Showing papers on "Renewable energy published in 2000"
TL;DR: In this paper, the relationship between renewable energy and sustainable development is discussed and the potential solutions to current environmental problems are identified along with renewable energy technologies, and an illustrative example is presented.
Abstract: Achieving solutions to environmental problems that we face today requires long-term potential actions for sustainable development. In this regard, renewable energy resources appear to be the one of the most efficient and effective solutions. That is why there is an intimate connection between renewable energy and sustainable development. Anticipated patterns of future energy use and consequent environmental impacts (focussing on acid precipitation, stratospheric ozone depletion and the greenhouse effect) are comprehensively discussed in this paper. Also, potential solutions to current environmental problems are identified along with renewable energy technologies. The relations between renewable energy and sustainable development are described with practical cases, and an illustrative example is presented. Throughout the paper several issues relating to renewable energy, environment and sustainable development are examined from both current and future perspectives. It is believed that the conclusions and recommendations drawn in the present study will be useful to energy scientists and engineers and policy makers.
1,791 citations
TL;DR: Fast pyrolysis for production of liquids has developed considerably since the first experiments in the late 1970s as mentioned in this paper, leading to significant advances in process development and a wide range of reactor configurations that have been developed to meet the stringent requirements for high yields of useful liquids, for use as a fuel in boilers, engines and turbines and as a source of chemical commodities.
Abstract: Fast pyrolysis for production of liquids has developed considerably since the first experiments in the late 1970s. Many reactors and processes have been investigated and developed to the point where fast pyrolysis is now an accepted feasible and viable route to renewable liquid fuels, chemicals and derived products. It is also now clear that liquid products offer significant advantages in storage and transport over gas and heat. These advantages have caused greater attention to be paid to fast pyrolysis, leading to significant advances in process development. The technology of fast pyrolysis for liquids is noteworthy for the wide range of reactor configurations that have been developed to meet the stringent requirements for high yields of useful liquids, for use as a fuel in boilers, engines and turbines and as a source of chemical commodities. This review summarizes the key features of fast pyrolysis and the resultant liquid product and describes the major reaction systems and processes that have been developed over the last 20 years.
1,686 citations
TL;DR: In this article, the authors argue that very little has come out of this research in terms of commercially interesting technologies and demonstrate that this perception is no longer entirely correct; in the 1990s there has been a double-digit growth rate in the market for some renewable energy technologies.
972 citations
TL;DR: There has been considerable emphasis on cofiring biomass opportunity fuels with coal in pulverized coal (PC) and cyclone boilers owned and operated by electricity generating utilities in order to address such issues as potential portfolio standards, voluntary actions to reduce fossil CO2 emissions, customer service, and the generation of green power within the context of deregulation.
Abstract: Cofiring, the practice of supplementing a base fuel with a dissimilar fuel, is an extension of fuel blending practices common to the solid fuels community. Recently, there has been considerable emphasis on cofiring biomass opportunity fuels with coal in pulverized coal (PC) and cyclone boilers owned and operated by electricity generating utilities in order to address such issues as potential portfolio standards, voluntary actions to reduce fossil CO2 emissions, customer service, and the generation of green power within the context of deregulation. Biomass fuels considered for cofiring include wood waste, short rotation woody crops, short rotation herbaceous crops (e.g., switchgrass), alfalfa stems, various types of manure, landfill gas and wastewater treatment gas. Of these, the solid biofuels such as sawdust, urban wood waste and switchgrass have received the most attention. The Electric Power Research Institute (EPRI), along with the Tennessee Valley Authority (TVA), GPU Genco, Northern Indiana Public Service Company (NIPSCO), Central and South West Utilities (CS this agreement was extensively supported by the energy efficiency and renewable energy (EERE) element of USDOE. European cofiring programs also have been extensive and include gasification-based cofiring in Lahti, Finland and straw cofiring in Denmark. Three general techniques comprise the cofiring technology family: blending the biomass and coal in the fuel handling system and feeding that blend to the boiler; preparing the biomass fuel separately from coal, and injecting it into the boiler without impacting the conventional coal delivery system; and gasifying the biomass with subsequent combustion of the producer gas in either a boiler or a combined cycle combustion turbine (CCCT) generating plant. Commercialization has proceeded on the direct combustion approaches to cofiring, beginning with engineering and economic studies, parametric testing and the construction of demonstration projects. The direct combustion cofiring techniques are now ready for commercial deployment. This paper reviews the key projects, and details some of the influences of cofiring on the combustion process.
505 citations
477 citations
TL;DR: In this paper, the authors examined small/medium commercial and industrial customers' choices among energy suppliers in conjoint-type experiments and estimated the distribution of customers' willingness to pay for more than 40 attributes of suppliers, including sign-up bonuses, amount and type of renewables, billing options, bundling with other services, reductions in voltage fluctuations, and charitable contributions.
Abstract: We examine small/medium commercial and industrial customers' choices among energy suppliers in conjoint-type experiments The distribution of customers' willingness to pay is estimated for more than 40 attributes of suppliers, including sign-up bonuses, amount and type of renewables, billing options, bundling with other services, reductions in voltage fluctuations, and charitable contributions These estimates provide guidance for suppliers in designing service options and to economists in anticipating the services that will be offered in competitive retail energy markets
369 citations
TL;DR: In this paper, the assessment of energy and emissions related to the production and manufacture of materials for an offshore wind farm as well as a wind farm on land based on a life cycle analysis (LCA) model is presented.
311 citations
TL;DR: In this paper, the authors analyzed the impact of key parameters such as photovoltaic array area, number of wind machines, and battery storage capacity on the operation of hybrid (wind + solar + diesel) energy conversion systems, while satisfying a specific annual load of 41,500 kWh.
264 citations
TL;DR: In this article, the authors evaluate the environmental impacts of major renewable energy sources and come up with the broad conclusion that renewable energies are not the panacea they are popularly perceived to be; indeed in some cases their adverse environmental impacts can be as strongly negative as the impacts of conventional energy sources.
235 citations
01 Jan 2000
TL;DR: In 1998, renewable energy sources supplied 56 ± 10 exajoules, or about 14 percent of world primary energy consumption as discussed by the authors, and the contribution of all other renewables, including small hydropower, geothermal, wind, solar, and marine energy, was about 2.
Abstract: In 1998 renewable energy sources supplied 56 ± 10 exajoules,or about 14 percent of world primary energy consumption. Thesupply was dominated by traditional biomass (38 ± 10 exajoules a year. Other major contributions came from large hydropower (9 exajoules a year) and from modern biomass (7 exajoules). The contribution of all other renewables — small hydropower, geothermal, wind, solar, and marineenergy — was about 2 exajoules. That means that the energy supply from new renewables was about 9 exajoules (about 2 percent of world consumption). The commercial primary energy supply from renewable sources was 27 ± 6 exajoules (nearly 7 percent of world consumption), with 16 ± 6 exajoules from biomass. Renewable energy sources can meet many times the present world energy demand, so their potential is enormous. They can enhance diversity in energy supply markets, secure long-term sustainable energy supplies, and reduce local and global atmospheric emissions. They can also provide commercially attractive options to meet specific needs for energy services (particularly in developing countries and rural areas), create new employment opportunities, and offer possibilities for local manufacturing of equipment. There are many renewable technologies. Although often commerciallyavailable, most are still at an early stage of development and not technically mature. They demand continuing research, development, and demonstration efforts. In addition, few renewable energy technologies can compete with conventional fuels on cost, except in some niche markets. But substantial cost reductions can be achieved for most renewables, closing gaps and making them more competitive. That will require further technology development and market deployment — and boosting production capacities to mass production. For the long term and under very favourable conditions, the lowest cost to produce electricity might be $0.01–0.02 a kilowatt-hour for geothermal, $0.03 a kilowatt-hour for wind and hydro, $0.04 a kilowatt-hour for solar thermal and biomass, and $0.05–0.06 a kilowatt-hour for photovoltaics and marine currents. The lowest cost to produce heat might be $0.005 a kilowatt-hour for geothermal, $0.01 a kilowatt-hour for biomass, and $0.02–0.03 a kilowatt-hour for solar thermal. The lowest cost to produce fuels might be $1.5 a gigajoule for biomass, $6–7 a gigajoule for ethanol, $7–10 a gigajoule for methanol, and $6–8 a gigajoule for hydrogen. Scenarios investigating the potential of renewables reveal that they might contribute 20–50 percent of energy supplies in the second half of the 21st century. A transition to renewables-based energy systems would have to rely on: Successful development and diffusion of renewable energy technologies that become more competitive through cost reductions from technological and organisational developments. Political will to internalise environmental costs and other externalities that permanently increase fossil fuel prices. Many countries have found ways to promote renewables. As renewable energy activities grow and require more funding, the tendency in many countries is to move away from methods that let taxpayers carry the burden of promoting renewables, towards economic and regulatory methods that let energy consumers carry the burden. (Less)
235 citations
TL;DR: In this article, the authors estimate the maximum potential power from electric drive vehicles (EDVs) in the Kanto region (which includes Tokyo) at 15.5 GW, 25% of Kanto's 1998 peak demand.
TL;DR: In this paper, the authors investigate the design of the control system (as opposed to the synthesis of the controller) for variable speed wind turbines, to cater for the implementation issues of accommodation of variation in the plant d...
Abstract: Owing to concern over the environment, there is much interest in renewable sources of electrical power generation, of which one of the most promising is wind power. There are essentially two types of wind turbines, namely constant speed and variable speed machines. In comparison to constant speed wind turbines, variable speed wind turbines are perceived to have several potential advantages which outweigh the considerable cost of the power electronics required to realize variable speed operation. The two frequently mentioned ones are: additional energy capture below rated wind speed and additional power-train compliance and associated load alleviation above rated wind speed. The purpose of this paper is to investigate the design of the control system (as opposed to the synthesis of the controller) for variable speed wind turbines. The choice of control strategy is investigated and appropriate realizations of the controller, to cater for the implementation issues of accommodation of variation in the plant d...
TL;DR: In this paper, the authors demonstrate the industrial dynamism of this "virtuous cycle" between R&D, market growth and price reduction in photovoltaic power generation.
TL;DR: In this paper, the authors used the life cycle inventory (LCI) to investigate the environmental load of selected bioenergy transport chains and showed that emissions from long range transportation, 1200 km, performed with ships, is of minor importance compared to emissions from local bioenergy systems in a local market.
Abstract: Biomass for energy conversion is usually considered as a local resource. With appropriate logistic systems, access to biomass can be improved over a large geographical area. In this study, life cycle inventory (LCI) has been used as a method to investigate the environmental load of selected bioenergy transport chains. As a case study, chains starting in Sweden and ending in Holland have been investigated. Biomass originates from tree sections or forest residues, the latter upgraded to bales or pellets. The study is concentrated on production of electricity, hot cooling water is considered as a loss. Electricity is, in the case study, produced from solid biomass in the importing country. Electricity can also be produced in the country of origin and exported via the transnational grid as transportation medium. The results show that emissions from long range transportation, 1200 km, performed with ships, is of minor importance compared to emissions from local bioenergy systems in a local market. In bioenergy systems the use of fuels and electricity for operating machines and transportation carriers requires a net energy input which amounts to typically 7‐9% of delivered electrical energy from the system. Emissions of key substances such as NOx, CO, S, hydrocarbons, and particles are low in a perspective of sustainability. Emissions of CO2 from biocombustion are considered to be zero since there is approximately no net contribution of carbon to the biosphere in an energy system based on biomass. The results indicate that biomass for energy can be transported from Scandinavia to Holland without losing its environmental benefits. 7 2000 Elsevier Science Ltd. All rights reserved.
TL;DR: In this article, the authors analyze possible ways to set up a green certificate market, treating as well some of the consequences produced when the market is actually funtioning, and special attention is given to wind power.
TL;DR: In Europe and the US, national energy planning agencies value resource alternatives using outmoded techniques, conceived around the time of the Model-T Ford, which bias in favor of riskier fossil alternatives while understating the true value of photovoltaics and similar low-risk, passive, capital-intensive technologies as mentioned in this paper.
TL;DR: The US Department of Energy (DOE), Electric Power Research Institute (EPRI) and utilities are evaluating, testing and applying technology that can give a new, and potentially profitable, mission to existing coal-fired power plants.
Abstract: The US Department of Energy (DOE), Electric Power Research Institute (EPRI) and utilities are evaluating, testing and applying technology that can give a new, and potentially profitable, mission to existing coal-fired power plants. The oldest of all fuels, wood, and the old original fuel of the industrial revolution, coal, are key to this move to a new mission. Technical issues that can lead to doubt about, or outright rejection of, wood (or biomass) cofiring are, in fact, being resolved through testing and experience. DOE, EPRI and utilities have joined to cosponsor tests in full-sized boilers and design/cost/supply studies related to these tests. Economic calculations, based on the measured performance and on cost estimates confirmed in purchases for the tests, are presented in this paper. The technical feasibility is proved. The constraints are identified. So far, the profits are in the future. Policy changes that produce stronger economic incentives could make profit possible today, and enable this low-cost form of renewable power to be deployed. But, without the policy, or market, change, the economic barrier is a strong one, when biomass cofiring must compete with low-cost coal at low fuel cost and with low-capital-cost gas turbine combined cycle power plants. The economics would not be a barrier at all if biomass cofiring were in competition against moderate-velocity wind power or solar PV power.
TL;DR: In this paper, the authors present a summary of the methodology and key results for the external costs of the major energy technologies, and show that the classic air pollutants (particles, NOx and SOx) from fossil fuels impose significant public health costs, comparable to the cost of global warming from CO2 emissions.
Abstract: ▪ Abstract Low environmental damage is one of the main justifications for continued efforts to reduce energy consumption and to shift to cleaner sources such as solar energy, especially now that supply security has slipped from public consciousness. In recent years there has been much progress in the analysis of environmental damages, in particular thanks to the ExternE (External Costs of Energy) Project of the European Commission. This paper presents a summary of the methodology and key results for the external costs of the major energy technologies. Even though the uncertainties are large, the results provide substantial evidence that the classic air pollutants (particles, NOx and SOx) from fossil fuels impose significant public health costs, comparable to the cost of global warming from CO2 emissions.
TL;DR: In this paper, the authors investigate the dynamics of variable speed wind turbines and determine suitable models to support the control design task, and derive detailed models for the rotor aerodynamics, the drive-train dynamics and the power generation unit dynamics before combining to form the complete model of the wind turbine dynamics.
Abstract: Owing to concern over the environment, there is much interest in renewable sources of electrical power generation, of which one of the most promising is wind power. Wind turbines exploit this energy source to directly generate electrical power. There are essentially two types of windturbines, namely constant speed and variable speed machines. The purpose of this paper is to investigate the dynamics of variable speed wind turbines and determine suitable models to support the control design task. A basic but widely used dynamic representation of variable speed wind turbines and the corresponding models of the control plant dynamics are initially discussed. More detailed, yet still simple models, are derived separately for the rotor aerodynamics, the drive-train dynamics and the power generation unit dynamics before being combined to form the complete model of the wind turbine dynamics. The resulting combined model, in addition to supporting the control design task, enables the extent, to which the basic mod...
TL;DR: The widespread introduction of anaerobic digestion in Germany has shown that biogenic organic wastes are a valuable source for energy and nutrients.
Abstract: Anaerobic treatment processes are especially suited for the utilization of wet organic wastes from agriculture and industry as well as for the organic part of source-separated household wastes. Anaerobic degradation is a very cost-effective method for treating biogenic wastes because the formed biogas can be used for heat and electricity production and the digester residues can be recycled to agriculture as a secondary fertilizer. Anaerobic technology will also be used for the common treatment of wastes together with renewable energy crops in order to reduce the CO2-emissions according the Kyoto protocol. Various process types are applied in Germany which differ in material, reaction conditions and in the form of the used reactor systems. The widespread introduction of anaerobic digestion in Germany has shown that biogenic organic wastes are a valuable source for energy and nutrients. Anaerobic waste treatment is done today in approx. 850 biogas plants on small farm scale as well as on large industrial scale with the best beneficial and economic outcome. Due to some new environmental protection acts which promote the recycling of wastes and their utilization for renewable energy formation it can be expected that several hundreds new biogas plants will be built per year in Germany. In order to use the synergetic effects of a combined fermentation of wastes and energy crops new process types must be developed in order to optimize the substrate combinations and the process conditions for maximum biodegradation.
TL;DR: In this paper, the authors analyze the history behind these changes and underlines the lessons to be learned and underline that renewable energy policies throughout Europe are converging, and that the United Kingdom is in the process of creating a new policy.
Abstract: ▪ Abstract The first phase of promoting renewable energy in Europe is coming to an end. The timetable of the European Commission's Single Electricity Market (SEM) Directive has been the key recent driver of change within European energy and electricity markets. As mainland European countries have been forced to restructure their electricity industries and reappraise their renewable energy policies, they have been impressed by the results of the England and Wales Renewable Non-Fossil Fuel Obligation (NFFO). The NFFO is a mechanism for promoting renewable energy that has a competitive basis. However, the United Kingdom is in the process of creating a new policy. As new renewable energy policies have been discussed or put in place in mainland European countries, so these have influenced those of the United Kingdom. Renewable energy policies throughout Europe are converging. This paper analyzes the history behind these changes and underlines the lessons to be learned.
TL;DR: In this paper, a comparative assessment of the environmental and health impacts of nuclear and other electricity-generation systems is presented, including normal operations and accidents in the full energy chain analysis.
TL;DR: In this paper, the authors defined two electric grids for the area of Jutland in Denmark, namely the existing grid versus a nature protection grid, in which all 400 kV AC overhead lines are replaced by 150 kV lines.
TL;DR: In this article, the authors presented an optimal renewable energy model that minimizes the cost/efficiency ratio and determines the optimum allocation of different renewable energy sources for various end-uses.
TL;DR: In this paper, the authors evaluate the performance of five renewable energy technologies used to generate electricity: biomass, geothermal, solar photovoltaics, solar thermal, and wind.
TL;DR: In this paper, the economics of stand-alone photovoltaic power system is studied to test its feasibility in remote and rural areas of Bangladesh and to compare renewable generators with non-renewable generators.
TL;DR: In this article, the second part of a two-part series that addresses modelling approaches and results that were obtained in several case studies and research projects at the National Renewable Energy Laboratory (NREL).
Abstract: As the worldwide use of wind turbine generators in utility-scale applications continues to increase, it will become increasingly important to assess the economic and reliability impact of these intermittent resources. Although the utility industry appears to be moving towards a restructured environment, basic economic and reliability issues will continue to be relevant to companies involved with electricity generation. This article is the second in a two-part series that addresses modelling approaches and results that were obtained in several case studies and research projects at the National Renewable Energy Laboratory (NREL). This second article focuses on wind plant capacity credit as measured with power system reliability indices. Reliability-based methods of measuring capacity credit are compared with wind plant capacity factor. The relationship between capacity credit and accurate wind forecasting is also explored. Published in 2000 by John Wiley & Sons, Ltd.
13 Jul 2000
TL;DR: In this paper, the authors explore the question of how sustainable energy development, specifically, decentralized renewable energy technologies, can complement and benefit from the goal of increasing women's role in development.
Abstract: This paper explores the question of how sustainable energy development--specifically, decentralized renewable energy technologies--can complement and benefit from the goal of increasing women's role in development. It is based on a paper that was originally presented at the World Renewable Energy Congress-V held in Florence, Italy, in September 1998, as a contribution to the National Renewable Energy Laboratory's program on gender and energy.
TL;DR: The most important aspect of wood as renewable energy carrier is its nearly closed C-circle as mentioned in this paper, which is the most important characteristic of wood for renewable energy and is the main source of renewable energy.
Book•
01 Jan 2000
TL;DR: The second edition of the Solar Electricity, published by the University of Southampton, UK as discussed by the authors, is a comprehensive introduction to all aspects of solar energy conversion, from cell types to environmental impact and applications.
Abstract: Solar Electricity Second Edition Edited by Tomas Markvart University of Southampton, UK "warmly recommended as a comprehensive, introductory text on a subject which should become increasingly important." (Review of the First Edition in Contemporary Physics) The rapid evolution of photovoltaic technology has highlighted the increasing capabilities of solar electricity as a power source for distributed energy generation. Building on the success of the first edition, Solar Electricity presents a balanced introduction to all aspects of solar energy conversion, from cell types to environmental impact and applications. Now fully revised to incorporate the latest industry achievements and featuring: New sections on the role of dye sensitised solar cells, photovoltaics in buildings, diesel hybrid systems, and photovoltaic markets and funding. Solar cell design and manufacturing technology including crystalline silicon and thin film devices. Introduction to a range of photovoltaic applications including rural electrification, grid connection issues, and the supply of electrical power to satellites in space. Illustrative case studies and self-assessment questions and answers at the end of each chapter. Undergraduate and postgraduate science and engineering students, practising mechanical and power engineers and those with a general interest in renewable energy will find this comprehensive text on invaluable reference. Solar Electricity, Second Edition forms part of the Energy Engineering Learning Package. Organised by UNESCO, this distance learning package has been established to train engineers to meet the challengs of today and tomorrow in this exciting field of energy engineering. It has been developed by an international team of distinguished academics, coordinated by Dr Boris Berkovski. This modular course will appeal to advanced undergraduates and post graduate students, as well as practising power engineers in industry.