns that connects the past and future. In the study, carbon peaking and carbon neutrality are taken as the time base. The FLUS model is used to simulate future land allocation in four basic scenarios: natural development scenario, agricultural development scenario, low-carbon development scenario and industrial development scenario; and townships, towns, and subdistricts are taken as the basic statistical unit. Based on this, we have examined the suitability of future development of biomass energy in rural and urban areas in each scenario, as well as its contribution to the future energy system transformation that substitutes for fossil energy. This method has been applied to the case study of townships, towns, and subdistricts in Harbin City in China. The study results show that: The degrees to which biomass energy potential can substitute for fossil energy in the four scenarios in 2030 reach 4.21%, 5.62%, 5.47%, and 3.82%, respectively. Under agricultural development scenario, the supply-demand balance areas account for 48.94%, meaning this scenario has the largest potential for energy development and transition; low-carbon development scenario sees the highest degree of spatial supply-demand match, and thus enjoys the most advantages in energy transportation. The degrees to which biomass energy potential can substitute for fossil energy under the four scenarios in 2060 reach 2.01%, 6.96%, 5.35%, and 1.26% respectively. Agricultural development scenario still has the largest development potential, with the proportion of supply-demand balance areas jumping to 50.46%; Finally, low supply-high demand mismatch clusters are mainly concentrated in the main urban area and the central areas of townships, towns, and subdistricts. The high supply-low demand mismatch clusters are mainly distributed in the northeast. Under low-carbon development scenario, the low supply-high demand mismatch ratio has been reduced to 0.92%, the lowest supply-demand mismatch among all scenarios. Therefore, low-carbon development scenario enjoys the most spatial match advantages. This study will serve as an assessment method to advance the spatial development of biomass, and provide a geospatial basis for optimizing the layout of future energy development. Compared with previous studies, it has more spatial attributes, better reflects the complexity of biomass energy changes and is more connected with the measurement results and future policy making. In future research, we will combine multiple types of clean energy into the comparison and combined use to form a more comprehensive and specific research framework for new energy conversion. Longer-term macro-planning will go beyond the application boundaries of this research. • The FLUS model is used to simulate future land allocation changes in the four scenarios. • The future population spatial distribution is simulated based on urban spatial simulation results and random forest model. • The future contribution of biomass energy to fossil fuel substitution is estimated. • A biomass energy spatial evaluation framework connecting the past and the future is built. [ABSTRACT FROM AUTHOR]

[Display omitted] • A fast transition to an almost fossil-free future is expected. • The transition will have profound implications on catalysis. • Develop a new catalysis, indicated as reactive, is required for this transition. • A science and technology gap exists to pass from thermal to reactive catalysis. • The case study of solar ammonia (NRR) is discussed to illustrate the need of this change. The substitution of fossil fuels requires redesigning chemical processes and this has major implications on catalysis. In this viewpoint, after analyzing the motivations why this transition to an almost fossil-free future will likely occur faster than often indicated, it is remarked the presence of a science and technology gap to pass from today catalysis to that dominant in the future scenario indicated with the term "reactive" catalysis. It defines catalysis operating in the presence of the highly reactive species generated either i) by application of a potential and electrical current or ii) by light absorption with creation of charge separation, or iii) by activation of the reactant molecules when generating a non-thermal plasma. It requires a different conceptual approach from "thermal" catalysis, where heat is the energy form provided to overcome the activation barrier. Reactive catalysis is not just an extension of that in use (thermal catalysis), but requires to redesign materials and related concepts, including in terms of fundamental science and technology aspects to understand and improve their behavior. The case study of solar ammonia (direct synthesis from N 2 , i.e., nitrogen reduction reaction - NRR) was used to illustrate the need of this change and some of the open questions to solve. [ABSTRACT FROM AUTHOR]

This study internalizes carbon pricing and other regulatory policy tools for decarbonizing the electricity generation mix of Sri Lanka. Carbon Pricing is shifted to the supply side as a decision-making tool. We consider $10/tCO2, $20/tCO2, $30/tCO2, $44/tCO2, $130/tCO2, and $297/tCO2 as potential carbon prices. Other regulatory policy tools, such as mandatory renewable energy (RE) development, fuel switching, fossil fuel phasing out, fossil fuel development moratoriums, and mandatory RE utilization, are included as possible supporting tools. Three capacity-development scenarios and three optimization models with three objective functions are designed and implemented in the General Algebraic Modeling System (GAMS). Six policy options are presented for the Sri Lankan context considering cost, emission, and diversification. Results suggest a carbon price that falls between $10/tCO2-$44/tCO2 as suitable for Sri Lanka. The study contributes to the ongoing debate on the effectiveness of carbon pricing by empirically testing the effectiveness of carbon prices in the electricity generation planning of a developing country. The findings support the emerging consensus of adopting other regulatory policy tools along with carbon prices to achieve deep decarbonization. The study also assesses the role LNG could play in a developing country's electricity generation mix. We recommend transitioning from coal to LNG as an intermediate decarbonization policy option until the RE capacities are developed to make the near-zero emission mix a reality. [ABSTRACT FROM AUTHOR]

Coal is an important fossil fuel, a resource primarily used for electric power generation, and currently supplies 41% of global electricity needs. Fossil fuel is one of the demanding energy source, and the consumption has gradually increased with the demand of energy consumption sector. The fuel stock is enough for few decades to meet the requirement of the energy sector, but it is depleting gradually. The increased consumption demands have pushed the researcher to search for a substitution to the fossil fuel and for a environmentally friendly and also a relatively inexpensive energy source. There comes a need to improve coal combustion performance to enhance the efficiency of the furnace and boiler. Adding additive to the coal is an option and has grabbed the attention of many researchers for developing an additive. These additives for coal can effectively improve the combustion performance of the coal. This review paper contributes information about the impact of additives on coal combustion properties, coal calorific value, binder for coal fines and a hybrid technology which use additives to modify the coal surface. The objective of this review is to relate the effect of additives on coal utilization and coal combustion performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • GWP ranging from −19 to −138 kg CO 2 -eq./t-FW in the biorefinery scenarios. • Introducing biogas upgrading to biomethane improved the GWP by 37%. • Producing bioethanol from FW was not advantageous in environment perspective. • Combining biodiesel and biomethane gave the largest improvement in GWP. Biorefining of Chinese food waste (FW) into transport fuels was assessed in terms of amount of fuel produced and over all Global Warming Potential (GWP) for six different scenarios including biogas, biomethane, bioethanol and biodiesel in different combinations. The life-cycle perspective used included GWP aspects of material and energy use, emissions during biorefining and management of residues, as well as substitution of fossil fuels according to the energy content of biofuels. All of the six FW biorefineries revealed savings in GWP ranging from −19 to −138 kg CO 2 eqv. per ton of wet FW. Compared to the reference scenario with only anaerobic digestion (S0), introducing biogas upgrading to biomethane (S1) improved the GWP by 37%; while producing bioethanol prior to anaerobic digestion (S2) decreased the savings in GWP. Introducing biodiesel prior to anaerobic digestion (S3) revealed around 60% improvement in GWP, while combining biodiesel and biomethane gave the largest improvement in GWP, 84% compared to the reference scenario, and the most fuels (around 2400 MJ in terms of 30 kg biodiesel and 35 kg biomethane per ton of wet FW). A sensitivity analysis revealed that the electricity production based on the biogas was an important parameter and appears in all refineries, while the results was less sensitive to the production of biodiesel and biomethane. The residue management contributed also to the GWP, but did not vary much among the biorefinery scenarios. [ABSTRACT FROM AUTHOR]

The global outcry for a sustainable energy system—energy transition regime, involves the substitution of fossil fuels with clean and affordable energy and the amelioration of greenhouse gas (GHG) effects on global health and environment. Studies have shown that economic growth proportionally links energy consumption, as seen in developed countries. Hence, countries with low economic activities such as those in sub-Saharan Africa (SSA) are supposedly not to panic over CO2 emissions. It is ascertained from energy reports, research articles, and several other sources of energy information and tools that economic activities in SSA resulted in 7.1% of the global share of carbon dioxide (CO2) emission. Ironically, despite this low share, the region is highly vulnerable to climate change due to low economic and technological advancement. The results of the studies on renewable energy (RE), CO2 emissions outlook, and global warming in SSA show that CO2 emission is increasing; global warming is about 0.5℃; anthropogenic global warming is between 0.8; and 1.2 °C locally and is increased at about 0.2 °C per decade. If not abated, a global warming of 1.5 °C will be reached between 2030 and 2053. To effectively boost RE deployment, and mitigate CO2 emissions in SSA, this study simplifies energy-GDP-CO2 nexus and identifies research and development areas to facilitate energy transition paradigm. The paper sees domestication of energy technology, deployment, and development of sustainable RE policies which are stern steps in mitigating CO2 emissions in SSA. [ABSTRACT FROM AUTHOR]

Zeolites today are a unique and highly successful class of catalytic materials, but their role in future low-carbon scenarios comes into question. This perspective article summarises the authors' joint view on zeolite chemistry's future direction for catalytic applications to stimulate discussion identifying pillars on which the scientific community should focus. Particular challenges discussed here include i) our view of the zeolite synthesis focused on new structures with optimised textural properties and design of zeolite catalysts with precise control of the location of active sites; ii) discussion of current, mostly new industrial, requests for zeolitic catalysts; iii) emerging catalytic applications in which zeolites should play a key role; and last but not least iv) opportunities for new types of microporous solids. Although some of these are rather challenging, with many barriers to overcome, we suggest fostering research on these directions as the key to maintaining the crucial role of zeolite as catalysts. Discussion on the future role of zeolite science and technology is organised in consideration of three possible future scenarios: (i) a low-carbon BAU (business-as-usual) scenario and (ii) two advanced scenarios, which differ in terms of the degree of circularity (low and high, LC and HC respectively), and (iii) level of substitution of fossil fuels with alternative energy and carbon sources. Trends characterising these scenarios and their impact on zeolite science and technology are discussed to provide the readers with the elements, tools and clues to identify priorities in research and application of zeolite catalysts. [Display omitted] • status and perspectives for zeolites catalyst in a low carbon scenario. • zeolite chemistry's future direction and catalytic applications. • current, mostly new industrial, requests for zeolitic catalysts. • emerging catalytic applications in which zeolites should play a key role. • opportunities for new types of microporous solids. [ABSTRACT FROM AUTHOR]

An extended Kaya identity and the Logarithm Mean Divisia Index approach were applied in this paper to identify, quantify and explain the main factors behind Cameroon's CO2 emissions before, during and after the economic crisis of the years 1980. The analyses covered the period from 1971 to 2014 and the results showed that: (1) Cameroon's carbon intensity increased by 75 and 47% during the periods before (1971–1984) and after (1984–1994) the economic crisis, while it decreased significantly by − 135% during the crisis period (1994–2014). At the same time, the country's emission factor increased by 30% between 2007 and 2014. (2) The effect of the demographic change was the main driver of Cameroon's CO2 emissions during the periods 1984–1994 and 1994–2014, whereas the effect of economic activity was the main driver of the increase in these emissions between 1971 and 1984. (3) The energy intensity effect contributed to the increase in CO2 emissions during the period 1984–1994 in the same way as the effect of demographic change. However, this factor helped reduce CO2 emissions in the other two periods. (4) Although the effect of substitution of fossil fuels and the effect of renewable energy all contributed to reducing CO2 emissions during the period of this study, we found that the effect of renewable energy behind CO2 emissions remains insignificant compared to the renewable energy potential available in Cameroon. Finally, policy recommendations aimed at enabling Cameroon to achieve its objectives of reducing CO2 emissions were formulated in this article. [ABSTRACT FROM AUTHOR]

The reduction in energy and emissions from the building sector can come from improved standards for new construction and retrofits to existing buildings. The retrofit viability for single-detached homes in Vancouver, Canada, is examined in terms of the key drivers and barriers involving economic and social forces. Local experts considered the likelihood of retrofits occurring to several archetypal dwellings that were synthesized from local building data and homeowner characteristics. The survey results (n = 56) raised less known but potentially significant issues regarding energy-efficiency retrofits in Vancouver. Domestic fuel switching, from fossil fuel energy services to electricity, is likely the most desirable future mechanism for decarbonizing homes. However, many of the respondents identified that Vancouver's real estate market has a significant negative influence on retrofitting due to high land values, which results in a high demolition rate of existing homes. Only 46% of responses returned a view that an existing home would remain standing by 2050. In addition, 41% of responses expressed a doubt that the dwelling, whether existing or new, would achieve carbon neutrality by 2050. Both issues confront the City of Vancouver's current emissions reduction planning, which has targeted nearcomplete decarbonization of the residential building stock by 2050. [ABSTRACT FROM AUTHOR]

Compression ignition (CI) engines are widely used in modern society, but they are also recognized as a significative source of harmful and human hazard emissions such as particulate matter (PM) and nitrogen oxides (NOx). Moreover, the combustion of fossil fuels is related to the growing amount of greenhouse gas (GHG) emissions, such as carbon dioxide (CO2). Stringent emission regulatory programs, the transition to cleaner and more advanced powertrains and the use of lower carbon fuels are driving forces for the improvement of diesel engines in terms of overall efficiency and engine-out emissions. Ethanol, a light alcohol and lower carbon fuel, is a promising alternative fuel applicable in the dual-fuel (DF) combustion mode to mitigate CO2 and also engine-out PM emissions. In this context, this work aims to assess the maximum fuel substitution ratio (FSR) and the impact on CO2 and PM emissions of different nozzle holes number injectors, 7 and 9, in the DF operating mode. The analysis was conducted within engine working constraints and considered the influence on maximum FSR of calibration parameters, such as combustion phasing, rail pressure, injection pattern and exhaust gas recirculation (EGR). The experimental tests were carried out on a single-cylinder light-duty CI engine with ethanol introduced via port fuel injection (PFI) and direct injection of diesel in two operating points, 1500 and 2000 rpm and at 5 and 8 bar of brake mean effective pressure (BMEP), respectively. Noise and the coefficient of variation in indicated mean effective pressure (COVIMEP) limits have been chosen as practical constraints. In particular, the experimental analysis assesses for each parameter or their combination the highest ethanol fraction that can be injected. To discriminate the effect on ethanol fraction and the combustion process of each parameter, a one-at-a-time-factor approach was used. The results show that, in both operating points, the EGR reduces the maximum ethanol fraction injectable; nevertheless, the ethanol addition leads to outstanding improvement in terms of engine-out PM. The adoption of a 9 hole diesel injector, for lower load, allows reaching a higher fraction of ethanol in all test conditions with an improvement in combustion noise, on average 3 dBA, while near-zero PM emissions and a reduction can be noticed, on the average of 1 g/kWh, and CO2 compared with the fewer nozzle holes case. Increasing the load insensitivity to different holes number was observed. [ABSTRACT FROM AUTHOR]

The implications of national or regional energy policies for technical efficiency and environmental outcomes in electricity generation depend on fossil fuel input substitution. This study uses state level data to examine fossil fuel (coal and natural gas) substitution in electricity generation under increased availability of natural gas in the United States. We observe that changes in elasticities of substitution from pre-2009 to post-2009 differ across states suggesting that the effects of increased availability of inexpensive natural gas on electricity generation have been spatially heterogeneous. We rely on the observed heterogeneity to assess the effects of fossil fuel input substitution on technical efficiency and CO2 emissions. The results reveal that state level elasticity of substitution between natural gas and coal has a positive effect on technical efficiency and a negative effect on CO2 emissions. Therefore, future policy design and analyses should reflect the implications for regional elasticities of fossil fuel substitution and associated environmental outcomes. [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]

Background: Many governments take the view that voluntary national targets to reduce greenhouse gas emissions are sufficient to avoid negative climate effects. In the absence of independent verification, however, pledges are unlikely to be sufficient for a rapid and strong reduction of emissions. It is often claimed that a global carbon tax could be an effective instrument. However, such a tax is difficult to set and to collect, especially in countries with poor administrative infrastructure. Results: Here, we formulate and discuss a novel approach, the Global Carbon Surcharge (GCS), that mimics a carbon tax but does not require tax collection by governments. We define GCS as a requirement or a voluntary commitment encompassing all companies extracting carbon-carrying raw materials, namely coal, oil, gas and limestone, with the aim to burden their extraction with costs proportional to their carbon intensity. GCS mandates all companies to store these materials immediately after mining for a given period of time in the vicinity of the production site. Thereby, GCS generates additional costs that propagate through all sectors of the global economy. We elucidate how the investment costs for the storage infrastructure translate into surcharges on the raw materials. Conclusions: We show that by a proper choice of the storage time and the size of the storage unit, GCS becomes equivalent to a carbon tax in the range between 50 and 100 € per ton of CO2 that is assumed to be necessary for the transition to a carbon-neutral energy system. An attractive feature of GCS is that it can be verified, in particular by citizens themselves, using publicly available satellite data. Finally, if compulsory storage is coupled to blockchain-based smart contracts and a mandatory (expensive) mining of cryptocurrency, GCS can be operated without governmental protectionism, corruption and fraud. However, the main uncertainties of the GCS approach lie in the substantial expansion of infrastructure and the fact that the induced price effects must be sufficient to achieve a rapid and far-reaching substitution of fossil fuels. [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]

Biomass has been promoted as a promising energy resource to mitigate global climate change. To evaluate the contribution of biomass utilization to climate change mitigation under the "Grain for Green" program in Northern Shaanxi, China, a soil carbon dynamic model and a life cycle assessment model were integrated to examine the benefits of using Caragana korshinskii Kom. as an energy crop. We found that the annual dry biomass output is maintained at 0.7 Tg during the simulation period (2020–2097). Due to the compensatory effect of biomass regrowth, the global warming potential of biomass‐derived CO2 emissions is approximately 0.045; therefore, the total annual biogenic CO2 emission is 57,211 ± 6,168 Mg CO2 eq. The total annual life cycle CO2 emissions approach 867,072 Mg CO2 eq yr−1. Under the scenario of no biomass removal, final carbon storage ranges from 15.7 to 19.3 TgC, and the highest carbon sequestration rate is 0.47 TgC yr−1. In comparison with the no biomass removal scenario, the carbon sequestration rate (close to 0 MgC yr−1) in the biomass utilization scenario indicates a carbon loss; however, a portion of the carbon loss (31.39–62.09%) can be offset by carbon emission reductions from the substitution of fossil fuels. [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]

The partial substitution of fossil fuels by alternative fuels is associated with economic benefits for the cement producers. This fact has been confirmed by their growing interest in such substitutions. In this paper, based on the energy balance, it was demonstrated for a selected cement plant that by cocombustion of fine coal with the PAS-r fuel the cement plant is able to save 3.03 Mg⋅h-1 of fine coal thanks to the use of 5.04 Mg⋅h-1 of the PAS-r fuel. An advantage worth emphasizing is the fact that waste co-incineration is a part of a sustainable development strategy. Energy recovery from waste also is an example of the use of renewable energy sources. The results of the present work allow concluding that the substitution of fossil fuels by alternative fuels is justified by both the environmental and economic objectives. [ABSTRACT FROM AUTHOR]

There is a global trend of substitution of fossil fuels for renewable energy sources, which are preferred by reasons including sustainability, reduction of greenhouse gases that contribute to climate change, regional and social systems advancement, among others. This review is part of the studies carried out on the integral use of wood industrial wastes due to its low costs and high availability. A possible high-value product is ethylene, obtained by catalytic dehydration of second-generation bioethanol from lignocellulosic materials and which can be an effective alternative for the production of polymers such as polyethylene (PE), which is conventionally obtained from petroleum. Biobased polyethylene or biopolyethylene (BioPE) may potentially contribute to close a pine biorefinery scheme to obtain high-value products, using processes of low pollution and contributing to the global environmental balance. The process involves the following stages: pretreatment, enzymatic saccharification, fermentation, dehydration, and polymerization. This review includes the different processes for second generation (2G) bioethylene productions from pine wastes as an example and the technologies that can potentially be applied on an industrial scale for BioPE production, focusing on the catalytic dehydration of 2G bioethanol through the use of catalysts able to achieve high ethanol conversions and ethylene selectivity. [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]

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]

Production, quality and quality assurance, as well as co-incineration of solid recovered fuels in cement industry, have become state-of-the-art in the European cement industry. At the global level, average thermal substitution rate is about 17%, whereby, only 13% in Canada and in the USA 16%, while in the European Union 28 it is about 44% (i.e. 11,300,000 t waste fuels utilised in 2016). In Austria, thermal substitution rate was ca. 80% in 2017, which was worldwide the highest one. Regarding solid recovered fuels for the cement industry, two types are relevant, namely solid recovered fuels PREMIUM Quality and solid recovered fuels MEDIUM Quality. In the case study shown, solid recovered fuels PREMIUM Quality from 11 and solid recovered fuels MEDIUM Quality from nine different solid recovered fuels production plants have been investigated. Investigations consist of sorting and sieving analyses (for PREMIUM), as well as physical–chemical analyses (for both solid recovered fuels types) according to the (inter)national standards (i.e. Austrian 'ÖNORM', European 'EN' standards and CEN TC 343 guidelines). The results gained from the first investigation were published in 2014 and here, results of further investigations are updated for 2016 and 2018 and confronted with legal and market relevant requirements. During the investigation, not enough parallel samples could be investigated and therefore no adequate scientific statistical analyses could be elaborated but a more practical indicative interpretation has been made. Finally, it can be confirmed, that all investigated solid recovered fuels fulfil the Austrian legal and international solid recovered fuels and co-incineration market requirements. [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]

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]

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Foundry based organizations consume significant amounts of energy for producing their final products. Recently, techno-commercial and environmental factors have started triggering change from fossil fuels to cleaner ones. In this paper, factors acting as driving forces for migration from one fuel to another in order to improve energy efficiency, including various performance parameters in support of environment preservation, have been identified. Focus is also given to challenges which encounter during fuel switching. A new framework has been applied that can be used for fuel switching in manufacturing organizations. A real case of switching from three types of fuels to a single fuel has been studied and the outcomes are evaluated. Analysis related to energy consumption before and after fuel switching with respect to corresponding production data have been performed. [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]

Bioenergy crops, such as sugarcane, have the potential to mitigate greenhouse gas emissions through fossil fuel substitution. However, increased sugarcane propagation and recent management changes have raised concerns that these practices may deplete soil carbon (C) stocks, thereby limiting the net greenhouse gas benefit. In this study, we use both a measured and modelled approach to evaluate the impacts of two common sugarcane management practices on soil C sequestration potential in Brazil. We explore how transitions from conventional (mineral fertiliser/burning) to improved (vinasse application/unburned) practices influence soil C stocks in total and in physically fractionated soil down to one metre. Results suggest that vinasse application leads to an accumulation of soil C of 0.55 Mg ha-1 yr-1 at 0-30 cm depth and applying unburned management led to gains of~0.7 Mg ha-1 yr-1 at 30-60 cm depth. Soil C concentration in the Silt+Clay fraction of topsoil (0-20 cm) showed higher C content in unburned management but it did not differ under vinasse application. The CENTURY model was used to simulate the consequences of management changes beyond the temporal extent of the measurements. Simulations indicated that vinasse was not the key factor driving increases in soil C stocks but its application may be the most readily available practice to prevent the soil C losses under burned management. Furthermore, cessation of burning may increase topsoil C by 40% after ~50 years. These are the first data comparing different sugarcane management transitions within a single area. Our findings indicate that both vinasse application and the cessation of burning can play an important role in reducing the time required for sugarcane ethanol production to reach a net C benefit (payback time). [ABSTRACT FROM AUTHOR]

Today different types of wastes are used as refuse-derived fuels (RDF) either in waste-to-energy plants or as fuel substitutes in energy-intensive industrial processes. In order to quantify their greenhouse-gas relevance (fossil carbon content), reliable and practical analytical methods are required, which allow differentiation between biogenic and fossil organic carbon. In the present paper, an alternative method to determine the fossil share in RDFs is examined and validated. The so-called “adapted Balance Method” (aBM) is applied to three different RDFs and the results are compared to three standardized methods, namely the Radiocarbon Method ( 14 C-Method), the Selective Dissolution Method (SDM), and the Manual Sorting Method (MS). The aBM is based on the distinctly different elemental composition of water-and-ash-free biogenic and of fossil matter ( TOX BIO and TOX FOS ). Within the study, these compositional data are derived by manual sorting of the RDFs. The results show that the values obtained by the aBM are in excellent agreement with the results of the 14 C-Method (considered as reference method). Mean deviations between the two methods of −0.9 to +1.9% absolute for the share of fossil carbon are found which are statistically insignificant. High trueness and reliability of the aBM can be expected, independent of the RDF type. In contrast, the reliability of the other standardized methods (SDM and MS) appears to strongly depend on the type and composition of the RDF. The results further indicate that the generation of RDF-specific data on TOX FOS is important for the aBM if significant shares of polymers with comparably high oxygen content might be present in the RDF and if low uncertainties of the results (<3% relative) are required. The findings demonstrate that the alternative method has advantages compared to standardized methods with respect to reliability and/or costs. [ABSTRACT FROM AUTHOR]

• Novel assessment and optimization method for TES in the petrochemical industry considering clean energy substitution is proposed. • The detailed model of TES and the double-parallel-loop application framework of the proposed method are presented. • The real-world case study demonstrates the validation and efficacy of the proposed method. • The optimal results show that the TExC decreased by 3200 kW with clean energy substitution. • The main findings contribute significantly to energy conservation and carbon emission reduction for petrochemical industrial practice. Carbon emission peak and neutrality prospect has expedited the revolution of conventional energy utilization mode, particularly in highly energy-intensive industries. The petrochemical industry bears great responsibility for energy conservation and carbon emission reduction. TES (Total Energy System) retrofit schemes in the petrochemical industry classified as REST (Retrofitting through Energy-Saving Techniques) and RSFC (Retrofitting through Substituting Fossil fuel with Clean energy) have emerged in large numbers recently. It is challenging for energy managers to optimize and assess TES retrofit schemes simultaneously and globally, once clean energy supply is involved. State-of-the-art assessment and optimization method for TES retrofitting is urgently needed. This work proposes a novel optimization and assessment method based on the exergy conversion and consumption processes to figure out the most cost-effective retrofit schemes in view of exergy analysis. The method features with the simulation of TES, the clean energy substitution for fossil fuel, the optimization of the subsystems, and the exergy efficiency assessment of retrofit schemes. The double-parallel-loop application framework is then presented, which deals with the optimization and assessment of RSFC and REST simultaneously. Combined plants of continuous catalytic reforming and aromatic extraction plants along with their matched TES are investigated. A MINLP optimization model is formulated and programmed with GAMS software. The optimal results show that the total exergy consumption decreased by 3200 kW with clean energy substitution. Sensitivity analysis explores the energy conservation benefits and exergy efficiency improvement when clean energy with different qualities and quantities substituting for fossil fuel, which provides valuable information for feasibly implementing retrofit schemes. Comparison of scenarios reveals the interacting influence between the implementation of RSFC and REST, which is significant for decision-making when multiple retrofit schemes are alternatives. Real-world case investigations demonstrate the validation and efficacy of the proposed method. The main findings of this study are significant and quantitative references for petrochemical industrial practice, which would contribute to energy conservation and carbon emission reduction in the future. [ABSTRACT FROM AUTHOR]

The modern scenario reveals that the world is facing energy crisis due to the dwindling sources of fossil fuels. Environment protection agencies are more concerned about the atmospheric pollution due to the burning of fossil fuels. Alternative fuel research is getting augmented because of the above reasons. Plant seed oils (vegetable oils) are cleaner, sustainable, and renewable. So, it can be the most suitable alternative fuel for compression ignition (CI) engines. This paper reviews the availability of different types of plant seed oils, several methods for production of biodiesel from vegetable oils, and its properties. The different types of oils considered in this review are cashew nut shell liquid (CNSL) oil, ginger oil, eucalyptus oil, rice bran oil, Calophyllum inophyllum, hazelnut oil, sesame oil, clove stem oil, sardine oil, honge oil, polanga oil, mahua oil, rubber seed oil, cotton seed oil, neem oil, jatropha oil, egunsi melon oil, shea butter, linseed oil, Mohr oil, sea lemon oil, pumpkin oil, tobacco seed oil, jojoba oil, and mustard oil. Several methods for production of biodiesel are transesterification, pre-treatment, pyrolysis, and water emulsion are discussed. The various fuel properties considered for review such as specific gravity, viscosity, calorific value, flash point, and fire point are presented. The review also portrays advantages, limitations, performance, and emission characteristics of engine using plant seed oil biodiesel are discussed. Finally, the modeling and optimization of engine for various biofuels with different input and output parameters using artificial neural network, response surface methodology, and Taguchi are included. [ABSTRACT FROM AUTHOR]

The combustion of fossil fuels for providing heat and power in the process industries is a major contributor of CO2 emissions. Heat integration methods have been widely used for energy-saving retrofit projects to improve the energy efficiency of process plants, reducing fuel consumed and consequently CO2 emissions. It is not straightforward to identify the most appropriate strategy for CO2 emissions reduction, as a wide range of options are available, including fuel switching, reducing energy demand through efficiency improvements, retrofit of heat exchanger networks, etc. The economic impact and design constraints of each option need to be considered. A systematic approach is presented to allow evaluation of trade-offs between the cost of emissions reduction options and the effect on overall CO2 emissions. The approach applies a hierarchical conceptual design procedure. The proposed procedure is applied to a case study to demonstrate how an economic retrofit solution to reducing site-wide CO2 emissions can be systematically developed and evaluated. [ABSTRACT FROM AUTHOR]

Globally, approximately 600–700 million tonnes/yr. of solid waste (SW) and 250–300 million tonnes/yr. of fecal sludge (FS) are not managed in an environmentally safe manner. Conversion of these two waste streams using this ratio (2–3: 1 of SW: FS) to produce biocrude for fossil fuel substitution would act as an integrated waste to energy approach to address current global crises (GHGs emissions, climate change, and global warming). This study took the opportunity to produce petroleum-like biocrude through co-liquefaction of organic solid waste (OSW) and fecal sludge (FS) and optimized crude production yield and quality by varying feedstock ratios (1:0, 1:3, 1:1, 3:1, and 0:1) and temperature (280–340 °C). A higher synergistic effect was observed at feedstock ratio 3:1 (OSW: FS) and 320 °C with 52% biocrude yield, of which 64% was lighter-fraction (C < 20). The produced light crude contained 60% ester, 14% heterocyclic, and 12% fuel hydrocarbon fractions and exhibited a heating value of 42.7 MJ/kg, suggesting a potential candidate for petro crude (42–49 MJ/kg) substitution. This energetically feasible process (energy recovery 86% and energy consumption ratio 0.36) would provide a revenue of US$ 467.8 per metric ton of waste feedstock, validating the high economic prospects for a cleaner production pathway. [Display omitted] • Organic waste-sludge co-liquefaction enhanced decarboxylation and esterification. • A maximum bio-oil yield of 52% with 64% lighter-fraction was obtained at 320 °C. • Co-liquefied bio-oil exhibited a 42.7 MJ/kg energy value, similar to petro crude. • A low energy consumption ratio (0.36) revealed the net energy gain of the process. • Co-liquefaction would provide a revenue of US$ 467.8/MT of waste feedstock. [ABSTRACT FROM AUTHOR]

Hydrogen and Compressed Natural Gas are great alternatives to the pure fossil fuels. Many researches confirm the advantages of using hydrogen and natural gas blended together for the internal combustion engine in both areas of improving performances and reducing emission levels. In a short to medium range terms, the air pollution throughout the globe could be significantly reduced by using HCNG in the internal combustion engine and in many other applications with the substitution of using HCNG as a main source of fuel or as a secondary source of fuel such as the dual fuel operation system in the diesel vehicle. This paper investigates the emission characteristics of using HCNG as a secondary source of fuels on a EURO 4 diesel vehicle with four cylinders of 2494 cc displacement D4D commonrail direct injection diesel engine comparing to the original diesel operation with diesel and HCNG blended dual fuel operation. The experiments were conducted with minimum pilot diesel injection into the engine and maximum additional HCNG into the engine with using H2 electrolyzer for hydrogen supplies. In this experiment, the pilot diesel and HCNG blended were operated with special designed closed loop stepping motor diesel to CNG dual fuel system and hydrogen electrolyzer for the internal combustion engine. The results indicated that the average CO emission decreased by 12.97%, HC emission decreased by 15.84%, NOx emission decreased by 1.16% and PM emission decreased by 9.14% with the diesel HCNG dual fuel mode comparing to the pure diesel operation from low RPM (800) to highest RPM (4000). [ABSTRACT FROM AUTHOR]