971 resultados para Fossil energy
Resumo:
Background If biofuels are to be a viable substitute for fossil fuels, it is essential that they retain their potential to mitigate climate change under future atmospheric conditions. Elevated atmospheric CO2 concentration [CO2] stimulates plant biomass production; however, the beneficial effects of increased production may be offset by higher energy costs in crop management. Methodology/Main findings We maintained full size poplar short rotation coppice (SRC) systems under both current ambient and future elevated [CO2] (550 ppm) and estimated their net energy and greenhouse gas balance. We show that a poplar SRC system is energy efficient and produces more energy than required for coppice management. Even more, elevated [CO2] will increase the net energy production and greenhouse gas balance of a SRC system with 18%. Managing the trees in shorter rotation cycles (i.e. 2 year cycles instead of 3 year cycles) will further enhance the benefits from elevated [CO2] on both the net energy and greenhouse gas balance. Conclusions/significance Adapting coppice management to the future atmospheric [CO2] is necessary to fully benefit from the climate mitigation potential of bio-energy systems. Further, a future increase in potential biomass production due to elevated [CO2] outweighs the increased production costs resulting in a northward extension of the area where SRC is greenhouse gas neutral. Currently, the main part of the European terrestrial carbon sink is found in forest biomass and attributed to harvesting less than the annual growth in wood. Because SRC is intensively managed, with a higher turnover in wood production than conventional forest, northward expansion of SRC is likely to erode the European terrestrial carbon sink.
Resumo:
Almost all the electricity currently produced in the UK is generated as part of a centralised power system designed around large fossil fuel or nuclear power stations. This power system is robust and reliable but the efficiency of power generation is low, resulting in large quantities of waste heat. The principal aim of this paper is to investigate an alternative concept: the energy production by small scale generators in close proximity to the energy users, integrated into microgrids. Microgrids—de-centralised electricity generation combined with on-site production of heat—bear the promise of substantial environmental benefits, brought about by a higher energy efficiency and by facilitating the integration of renewable sources such as photovoltaic arrays or wind turbines. By virtue of good match between generation and load, microgrids have a low impact on the electricity network, despite a potentially significant level of generation by intermittent energy sources. The paper discusses the technical and economic issues associated with this novel concept, giving an overview of the generator technologies, the current regulatory framework in the UK, and the barriers that have to be overcome if microgrids are to make a major contribution to the UK energy supply. The focus of this study is a microgrid of domestic users powered by small Combined Heat and Power generators and photovoltaics. Focusing on the energy balance between the generation and load, it is found that the optimum combination of the generators in the microgrid- consisting of around 1.4 kWp PV array per household and 45% household ownership of micro-CHP generators- will maintain energy balance on a yearly basis if supplemented by energy storage of 2.7 kWh per household. We find that there is no fundamental technological reason why microgrids cannot contribute an appreciable part of the UK energy demand. Indeed, an estimate of cost indicates that the microgrids considered in this study would supply electricity at a cost comparable with the present electricity supply if the current support mechanisms for photovoltaics were maintained. Combining photovoltaics and micro-CHP and a small battery requirement gives a microgrid that is independent of the national electricity network. In the short term, this has particular benefits for remote communities but more wide-ranging possibilities open up in the medium to long term. Microgrids could meet the need to replace current generation nuclear and coal fired power stations, greatly reducing the demand on the transmission and distribution network.
Resumo:
International carbon credit markets are based in differences between developing and developed countries greenhouse gases emissions mitigation costs and technological limits faced by developed countries. Potential of energy efficiency measures to reduce fossil fuel usage in Brazilian industrial segments is assessed, and analysis of such potentials singles out those segments and regions more apt to generate carbon credits through Clean Development Mechanism (CDM) projects. Though there are currently few Brazilian CDM projects, their number may be significantly increased, which is a positive outcome. For this purpose, it is crucial that energy conservation programs estimate how CDM may improve their economic competitiveness.
Resumo:
Over the past few years, renewable energy subsidies have become one of the main sources of trade disputes in the WTO. A total of six cases have been initiated against renewable energy subsidy programs since the first of such disputes was brought by Japan against Canada’s Feed in Tariff (FIT) program in 2010. Yet not even a single case has so far been initiated against the much larger and environmentally harmful fossil fuel subsidies. The main objective of this paper is to examine what makes renewable energy subsidies vulnerable to WTO dispute, as compared fossil fuel subsidies.
Resumo:
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Resumo:
Incluye Bibliografía
Resumo:
Incluye Bibliografía
Resumo:
Biofuels and their blends with fossil fuel are important energy resources, whose production and application have been largely increased internationally. This study focuses on the evaluation of the activation energy of the thermal decomposition of three pure fuels: farnesane (renewable diesel from sugar cane), biodiesel and fossil diesel and their blends (20% farnesene and 80% of fossil diesel - 20F80D and 20% farnesane, 50% fossil diesel and 30% biodiesel - 20F50D30B). Activation energy has been determined from thermogravimetry and Model-Free Kinetics. Results showed that not only the cetane number is important to understand the behavior of the fuels regarding ignition delay, but also the profile of the activation energy versus conversion curves shows that the chemical reactions are responsible for the performance at the beginning of the process. In addition, activation energy seemed to be suitable in describing reactivity in the case of blends of renewable and fossil fuels. © 2013 Elsevier B.V.
Resumo:
Includes bibliography
Resumo:
Includes bibliography.
Resumo:
Belize is currently faced with several critical challenges associated with the production, distribution and use of energy. Despite an abundance of renewable energy resources, the country remains disproportionately dependent on imported fossil fuels, which exposes it to volatile and rising oil prices, limits economic development, and retards its ability to make the investments that are necessary for adapting to climate change, which pose a particularly acute threat to the small island states and low-lying coastal nations of the Caribbean. This transition from energy consumption and supply patterns that are based on imported fossil fuels and electricity towards a more sustainable energy economy that is based on environmentally benign, indigenous renewable energy technologies and more efficient use of energy requires concerted action as the country is already challenged by limited fiscal space which reduces its ability to provide some fiscal incentives, which have been proven to be effective tools for the promotion of sustainable energy markets in a number of countries. This report identifies the fiscal and regulatory barriers to implementation of energy efficiency measures and renewable energy technologies in Belize. Data and information were derived from stakeholder consultations conducted within the country. The major result of the assessment is that the transition of policies and plans into tangible action needs to be increased. In this regard, it is necessary to articulate sub-policies of the National Energy Policy to amend the Public Utilities Commission Act, to develop a grid interconnection policy, to establish minimum energy performance standards for buildings and equipment and to develop a public procurement policy. Finally, decisions on renewable energy and energy efficiency-related incentives from the Government formally requires decision-makers to solve what may be extremely complex optimization problems in order to obtain the lowest-cost provision of energy services to society, thereby weighing the cost of revenue losses with the benefits of fuel and infrastructure expansion savings. The establishment of a management system that is efficient, flexible, and transparent, which will facilitate the implementation of the strategic objectives and outputs in the time available, with the financial resources allocated is recommended. Support is required for additional institutional and capacity strengthening.
Resumo:
The current energy systems within Curaçao depend primarily on high cost, imported fossil fuels, and typically constitute power sectors that are characterized by small, inefficient generation plants which result in high energy prices. As a consequence of its dependence on external fuel supplies, Curaçao is extremely vulnerable to international oil price shocks, which can impact on economic planning and foreign direct investment within their industrial sectors. The ability of the successive governments to source capital for economic stimulation and social investment is therefore significantly challenging. Additionally, there is over-dependence on two of the most climate-sensitive economic sectors, namely the tourism and fisheries sectors, but the vulnerabilities of the country to the effects of climate change make adaptation difficult and costly. It is within this context that this report focuses on identification of the fiscal and regulatory barriers to implementation of energy efficiency and renewable energy technologies in Curaçao with a view of making recommendations for removal of these barriers. Consultations with key Government officials, the private sector as well as civil society were conducted to obtain information and data on the energy sector in the country. Desktop research was also conducted to supplement the information gathered from the consultations. The major result of the assessment is that Curaçao is at an early stage in the definition of its energy sector. Despite some infrastructural legacies of the pre-independence era, as well as a number of recent developments including the modernization and expansion of its windfarms and completion of a modern Electricity Policy, there are still a number of important institutional and policy gaps within the energy sector in Curaçao. The most significant deficiency is the absence of a ministry or Government agency with portfolio responsibility for the energy sector as a whole; this has: limited the degree to which the activities of energy sector stakeholders are coordinated and retarded the development and implementation of a comprehensive national energy policy. The absence of an energy policy, which provides the framework for energy planning, increases investor risk. Also, the lack of political continuity that has emanated from the frequent changes in Government administrations is a concern among stakeholders and has served to reduce investor confidence in particular, and market confidence in general.
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
This article evaluates the efficiency of Brazil's industrial sectors from 1996 to 2009, taking into account energy consumption and respective contributions to the country's economic and social aspects. This analysis used a mathematical programming method called Data Envelopment Analysis (DEA), which enabled, from the SBM model and the window analysis, to evaluate the ability of industries to reduce energy consumption and fossil-fuel CO2 emissions (inputs), as well as to increase the Gross Domestic Product (GDP) by sectors, the persons employed and personnel expenses (outputs). The results of this study indicated that the Textile sector is the most efficient industrial sector in Brazil, according to the variables used, followed by these sectors: Foods and Beverages, Chemical, Mining, Paper and Pulp, Nonmetallic and Metallurgical.