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Innovative technological paradigm-based approach towards biofuel feedstock
Abstract
Biofuels produced from renewable energy biomass are playing a more significant role because of the environmental problems resulting from the use of fossil fuels. However, a major problem with biofuel production is that despite the range of feedstock that can be used, raw material availability varies considerably. By combining a series of theories and methods, the research objective of this study is to determine the current developments and the future trends in biofuel feedstock. By combining technological paradigm theory with literature mining, it was found that biofuel feedstock production development followed a three-stage trajectory, which was in accordance with the traditional technological paradigm - the S-curve. This new curve can be divided into BFDP (biofuel feedstock development paradigm) competition, BFDP diffusion, and BFDP shift. The biofuel production diffusion velocity model showed that there has been constant growth from 2000, with the growth rate reaching a peak in 2008, after which time it began to drop. Biofuel production worldwide is expected to remain unchanged until 2030 when a paradigm shift is expected. This study also illustrates the results of our innovative procedure - a combination of the data analysis system and the technological paradigm theory - for the present biofuel feedstock soft path that will lead to this paradigm shift, with integrated biofuel production feedstock systems expected to be a significant new trend.
... Biofuels like bioethanol have emerged as a promising alternative to fossil fuels (Thangaraj et al. 2024). Produced from renewable resources, bioethanol has attracted significant attention for its potential to lower greenhouse gas emissions, support sustainable energy production, and reduce dependence on non-renewable fossil fuels (Asase et al. 2024;Xu and Li 2017;Chen et al. 2015;Su et al. 2015). However, current bioethanol production methods largely rely on food crops such as corn and sugarcane, which raises concerns about food security and competition for agricultural resources. ...
In this study, Turbinaria conoides and Gelidium elegans were evaluated for their potential in bioethanol production. The process involved breaking down the cellulose in these seaweeds into glucose, which was then fermented by Saccharomyces cerevisiae to produce ethanol. The glucose and ethanol yields for T. conoides were 4.3 g kg−1 and 2.8 g g−1, respectively, while G. elegans demonstrated higher yields of 9.8 g kg−1 and 5.2 g g−1. To optimize the saccharification conditions, various operational factors including temperature, acid concentration, and incubation time were explored to maximize sugar detection. The optimal conditions for T. conoides were identified as 7.5% w/v H2SO4 at 140 °C for 45 min, achieving 41.8% dry weight (DW) sugar yield. In contrast, G. elegans achieved a higher sugar yield of 48.5% DW under conditions of 10% w/v H2SO4 at 140 °C for 60 min of incubation. Following saccharification, the biomass was subjected to hydrolysis and fermentation, with G. elegans yielding a maximum ethanol concentration of 14.13 gL−1 in less than 60 h. To confirm the presence of bioethanol, Gas Chromatography-Mass Spectroscopy (GC–MS) analysis was performed, identifying and quantifying the bioethanol compounds. Additionally, Nuclear Magnetic Resonance spectroscopy was employed to verify the structural composition of the bioethanol. The results of this research indicate that bioethanol production from seaweed, particularly G. elegans, is a feasible and promising alternative energy source. G. elegans showed especially favorable results in terms of yield and efficiency. As a renewable and carbon–neutral energy source, bioethanol from these seaweeds could play a pivotal role in future energy systems, contributing to global efforts in mitigating climate change and reducing fossil fuel dependence. This study opens new avenues for research and commercial bioethanol production from marine biomass, fostering a more sustainable and eco-friendly energy future.
... The growth curve has been widely used to model technological life cycles and determine current maturity Islam 1995, 1998;Yoon et al. 2018;Sinigaglia et al. 2022). Many studies have assumed that the evolutionary technological process has an S-shaped growth, with the growth curves fitted to identify the technology life cycle revealing several distinct stages; emerging, growth, maturity, and saturation (Gao et al. 2013;Ernst 1997;Xu and Li 2017;Li et al. 2021). This study used the patent activities over the technological life cycle and applied the growth curve and S-curve concepts to analyze the current and future biomass power generation trends. ...
Biomass power generation technologies, which are now mature and competitive, can alleviate power shortages, reduce the damaging environmental effects of coal-based power generation, and provide alternative renewable energy. While understanding trends is essential for making policies and decisions, few studies to date have examined biomass power generation’s technological evolutionary development path from a patent data perspective. This paper uses patent data to reveal the biomass power generation technological evolutionary trajectory. Using growth curve and citation network approaches, the evolution of the core technologies and the main trajectories over time were identified. After simulations and predictions based on the logistic growth curve, it was revealed that biomass power generation had entered technological maturity and would meet saturation in 2031. Main path analysis was introduced to trace the technological trajectory. The patent citation analysis revealed six main technology paths. Further analysis identified biomass power generation hybridization, the use of waste to generate power, and bioenergy with carbon capture and storage as potential technologies to achieve negative emissions.
... Generally, biofuel has been widely produced from renewable sources such as crops, plant materials, animal by-products, and recycled waste [4,5]. Among these, biofuel from non-edible oil (triglycerides) was found to be an up-andcoming alternative for the second generation biofuel [6]. The conventional first-generation biofuel or fatty acid methyl ester (FAME) is derived from a transesterification reaction. ...
The need to explore a sustainable manner to produce hydrocarbon-like biofuel has attracted tremendous interest. A series of bimetallic catalysts comprised of Fe and Ni with different Ni loadings supported on hexagonal mesoporous silica (HMS) were synthesized for the production of hydrocarbon-like biofuel via deoxygenation (DO) reaction without the use of external hydrogen. The bimetallic 10Fe40Ni/HMS catalyst possesses a high conversion (96.1%) and selectivity towards C8-C20 hydrocarbon (91.8%) during the DO reaction. This is because the finely dispersed Fe and Ni consisting of NiO and NiFe2O4 demonstrate strong acidity along with higher amount of Brönsted-Lewis acid properties. The DO reaction of triglycerides with bimetallic Fe and Ni supported on HMS is a sustainable process to produce hydrocarbon biofuel.
... The recent worldwide attention given to renewable energy sources is a result of raised concerns over long-term effects of global warming and new developments in the petroleum geopolitics [1]. In this context, owing to several other advantages regarding their sustainability, technical adaptability and environmental impact, biofuels are considered a promising alternative for mitigating greenhouse gas emissions [2]. ...
Biodiesel is a renewable, non-toxic and sustainable biofuel, considered to be the main candidate for a fossil fuel alternative in many countries. However, its manufacturing process results in about 0.2 to 3 L of effluent per litre of biodiesel produced. In addition to an inherently high organic load, its composition includes by-products, traces of unreacted chemicals and catalysts, which inhibit microorganism growth and prevent its direct treatment by tertiary methods. In this context, this work aims to evaluate the combination of the coagulation-flocculation technique with dissolved air flotation (DAF). Real wastewater samples were obtained by synthesising biodiesel from soybean oil in-loco and performing the required washing procedures. The highest turbidity reduction efficiency (92.03%) was obtained using 1200 of clay. By using response surface methodology, it was possible to analyse the effect of the chosen experimental factors and show that the best results (81.28%, 58.95% and 89.34% for turbidity, oil and grease and chemical oxygen demand - respectively) were obtained using 925 of clay and 1000 of coagulant. Ultimately, clay proved to be an efficient coadjutant in the removal of organic matter, oils, grease, suspended solids and soluble organic matter from the biodiesel wastewater. Moreover, its low cost over traditional flocculants makes it an attractive alternative to industrial wastewater treatment processes.
... With the gradual maturity of technical paradigm theory system, the application fields of the technical paradigm are becoming more and more extensive, involving energy, electricity, economy, finance, science and technology. There are many studies on technology paradigm in energy field, such as hydropower [14,15], geothermal energy [16], wind energy [17], biofuel [18], bioethanol [19], natural gas and renewable energy hybrid power generation [20], carbon-free hydrogen production [21]. In short, the low-carbon technology represented by renewable energy has a good development and is a trend in the future energy development [22]. ...
Photovoltaic (PV) has been regarded as the most promising, technically viable large-scale renewable energy source for a sustainable society. However, as the demand for solar energy is generally rising, the world needs to fundamentally reconsider the development of PV generation technology. The objective of this study is to propose a comprehensive method to study the role of technological paradigms in the development of PV generation, and to contribute to PV generation policy recommendations and system management. A novel document data mining analysis system and the technological paradigm theory are used to conduct the study. PV generation technology paradigm composed of paradigm competition, diffusion and shift is established to explain the technological changes in the use of PV energy. In this paper, the autoregressive moving average model is used to make short-term forecasts of the PV generation installed capacity, and to compare with the data predicted by Prospective Industry Research Institute. The results show that the forecasting method herein is effective and reliable. Also, this paper discusses the benefits and barriers of PV generation technology. However, to achieve higher market share in electricity generation, more support policies, multi-level cooperation, technical support and capital investment are needed. Moreover, this study provides an analysis framework for the soft path analysis of PV generation technology to achieve sustainable PV technological development.
... If the feedstock used for advanced biofuels derives from the organic fraction of wastes and residual streams from agriculture and forestry, then a key challenge is the efficient mobilisation patterns for year-round, sustainable provision of raw materials [191,192]. Other challenges also include: i) biodiversity loss, soil carbon and soil erosion risk [193] from over-harvesting agricultural and forest feedstocks [194] and ii) collection and sorting of the organic fraction from variable quality wastes. ...
Advanced biofuels are among the available options to decarbonise transport in the short to medium term especially for aviation, marine and heavy-duty vehicles that lack immediate alternatives. Their production and market uptake, however, is still very low due to several challenges arising across their value chain. So far policy has established targets and monitoring frameworks for low carbon fuels and improved engine erformance but has not yet been sufficient to facilitate their effective market uptake. Their market roll-out must be immediate if the 2030 targets are to be met. Analysis in this paper reiterates that the future deployment of these fuels, in market shares that can lead to the desired decarbonisation levels, still depends largely on the integration of tailored policy interventions that can overcome challenges and improve upstream and downstream performance.
The work presented aims to i) inform on policy relevant challenges that restrict the flexible, reliable and costefficient market uptake of sustainable advanced biofuels for transport, and ii) highlight policy interventions that, have strong potential to overcome the challenges and are relevant to current policy, Green Deal and the Sustainable Development Goals (SDGs).
... Biodiesel is the largest fraction of biofuels produced in Europe, accounting for nearly 37% of the global production [1]. The transesterification process to produce biodiesel from triglycerides generates large quantities of crude glycerol as a by-product [2][3][4][5][6]. ...
We report the role of the acidity of support during the selectivity hydrogenolysis of glycerol over supported bimetallic palladium–ruthenium (PdRu) catalysts. The PdRu nanoparticles were supported on a series of metal oxides and zeolitic supports via the modified impregnation method and tested for the liquid-phase hydrogenolysis of glycerol using gaseous hydrogen. The relative acid site densities of selected catalysts were determined by ammonia temperature-programmed desorption and pyridine desorption experiments. Based on these studies, we report a direct correlation between the catalytic activity (conversion and 1,2 propane diol yield) and two different acid sites (strong acid sites and very strong acid sites). Besides zeolite-supported catalysts, TiO2 supported PdRu nanoparticles exhibit moderate catalytic activity; however, this catalyst shows high selectivity for the desired C–O bond cleavage to produce C3 products over the undesired C–C bond cleavage to produce < C3 products.
This article is part of a discussion meeting issue ‘Science to enable the circular economy’.
... First-generation biofuels are mainly obtained from food crops, e.g., corn, wheat, soybean, sugarcane, and sunflower oil (Adekunle et al., 2016). However, due to food shortages in some parts of the globe and the increasing effect of food sources used for biofuels on their global prices, food-versus-fuel becomes an important issue (Hassan et al., 2015;Xu and Li, 2017). Hence, the use of waste for energy production has attracted major interest in nonfood, inexpensive, and broadly available materials, lignocellulosic feedtsocks, which are important substrates for the production of second-generation biofuels (Bhatia et al., 2017;Jain and Agrawal, 2018). ...
The softwood pine and hardwood poplar were subjected to NaOH and Na2CO3 alkaline pretreatments for their conversion into ethanol. The resulting solids were characterized in detail for structural modifications. Both alkaline pretreatments enhanced ethanol yields, and the NaOH pretreatment at 93 °C resulted in the highest increase in ethanol yields of 297.5 and 249.5 % for pine and poplar woods, respectively, as compared to untreated woods. In all cases, the content of lignin and hemicellulose in pretreated solids was decreased by the pretreatments, while glucan contents, accessible surface area, and enzymatic hydrolysis yields were increased. New correlations between the accessible surface area, lignin removal, and the ethanol yields were obtained for both feedstocks, indicating that the accessibility of enzyme to the surface area is the most important factor affecting enzymatic hydrolysis. The results also showed that the solute exclusion technique is a simple approach that can be applied to predict ethanol yields from pine and poplar. Among the pretreatment conditions employed for soft- and hardwood, the NaOH pretreatment at 93 °C is the most efficacious. The glucose yields were 8.4 % and 13.1 % for untreated pine and poplar woods, respectively. However, pretreatment at 93 °C with NaOH increased the glucose yield to 46.5 % and 69.3 % for pine and poplar, respectively.
... Considered a CO 2 -neutral energy source, biomass shows promise as being one of the most abundant renewable energy sources in the world [4]. Thus, the use of biofuels derived from biomass is one of the options that could help in reducing both the world's dependence on oil and CO 2 emissions [5]. ...
Brazil has the world’s second largest cattle herd, which produces 1.9 billion tons of cattle manure per year. This work describes, for the first time, the processing of cattle manure by pyrolysis at 400, 500, and 600 °C in a rotary kiln reactor, as an alternative means of treating this waste to produce second generation biofuels. The biomass was mainly composed of hemicellulose (18.24%), cellulose (14.24%), and lignin (6.09%), with high ash content (18.86%). Pyrolysis of the cattle manure at 500 °C resulted in the best bio-oil yield (5.8% organic phase; 34.4% aqueous phase). The bio-oil consisted mainly of phenolic compounds such as phenol and 3-vinyl-phenol. The results for the biochar were indicative of its potential use in agricultural applications for correcting soil acidity. The biochars produced at higher temperatures presented a high degree of aromaticity, indicating the formation of a more stable material for the purposes of carbon sequestration.
... By 2035, biofuels could realistically provide at least a quarter of the estimated world's TPES of 623 EJ. To increase the proportions of renewables in the TPES, innovative feedstocks or inputs are required [8]. A significant source of biomass for renewable energy is available globally in the form of agricultural waste. ...
Cotton stalk (CS) plant residue left in the field following harvest must be buried or burned to prevent it from serving as an overwintering site for insects such as the pink bollworm (PBW). This pest incurs economic costs and detrimental environmental effects. However, CS contains lignin and carbohydrates, like cellulose and hemicelluloses, which can be converted into a variety of usable forms of energy. Thermochemical or biochemical processes are considered technologically advantageous solutions. This chapter reviews potential energy generation from cotton stalks through combustion, hydrothermal carbonization, pyrolysis, fermentation, and anaerobic digestion technologies, focusing on the most relevant technologies and on the properties of the different products. The chapter is concluded with some comments on the future potential of these processes.
... Advances in Microbiology age have become of increased interest in recent decades; however, the production of alternative fuels like biofuels is economically unfavourable compared to the fossil fuel market. Despite this, many biofuels (e.g., bioethanol, biogas and biodiesel), are promising alternatives due to their potential sustainability and low environmental impact [1] [2] [3] [4]. Furthermore, many of these biofuels can be utilised by conventional means (e.g., internal combustion engines) when supplimented with fossil fuels [5]. ...
The demand for fuel for utilisation of machinery and transport has culmi-nated in large amounts of fossil fuel usage in the last century. The environ-mental dangers attached with the usage of fossil fuels have created a large demand for alternative sources of fuels. There is an array of polysaccharides contained within macroalgae, such as mannitol, cellulose and laminarin. These polysaccharides have potential for production of alternative biofuels; however, they are not easily accessible for biological digestion. By pretreat-ment of macroalgae with enzymes, these polysaccharides may be easier to ac-cess by microbes, allowing effective utilization in anaerobic digestion. Sac-charina latissima, available in abundance on the Norwegian coast line, is a brown macroalgae with a high level of carbohydrates. This study assesses the ability for utilisation of enzymatically pre-treated Saccharina latissima for production of biogas through anaerobic digestion. The harvested Saccharina latissima was analysed to contain 30.11 ± 2.30 g of reducing sugars per 100 g of dry sample upon enzymatic hydrolysis. This was able to yield 459 ± 30 mL per gVS of biogas through anaerobic digestion, with a methane content of 56%. This suggests a biomethane potential of 1760 m3 per ha of productive sea floor growing Saccharina latissima. An evaluation of this process has been performed to demonstrate the industrial potential of Saccharina latissima in biogas production.
... Moreover, there are various renewable energy sources usually found on Earth, including biomass, solar, wind, and nuclear sources, which can substitute fossil fuels [12,[20][21][22][23][24][25]. More importantly, the consumption of renewable energy is a potential mechanism for the growth of economic, industrial, and agricultural sectors, domestic needs, and transportation to serve fundamental needs of human beings [9,18,22,[26][27][28][29]. However, these renewable energy sources have inevitably generated several problems during its handling, associated with the disposal of waste and radioactive pollution, derived from biomass and nuclear energy respectively [21,30,31]. ...
A series of modified hexagonal mesoporous silica (HMS) supported by various Ni loading (5 wt% Ni, 10 wt% Ni, 40 wt% Ni and 100 wt% Ni) have been synthesized and systematically characterized. The resultant Ni catalysts improved the performance of the deoxygenation (DO) of triolein at a reaction temperature of 380 °C in a simple glass batch reactor under a solvent-free condition and are hydrogen-free. The incorporation of Ni loading into the HMS framework casued the catalytic activity to increase when compared to that of HMS. Surprisingly, 10 wt% Ni/HMS catalyst exhibited the highest conversion. It was observed that 10 wt% Ni loading was highly dispersed on the HMS which is capable of achieving 92.5% and 95.2% of conversion and selectivity, respectively. This is due to the synergistic effect of Si-O-Ni bonding and high dispersion of NiO on HMS. In this respect, the nature of catalyst support such as pore size and the high surface areas of HMS play an important role in enhancing the catalytic performance of DO reaction. This study has revealed that Ni/HMS catalyst is a promising catalyst that can be applied to the development of sustainable biofuel from non-edible oil.
... However, the depletion of the fossil energy sources and the concern over the global climatic change has intensified the discovery and applications of the alternative fuels [2][3][4]. In this context, biofuels (which is in the form of biodiesel, bioethanol, and biogas) are considered to be promising options due to several advantages, namely sustainability, environmentally friendly and good adaptability [5][6][7]. They can be used in existing combustion engines after blending with petroleum diesel [8]. ...
... CiteSpace is a visual analysis software which is designed for scientific literature research, and its cluster analysis is used to find the foci and display it in a visual way [20,21], which can help to explore the research foci, the evolution trend, and the frontier of the field of biomass energy technology. From the visual graphs generated through CiteSpace, the trend foci which were found and expressed in the keywords and clusters are in accordance with the characteristics of technological paradigm theory [22][23][24]. ...
Renewable energy plays a significant role in the world for obvious environmental and economic reasons with respect to the increasing energy crisis and fossil fuel environmental problems. Biomass energy, one of the most promising renewable energy technologies, has drawn increasing attention in recent years. However, biomass technologies still vary without an integrated framework. Considering the theory of a technological paradigm and implementing a literature analysis, biomass technological development was found to follow a three-stage technological paradigm, which can be divided into: BETP (biomass energy technological paradigm) competition, BETP diffusion, and BETP shift. Further, the literature review indicates that waste, like municipal solid waste (MSW), has the potential to be an important future trend in the world and waste-to-energy (WTE) is designed for sustainable waste management. Among WTE, anaerobic digestion has the potential to produce energy from waste sustainably, safely, and cost-effectively. The new BETP technological framework proposed in this paper may offer new research ideas and provide a significant reference for scholars.
... However, the depletion of the fossil energy sources and the concern over the global climatic change has intensified the discovery and applications of the alternative fuels [2][3][4]. In this context, biofuels (which is in the form of biodiesel, bioethanol, and biogas) are considered to be promising options due to several advantages, namely sustainability, environmentally friendly and good adaptability [5][6][7]. They can be used in existing combustion engines after blending with petroleum diesel [8]. ...
In this study, an integrated biomass conversion concept of producing liquid biofuels from brown marine macroalga Padina tetrastromatica was investigated. The algal biomass was collected from the Mandapam coastal region and processed under laboratory. Various parameters were studied to extract crude lipids from the biomass. A kinetic study was conducted for extracting the lipids from the biomass, which follows the first order kinetics and the lipid yield was 8.15 wt.%. The activation energy; Ea = 34.314 kJ mol À1 and their thermodynamic parameters were determined. Since the crude algal lipids contain high amount of free fatty acids, a sequential transesterification technique was examined and 7.8% of biodiesel (78 mg/g algal biomass) yield was obtained. The biodiesel was analyzed by 1 H and 13 C–NMR spectroscopy and the conversion yield was estimated. Further, the biodiesel fuel properties were investigated and found that all the features fit the required ASTM D6751 specification limits. The residual bio-mass after lipid extraction was further explored for bioethanol production through the anaerobic fermentation process. The ethanol yield obtained after saccharification and fermentation were estimated and 161 mg/g residue biomass was reported. The theoretical yield of conversion of hydrolysate to bioethanol was estimated and found to be 83.4%. Therefore, this study demonstrates that macroalga P. tetrastromatica biomass has great potential to produce liquid biofuels such as biodiesel and bioethanol.
The valorization of marine macroalgal biomass is among the most promising international programs focusing on the sustainable exploitation of marine environment. However, macroalgal biomass remains unexploited in Tunisia, even though it represents a highly abundant renewable biomass. The excessive proliferation of several algal species causes severe environmental disorders. The objective of this work is to study the potential use of macroalgae as biofuels feedstock in the Mediterranean region and particularly in Tunisia. This study focuses on certain macroalgal species collected from Bizerte and Tunis lagoons (e.g., Chaetomorpha linum, Enteromorpha intestinalis, Gracillaria gracillis, Ulva rigida, Gracillaria verrucosa, Cystoseira brachycarpa, Laurencia obtusa, Cystoseira sedoides, and Dictyopteris polypodioides). The macroalgae’s biochemical composition was determined in a way that maximizes its valorization. To achieve this objective, a process of three steps was performed. First, the macroalgal biomass was pretreated by dilute sulfuric acid. Then, an enzymatic saccharification was performed to produce fermentable sugars. Finally, the obtained sugars were converted into bioethanol using Saccharomyces cerevisiae yeast. In fact, our experiments show that the maximum protein content of 16.22% ± 0.270 was obtained with G. verrucosa, whereas the maximum carbohydrates content of 58.46% ± 1.52% was obtained with D. polypodoies. This leads us to believe that macroalgae constitute a potential source of fiber and proteins. After a sulfuric acid pretreatment. The maximum reducing sugars and bioethanol yields were obtained, respectively, were of 324.6 mg/gDM (dry matter) and 0.24 g/gDM.
The valorization of marine macroalgal biomass is among the most promising international programs focusing on the sustainable exploitation of marine environment. However, macro-algal biomass remains unexploited in Tunisia even though it represents a renewable and highly abundant biomass. This causes several environmental disorders due to the excessive proliferation of several algal species.
The objective of this work is to study the potential use of macroalgae as biofuels feedstock in the Mediterranean region and particularly in Tunisia. This study focuses on certain macroalgal species collected from Bizerte and Tunis lagoons. It reports the biochemical characterization of the studied macroalgae in order to determine their possible valorization areas and demonstrate their richness in high value molecules. In fact, our experiments show that the maximum protein content of 16.22%±0.270 was obtained with G. verrucosa and the maximum carbohydrates content of 58.46%±1.52 was obtained with Dictyopteris polypodoies. This leads us to believe that macroalgae constitute a potential source of fiber and proteins. After a sulfuric acid pretreatment, the macroalgae’s solid fractions were hydrolyzed using cellic Ctec2 enzymatic extract leading to a maximum reducing sugars yield of 324.6 mg/gDM. Monomeric sugars from the studied macroalgae hydrolyzates were fermented, leading to maximum ethanol yield of 0.24g/gDM.
The shortage of landfill space and the environmental pollution from urbanization and industrialization have led to an increase in the recycling and reuse of construction and demolition waste (CDW). Based on the technological paradigm, this paper proposes a closed-loop supply chain (CLSC) that integrates forward and reverse logistics and has multiple centers that regulate end-of-life CDW recycling and promote new product remanufacturing. Carbon price (CP) and carbon trading (CT) policies are then innovatively applied to manage the proposed supply chain, incentivize technological CDW disposal improvements, encourage policy adherence, and ensure that the economic and environmental benefits are built into the proposed CLSC. A mixed integer nonlinear programming model (MINLP) is developed to optimize the proposed CLSC by minimizing the total costs under the two carbon policies, and a real case study from China is given. Scenario analyses under the two carbon polices and practical policy suggestions are given, and comprehensive conclusions are provided in the conclusions. It was found that with the adjustment of recycling ratio, the proposed CDW CLSC was able to minimize total costs and overall carbon emissions. Moreover, the CP policy could improve the CDW recycling ratio from 19.4% to 85.3% and reduced carbon emissions by 6393 tonnes, and the CT policy should be an incentive policy to further encourage a higher recycling ratio and lower carbon emissions.
Excessive greenhouse gas (GHG)emissions have caused serious global warming and climate change. As the construction and demolition waste (CDW)end of life disposal process is a source of GHG emissions, it is vital to precisely estimate and reduce CDW end of life GHG emissions. The precise estimation of CDW information is essential for GHG estimation and reduction. However, as current CDW information and associated GHG estimation methods tend to be inaccurate, in this paper, a building information modeling (BIM)-based CDW information management system (IMS)is constructed that provides precise CDW information and a detailed information estimation process. To facilitate the accurate quantification of CDW disposal GHG emissions, mathematical formulae that include several GHG emission factors are proposed. A practical case study from China is then given to demonstrate the efficiency and effectiveness of the proposed methodology in quantifying and reducing CDW disposal GHG emissions. Accurate GHG emission estimation are determined for fifteen CDW disposal types and a comparison are conducted. Concrete was found to have the highest carbon dioxide, methane, and nitrous oxide emissions during transportation and the highest carbon dioxide emissions during handling, and organics were found to have the highest decomposition methane emissions. Targeted suggestions are given for source-separated CDW disposal GHG emission reduction based on the different emission characteristics. The combination of the BIM-based CDW IMS and the developed mathematical formulae were found to efficiently and accurately determine the CDW information and the associated GHG emissions, and therefore provide a practical guide to reducing the serious environmental damage generated by CDW disposal.
In the face of climate change and possible future energy shortages, the installed capacity of clean energy natural gas (NG) and renewable energy (RE) for power generation has gradually increased. However, in the traditional electricity market, there is significant competition between NG and RE as gas prices tend to be volatile, and RE power generation from wind and solar can be intermittent and somewhat unreliable, indicating that these power sources have some drawbacks if used to independently generate electricity; therefore, determining the balance of NG and RE to ensure are resilient, reliable, flexible and affordable power generation system is an important goal. Based on the data analysis system (DAS) combined with paradigm theory, this paper examines the possibility of hybrid power generation in the future. The results of literature analysis visualization show that NG or RE has its own power generation paradigm, and a paradigm shift towards hybrid NG-RE power generation was found, so NG-RE power generation paradigm (NGREP) was proposed. To determine whether these NG-RE hybrid energy developments could be more competitive than separate developments, a comparative analysis was conducted, from which it was found that hybrid NG-RE systems are more attractive in some cases. However, as there are still challenges in the developments of these systems, a driving force is needed to promote further hybrid developments. Using hybrid power generation in areas with plentiful wind, solar and gas can maximize energy use efficiency and significantly reduce carbon emissions and other pollutants.
Most prior studies have found that substituting biofuels for gasoline will reduce greenhouse gases because biofuels sequester
carbon through the growth of the feedstock. These analyses have failed to count the carbon emissions that occur as farmers
worldwide respond to higher prices and convert forest and grassland to new cropland to replace the grain (or cropland) diverted
to biofuels. By using a worldwide agricultural model to estimate emissions from land-use change, we found that corn-based
ethanol, instead of producing a 20% savings, nearly doubles greenhouse emissions over 30 years and increases greenhouse gases
for 167 years. Biofuels from switchgrass, if grown on U.S. corn lands, increase emissions by 50%. This result raises concerns
about large biofuel mandates and highlights the value of using waste products.
This study introduces and analyzes a novel system for algal biofuel production that synergistically integrates algal wastewater treatment with hydrothermal liquefaction (HTL) of wastewater biosolids and algae into bio-crude oil. This system maximizes the biofuel potential of wastewater inputs by internally capturing and recycling carbon and nutrients - a powerful concept referred to as multi-cycle nutrient reuse, which amplifies waste nutrients into multiple cycles of algal biomass and bioenergy production. We call this system “Environment-Enhancing Energy” (E2-Energy) because it can simultaneously improve conventional wastewater treatment by nutrient removal and production of a large amount of biofuel co-products. Moreover, E2-Energy resolves several key bottlenecks commonly associated with large-scale algal biofuel production including: contamination of target high-oil algal cultures, high nutrient costs/usage, unsustainable fresh water usage, and large energy inputs for dewatering/extraction. A series of algal cultivation and HTL experiments were conducted to confirm the primary steps and performance characteristics of the E2-Energy system. These experiments showed: (1) low-oil, mixed algal-bacterial biomass can be successfully cultured with the recycled HTL aqueous product; (2) both organics and nutrients are removed from wastewater during algal-bacterial biomass production (63-95% reduction); (3) this low-oil, algal-bacterial biomass can be converted into bio-crude oil via HTL with a high yield (50%) and a net positive energy balance; and (4) the HTL step re-releases nutrients to an aqueous phase product that can be recycled back to step (1). This repeating loop of steps 1-4 facilitates multi-cycle reuse of nutrients and thus provides biomass amplification. A mathematical model was also developed using STELLA® to simulate mass balances for long-term E2-Energy operations with internal recycling of nutrients and carbon. The model results showed that E2-Energy can amplify the biomass and biofuel production from wastewater by up to 10 times, which gives it the potential to replace all US petroleum imports using only current wastewater feedstocks and carbon dioxide from the atmosphere or point sources. Thus, E2-Energy represents a major paradigm shift—where wastewater treatment systems become optimized biofuel producers with enhanced effluent quality, which provides a viable and advantageous pathway to sustainable, carbon-neutral energy independence.
"Second generation" bioethanol, with lignocellulose material as feedstock, is a promising alternative for first generation bioethanol. This paper provides an overview of the current status and reveals the bottlenecks that hamper its implementation. The current literature specifies a conversion of biomass to bioethanol of 30 to ~50% only. Novel processes increase the conversion yield to about 92% of the theoretical yield. New combined processes reduce both the number of operational steps and the production of inhibitors. Recent advances in genetically engineered microorganisms are promising for higher alcohol tolerance and conversion efficiency. By combining advanced systems and by intensive additional research to eliminate current bottlenecks, second generation bioethanol could surpass the traditional first generation processes.
Obesity is a major global health problem. However, current therapeutic strategies for obesity are limited. Obesity results from an imbalance between energy intake and energy expenditure, and the treatment of obesity is based on the correction of this metabolic imbalance. Anti-obesity drugs can shift this balance in a favorable way by reducing food intake, altering metabolism, and by increasing energy expenditure. There is a growing consensus that pharmacotherapy is appropriate for many individuals who are unable to lose weight through less intensive measures. However, side effects may ensue phamacotherapy for obesity. Only two drugs (sibutramine and orlistat) are currently approved for the long-term treatment of obesity. Sibutramine inhibits the reuptake of serotonin and norepinephrine. Orlistat works by blocking the pancreatic lipase. However, phamarcotherapy may not be the ultimate resolution for obesity management. Because the underlying pathophysiology in each individual varies in many aspects, it is recommended to provide individualized and tailored medication in addition to other anti-obesity supportive treatments.
The soft path seeks to improve the overall productivity of water use and deliver water services matched to the needs of end users, rather than seeking sources of new supply.
The increasing demands placed on natural resources for fuel and food production require that we explore the use of efficient, sustainable feedstocks such as brown macroalgae. The full potential of brown macroalgae as feedstocks for commercial-scale fuel ethanol production, however, requires extensive re-engineering of the alginate and mannitol catabolic pathways in the standard industrial microbe Saccharomyces cerevisiae. Here we present the discovery of an alginate monomer (4-deoxy-l-erythro-5-hexoseulose uronate, or DEHU) transporter from the alginolytic eukaryote Asteromyces cruciatus. The genomic integration and overexpression of the gene encoding this transporter, together with the necessary bacterial alginate and deregulated native mannitol catabolism genes, conferred the ability of an S. cerevisiae strain to efficiently metabolize DEHU and mannitol. When this platform was further adapted to grow on mannitol and DEHU under anaerobic conditions, it was capable of ethanol fermentation from mannitol and DEHU, achieving titres of 4.6% (v/v) (36.2 g l(-1)) and yields up to 83% of the maximum theoretical yield from consumed sugars. These results show that all major sugars in brown macroalgae can be used as feedstocks for biofuels and value-added renewable chemicals in a manner that is comparable to traditional arable-land-based feedstocks.
Rising concern about the effect of greenhouse gas (GHG) emissions on climate change is pushing national governments and the international community to achieve sustainable development in an economy that is less dependent on carbon emitting activities – a vision that is usually termed a “low-carbon society” (LCS). Since the utilization of energy resources is the main source of GHG emissions, restructuring current energy systems in order to incorporate low-carbon energy technologies is essential for the realization of the LCS vision. Energy policies promoting the penetration of these technologies must view the role of energy in society as a system, composed of several energy resources, conversion technologies and energy demand sectors. The feasibility of the LCS in the future can be better understood by means of energy models. Energy models are valuable mathematical tools based on the systems approach. They have been applied to aid decision-making in energy planning, to analyze energy policies and to analyze the implications arising from the introduction of technologies. The design of the LCS requires innovative energy systems considering a trans-disciplinary approach that integrates multi-dimensional elements, related to social, economic, and environmental aspects. This paper reviews the application of energy models considering scenarios towards an LCS under the energy systems approach. The models reviewed consider the utilization of waste for energy, the penetration of clean coal technologies, transportation sector models as a sample of sectoral approaches, and models related to energy-for-development issues in rural areas of developing countries.
Sugar cane was introduced in Brazil for sugar production but it was later developed as a major source of fuelethanol, chemicals, materials and electricity. While food sugar continues to be the leading income source for plantations, synergy between food, fuel and materials production is possible as opposed to simple arithmetic reasoning that exacerbates the conflict in land use for different kinds of products. Cane plantations now occupy a small fraction of agricultural land in Brazil and the recent zoning laws allow a manifold expansion but only on currently under-used pasture land, while prohibiting expansion in any area covered by native vegetation, rain forests, flood plains and central savannas. The same positive results obtained in Brazil can be extended to many other countries in the world and to many other plants, like the eucalyptus, currently used in Brazil to make charcoal for smelting. The large emissions of waste carbon compounds from this process could be converted into valuable by-products for chemicals and energy production. Other synergies are described and new possibilities for land use and agriculture products are discussed, considering also environmental issues.
This paper attempts to highlight the role of bibliometrics in studying the dynamics of science and technology. Tools and techniques available in bibliometrics to address and understand the complexities of scientific fields are explored. The paper concludes that for wider acceptance among academicians and policy makers, bibliometric approach should ingrain itself within sociology and philosophy of science in studying the different facets of science and technology.
The objective of this study is to develop an econometric model for the diffusion of innovations at the individual country level, but which also allows the parameters of the process to differ systematically across countries. The conceptualization rests on behavioral and spatial theories of diffusion and extends the domain to international markets. The cross-national model of innovation diffusion which is developed highlights substantive differences and similarities among international markets. It also provides estimates for the diffusion parameters, even for countries where sales data are not available, thereby yielding some insights into the nature of the expected diffusion pattern in these countries prior to market entry.
In our 1975 monograph Evaluative Bibliometrics we discussed the many uses of publication and citation analysis in the evaluation of scientific activities, and some of the basic statistical properties of the scientific literature, particularly the skewness of the distributions of publications and citations, reference time distributions, and various anomalies in the citation patterns from one country to another. Over the last ten years we have devoted much of our energy to the development of an analogous research base and infrastructure for patent bibliometrics, that is for the use of patents, and patent citations in the evaluation of technological activities. There are remarkable similarities between literature bibliometrics and patent bibliometrics, and they are both applicable to the same wide ranges of problems. This paper will show that there are striking similarities between literature and patent distributions of national productivity, inventor productivity, referencing cycles, citation impact and within country citation preferences.
This article is an up-to-date review of the literature available on the subject of liquid biofuels. In search of a suitable fuel alternative to fast depleting fossil fuel and oil reserves and in serious consideration of the environmental issues associated with the extensive use of fuels based on petrochemicals, research work is in progress worldwide. Researchers have been re-directing their interests in biomass based fuels, which currently seem to be the only logical alternative for sustainable development in the context of economical and environmental considerations. Renewable bioresources are available globally in the form of residual agricultural biomass and wastes, which can be transformed into liquid biofuels. However, the process of conversion, or chemical transformation, could be very expensive and not worth-while to use for an economical large-scale commercial supply of biofuels. Hence, there is still need for much research to be done for an effective, economical and efficient conversion process. Therefore, this article is written as a broad overview of the subject, and includes information based on the research conducted globally by scientists according to their local socio-cultural and economic situations.
Recent empirical research shows that supply and demand conditions are typically not stable over time. The evolution of these factors and the firm's ability to impact the evolution have important pricing implications. This paper presents a general methodology for determining the optimal pricing strategy over the product life cycle given evolutionary forces in the environment, and derives the optimal pricing strategy for some well known dynamic models.
This paper investigates the role of the technological paradigm for the development of wind energy technology, and aims to contribute towards recommendations on technology policy and management. The paradigmatic research was conducted using a novel data analysis system (DAS) and a wind energy generation technological diffusion mathematical model. The wind energy generation technological paradigm (WEGTP) composed of paradigm competition, diffusion and shift was established to explain the technological changes in the use of wind energy. Simulation results show that the development of installed capacity for wind energy generation has a strong inertia force along with the S-curve. Global annual installed wind capacity reached a peak in 2012 and is estimated to be saturated by 2030. Hybrid wind and solar energy generation technology appeared to be more promising than wind energy technologies that rely only on onshore or offshore winds. To further accelerate wind energy development, specific subsidies and incentives need to be provided in areas such as capital costs and technological support.
Database Tomography (DT) is a textual database analysis system consisting of two major components: 1) Algorithms for extracting multiword phrase frequencies and phrase proximities (physical closeness of the multiword technical phrases) from any type of large textual database, to augment 2) interpretative capabilities of the expert human analyst. DT was used to derive technical intelligence from a hypersonic/supersonic flow (HSF) database derived from the Science Citation Index and the Engineering Compendex. Phrase frequency analysis by the technical domain expert provided the pervasive technical themes of the HSF database, and the phrase proximity analysis provided the relationships among the pervasive technical themes. Bibliometric analysis of the HSF literature supplemented the DT results with author/journal/institution publication and citation data. Comparisons of HSF results with past analyses of similarly structured near-earth space and Chemistry databases are made. One important finding is that many of the normalized bibliometric distribution functions are extremely consistent across these diverse technical domains.
Hydropower has long been considered the backbone of the power generation sector in low-carbon and sustainable energy systems. Yet, as reliance on hydropower has been generally declining, the world is awakening to the need to fundamentally rethink the way hydropower is developed and managed. The paper proposes a systematic methodology to research the development trends and find a more sustainable hydropower path. Literature mining using the data analysis system and the technological paradigm theory were adopted to conduct the research. The keyword visualization results were found to meet the laws for the three phases of the technological paradigm. Specific key areas, such as small hydropower plants, hybrid power systems, and hydropower from seawater were identified as past, present and near future trajectories. To further accelerate hydropower development, specific subsidies and incentives need to be provided in areas such as capital costs and technological support. The study paves the way for a soft path solution which complements the hard path in hydropower field.
Bio-fuels are important because they replace petroleum fuels. There are many benefits for the environment, economy and consumers in using bio-fuels. Bio-oil can be used as a substitute for fossil fuels to generate heat, power and/or chemicals. Upgrading of bio-oil to a transportation fuel is technically feasible, but needs further development. Bio-fuels are made from biomass through thermochemical processes such as pyrolysis, gasification, liquefaction and supercritical fluid extraction or biochemical. Biochemical conversion of biomass is completed through alcoholic fermentation to produce liquid fuels and anaerobic digestion or fermentation, resulting in biogas. In wood derived pyrolysis oil, specific oxygenated compounds are present in relatively large amounts. Basically, the recovery of pure compounds from the complex bio-oil is technically feasible but probably economically unattractive because of the high costs for recovery of the chemical and its low concentration in the oil. (c) 2005 Elsevier Ltd. All rights reserved.
Recent empirical research shows that supply and demand conditions are typically not stable over time. The evolution of these factors and the firm's ability to impact the evolution have important pricing implications. This paper presents a general methodology for determining the optimal pricing strategy over the product life cycle given evolutionary forces in the environment, and derives the optimal pricing strategy for some well known dynamic models.
The use of geothermal energy and its associated technologies has been increasing worldwide. However, there has been little paradigmatic research conducted in this area. This paper proposes a systematic methodology to research the development trends for the sustainable development of geothermal energy. A novel data analysis system was created to research the geothermal energy utilization trends, and a technological paradigm theory was adopted to explain the technological changes. A diffusion velocity model was used to simulate and forecast the geothermal power generation development in the diffusion phase. Simulation results showed that the development of installed capacity for geothermal generation had a strong inertia force along with the S-curve. Power generation from geothermal power sources reached a peak in 2008 and is estimated to be saturated by 2030. Geothermal energy technologies in hybrid power systems based on other renewable energy sources look to be more promising in the future.
Three alternative processes for the production of liquid transportation biofuels from sugar cane bagasse were compared, on the perspective of energy efficiencies using process modelling, Process Environmental Assessments and Life Cycle Assessment. Bio-ethanol via two biological processes was considered, i.e. Separate Hydrolysis and Fermentation (Process 1) and Simultaneous Saccharification and Fermentation (Process 2), in comparison to Gasification and Fischer Tropsch synthesis for the production of synthetic fuels (Process 3). The energy efficiency of each process scenario was maximised by pinch point analysis for heat integration. The more advanced bio-ethanol process was Process 2 and it had a higher energy efficiency at 42.3%. Heat integration was critical for the Process 3, whereby the energy efficiency was increased from 51.6% to 55.7%. For both the Process Environmental and Life Cycle Assessment, Process 3 had the least potential for detrimental environmental impacts, due to its relatively high energy efficiency. Process 2 had the greatest Process Environmental Impact due to the intensive use of processing chemicals. Regarding the Life Cycle Assessments, Process 1 was the most severe due to its low energy efficiency.
Elevated concentrations of atmospheric greenhouse gases (GHGs), particularly carbon dioxide (CO2), have affected the global climate. Land-based biological carbon mitigation strategies are considered an important and viable pathway towards climate stabilization. However, to satisfy the growing demands for food, wood products, energy, climate mitigation and biodiversity conservation-all of which compete for increasingly limited quantities of biomass and land-the deployment of mitigation strategies must be driven by sustainable and integrated land management. If executed accordingly, through avoided emissions and carbon sequestration, biological carbon and bioenergy mitigation could save up to 38 billion tonnes of carbon and 3-8% of estimated energy consumption, respectively, by 2050.
Excessive use of fossil fuels to satisfy our rapidly increasing energy demand has created severe environmental problems, such as air pollution, acid rain and global warming. Biofuels are a potential alternative to fossil fuels. First- and second-generation biofuels face criticism due to food security and biodiversity issues. Third-generation biofuels, based on microalgae, seem to be a plausible solution to the current energy crisis, as their oil-producing capability is many times higher than that of various oil crops. Microalgae are the fastest-growing plants and can serve as a sustainable energy source for the production of biodiesel and several other biofuels by conversion of sunlight into chemical energy. Biofuels produced from microalgae are renewable, non-toxic, biodegradable and environment friendly. Microalgae can be grown in open pond systems or closed photobioreactors. Microalgal biofuels are a potential means to keep the development of human activities in synchronization with the environment. The integration of wastewater treatment with biofuel production using microalgae has made microalgal biofuels more attractive and cost effective. A biorefinery approach can also be used to improve the economics of biofuel production, in which all components of microalgal biomass (i.e., proteins, lipids and carbohydrates) are used to produce useful products. The integration of various processes for maximum economic and environmental benefits minimizes the amount of waste produced and the pollution level. This paper presents an overview of various aspects associated with biofuel production from microalgae, including the selection and isolation of microalgal species, various cultivation and harvesting techniques as well as methods for their subsequent conversion into biofuels.
Due to energy shortage, global warming and climate change, balanced development of energy security, economic growth, and environmental protection (3Es) has become a major energy policy issue and prompted the development of low-carbon economies. The goals of exploiting new clean energies, improving the efficiency of conventional energy sources, and improving renewable energy technologies have gathered considerable attention of governments worldwide. Among the many clean energies, hydrogen energy plays an important part in new clean energy fields nowadays. However, little has been done in discussing the technology forecasting for the hydrogen energy development. Therefore, this study predicts the technological S-curves for hydrogen energy and fuel cell technologies by integrating bibliometric and patent analysis into the logistic growth curve model, which includes generation, storage, proton exchange membrane fuel cell (PEMFC), solid oxide fuel cell (SOFC) and direct methanol fuel cell/direct alcohol fuel cell (DMFC/DAFC). Empirical analysis is via an expert survey and co-word analysis using the USPTO database to obtain useful data. The results demonstrate that technologies for generating and storing hydrogen have not yet reached technological maturity, and the fuel cell technology is either in the mature stage or approaching maturity.
The biofuels include bioethanol, biobutanol, biodiesel, vegetable oils, biomethanol, pyrolysis oils, biogas, and biohydrogen. There are two global biomass based liquid transportation fuels that might replace gasoline and diesel fuel. These are bioethanol and biodiesel. World production of biofuel was about 68 billion L in 2007. The primary feedstocks of bioethanol are sugarcane and corn. Bioethanol is a gasoline additive/substitute. Bioethanol is by far the most widely used biofuel for transportation worldwide. About 60% of global bioethanol production comes from sugarcane and 40% from other crops. Biodiesel refers to a diesel-equivalent mono alkyl ester based oxygenated fuel. Biodiesel production using inedible vegetable oil, waste oil and grease has become more attractive recently. The economic performance of a biodiesel plant can be determined once certain factors are identified, such as plant capacity, process technology, raw material cost and chemical costs. The central policy of biofuel concerns job creation, greater efficiency in the general business environment, and protection of the environment.
This paper investigates the factors determining how rapidly the use of a new technique spreads from one firm to another. A simple model is presented to help explain differences among innovations in the rate of imitation. Deterministic and stochastic versions of this model are tested against data showing how rapidly firms in four industries came to use twelve important innovations. The empirical results seem quite consistent with both versions of the model.
This is a study of factors responsible for the wide cross-sectional differences in the past and current rates of use of hybrid seed corn in the United States. Logistic growth functions are fitted to the data by states and crop reporting districts, reducing differences among areas to differences in estimates of the three parameters of the logistic: origins, slopes, and ceilings. The lag in the development of adaptable hybrids for particular areas and the lag in the entry of seed producers into these areas (differences in origins) are explained on the basis of varying profitability of entry, "profitability" being a function of market density, and innovation and marketing cost. Differences in the long-run equilibrium use of hybrid corn (ceilings) and in the rates of approach to that equilibrium (slopes) are explained, at least in part, by differences in the profitability of the shift from open pollinated to hybrid varieties in different parts of the country. The results are summarized and the conclusion is drawn that the process of innovation, the process of adapting and distributing a particular invention to different markets and the rate at which it is accepted by entrepreneurs are amenable to economic analysis.
Science and technology for renewable and sustainable energy are indispensable for our future society and economics. To meet the goal of sustainable energy development, there is a growing body of research efforts world wide. The planner of energy research has to grasp the broader coverage of scientific and technological research, and make decisions on effective investment in promising and emerging technologies especially under circumstances of limited resources. In this paper, we track emerging research domains in energy research by using citation network analysis. Our analysis confirms that the fuel cell and solar cell are rapidly growing domains in energy research. We further investigate the detailed structure of these two domains by clustering publications in these domains. Each citation cluster has characteristic research topics, and there is a variety of growth trends among the clusters. By using citation network analysis, we can track emerging research domains among a pile of publications efficiently and effectively.
Biomass and bio-fuels have gained a growing interest as sustainable and renewable energy. In this paper, we perform a citation network analysis of scientific publications to know the current structure of biomass and bio-fuel research. By clustering and visualizing the network, we revealed their taxonomic structure. Emerging technologies are detected by analyzing the average publication year of clusters. According to the results, bio-diesel and hydrogen production are the most rapidly developing domains among biomass bio-fuel researches. We also analyzed the position of each cluster in the global structure of research. By using citation counts within and out of the cluster, we categorized each cluster into the following four categories: (I) topic specific; (II) domain specific; (III) global link; and (IV) specific & global. For research domains of category (III) or (IV), it is difficult that single technology overcomes the current limitation of bio-energy productions. Research on lignocellulose feedstock is a typical case where knowledge from other scientific disciplines is necessary.
An overview is first given of the soft-energy notion as well as of its social impact. Then a discussion is given of the logical and theoretical considerations that social scientists must address if the claims for soft-energy are to be considered researchable. Finally, a set of methodological considerations are sketched. In particular, the specifics of the soft-energy system as enumerated by Amory Lovins are examined. 54 refs.
137Cs was applied with simulated rainfall to 0.25 m2 soil boxes at an intensity of 20 mm hr−1 for 30 minutes. Ten simulations were performed on six soil boxes at 2° and 4° slopes. Soil was compacted in one box to simulate the effects of tractor wheelings. The depth distribution of 137Cs was analysed in six soil cores. In addition, a 1 m long × 16 cm wide soil trough was placed under the simulator until a constant rate of overland flow was generated. 137Cs was added at four locations at increasing distance from the trough outflow. Overland flow, drainage water and suspended sediments were collected and analysed separately for 137Cs in all experiments.At 2° slopes, the highest proportion of the 137Cs input was lost by drainage. At 4° slopes, and with compaction, the greatest amount of 137Cs was eroded with sediment. Approximately 10% of the added 137Cs was lost from the compacted soil over the ten simulations. 137Cs retention in the upper 10 cm of the profile ranged from more than 95% (compacted soil) to less than 45% (uncompacted soils). Results from the trough experiment suggested that 137Cs could be preferentially adsorbed by sediments entrained in overland flow.
This paper reviews the current state of biomass potential studies, discusses the essential driving factors for energy crop potentials and shows the results of a scenario analysis for worldwide energy crop potentials till 2050. The results of previous potential estimates vary widely. A comparison of 19 different assessments showed energy crops potentials ranging from 0 EJ/yr to 1,272 EJ/yr in 2050. However, relatively little information is available for the short and mid-term perspective (2020 and 2030). As an increasing demand of energy crops can be expected, the energy crop potentials for 133 individual countries are calculated on the premise that food demand takes priority. Applying a scenario approach with three different scenarios for the years 2010, 2015, 2020 and 2050 the resulting potential changes in a "business as usual" development from 27 EJ in 2010 to 96 EJ in 2050. In comparison, the "sustainable land use" scenario shows much lower potentials with 18 EJ in 2010 and 16 EJ in 2050. The "environment and health" scenario finally produces an almost stable worldwide energy crop potential in the order of 40 EJ for the investigated timeframe.
The production costs of a lignocellulosic ethanol process, both currently and projected for 2020, were compared to a corn ethanol process, to determine its economic competitiveness. A techno-economic model was used to estimate the current production costs for a base-case, 50 ML yr –1 softwood facility, as well as provid-ing a basis for cost-reduction test cases assessing different feedstock, scaling, enzyme, and coproduct options. The progress ratio indicated that lignocellulosic ethanol could be competitive with corn ethanol by 2020, based on volumes mandated by 2007 EISA. However, cost reductions must occur across all components of the produc-tion process. The ambitious cellulase enzyme cost reductions that have been projected were shown to be chal-lenging as cellulase costs still need to be signifi cantly lower than those of amylase enzymes on a unit-of-protein basis. Opportunities for capital cost reduction relative to fi rst-generation plants were primarily restricted to the pre-treatment/hydrolysis unit operations, with operational conditions such as the severity of pre-treatment and hydroly-sis residence times, signifi cantly infl uencing operating costs. Alternative operating strategies, such as maximizing hydrolysis rate with shorter residence times rather than maximizing ethanol yield and using the unhydrolyzed residue for heat and power production, showed some promise. Increasing the size of the facility to 1 BL yr –1 output substan-tially reduced the per unit capital costs, but not to a level competitive with an average (150 ML yr –1) corn ethanol facility.
The present paper addresses some of the many possible uses of citations, including bookmark, intellectual heritage, impact tracker, and self-serving purposes. The main focus is on the applicability of citation analysis as an impact or quality measure. If a paper's bibliography is viewed as consisting of a directed (research impact or quality) component related to intellectual heritage and random components related to specific self-interest topics, then for large numbers of citations from many different citing paper, the most significant intellectual heritage (research impact or quality) citations will aggregate and the random author-specific self-serving citations will be scattered and not accumulate. However, there are at least two limitations to this model of citation analysis for stand-alone use as a measure of research impact of quality. First, the reference to intellectual heritage could be positive or negative. Second, there could be systemic biases which affect the aggregate results, and one of these, the “Pied Piper Effect”, is described in detail. Finally, the results of a short citation study comparing Russian and American papers in different technical fields are presented. The questions raised in interpreting this data highlight a few of the difficulties in attempting to interpret citation results without supplementary information.
Leydesdorff (Leydesdorff, 1998) addresses the history of citations and citation analysis, and the transformation of a reference mechanism into a purportedly quantitive measure of research impact/quality. The present paper examines different facets of citations and citation analysis, and discusses the validity of citation analysis as a useful measure of research impact/quality.
In this paper, the modern biomass-based transportation fuels such as fuels from Fischer–Tropsch synthesis, bioethanol, fatty acid (m)ethylester, biomethanol, and biohydrogen are briefly reviewed. Here, the term biofuel is referred to as liquid or gaseous fuels for the transport sector that are predominantly produced from biomass. There are several reasons for bio-fuels to be considered as relevant technologies by both developing and industrialized countries. They include energy security reasons, environmental concerns, foreign exchange savings, and socioeconomic issues related to the rural sector. The term modern biomass is generally used to describe the traditional biomass use through the efficient and clean combustion technologies and sustained supply of biomass resources, environmentally sound and competitive fuels, heat and electricity using modern conversion technologies. Modern biomass can be used for the generation of electricity and heat. Bioethanol and biodiesel as well as diesel produced from biomass by Fischer–Tropsch synthesis are the most modern biomass-based transportation fuels. Bio-ethanol is a petrol additive/substitute. It is possible that wood, straw and even household wastes may be economically converted to bio-ethanol. Bio-ethanol is derived from alcoholic fermentation of sucrose or simple sugars, which are produced from biomass by hydrolysis process. Currently crops generating starch, sugar or oil are the basis for transport fuel production. There has been renewed interest in the use of vegetable oils for making biodiesel due to its less polluting and renewable nature as against the conventional petroleum diesel fuel. Biodiesel is a renewable replacement to petroleum-based diesel. Biomass energy conversion facilities are important for obtaining bio-oil. Pyrolysis is the most important process among the thermal conversion processes of biomass. Brief summaries of the basic concepts involved in the thermochemical conversions of biomass fuels are presented. The percentage share of biomass was 62.1% of the total renewable energy sources in 1995. The reduction of greenhouse gases pollution is the main advantage of utilizing biomass energy.
This paper first proposes a modeling framework to study diffusion of innovations which exhibit strong interaction with the institution systems across which they diffuse. A unique character of such generic innovation is that specific applications are continually developed during its diffusion. This self-propagation in continual applications generation, which is dependent upon the cumulative installed base of the technological innovation, can be modeled to lead to a dynamic changing carrying capacity in an otherwise simple logistic diffusion curve. The cumulative installed base is dependent upon the price of technology and the cost learning dynamics. This paper utilizes a multi-factors learning function to represent such learning dynamics. Empirical estimates from our model are compared with those from other logistics curve formulations and are shown to better fit the annual PV production data during the past quarter century in the case of Japan.The very fact that the potential of this class of innovation can be leveraged only if it interacts closely with the institution highlights the importance of institutional determinants of adoption and diffusion of such innovations like PV. We therefore attempt to put forward an institutional framework, based on viewing PV as a technology platform, to consider PV diffusion beyond mathematical and empirical modeling. Some future research directions are also proposed.
Biomass resources include wood and wood wastes, agricultural crops and their waste byproducts, municipal solid waste, animal wastes, waste from food processing and aquatic plants and algae. Biomass is used to meet a variety of energy needs, including generating electricity, heating homes, fueling vehicles and providing process heat for industrial facilities. The conversion technologies for utilizing biomass can be separated into four basic categories: direct combustion processes, thermochemical processes, biochemical processes and agrochemical processes. Thermochemical conversion processes can be subdivided into gasification, pyrolysis, supercritical fluid extraction and direct liquefaction. Pyrolysis is the thermochemical process that converts biomass into liquid, charcoal and non-condensable gases, acetic acid, acetone and methanol by heating the biomass to about 750 K in the absence of air. If the purpose is to maximize the yield of liquid products resulting from biomass pyrolysis, a low temperature, high heating rate, short gas residence time process would be required. For high char production, a low temperature, low heating rate process would be chosen. If the purpose is to maximize the yield of fuel gas resulting from pyrolysis, a high temperature, low heating rate, long gas residence time process would be preferred.
In many cases of technological development, successive generations of a technology evolve, each more efficient than its predecessor. It has been assumed when modeling and forecasting the adoption of these technologies that the market reaction to each generation was similar. Using the terminology of the Bass model, this similarity is encapsulated in the assumption that the coefficients of innovation and imitation are constant. New data for two and three generations of mobile telephone technology from eleven countries are modeled. The modeling framework used—simultaneous estimation for successive generations using a full information maximum likelihood procedure—demonstrates that, in most cases, the hypothesis of constant coefficients can be rejected. Use of a model with changing coefficients is shown to considerably improve forecasting performance. These results were reinforced by analysis of data for four generations of IBM mainframes.
The literature on new technology diffusion is vast, and it spills over many conventional disciplinary boundaries. This paper surveys the literature by focusing on alternative explanations of the dominant stylized fact: that the usage of new technologies over time typically follows an S-curve. The most commonly found model which is used to account for this model is the so-called epidemic model, which builds on the premise that what limits the speed of usage is the lack of information available about the new technology, how to use it and what it does. The leading alternate model is often called the probit model, which follows from the premise that different firms, with different goals and abilities, are likely to want to adopt the new technology at different times. In this model, diffusion occurs as firms of different types gradually adopt it. There are actually many ways to generate an S-curve, and the third class of models which we examine are models of density dependence popularized by population ecologists. In these models, the twin forces of legitimation and competition help to establish new technologies and then ultimately limit their take-up. Finally, we look at models in which the initial choice between different variants of the new technology affect the subsequent diffusion speed of the chosen technology. Such models often rely on information cascades, which drive herd like adoption behaviour when a particular variant is finally selected.
It is argued that technological progress is marked by a series of discrete “barriers” and “breakthroughs,” which create new fields of technological opportunity. These are not random events, although their exact timing is undoubtedly very difficult to predict. They occur when and where they do because of discontinuities in the laws of nature. The technological life cycle can be defined as the period from a major breakthrough which opens up a new territory for exploitation to the next major barrier. It is characterized by a rapid increase in marginal productivity of R&D to a peak, followed by a more-or-less continuous decline thereafter, as the territory is gradually exhausted. This model is qualitatively consistent with the well-known “S-shaped curve” phenomenon, describing measures of technological performance over time. The model is also qualitatively consistent with Schumpeter's explanation of the so-called Kondratieff or “long” wave.
The term biofuel is referred to liquid, gas and solid fuels predominantly produced from biomass. Biofuels include energy security reasons, environmental concerns, foreign exchange savings, and socioeconomic issues related to the rural sector. Biofuels include bioethanol, biomethanol, vegetable oils, biodiesel, biogas, bio-synthetic gas (bio-syngas), bio-oil, bio-char, Fischer-Tropsch liquids, and biohydrogen. Most traditional biofuels, such as ethanol from corn, wheat, or sugar beets, and biodiesel from oil seeds, are produced from classic agricultural food crops that require high-quality agricultural land for growth. Bioethanol is a petrol additive/substitute. Biomethanol can be produced from biomass using bio-syngas obtained from steam reforming process of biomass. Biomethanol is considerably easier to recover than the bioethanol from biomass. Ethanol forms an azeotrope with water so it is expensive to purify the ethanol during recovery. Methanol recycles easier because it does not form an azeotrope. Biodiesel is an environmentally friendly alternative liquid fuel that can be used in any diesel engine without modification. There has been renewed interest in the use of vegetable oils for making biodiesel due to its less polluting and renewable nature as against the conventional petroleum diesel fuel. Due to its environmental merits, the share of biofuel in the automotive fuel market will grow fast in the next decade. There are several reasons for biofuels to be considered as relevant technologies by both developing and industrialized countries. Biofuels include energy security reasons, environmental concerns, foreign exchange savings, and socioeconomic issues related to the rural sector. The biofuel economy will grow rapidly during the 21st century. Its economy development is based on agricultural production and most people live in the rural areas. In the most biomass-intensive scenario, modernized biomass energy contributes by 2050 about one half of total energy demand in developing countries.
The global annual potential bioethanol production from the major crops, corn, barley, oat, rice, wheat, sorghum, and sugar cane, is estimated. To avoid conflicts between human food use and industrial use of crops, only the wasted crop, which is defined as crop lost in distribution, is considered as feedstock. Lignocellulosic biomass such as crop residues and sugar cane bagasse are included in feedstock for producing bioethanol as well. There are about of dry wasted crops in the world that could potentially produce of bioethanol. About of dry lignocellulosic biomass from these seven crops is also available for conversion to bioethanol. Lignocellulosic biomass could produce up to of bioethanol. Thus, the total potential bioethanol production from crop residues and wasted crops is , about 16 times higher than the current world ethanol production. The potential bioethanol production could replace of gasoline (32% of the global gasoline consumption) when bioethanol is used in E85 fuel for a midsize passenger vehicle. Furthermore, lignin-rich fermentation residue, which is the coproduct of bioethanol made from crop residues and sugar cane bagasse, can potentially generate both of electricity (about 3.6% of world electricity production) and of steam. Asia is the largest potential producer of bioethanol from crop residues and wasted crops, and could produce up to of bioethanol. Rice straw, wheat straw, and corn stover are the most favorable bioethanol feedstocks in Asia. The next highest potential region is Europe ( of bioethanol), in which most bioethanol comes from wheat straw. Corn stover is the main feedstock in North America, from which about of bioethanol can potentially be produced. Globally rice straw can produce of bioethanol, which is the largest amount from single biomass feedstock. The next highest potential feedstock is wheat straw, which can produce of bioethanol. This paper is intended to give some perspective on the size of the bioethanol feedstock resource, globally and by region, and to summarize relevant data that we believe others will find useful, for example, those who are interested in producing biobased products such as lactic acid, rather than ethanol, from crops and wastes. The paper does not attempt to indicate how much, if any, of this waste material could actually be converted to bioethanol.
A bibliometric analysis was applied in this work to evaluate global scientific production of geographic information system (GIS) papers from 1997 to 2006 in any journal of all the subject categories of the Science Citation Index compiled by Institute for Scientific Information (ISI), Philadelphia, USA. ‘GIS’ and ‘geographic information system’ were used as keywords to search parts of titles, abstracts, or keywords. The published output analysis showed that GIS research steadily increased over the past 10 years and the annual paper production in 2006 was about three times 1997s paper production. There are clear distinctions among author keywords used in publications from the five most productive countries (USA, UK, Canada, Germany and China) in GIS research. Bibliometric methods could quantitatively characterize the development of global scientific production in a specific research field. The analytical results eventually provide several key findings.