The aim of this paper is to present and analyze the factors, motivations and criteria considered in the decision-making processes of the actors belonging to the biodiesel production chain in Brazil. The biodiesel prod...The aim of this paper is to present and analyze the factors, motivations and criteria considered in the decision-making processes of the actors belonging to the biodiesel production chain in Brazil. The biodiesel production chain consists of three main agents： the farmers, the soybean processing plants and the oil refinery/distributor. For the farmers organized in cooperatives the central decision is whether to sell oil-bearing crops for the production of biodiesel. In contrast, for the soybean processing plants that convert the crops into vegetable and/or biodiesel, the decision to produce this fuel is based on the wish to expand their market portfolio. Government tax incentives strongly influence both decisions regarding which oil-bearing crop to use and the amount of vegetable oil to be transformed into biodiesel. Finally, the oil refinery/distributor is obliged by law to mix the biodiesel with the mineral diesel and perceives this as a liability. The results show the existence of different characteristics linked to the decision-making process and a significant lack of synchronicity in the aims and motivations behind the agents＇ decisions. This state of decisional misalignment leads to heightened uncertainty regarding the sustainability of the Brazilian biodiesel production program.展开更多
Wind power is an increasingly important alternative for obtaining energy supplies, both in large interconnected power systems and in smaller hybrid systems and even in backup systems. The temporal and spatial variabil...Wind power is an increasingly important alternative for obtaining energy supplies, both in large interconnected power systems and in smaller hybrid systems and even in backup systems. The temporal and spatial variability of the winds represent an obstacle to be overcome so that wind energy can be increasingly used. The capacity factor of wind farms shows how this variability impacts the operation of the plants and its value is of the order of 30% to 35%. The variability of the wind speed is influenced if the point of interest is on land or on sea, the shape of the surface, the proximity of water bodies, among other factors. The availability of wind is best described by the Weibull probability distribution, which has as one of its defining parameters one which is termed as shape parameter. This parameter is much higher as higher is the variability of the wind speed. This paper studies the subtle influence of Weibull shape parameter on the optimal combination of components in a wind diesel hybrid system, by means of computer simulations with the well known software Homer. The results indicate a relatively small influence (as expected) in the studied system, which appears particularly when the cost of diesel is higher and the availability of wind is lower.展开更多
This work studies the complementarity between hydro, wind and solar photovoltaic energy in the Brazilian state of Rio Grande do Sul. Brazil is a country highly dependent on hydro energy;however, the existent plants ar...This work studies the complementarity between hydro, wind and solar photovoltaic energy in the Brazilian state of Rio Grande do Sul. Brazil is a country highly dependent on hydro energy;however, the existent plants are not being able to cover the energy demand in recent years. In this context, the state of Rio Grande do Sul becomes important because of its potential for wind and solar photovoltaic energy, having complementarity between water, wind and solar photovoltaic schemes when hydroelectric reservoirs are at their lowest levels. This study aims to survey the complementarity of various parts of Rio Grande do Sul by proposing mathematical dimensionless ratios, focusing on intra-annual period to carry out a mapping of the entire state. It also analyses the ability to provide power supply throughout the year, through the stabilization of the energy supply, which depends on an adequate scale for photovoltaic, wind power and hydroelectric harnessing. According to the results obtained, the regions with the best complementarity indexes for deployment of a hybrid system in relation to water and wind power were the Metropolitan Region of Porto Alegre and the Southeast region, and the same regions also presented the best results for the complementarity between hydro and solar photovoltaic. Regarding wind and solar photovoltaic energy, the state’s northeast region presented the best results. Finally, the Northeast region of the state also presented the best results for the three energies together.展开更多
Aims South American Pampa grasslands are habitats of great conservation interest,with a distinct and rich flora,but have been intensely con-verted to other land uses,including tree plantations.While neces-sity for res...Aims South American Pampa grasslands are habitats of great conservation interest,with a distinct and rich flora,but have been intensely con-verted to other land uses,including tree plantations.While neces-sity for restoration grows,no information on restoration potential of grasslands after afforestation exists.Here,we aim at analyzing composition and structure of grassland vegetation with a history of eucalyptus plantations in order to assess recovery potential of these areas.We hypothesized that areas with history of eucalyptus would differ from reference grasslands with no history of land-use change in terms of floristic and functional composition and would present lower species richness.Methods Our study region comprised four sites in the southeastern part of the Pampa biome,in the coastal plain in the extreme south of Brazil,always with sites with long(50 years)history of eucalyptus plantation and reference grassland.We sampled vegetation at post-eucalyptus sites(with and without resprouting)10 years after clear-clutting and in natural grasslands.We analyzed data by analysis of variance and ordination techniques,considering compositional parameters and life forms,and indicator species analysis.Important Findings Species richness and vegetation cover were higher in reference grassland than in resprout areas but did not differ from post-eucalyp-tus areas.Exotic species cover was significantly higher in areas with afforestation history.In terms of total composition,natural grasslands differed significantly from areas with past plantation use.Indicator species analyses revealed considerable differences between grass-land types.In conclusion,vegetation development led to grassland communities that are still quite distinct from reference sites.Likely,the specificity of grassland management has a high importance in defining vegetation trajectories in time and importance for grassland recovery,and restoration needs to be addressed in more studies.展开更多
文摘The aim of this paper is to present and analyze the factors, motivations and criteria considered in the decision-making processes of the actors belonging to the biodiesel production chain in Brazil. The biodiesel production chain consists of three main agents： the farmers, the soybean processing plants and the oil refinery/distributor. For the farmers organized in cooperatives the central decision is whether to sell oil-bearing crops for the production of biodiesel. In contrast, for the soybean processing plants that convert the crops into vegetable and/or biodiesel, the decision to produce this fuel is based on the wish to expand their market portfolio. Government tax incentives strongly influence both decisions regarding which oil-bearing crop to use and the amount of vegetable oil to be transformed into biodiesel. Finally, the oil refinery/distributor is obliged by law to mix the biodiesel with the mineral diesel and perceives this as a liability. The results show the existence of different characteristics linked to the decision-making process and a significant lack of synchronicity in the aims and motivations behind the agents＇ decisions. This state of decisional misalignment leads to heightened uncertainty regarding the sustainability of the Brazilian biodiesel production program.
文摘Wind power is an increasingly important alternative for obtaining energy supplies, both in large interconnected power systems and in smaller hybrid systems and even in backup systems. The temporal and spatial variability of the winds represent an obstacle to be overcome so that wind energy can be increasingly used. The capacity factor of wind farms shows how this variability impacts the operation of the plants and its value is of the order of 30% to 35%. The variability of the wind speed is influenced if the point of interest is on land or on sea, the shape of the surface, the proximity of water bodies, among other factors. The availability of wind is best described by the Weibull probability distribution, which has as one of its defining parameters one which is termed as shape parameter. This parameter is much higher as higher is the variability of the wind speed. This paper studies the subtle influence of Weibull shape parameter on the optimal combination of components in a wind diesel hybrid system, by means of computer simulations with the well known software Homer. The results indicate a relatively small influence (as expected) in the studied system, which appears particularly when the cost of diesel is higher and the availability of wind is lower.
文摘This work studies the complementarity between hydro, wind and solar photovoltaic energy in the Brazilian state of Rio Grande do Sul. Brazil is a country highly dependent on hydro energy;however, the existent plants are not being able to cover the energy demand in recent years. In this context, the state of Rio Grande do Sul becomes important because of its potential for wind and solar photovoltaic energy, having complementarity between water, wind and solar photovoltaic schemes when hydroelectric reservoirs are at their lowest levels. This study aims to survey the complementarity of various parts of Rio Grande do Sul by proposing mathematical dimensionless ratios, focusing on intra-annual period to carry out a mapping of the entire state. It also analyses the ability to provide power supply throughout the year, through the stabilization of the energy supply, which depends on an adequate scale for photovoltaic, wind power and hydroelectric harnessing. According to the results obtained, the regions with the best complementarity indexes for deployment of a hybrid system in relation to water and wind power were the Metropolitan Region of Porto Alegre and the Southeast region, and the same regions also presented the best results for the complementarity between hydro and solar photovoltaic. Regarding wind and solar photovoltaic energy, the state’s northeast region presented the best results. Finally, the Northeast region of the state also presented the best results for the three energies together.
基金We thank the Fundação Grupo Boticário de ProteçãoàNatureza,Brazil(grant 0950_20122 to GEO)CAPES,Brazil(CAPES/UDELAR cooperation between GEO and MC,grant 048/2013 to GEO),for funding of the research that led to this paperFPT received a Doctorate grant from CAPES.GEO receives support from CNPq(310022/2015-0).
文摘Aims South American Pampa grasslands are habitats of great conservation interest,with a distinct and rich flora,but have been intensely con-verted to other land uses,including tree plantations.While neces-sity for restoration grows,no information on restoration potential of grasslands after afforestation exists.Here,we aim at analyzing composition and structure of grassland vegetation with a history of eucalyptus plantations in order to assess recovery potential of these areas.We hypothesized that areas with history of eucalyptus would differ from reference grasslands with no history of land-use change in terms of floristic and functional composition and would present lower species richness.Methods Our study region comprised four sites in the southeastern part of the Pampa biome,in the coastal plain in the extreme south of Brazil,always with sites with long(50 years)history of eucalyptus plantation and reference grassland.We sampled vegetation at post-eucalyptus sites(with and without resprouting)10 years after clear-clutting and in natural grasslands.We analyzed data by analysis of variance and ordination techniques,considering compositional parameters and life forms,and indicator species analysis.Important Findings Species richness and vegetation cover were higher in reference grassland than in resprout areas but did not differ from post-eucalyp-tus areas.Exotic species cover was significantly higher in areas with afforestation history.In terms of total composition,natural grasslands differed significantly from areas with past plantation use.Indicator species analyses revealed considerable differences between grass-land types.In conclusion,vegetation development led to grassland communities that are still quite distinct from reference sites.Likely,the specificity of grassland management has a high importance in defining vegetation trajectories in time and importance for grassland recovery,and restoration needs to be addressed in more studies.
