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Showing papers on "Renewable energy published in 2006"


Journal ArticleDOI
TL;DR: Solar energy is by far the largest exploitable resource, providing more energy in 1 hour to the earth than all of the energy consumed by humans in an entire year, and if solar energy is to be a major primary energy source, it must be stored and dispatched on demand to the end user.
Abstract: Global energy consumption is projected to increase, even in the face of substantial declines in energy intensity, at least 2-fold by midcentury relative to the present because of population and economic growth. This demand could be met, in principle, from fossil energy resources, particularly coal. However, the cumulative nature of CO2 emissions in the atmosphere demands that holding atmospheric CO2 levels to even twice their preanthropogenic values by midcentury will require invention, development, and deployment of schemes for carbon-neutral energy production on a scale commensurate with, or larger than, the entire present-day energy supply from all sources combined. Among renewable energy resources, solar energy is by far the largest exploitable resource, providing more energy in 1 hour to the earth than all of the energy consumed by humans in an entire year. In view of the intermittency of insolation, if solar energy is to be a major primary energy source, it must be stored and dispatched on demand to the end user. An especially attractive approach is to store solar-converted energy in the form of chemical bonds, i.e., in a photosynthetic process at a year-round average efficiency significantly higher than current plants or algae, to reduce land-area requirements. Scientific challenges involved with this process include schemes to capture and convert solar energy and then store the energy in the form of chemical bonds, producing oxygen from water and a reduced fuel such as hydrogen, methane, methanol, or other hydrocarbon species.

7,076 citations


Journal ArticleDOI
TL;DR: An overview of the structures for the DPGS based on fuel cell, photovoltaic, and wind turbines is given and the possibility of compensation for low-order harmonics is discussed.
Abstract: Renewable energy sources like wind, sun, and hydro are seen as a reliable alternative to the traditional energy sources such as oil, natural gas, or coal. Distributed power generation systems (DPGSs) based on renewable energy sources experience a large development worldwide, with Germany, Denmark, Japan, and USA as leaders in the development in this field. Due to the increasing number of DPGSs connected to the utility network, new and stricter standards in respect to power quality, safe running, and islanding protection are issued. As a consequence, the control of distributed generation systems should be improved to meet the requirements for grid interconnection. This paper gives an overview of the structures for the DPGS based on fuel cell, photovoltaic, and wind turbines. In addition, control structures of the grid-side converter are presented, and the possibility of compensation for low-order harmonics is also discussed. Moreover, control strategies when running on grid faults are treated. This paper ends up with an overview of synchronization methods and a discussion about their importance in the control

4,655 citations


Journal ArticleDOI
TL;DR: New trends in power electronics for the integration of wind and photovoltaic (PV) power generators are presented and a review of the appropriate storage-system technology used for the Integration of intermittent renewable energy sources is introduced.
Abstract: The use of distributed energy resources is increasingly being pursued as a supplement and an alternative to large conventional central power stations. The specification of a power-electronic interface is subject to requirements related not only to the renewable energy source itself but also to its effects on the power-system operation, especially where the intermittent energy source constitutes a significant part of the total system capacity. In this paper, new trends in power electronics for the integration of wind and photovoltaic (PV) power generators are presented. A review of the appropriate storage-system technology used for the integration of intermittent renewable energy sources is also introduced. Discussions about common and future trends in renewable energy systems based on reliability and maturity of each technology are presented

3,799 citations


Journal ArticleDOI
TL;DR: In this paper, the authors proposed to use CO2 for environmentally-benign physical and chemical processing that adds value to the process, using CO2 as an alternate medium or solvent or co-reactant or a combination of them.

1,541 citations


Journal ArticleDOI
TL;DR: In this paper, an overview of these technologies for hydrogen production from biomass is presented. And the future development will also be addressed, as well as future development of the future technologies.

1,065 citations


Journal ArticleDOI
TL;DR: In this paper, the authors explore the reasons for the particularly rapid spread of two such technologies in Germany, wind turbines and solar cells, and trace this diffusion to the nature of the policy instruments employed and to the political process which led to the adoption of these instruments.

1,061 citations


Journal ArticleDOI
S. Jebaraj, S. Iniyan1
TL;DR: In this paper, a review paper on energy modeling will help the energy planners, researchers and policy makers widely, and an attempt has been made to understand and review the various emerging issues related to the energy modeling.
Abstract: Energy is a vital input for social and economic development of any nation. With increasing agricultural and industrial activities in the country, the demand for energy is also increasing. Formulation of an energy model will help in the proper allocation of widely available renewable energy sources such as solar, wind, bioenergy and small hydropower in meeting the future energy demand in India. During the last decade several new concepts of energy planning and management such as decentralized planning, energy conservation through improved technologies, waste recycling, integrated energy planning, introduction of renewable energy sources and energy forecasting have emerged. In this paper an attempt has been made to understand and review the various emerging issues related to the energy modeling. The different types of models such as energy planning models, energy supply–demand models, forecasting models, renewable energy models, emission reduction models, optimization models have been reviewed and presented. Also, models based on neural network and fuzzy theory have been reviewed and discussed. The review paper on energy modeling will help the energy planners, researchers and policy makers widely.

670 citations


Journal ArticleDOI
TL;DR: In this article, a dynamic approach towards the Life Cycle Assessment (LCA) of renewable energy technologies is presented and it is shown that for all renewable energy chains, the inputs of finite energy resources and emissions of greenhouse gases are extremely low compared with the conventional system.

612 citations


Journal ArticleDOI
TL;DR: In this paper, the authors present a simplified method for reliability evaluation of power systems with wind power and illustrate with an example the development of a common wind speed model applicable to multiple wind farm locations.
Abstract: Renewable energy sources, especially wind turbine generators, are considered as important generation alternatives in electric power systems due to their nonexhausted nature and benign environmental effects. The fact that wind power penetration continues to increase has motivated a need to develop more widely applicable methodologies for evaluating the actual benefits of adding wind turbines to conventional generating systems. Reliability evaluation of generating systems with wind energy sources is a complex process. It requires an accurate wind speed forecasting technique for the wind farm site. The method requires historical wind speed data collected over many years for the wind farm location to determine the necessary parameters of the wind speed models for the particular site. The evaluation process should also accurately model the intermittent nature of power output from the wind farm. A sequential Monte Carlo simulation or a multistate wind farm representation approach is often used. This paper presents a simplified method for reliability evaluation of power systems with wind power. The development of a common wind speed model applicable to multiple wind farm locations is presented and illustrated with an example. The method is further simplified by determining the minimum multistate representation for a wind farm generation model in reliability evaluation. The paper presents a six-step common wind speed model applicable to multiple geographic locations and adequate for reliability evaluation of power systems containing significant wind penetration. Case studies on a test system are presented using wind data from Canadian geographic locations.

593 citations


Journal ArticleDOI
André Faaij1
TL;DR: In this paper, the authors proposed a supra-national approach for bio-energy development, demonstration and deployment trajectories for key options such as biomass integrated gasification/combined cycle and advanced biofuel concepts, developing an international biomass market allowing for international trade and an integral policy approach for Bio-energy incorporating energy, agricultural, forestry, waste and industrial policies.

536 citations


Book
22 Nov 2006
TL;DR: The Power Electronics Handbook, 3rd edition as mentioned in this paper contains 45 chapters covering all aspects of power electronics and its applications, including switching devices, converter circuit topologies, control techniques, analytical methods and some examples of their applications.
Abstract: Power electronics, which is a rapidly growing area in terms of research and applications, uses modern electronics technology to convert electric power from one form to another, such as ac-dc, dc-dc, dc-ac, and ac-ac with a variable output magnitude and frequency. It has many applications in our every day life such as air-conditioners, electric cars, sub-way trains, motor drives, renewable energy sources and power supplies for computers. This book covers all aspects of switching devices, converter circuit topologies, control techniques, analytical methods and some examples of their applications. Designed to appeal to a new generation of engineering professionals, "Power Electronics Handbook, 3rd Edition" features four new chapters covering renewable energy, energy transmission, energy storage, as well as an introduction to Distributed and Cogeneration (DCG) technology, including gas turbines, gensets, microturbines, wind turbines, variable speed generators, photovoltaics and fuel cells, has been gaining momentum for quite some time now. With this book readers should be able to provide technical design leadership on assigned power electronics design projects and lead the design from the concept to production involving significant scope and complexity. It contains 45 chapters covering all aspects of power electronics and its applications. It features three new chapters now including coverage Energy Sources, Energy Storage and Electric Power Transmission. It includes contributions from more than fifty leading experts spanning twelve different countries.

Journal ArticleDOI
TL;DR: In this paper, the effective use of biomass as the first of the renewable energy sources to be developed for large-scale applications, especially in the palm oil industry and the methodology for energy harness by innovative utilization of waste from palm oil cultivation and processing.

Book
01 Jan 2006
TL;DR: This chapter contains sections titled: Introduction Principles of Power Injection Instantaneous Active and Reactive Power Control Approach Integration of Multiple Renewable Energy Sources Islanding and Interconnection Control DG Control and Power In injection References.
Abstract: This chapter contains sections titled: Introduction Principles of Power Injection Instantaneous Active and Reactive Power Control Approach Integration of Multiple Renewable Energy Sources Islanding and Interconnection Control DG Control and Power Injection References

Journal ArticleDOI
TL;DR: In this article, the authors evaluated thermophysical properties and performed numerical simulations to explore the fluid dynamics and heat transfer issues in an engineered geothermal reservoir that would be operated with CO2.

Journal ArticleDOI
TL;DR: In this article, the authors present a control strategy for a doubly fed induction generator with a hierarchical structure with both a central control level and a local control level, where the central wind farm control level controls the power production of the whole farm by sending out reference power signals to each individual wind turbine, while the local wind turbine control level ensures that the reference power signal send by the central level is reached.

Journal ArticleDOI
TL;DR: In this article, the authors estimate the magnitude of these external costs and benefits for the case of renewable technologies in Scotland, a country which has set particularly ambitious targets for expanding renewable energy.

Journal ArticleDOI
Horace Herring1
01 Jan 2006-Energy
TL;DR: In this article, the authors argue that a more effective CO 2 policy is to concentrate on shifting to non-fossil fuels, like renewables, subsidized through a carbon tax.

01 Jan 2006
TL;DR: In this article, the authors used the Controls Advanced Research Turbine (CART) as a model for this article's research, which is located in Golden, Colorado, at the U.S. National Renewable Energy Laboratory's National Wind Technology Center.
Abstract: 1066-033X/06/$20.00©2006IEEE W ind energy is the fastest-growing energy source in the world, with worldwide wind-generation capacity tripling in the five years leading up to 2004 [1]. Because wind turbines are large, flexible structures operating in noisy environments, they present a myriad of control problems that, if solved, could reduce the cost of wind energy. In contrast to constantspeed turbines (see “Wind Turbine Development and Types of Turbines”), variable-speed wind turbines are designed to follow wind-speed variations in low winds to maximize aerodynamic efficiency. Standard control laws [2] require that complex aerodynamic properties be well known so that the variable-speed turbine can maximize energy capture; in practice, uncertainties limit the efficient energy capture of a variable-speed turbine. The turbine used as a model for this article’s research is the Controls Advanced Research Turbine (CART) pictured in Figure 1. CART is located in Golden, Colorado, at the U.S. National Renewable Energy Laboratory’s National Wind Technology Center (see “The National Renewable Energy Laboratory and National Wind Technology Center”). A modern utility-scale wind turbine, as shown in Figure 2, has several levels of control systems. On the uppermost level, a supervisory controller monitors the turbine and wind resource to determine when the wind speed is sufficient to start up the turbine and when, due to high winds, the turbine must be shut down for safety. This type of control is the discrete if-then variety. On the middle level is turbine control, which includes generator torque control, blade pitch control, and yaw control. Generator torque control, performed using the power electronics, determines how much torque is extracted from the turbine, specifically, the high-speed shaft. The extracted torque opposes the aerodynamic torque provided by the wind and, thus, indirectly regulates the turbine speed. Depending on the pitch actuators and type of generator and power electronics, blade pitch control and generator torque control can operate quickly relative to the rotor-speed time constant. STANDARD AND ADAPTIVE TECHNIQUES FOR MAXIMIZING ENERGY CAPTURE

Journal ArticleDOI
TL;DR: In this article, the authors investigated the relative importance of energy policy and green power marketing in shaping the renewable energy market and concluded that the German case can be used for policy design and market development in other countries.

Journal ArticleDOI
Henrik Lund1
TL;DR: In this article, the authors present the results of analyses of large-scale integration of wind power, photo voltaic (PV) and wave power into a Danish reference energy system.

Journal ArticleDOI
TL;DR: In this paper, the authors analyzed the contribution of renewable portfolio standards (RPS), fuel generation disclosure rules, mandatory green power options, and public benefits funds to wind power development in the United States.

Journal ArticleDOI
André Faaij1
TL;DR: An overview of the state-of-the-art of key biomass conversion technologies currently deployed and technologies that may play a key role in the future, including possible linkage to CO2 capture and sequestration technology (CCS) is given in this paper.
Abstract: This article gives an overview of the state-of-the-art of key biomass conversion technolo- gies currently deployed and technologies that may play a key role in the future, including possible linkage to CO2 capture and sequestration technology (CCS). In doing so, special attention is paid to production of biofuels for the transport sector, because this is likely to become the key emerging market for large-scale sustainable biomass use. Although the actual role of bio-energy will depend on its competitiveness with fossil fuels and on agricultural policies worldwide, it seems realistic to expect that the current contribution of bio-energy of 40-55 EJ per year will increase considerably. A range from 200 to 300 EJ may be observed looking well into this century, making biomass a more important energy supply option than mineral oil today. A key issue for bio-energy is that its use should be modernized to fit into a sustainable development path. Especially promising are the production of electricity via advanced conversion concepts (i.e. gasification and state-of-the-art combustion and co- firing) and modern biomass derived fuels like methanol, hydrogen and ethanol from ligno-cellulosic biomass, which can reach competitive cost levels within 1-2 decades (partly depending on price developments with petroleum). Sugar cane based ethanol production already provides a competitive biofuel production system in tropical regions and further improvements are possible. Flexible energy systems, in which biomass and fossil fuels can be used in combination, could be the backbone for a low risk, low cost and low carbon emission energy supply system for large scale supply of fuels and power and providing a framework for the evolution of large scale biomass raw material supply systems. The gasification route offers special possibilities to combine this with low cost CO2 capture (and storage), resulting in concepts that are both flexible with respect to primary fuel input as well as product mix and with the possibility of achieving zero or even negative carbon emissions. Pro- longed RD&D efforts and biomass market development, consistent policy support and international collaboration are essential to achieve this.

Journal ArticleDOI
Tony Bridgwater1
TL;DR: In this paper, a review of thermochemical conversion processes for their higher efficiencies, lower costs and greater versatility in providing a wide range of energy, fuel and chemical options is presented.
Abstract: Bio-energy is now accepted as having the potential to provide the major part of the projected renewable energy provisions of the future as biofuels in the form of gas, liquid or solid fuels or electricity and heat. There are three main routes to providing these biofuels - thermal conversion, biological conversion and physical conversion - all of which employ a range of chemical reactor configurations and designs. This review focuses on thermochemical conversion processes for their higher efficiencies, lower costs and greater versatility in providing a wide range of energy, fuel and chemical options. The technologies of gasification and fast pyrolysis are described, particularly the reactors that have been developed to provide the necessary conditions to optimise performance. The primary products that can be derived as gas, liquid and solid fuels are characterised, as well as the secondary products of electricity and/or heat, liquid fuels and a considerable number of chemicals.

Journal ArticleDOI
TL;DR: In this article, the authors proposed the installation on Gran Canaria island (Canarian Archipelago) of an appropriately administered wind powered pumped hydro storage system, which would have no negative effect on either the reliability of the electrical system or consumer satisfaction.
Abstract: A significant number of islands have found themselves obliged to place restrictions on the penetration of renewable sourced energy in their conventional electrical grid systems. In general, this has been due to certain energy related characteristics often connected to their very nature as islands. These limitations attempt to prevent the appearance of problems that might affect the stability and safety of the electrical system. The restrictions imposed on the direct penetration of wind sourced energy in the conventional grids of the Canary Islands are an obstacle to meeting the renewable energy objectives set out by the European Union. As a partial solution to the problem, this paper proposes the installation on Gran Canaria island (Canarian Archipelago) of an appropriately administered wind powered pumped hydro storage system. The results obtained from the application of an optimum-sized economic model of such a system indicates that penetration of renewable sourced energy can be increased by 1.93% (52.55 GW h/year) at a competitive cost for the unit energy supplied. These results are obtained on the hypothesis that two of the largest existing reservoirs on the island (with a difference in height between the two of 281 m and a capacity of some 5,000,000 m3 used in each) are employed as storage deposits. Investment, operating and maintenance costs are taken into account, as well as those costs involving health and environmental damage associated with energy production and use (externalities). The system would consist of: a wind farm with a rated output of 20.40 MW; a modular pumping station with a rated output of 17.80 MW, operated so that the variation in the energy demand for pumping is in sympathy with the wind generation; and a hydraulic plant with a rated output of 60.00 MW. The proposed system would have no negative effect on either the reliability of the electrical system or consumer satisfaction. Furthermore, it would mean a fossil fuel saving of 13,655 metric tonnes/year and a reduction in CO2 emissions into the atmosphere of 43,064 metric tonnes/year. For regions that have topographically suitable sites and which suffer energy problems similar to those of the Canary Islands it is thus suggested that an analysis be made of the technical and economic feasibility of the installation of power systems such as that proposed in this paper. Within the general guiding framework of a policy promoting clean and renewable energy, these systems represent an enormous and as yet barely explored potential.

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the willingness to pay of a sample of residents of Bath, England, for a hypothetical program that promotes the production of renewable energy and found that consumers are willing to pay a higher price for electricity in order to internalize the external costs caused by fossil fuel technologies.
Abstract: This paper investigates the willingness to pay of a sample of residents of Bath, England, for a hypothetical program that promotes the production of renewable energy. Using choice experiments, we assess the preferences of respondents for a policy for the promotion of renewable energy that (i) contributes to the internalization of the external costs caused by fossil fuel technologies; (ii) affects the security of energy supply; (iii) has an impact on the employment in the energy sector; (iv) and leads to an increase in the electricity bill. Responses to the choice questions show that our respondents are in favour of a policy for renewable energy and that they attach a high value to a policy that brings private and public benefits in terms of climate change and energy security benefits. Our results therefore suggest that consumers are willing to pay a higher price for electricity in order to internalize the external costs in terms of energy security, climate change and air pollution caused by the production of electricity.

Journal ArticleDOI
TL;DR: In this paper, the authors proposed that biomass fuels represent a renewable energy source, they are CO2 neutral fuels, and their use reduces the consumption of fossil fuels and limits the emissions of SOx, NOx, and heavy metals.
Abstract: Biomass fuels represent a renewable energy source, they are CO2 neutral fuels, and their use reduces the consumption of fossil fuels and limits the emissions of SOx, NOx, and heavy metals. They are...

Journal ArticleDOI
TL;DR: A review of the technical literature on alternative fuel vehicles (AFVs) and discussions with experts in vehicle technology and energy analysis is presented in this paper, based on analysis provided to the bipartisan National Commission on Energy Policy.

Journal ArticleDOI
TL;DR: The use of methyl esters (commonly known as biodiesel) instead of conventional diesel fuel reduces emissions such as the overall life cycle of carbon dioxide (CO2), particu... as mentioned in this paper.
Abstract: The demand for energy around the world is increasing, specifically the demand for petroleum-based energy. Appeasing this growing energy demand without irreparably damaging the environment is of primary concern. With rising fuel prices and environmental concerns, alternative fuels could satisfy the need for renewable energy with low environmental impact. Some of the more popular alternative fuels for new vehicles are ethanol, hydrogen, and biodiesel. Although gasoline engines are expected to be replaced by hydrogen-powered fuel cells, compression-ignition engines, the diesel engines, are expected to remain in use for high-power applications because of limitations of hydrogen-storage densities. The viable environmental friendly alternative fuel for compression-ignition engines is methyl esters (commonly known as biodiesel), which is derived from vegetable oils or animal fats. Using biodiesel instead of conventional diesel fuel reduces emissions such as the overall life cycle of carbon dioxide (CO2), particu...

Journal ArticleDOI
01 Jan 2006-Energy
TL;DR: The hydrogen economy is defined as the industrial system in which one of the universal energy carriers is hydrogen (the other is electricity) and hydrogen is oxidized to water that may be reused by applying an external energy source for dissociation of water into its component elements hydrogen and oxygen as discussed by the authors.

Journal ArticleDOI
TL;DR: In this paper, a dispatch model was developed that analyzes the impact that wind generation has on the operation of conventional plants and the resulting emissions of carbon dioxide (CO/sub 2/), sulphur dioxide (SO/sub dioxide), and oxides of nitrogen (NO/sub X/).
Abstract: With increasing concern over global climate change, policy makers are promoting renewable energy sources, predominantly wind generation, as a means of meeting emissions reduction targets. Although wind generation does not itself produce any harmful emissions, its effect on power system operation can actually cause an increase in the emissions of conventional plants. A dispatch model was developed that analyzes the impact that wind generation has on the operation of conventional plants and the resulting emissions of carbon dioxide (CO/sub 2/), sulphur dioxide (SO/sub 2/), and oxides of nitrogen (NO/sub X/). The analysis concentrates on a "forecasted" approach that incorporates wind generation forecasts in the dispatch decisions. It was found that wind generation could be used as a tool for reducing CO/sub 2/ emissions but alone, it was not effective in curbing SO/sub 2/ and NO/sub X/ emissions.