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The motivation of this paper is to investigate the resistance of countries' energy research and development (RD&D) expenditures to random shocks. The analysis includes the five countries (France, Germany, Japan, the United States, and the United Kingdom) that are the biggest investors in RD&D in fossil fuels, renewables, energy efficiency, and nuclear energy. Thus, economies will be able to take precautions against global shocks in producing sustainable energy policies. To achieve this aim, this paper uses the artificial neural network approach, which uses a distributed computing model that can store and generalize data after a learning period. Empirical results widely depend on countries and distinct energy technology policy fields. The key findings provide evidence that RD&D expenditures, except for renewables, do not tend to mean revert. The economies of Japan, Germany, and the United States should make more renewable investments to reduce the resistance of renewable energy sources to shocks and thus produce policies for both environmental sustainability and energy security. The economies of France and the United Kingdom can ensure energy security by continuing their sustainable energy policies. • Applied SDG policies focused on energy technology RD&D are presented. • The stochastic characteristics of energy technology investments are examined. • Carbon-reducing policies are recommended for the top five economies. • Energy technologies are perused through artificial intelligence approach. [ABSTRACT FROM AUTHOR]

This paper aims to holistically study hydrogen production options essential for a sustainable and carbon-free future. This study also outlines the benefits and challenges of hydrogen production methods to provide sustainable alternatives to fossil fuels by meeting the global energy demand and net-zero targets. In this study, sixteen hydrogen production methods are selected for sustainability investigation based on seven different criteria. The criteria selected in the comparative evaluation cover various dimensions of hydrogen production in terms of economic, technical, environmental, and thermodynamic aspects for better sustainability. The current study results show that steam methane reforming with carbon capture could provide sustainable hydrogen in the near future while the other technologies' maturity levels increase and the costs decrease. In the medium- and long-terms, photonic and thermal-based hydrogen production methods can be the key to sustainable hydrogen production. [Display omitted] • A holistic study of hydrogen production options for a sustainable and carbon-free future. • It outlines the benefits and challenges of hydrogen production methods. • Sixteen methods are selected for sustainability investigation based on seven different criteria. • It covers economic, technical, environmental, and thermodynamic aspects of sustainability. • It can help stakeholders deploy a hydrogen roadmap for a more sustainable future. [ABSTRACT FROM AUTHOR]

• Dependence on fossil fuel reduces the hazard of private sector investment in renewable energy sector. • The role of fossil fuel dependence decreases in countries with prior investment projects. • Changes in oil price have competing effects on investment hazard. • Regulatory quality and renewable energy policies stimulate private sector investments in developing countries. Given the rapid population growth and subsequent increase in energy demand in developing countries, private sector investment in renewable energy projects is key for sustainable economic development. However, the current energy mix is still dependent on conventional fossil fuels. The paper examines the time duration to private sector investment in renewable energy projects and how the hazard rate is affected by dependence on fossil fuels. Using data on private sector participation in renewable energy projects in 134 developing and middle-income countries for the (1990–2012) period, this paper applies multiple failure time model. The results show significant negative effects of fossil fuel consumption and fuel rent on investment likelihood. Consistent with literature, a set of socio-economic variables, such as renewable energy policy and energy security concerns, play an important role in increasing the likelihood of private sector investment in renewable energy technologies. The findings of the paper resonate with concerns of the international community regarding the effect of fossil fuel dependence on the rate of adoption of renewable energy sources in developing countries. [ABSTRACT FROM AUTHOR]

The small island developing states of the Pacific suffer from both the high cost of fossil fuel imports and from numerous climate-related disasters. These vulnerabilities will worsen unless there is a substantial global shift away from fossil fuels towards renewable energy (RE) sources, coupled with significant improvements in energy efficiency. Apart from traditional biomass-fuelled cooking, the most substantial uses of RE in the Pacific in 2016 were hydropower in some of the hillier island countries and the thousands of household photovoltaic (PV) systems in the remoter parts of island countries. This paper considers also the prospects for grid PV, geothermal, and biofuels – all of which have good technical potential in at least some islands. Barriers to wider use of RE in the region are mostly institutional and financial, but also include opportunity costs, environmental factors, and the limited skills base in small island states. The paper examines the mixed progress since the 1990s towards overcoming these barriers. The Fiji Electricity Authority has a reasonably realistic plan to have 81% of its supply from RE by 2020, drawing on hydropower (~ 50% in 2015), biomass (including bagasse), and some solar and wind. Tonga has its Renewable Energy Roadmap with clear milestones. Several other Pacific Island countries have ambitious RE targets but some are rather vague about how they are to be achieved. [ABSTRACT FROM AUTHOR]

In recent decades global warming has turned into an international concern. Anthropogenic Greenhouse gases (GHG) are produced through burning fossil fuel leading to an increase in the global warming effect; thus, GHG reduction contributes to mitigating climate change. Utilizing renewable energies, increasing efficiency of and capacity factor (CF) of existing power plants, and recycling waste energy in various industries are convenient solutions to improve the energy systems performance to reduce fossil fuel consumption, leading to GHG emission. So, there is a substantial need for planning and evaluating the energy systems in which various technologies are used, technically and economically. Theis study's main objectives are utilizing the capacity of renewable energies such as biomass, wind, solar, hydropower, and enhancement of CF and efficiency of the power plants in the Mazandaran region in the south of the Caspian Sea. The energy system considered for the region is modeled and analyzed by six scenarios in this paper. The results indicated that the share of renewable energies in electricity production could be increased from 5.4% to 47.7%. The results of cost analysis show that by applying the sixth scenario, which is integrated policies of increasing RER share and improvement of efficiency and capacity factor. The trends of total annual cost, CO 2 emission, and fossil fuel consumption are reduced compared to the business as usual (BAU) scenario. The average cost saved by this scenario is about 220 MUSD/year. The average amount of fossil fuels and CO 2 emission save are 11 TWh/year and 2.438 Mt/year between 2020 and 2030, respectively. [ABSTRACT FROM AUTHOR]

This research investigates the relationship between greenhouse gas (GHG) emissions and energy production and consumption patterns in 122 countries over the period from 1990 to 2020. Particular attention is paid to the role of different types of energy, including renewable, hydro and nuclear energy, as well as oil, gas and coal, in shaping GHG emissions. Unlike previous studies, the paper analyzes the full range of energy resources and focuses on different quantiles of data using the quantile-quantile regression (QQR) method. The results of this approach are compared with traditional quantile regression (QR) to assess its validity. Among the findings of this study are: (1) different parts of the energy mix have a heterogeneous impact on GHG emissions in different quantiles; (2) energy consumption patterns play a more significant role in shaping GHG emissions than production patterns; (3) increasing production and consumption of fossil fuels does not necessarily increase GHG emissions; (4) similarly, the development of renewable energy sources is not always accompanied by a reduction in GHG emissions. Our general conclusion is that existing climate policy requires significant diversification to not be focused only on renewable energy, which impact on GHG emissions is not as homogeneous as it usually considered, and which cannot solve the problem of raising emissions solely. Instead of this, it could be more rational to focus on the searching the ways of hydrocarbon industries sustainable development and support them in this journey, especially in the field of Scope 2 and Scope 3 operations management. • Impact of energy consumption and production on GHG emissions were analyzed for 122 countries in 1990–2020. • Quantile and Quantile-on-Quantile regression were used to catch the specifics of energy consumption and production patterns. • Two temporal breakpoints (1999/2000 and 2009/2010) were introduced to catch shifts in variables dependencies. • The influence of fossil fuels on GHG emissions is not homogeneous as it usually considered, the same is fare for renewables. • A promising option to reduce GHG emissions is carbon capture, utilization and storage (CCUS). [ABSTRACT FROM AUTHOR]

This paper presents a review of the optimization techniques and strategies applied to wind turbine performance optimization. The topic is addressed by identifying the most significant objectives, targets and issues, as well as the optimization formulations, schemes and models available in the published literature. The current energy demand combined with depletion of fossil-fuel reserves and stricter environmental regulations have led to the development of alternative renewable energy solutions like wind energy. The current 2030 United States target is to have at least 20% of the US energy supply by onshore and offshore wind farms. To meet these demands, wind energy costs have to be able to compete with traditional fossil fuel sources. Hence, it is essential and vital that wind turbine designers and manufactures search the optimal solution that fits the objectives under a set of design constraints. Throughout the last 30 years, the objective function has evolved from the earlier maximized metric of the power coefficient to the maximization of the annual energy production. Common alternatives such as blade mass minimization and maximization of the rotor thrust and torque have been examined. However, the main objective has been focused on the minimization of the cost of energy in order for wind energy to become more competitive and economically attractive. The purpose of this paper is to review previous work that undertakes the performance optimization of horizontal wind turbines by highlighting the main aspects when tackling the wind turbine optimization problem such as: objective functions, design constraints, tools and models and optimization algorithms. In addition, in a conclusion of the review, a discussion and argument about the challenges, issues and future developments are identified. [ABSTRACT FROM AUTHOR]

Many ports and terminals endeavor to enhance energy efficiency as energy prices have increased through years and climate change mitigation is a key target for the port industry. Stricter environmental regulations are adopted by authorities to limit pollutants and GHG emissions arising from energy consumption. Increasingly, port operational strategies and energy usage patterns are under scrutiny. To ingrain sustainability and environmental protection of ports, the use of innovative technology appears as a critical conduit in achieving a transition from a carbon-intensive port industry (dependent on fossil fuels) to a low-carbon port model by harnessing renewable energy, alternative fuels (e.g. LNG, hydrogen, biofuel), smarter power distribution systems, energy consumption measurement systems. In this context, this paper conducts a systematic literature review to analyze operational strategies (e.g. peak shaving, operations optimization), technology usage (e.g. electrification of equipment, cold-ironing, energy storage systems), renewable energy, alternative fuels and energy management systems (e.g. smart grid with renewable energy) for improving the energy efficiency and environmental performance of ports and terminals. Research gaps and future research directions are identified. Analysis shows that there is a great potential for ports to achieve further energy efficiency and researchers have many impactful research opportunities. • A detailed literature review on energy efficiency in ports and container terminals is conducted. • Operational strategies such as optimization of port operations and peak shaving methods are presented. • Technologies such as electrification of equipment, cold-ironing, energy storage systems, smart grid, microgrid are reviewed. • Renewable energy and clean fuel use in ports are presented. • Methods regarding energy consumption and emission measuring/assessment are detailed for ports. [ABSTRACT FROM AUTHOR]

The Norwegian Agrarian Association has the ambition to reduce greenhouse gas (GHG) emissions by 4–6 million tons of carbon dioxide equivalents (CO 2 -eq) by 2030 in the agricultural sector. As a part of this, 10–25% is expected to come from substituting fossil fuels with renewable energy sources. This paper focuses on the effects of phasing-out fossil fuel consumption in on-field tractor operations with electrification by introducing battery-electric and/or fuel cell tractors and on-site renewable energy generation and storage. The results show that electrification of on-field tractor operations can be a techno-economically feasible pathway to reduce tractor energy-use-related CO 2 emissions in the agricultural sector. Annual CO 2 emissions are observed to reduce by 69% in 2030 and 97% in 2050. However, the CO 2 reduction potential can vary significantly based on the farm type. In this regard, the analysis revealed high sensitivity to manufacturing costs of zero-emission tractors (ZETs), which in combination with a low utilization rate can render the investment to ZETs unprofitable. Moreover, electrification increases electricity consumption, especially peak electricity demand in the agricultural sector. This effect can be reduced with on-site renewable energy generation and energy storage systems. • TIMES-models with differing spatial and temporal resolutions are soft-linked. • The long-term effects of electrification in the agricultural sector in Norway are analysed. • Electrification of on-field tractor operations can reduce energy-use related CO 2 emissions. • Adverse effects of electrification can be mitigated with distributed energy generation. [ABSTRACT FROM AUTHOR]

Despite the positive momentum achieved by the renewable energy sector in recent years, there are substantial challenges that need the attention of the global community, and one of the more pressing issues is dealing with the deleterious external costs of power generation. One of the parameters to compare costs of energy across various technologies is levelised cost of energy (LCOE), but it has been conventional practice to neglect the external costs in estimating the LCOE of power generation technologies. Furthermore, as LCOE is a critical indicator for policy and decision makers, there is a need to juxtapose actual costs of renewable and conventional power generation technologies. This research paper attempts to internalise some of these external and GHG emission costs across various power generation and storage technologies in all the G20 countries, as they account for 85% of global power consumption. As future investment decisions are largely influenced by costs, estimates in this research prove renewables and storage to be far cheaper than fossil and nuclear sources by 2030, even without considering external costs. The myth that renewables are ‘way too expensive’ has been debunked repeatedly, and the cost decline of wind and solar photovoltaic (PV) technologies have outpaced most industry expectations. The results of this research not only substantiate this trend, but also statistically display that all the G20 countries have the opportunity to decrease their energy costs significantly, between now and 2030. Renewable energy technologies offer the lowest LCOE ranges across G20 countries in 2030. Utility-scale solar PV generally shows the lowest values ranging from 16 to 117 €/MWh el and onshore wind LCOE range is from 16 to 90 €/MWh el . Rooftop solar PV generally offers the next lowest LCOE ranging from 31 to 126 €/MWh el , followed by LCOE of offshore wind power ranging from 64 to 135 €/MWh el . Solar PV and battery systems are highly competitive on an LCOE basis at utility-scale ranging from 21 to 165 €/MWh el and at residential scale from 40 to 204 €/MWh el . The G20, as well as other countries, can continue to develop their economies in a sustainable manner, along with substantial co-benefits in adjacent policy fields such as higher national welfare, better health of citizens, lower respective health costs and improved energy security. [ABSTRACT FROM AUTHOR]

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

This paper investigates the effect of renewable energy consumption on material consumption, considering the relationship between Material Footrprint and Gross Domestic Product (GDP), and testing the assumptions of the Environmental Kuznets Curve. A STIRPAT variation is used to specify a model relating the Material Footprint to renewable energy consumption and GDP. The effect is tested for the Material Footprint of fossil fuels and for the Material Footprint of the other categories. The analysis is applied to the seven European countries with the highest proportion of renewable energy consumption. The model estimation shows that the relationship between GDP and Material Footprint follows an inverted N-shaped form, and that the renewable energy favours the reduction of the material consumption of fossil fuels. However, there is a positive effect between the renewable energy consumption and the Material Footprint of the other categories beyond fossil fuels. These results must be interpreted considering the context, as the development of renewable energy coincides with the effects of the 2008 crisis, which may distort the relation between the variables. To pose dematerialization scenarios, it seems necessary to consider reducing energy consumption even if it comes from renewable sources. • The hypotheses of the Environmental Kuzntes Curve are tested. • Renewable energy does not seem to contribute to dematerialization. • Renewable energy contributes to reducing the consumption of Fossil Fuels. • An inverted N-shaped relationship between the Material Footprint and GDP is verified. [ABSTRACT FROM AUTHOR]

The ever increasing rate of energy consumption, limited fossil fuels and pollution have made the expansion of renewable resources essential. Due to the suitable solar potential available in Iran, the use of solar energy has been developed more than other renewable resources. In this paper, photovoltaic (PV) panels are hybridized with battery banks and the power grid to provide electricity for 100 residential units and by performing a techno-economic-environmental analysis on the use of different solar tracking systems PV power generation is maximized. The final aim of this paper is to find the optimum scenario for reaching the highest efficiency along with emissions that are within the standard range. Also, the effect of grid sell back on the results is estimated and a sensitivity analysis is performed to generalize the results for other economic and climate conditions. Results show that the use of the solar tracking system significantly reduces the number of needed panels, but this size reduction is not always cost-effective due to the high cost of tracking units. The vertical tracking system indicated the best cost-efficiency with 0.241 $/kWh cost of energy and an average of 23% improvement on the output power. Although the dual-axis tracker improved power production by 32%, it was less cost-efficient. Sensitivity analysis indicated that with 33% renewable fraction and slightly different initial costs, the optimum cost of energy will vary from 0.227 to 0.255 $/kWh. • A grid-connected photovoltaic-battery system is optimized in different climates. • Techno-enviro-economic comparison of different solar tracking systems is done. • Residential demand at a standard level of CO 2 production is provided. • Vertical tracker is the most cost-effective system with 0.241 $/kWh cost of energy. • Power production is improved by 23%, compared to the without tracking scenario. [ABSTRACT FROM AUTHOR]

There is a considerable diversity of district heating (DH) technologies, components and interaction in EU countries. The trends and developments of DH are investigated in this paper. Research of four areas related to DH systems and their interaction with: fossil fuels, renewable energy (RE) sources, energy efficiency of the systems and the impact on the environment and the human health are described in the following content. The key conclusion obtained from this review is that the DH development requires more flexible energy systems with building automations, more significant contribution of RE sources, more dynamic prosumers׳ participation, and integration with mix fuel energy systems, as part of smart energy sustainable systems in smart cities. These are the main issues that Europe has to address in order to establish sustainable DH systems across its countries. [ABSTRACT FROM AUTHOR]

The energy sector situation in Palestine is highly different compared to other countries in the Middle East due to many reasons: non-availability of natural resources, unstable political conditions, financial crisis and high density population. Furthermore, Palestine depends on other countries for 100% of its fossil fuel imports and for 87% of its electricity imports. In addition high growth of population, increasing living standards and rapid growth of industrial have led to tremendous energy demand in Palestine in recent years. The total energy consumption per habitant in Palestine is the lowest in the region (0.79 MW h/inhabitant) and costs more than anywhere else in the Middle East countries. The primary goal of this paper is to analyze the current energy sector situation in Palestine and to highlight the status of the potential of renewable energy as an essential future energy source sector in Palestine. Regarding the main possibilities of RE, the wind speed averages (m/s) for main 5 cities were: Tubas 4.97, Salfeet 4.26, Ramallah 3.09, Hebron 2.90 and Jericho 1.32. With these data, Palestine can be considered as a country of moderate wind speeds. By the other hand, Palestine has a high solar energy potential about 3000 sunshine hours per year with a solar radiation (kW h/m 2 /day) for year 2013 of 8.27 in Ramallah, 7.51 in Hebron, 6.86 in Salfeet and 6.15 in Tubas. These values are encouraging to exploit the solar energy for different applications. This study highlights that the main renewable energy sources in Palestine are solar energy, wind energy and biomass, thereby the energy dependence on neighbouring countries may significantly decrease, when Palestine uses the available renewable energy sources. The renewable energies in Palestine open new perspectives for energy sector in order to prompt practices for sustainable development. [ABSTRACT FROM AUTHOR]

Biomass is low-carbon energy and has tremendous potential as an alternative to fossil fuels. However, the significant role of biomass in future low-carbon energy portfolio depends heavily on its consumption. The paper presents a first attempt to examine the spatial-temporal patterns of biomass consumption in the United States (US), using a novel method-spatial Seemingly Unrelated Regression (SUR) model, in order to strengthen the link between energy planning and spatial planning. In order to obtain the robust parameters of spatial SUR models and estimate the parameters efficiently, an iterative maximum likelihood method, which takes full advantage of the stationary characteristic of maximum likelihood estimation, has been developed. The robust parameters of models can help draw a proper inference for biomass consumption. Then the spatial-temporal patterns of biomass consumption in the US at the state level are investigated using the spatial SUR models with the estimation method developed and data covering the period of 2000–2012. Results show that there are spatial dependences among biomass consumption. The presence of spatial dependence in biomass consumption has informative implications for making sustainable biomass polices. It suggests new efforts to adding a cross-state dimension to state-level energy policy and coordinating some elements of energy policy across states are still needed. In addition, results consistent with classic economic theory further proves the correctness of applying the spatial SUR models to investigate the spatial-temporal patterns of biomass consumption. [ABSTRACT FROM AUTHOR]

With the surge in the fossil fuel prices and increasing environmental concerns, significant efforts have been made to propel and develop alternative energy technologies to cope with the energy shortage for island power grids. Recent advancements and developments on power electronic technologies have enabled the renewable energy sources to be grid-connected with gradually higher penetration in island electricity supply. Consequently, the utilization and efficiency of renewable energy resources in islands has received remarkable attention from both the academia and industry. In this paper, a brief overview on the current status of island energy resources is described. Then, the existing utilization status and development potential of various renewable generations for island power grids, including solar, wind, hydropower, biomass, ocean and geothermal energy, are investigated. Furthermore, the advanced technologies to improve the penetration level of island renewables, including energy storage techniques, hybrid renewable energy system, microgrid, demand side management, distributed generation and smart grid, are presented. [ABSTRACT FROM AUTHOR]

The continuous growth in size, complexity and energy density of data centres due to the increasing demand for storage, networking and computation has become a worldwide energetic problem. The emergent awareness of the negative impact that the uncontrolled energy consumption has on natural environment, the predicted limitation of fossil fuels production in the upcoming decades and the growing associated costs have strongly influenced the energy systems engineering work in the last decades. Therefore, the implementation of well known and advanced energy efficiency measures to reduce data centres energy demand play an important role not only to a supportable growth but also to reduce its operational costs. The carbon footprint is greatly influenced by the energy sources used. Therefore, there have been recent efforts to exploit and reuse or combine green energy sources in data centres to lower brown energy consumption and CO 2 emissions. This paper presents a comprehensible overview of the current data centre infrastructure and summarizes a number of currently available energy efficiency strategies and renewable energy integration into data centres and its characterization using numerical models. Moreover it would be necessary to develop dynamic models and metrics for properly understand and quantify the energy consumption and the benefits of applying the incoming energy efficiency strategies and renewable energy sources in the data centres. Thus, the researches or investors will be able to compare with reliability the different data centre designs and choose the best option depending on the renewable energy sources and capital available. [ABSTRACT FROM AUTHOR]

This paper aims to investigate the level of awareness and prevailing attitudes of the Oman government’s electrical sectors towards renewable energy. The geographical landscape of the Sultanate of Oman lends itself to energy generation from solar radiation, yet no decisive steps have been taken to initiate relevant projects that will reduce the country’s reliance on oil and gas in electricity production. This study is motivated by the need to better understand the obstacles that impede the implementation of renewable energy projects in Oman and the factors that cause delays in project initiation. To this end, we developed a questionnaire with sections intended for three government sectors: research groups, electrical companies and ministries, and regulatory bodies. Results indicate that ministries and regulatory bodies primarily support the increased exploitation of fossil fuels—a core reason for the slow adoption of renewable energy sources. Moreover, 82% of the respondents place priority on natural gas for use in power plants and more than 19% encourage the implementation of energy efficiency standards. All respondents consider renewable energy a viable future energy option and generally agree that the government should promote renewable energy and support relevant pilot projects. This study highlights the importance of immediately shifting to renewable energy and encouraging its development; a move necessary to alleviate the environmental risk posed by the use of fossil fuel-based energy. [ABSTRACT FROM AUTHOR]

Subsidies to fossil-fuel consumption have made China's energy system fragile and unsustainable. It is necessary for China to reform fossil-fuel subsidies and reflect the resource cost and environmental cost in energy prices. Considering the life-cycle external costs, this paper estimates the scale of fossil-fuel subsidy and the true cost of renewable energy in 2010 and evaluates impacts of increasing renewable energy subsidies and phasing out fossil fuel subsidies on macro-economy and energy system in China based on scenario analysis. Simulation results show that the negative impacts on economic growth can be reduced from 4.460% to 0.432%, if only 10% of fossil fuel subsidies were removed. Increasing subsidies for renewable energy has positive impacts on macroeconomic variables. Although the economic benefits per unit of subsidies for renewable energy are lower than those for fossil fuels by 0.06-0.19 CNY, the revenue gap can be narrowed by shifting more subsidies from fossil fuels to renewables. Increasing subsidies for renewable energy helps optimize China's energy system in three ways: the first is making energy consumption structure cleaner; the second is improving energy efficiency; and the third is addressing the problem of imbalanced distribution and consumption of energy. [ABSTRACT FROM AUTHOR]

The livestock sector is a key source of greenhouse gas emissions and other impacts. Poultry (meat and eggs) is the fastest growing livestock sector globally. Poultry housing, including both infrastructure and operating energy, may account for as much as 50% of the total non-renewable energy (non-RE) use and up to 20%–35% of some of the life cycle impacts of poultry production. The application of net zero energy (NZE) building technologies (i.e. that enable net zero non-RE consumption on site) for poultry housing represents a promising but under-considered mitigation strategy, which could help lessen reliance on fossil fuels and reduce greenhouse gas (GHG) emissions. Insights from commercial and residential net zero energy building (NZEB) research can, to a limited extent, inform design considerations for NZE poultry housing, but a variety of unique design considerations and challenges inherent to confined, intensive animal husbandry must be considered. Towards this end, this review seeks to: 1) identify insights from research of residential and commercial NZEBs that might be applied in designing NZE poultry housing; 2) quantify the magnitude and distribution of energy use in poultry housing in order to determine key energy consuming components; and 3) identify priority design considerations for NZEBs for intensive confined poultry production, taking into account the physiological requirements of poultry as well as specific requirements for intensive, confined production. To accomplish these goals, 249 relevant papers were identified and reviewed. It was found that, similar to commercial/residential applications, design strategies should focus on a combination of aspects respectively aimed at (1) reducing direct energy (DE) use via structural design, (2) improving the energy efficiency of active technology systems and (3) installing context-appropriate renewable energy (RE) generation systems. Some common passive design strategies like maximizing glazed area may be less applicable for poultry housing where photoperiod control is required. Heating (during heating seasons) and ventilation (during cooling seasons) are the two main contributors to DE use in poultry housing but vary considerably based on geography and climate. HVAC systems should hence be a priority focus, considering the high ventilation rates required in confined poultry housing in order to maintain air quality. However, any modifications to current technologies should be based on careful consideration of the physiological requirements of poultry (for example, ambient temperature, air quality, feed and water provision, etc.), along with local climatic factors, technical feasibility and availability of alternative technologies, as well as both environmental and economic payback times. [Display omitted] • Poultry is the fastest growing sub-sector of the GHG-intensive livestock sector. • Infrastructure and operating energy contributes 50% of non-renewable energy use. • Net zero energy buildings (NZEBs) are a potential mitigation strategy. • Research of commercial/residential NZEBS can inform design considerations. • Physiological requirements of poultry and confined production must be considered. [ABSTRACT FROM AUTHOR]

Biofuel manufacturing from renewable biomass through a smart manufacturing system is an important alternative to fossil fuels, which helps to decrease dependability on conventional fuel and decrease carbon emanations. By utilizing efficient labors, smart machines, and minimized energy utilization, the conventional biofuel manufacturing framework can be converted into a smart sustainable manufacturing framework. The existing conventional fuel demand can be replaced by biofuel. This study efforts to make pure biofuel with less amount of carbon emanations and energy utilization through a smart multi-type biofuel manufacturing framework, where the demand of the biofuel is selling price dependent. The different energy costs including air handling cost, lighting cost are calculated in this work-in-process inventory. The carbon emissions cost is included in every stage of this model. A variable demand has introduced for the maximization of profit. To reduce energy consumption and carbon emissions, a two-stage inspection cost with a variable manufacturing rate is taken to make the manufacturing process flexible such that the amount of impure biofuel is minimized. Although a random manufacturing rate is applied through a smart manufacturing system, still impure biofuel is manufactured. The impure biofuel is remanufactured again through refining just after the well-planned manufacturing ends. In this model, the multi-delivery technique is used such that a fixed amount of biofuel of n segments of the pure biofuel is transported to market places at predetermined intervals at the time of delivery frame. The classical optimization technique is used for continuous and differentiable variables and the mixed integer programming technique is utilized for discrete variables to maximize the total profit globally. To validate the model's usefulness, four numerical observations are studied. It is shown that by utilizing the said procedure, the percentage of impure biofuel can be decreased truly through the minimized energy consumption. The graphical representation and the sensitivity experiment show the impact of every parameter with the whole cost of the research paper. Numerical results assist to get the maximum profit and the optimum selling price of biofuel globally in a sustainable smart multi-type biofuel manufacturing system. [Display omitted] [ABSTRACT FROM AUTHOR]

• Algae biomass are a promising source of sustainable biofuel production. • Recent thermochemical routes for algae conversion to biofuels are discussed. • Challenges and perspectives of algae conversion to biofuels are discussed. • Future research on algae-derived biofuels is suggested. Biofuels have become an attractive energy source because of the growing energy demand and environmental issues faced by fossil fuel consumption. Algal biomass, particularly microalgae, has excellent potential as feedstock to be converted to bio-oil, biochar, and combustible syngas via thermochemical conversion processes. Third-generation biofuels from microalgal feedstock are the promising option, followed by the first-generation and second-generation biofuels. This paper provides a review of the applications of thermochemical conversion techniques for biofuel production from algal biomass, comprising pyrolysis, gasification, liquefaction, and combustion processes. The progress in the thermochemical conversion of algal biomass is summarized, emphasizing the application of pyrolysis for its benefits over other processes. The review also encompasses the challenges and perspectives associated with the valorization of microalgae to biofuels ascertaining the potential opportunities and possibilities of extending the research into this area. [ABSTRACT FROM AUTHOR]

The composition of worldwide energy consumption is undergoing tremendous changes due to the consumption of non-renewable fossil energy and emerging global warming issues. Renewable energy is now the focus of energy development to replace traditional fossil energy. Energy storage system (ESS) is playing a vital role in power system operations for smoothing the intermittency of renewable energy generation and enhancing the system stability. We divide ESS technologies into five categories, mainly covering their development history, performance characteristics, and advanced materials. Biomass storage and gas storage are also discussed, which are not considered in most reviews. After detailed research, the rapid development of each technology in recent years is introduced, and some representative research works are surveyed. We comprehensively summarized the advantages and disadvantages of various ESS technologies and presented several evaluation indicators for quantitative analysis. Hybrid ESS is also considered based on the complex market demand. Then, we investigate the applications of various ESS technologies as short-term, medium-term, and long-term storages in power systems, covering the power generation, transmission and distribution, and end-user. Finally, this paper reviews global developing trends, and identifies critical challenges and promising opportunities. • Comprehensively review five types of energy storage technologies. • Introduce the performance features and advanced materials of diverse energy storages. • Investigate the applications of various energy storage technologies. [ABSTRACT FROM AUTHOR]

The term "circular economy" has become more prevalent over the last decade, especially in the areas of sustainability, resource management and productivity. Globally, more national, public and private sector organizations are considering the concept in their daily operations. With growing concerns about the impacts of climate change, there are equally growing debates about curbing the impacts. One such debate is to transition from fossil fuels to renewable energy. This paper reviewed existing literature relevant to Africa's energy transition – whether it is enabled and can be guided by the principles of a circular economy. Various journal articles and business studies published between 2009 and 2019 were reviewed using a Systematic Literature Review Process. The study found that Africa's energy demand is expected to increase significantly, and it will be driven by industrialization and population growth. Most of sub-Saharan Africa's energy supply comes from renewable energy sources, while countries such as Algeria, Nigeria, Morocco, South Africa and Egypt (the Big Five) are still heavily dependent on fossil fuels. The researchers concluded that a circular economy approach can enable greater renewable energy uptake and transitioning. To support and enable a sustainable energy transition, regional finance institutions such as the African Development Bank and governments, can continue to finance more scalable technologies and adopt 'intentional' regulations which are guided by circular principles and a just-transition. Although data pertaining to how the transition can be underpinned by circularity is limited, there is great opportunity for more scientific and industry research that can provide further contextualized support. • The African Development Bank will no longer finance coal projects from 2020. • Africa's Big Five economies predominantly use fossil fuels such as coal and oil. • Positive economic growth and increasing energy demand are forecasted for the continent between 2030 and 2050. • Africa can leapfrog the transition from fossil fuel to renewable energy sources to sustainably address these forecasts. • Adopting and contextualising Circular Economy principles and models can optimise the energy transition. • However, more research is required to further unpack how this can be done across Africa. [ABSTRACT FROM AUTHOR]

Currently, 57.4% of the European Union (EU-28) population live in houses which usually need separate boilers to generate thermal energy. The research presented in this paper pertained to a detached house in the north-east of Poland, in which thermal energy was generated over 12 consecutive years by burning wood briquettes. This study analysed the quality and quantity of wood briquettes, energy consumption and cost of thermal energy generation for the house with the use of an automatic biomass burning unit, compared with other types of fuels. The annual consumption of briquette energy was 124.5 GJ year−1. The average annual cost of thermal energy generation for a house was 739 € year−1. When the cost of the boiler purchase and its service and fuel purchase costs were taken into account, the 12-year operating cost for a briquette-fired boiler was found to be similar to the operation cost for a coal-fired boiler and higher by 21% compared to willow chips-fired boiler. The operation of a boiler fired with other fuels, like pellets, natural gas or heating oil during the same period was more expensive by 39%, 46% and 157%, respectively. • Wood briquette can be successfully used in automatic boilers for as long as 12 years. • The average consumption of briquettes for thermal energy generation was 7 Mg year−1. • Average heat energy consumption per 1 m2 of the house area was 0.45 GJ. • 12 year operating cost for a briquette boiler was similar to the cost for a coal. • The operation cost for a pellets, gas and oil boiler was expensive by 39, 46, 157%. [ABSTRACT FROM AUTHOR]