Simulation and interpretation of marine controlled-source electromagnetic(CSEM) data often approximate the transmitter source as an ideal horizontal electric dipole(HED) and assume that the receivers are located on a ...Simulation and interpretation of marine controlled-source electromagnetic(CSEM) data often approximate the transmitter source as an ideal horizontal electric dipole(HED) and assume that the receivers are located on a flat seabed.Actually,however,the transmitter dipole source will be rotated,tilted and deviated from the survey profile due to ocean currents.And free-fall receivers may be also rotated to some arbitrary horizontal orientation and located on sloping seafloor.In this paper,we investigate the effects of uncertainties in the transmitter tilt,transmitter rotation and transmitter deviation from the survey profile as well as in the receiver's location and orientation on marine CSEM data.The model study shows that the uncertainties of all position and orientation parameters of both the transmitter and receivers can propagate into observed data uncertainties,but to a different extent.In interpreting marine data,field data uncertainties caused by the position and orientation uncertainties of both the transmitter and receivers need to be taken into account.展开更多
The paper presents the measurement campaign of wind energy potential undertaken in Republic of Macedonia on four sites from the middle of 2006. The wind data analysis has been performed for one site, following with th...The paper presents the measurement campaign of wind energy potential undertaken in Republic of Macedonia on four sites from the middle of 2006. The wind data analysis has been performed for one site, following with the assessment of energy production of simulated wind park with six wind turbine generators.展开更多
The probability distributions of wind speeds and the availability of wind turbines were investigated by considering the vertical wind shear. Based on the wind speed data at the standard height observed at a wind farm,...The probability distributions of wind speeds and the availability of wind turbines were investigated by considering the vertical wind shear. Based on the wind speed data at the standard height observed at a wind farm, the power-law process was used to simulate the wind speeds at a hub height of 60 m. The Weibull and Rayleigh distributions were chosen to express the wind speeds at two different heights. The parameters in the model were estimated via the least square(LS) method and the maximum likelihood estimation(MLE) method, respectively. An adjusted MLE approach was also presented for parameter estimation. The main indices of wind energy characteristics were calculated based on observational wind speed data. A case study based on the data of Hexi area, Gansu Province of China was given. The results show that MLE method generally outperforms LS method for parameter estimation, and Weibull distribution is more appropriate to describe the wind speed at the hub height.展开更多
A new biomass-gasification power plant, of medium-size downdraft type, is presented and discussed in its design features and performance characteristics. Its configuration and overall dimensions, initially conceived f...A new biomass-gasification power plant, of medium-size downdraft type, is presented and discussed in its design features and performance characteristics. Its configuration and overall dimensions, initially conceived for 800 kW, were recently re-tuned, from a functional point of view and on the base of a parallel theoretical analysis, by decreasing to about 400 kW the former nominal power level. This provision, jointly with the basic design choice of adopting a long and amply dimensioned inlet-biomass thermal pretreatment section, turned out quite effective in achieving high gasification temperatures and a low-tar content in the produced gas at fuel-to-air ratios well below the usually imposed ones, to the advantage of the heat value of the product-gas. The paper discusses the numerical analysis results which helped to properly re-adjust the operational parameters of the gasifier and then presents the experimental performance data of the overall power plant including biomass consumption, gasification temperatures, gas production, composition and pollutants content, cold-gas conversion efficiency and global electric efficiency. Special care is devoted to investigating the issue of a significant production of carbon-containing particulate matter in the product gas, which turns out made up of char and fixed carbon much more than of tar species.展开更多
Multi-GW renewables need multi-GW storage, or fossil fuelled power stations will be needed to balance for intermittency. For the same reason, such balancing must be able to last for an entire evening peak if renewable...Multi-GW renewables need multi-GW storage, or fossil fuelled power stations will be needed to balance for intermittency. For the same reason, such balancing must be able to last for an entire evening peak if renewables are not generating at the same time. Batteries and DSR (demand side response) make very useful contributions and there is a large market for both, but without large scale and long duration storage, they cannot do the job. Interconnectors also contribute to the solution, and storage will make them more profitable, but (taking a UK perspective) Ofgem identified that all our neighbours have similar generation capacity crunches and similar demand patters, so if we need the electricity when they do, we’ll have to pay through the nose for it. Last winter’s £ 1,500/MWh prices proved that―even with only 4 GW interconnection. Following exit from the single market, our neighbours will be able to say “our consumers are more important than yours at any price”. We need UK-based storage at the right scale, to store UK-generated electricity for UK use and for export―otherwise we lose security of supply. CAES (compressed air energy storage) and pumped hydro are the only technologies currently able to deliver this scale and duration of storage. Pumped hydro is cost-effective in the long term but there are few sites, and it is (location dependent) over 3x the cost of CAES. Storelectric has 2 versions of CAES: one is a comparable price to existing CAES, but much more efficient (~70% v 50%) and zero emissions (existing CAES emits 50%-60% of the gas of an equivalent sized power station). The other is retro-fittable to suitable gas power stations, is more efficient (-60% v 50%), almost halves their emissions, adds storage-related revenue streams and is much cheaper. Both are new configurations of existing and well proven technologies, supported by engineering majors.展开更多
The aim of this work is double. Firstly, we want to stress out that investing in renewable energies in 2009 in Spain was a profitable activity. This question will be answered studying the possibilities of expanding "...The aim of this work is double. Firstly, we want to stress out that investing in renewable energies in 2009 in Spain was a profitable activity. This question will be answered studying the possibilities of expanding "Sierra de Tineo" wind farm in the Principality of Asturias (location, wind resource, data analysis, simulation, legal standards and economic and sensitivity study of the investment), and for that, data from the year 2009 have been used. And secondly, the goal is to set the bases for a future paper where the current situation of Spain (within the renewable framework), will be compared with the 2009 scenario.展开更多
The fluctuation characteristics is the inherent property of wind power.Through analysis of a large number of wind t'anns based on measured data,we find it describes the best probability distribution of wind power flu...The fluctuation characteristics is the inherent property of wind power.Through analysis of a large number of wind t'anns based on measured data,we find it describes the best probability distribution of wind power fluctuation for the mixed Gauss distribution of two components,and try to carry out the physical interpretation of two components.Further discussion is between the probability distribution of fluctuating wind power time difference and whole relationship.It is found that the two have basic similarity.Through comparing the different time level data quantified losses the information of wind power fluctuation,quantitative determination of the degree of impact prediction.We can summarize and understand of wind power fluctuation,constructing instance from the wind farm construction and monitoring prediction two aspect recommendations to overcome the adverse effects of wind power fluctuations on the power grid operation.展开更多
This paper introduces a set of automatic dust removal device for street lamp solar panels. The device realizes the automatic dust removal for street lamp solar panels by three steps consisting of data acquisition, aut...This paper introduces a set of automatic dust removal device for street lamp solar panels. The device realizes the automatic dust removal for street lamp solar panels by three steps consisting of data acquisition, automatic control and mechanical dust removal. Our scheme is as follows, according to the comparison between the actual power generation and the relatively ideal condition of power generation of solar panels, we selectively conduct dust removal operation to panels. The paper demonstrates the feasibiliW of the technology based on the example of street lamp solar panels (40w). According to the calculation, the solar panels equipped with our device will greatly improve the power generation efficiency of solar panels, which means there will be 32 more degrees generated every year. Extension and application of the technique device will be beneficial for the improvement of solar panels power generation efficiency and the extension of the service life of the panels.展开更多
This research seeks to evaluate the economic benefits to be gained by installing a small-scale wind turbine for a customer with a three-phase electrical supply requirement. The evidence for the claims made in this pap...This research seeks to evaluate the economic benefits to be gained by installing a small-scale wind turbine for a customer with a three-phase electrical supply requirement. The evidence for the claims made in this paper is obtained by using actual data obtained from the installed equipment over a three year period. The objective is to accurately appraise the financial investment using real data. There appears to be limited studies conducted into this type of research, possibly because the renewable energy sector is in the infancy stage in the host country, Ireland. There are some wind energy installations with financial appraisal techniques based on modeled data, which may, or may not, be accurate. The study concludes by claiming that the financial benefits of the wind energy turbine installation had disappointing results when compared to predicted benefits based on modeled data.展开更多
In this paper, the authors present the development of a data modelling tool that visualizes the transformation process of an "Entity-Relationship" Diagram (ERD) into a relational database schema. The authors' foc...In this paper, the authors present the development of a data modelling tool that visualizes the transformation process of an "Entity-Relationship" Diagram (ERD) into a relational database schema. The authors' focus is the design of a tool for educational purposes and its implementation on e-learning database course. The tool presents two stages of database design. The first stage is to draw ERD graphically and validate it. The drawing is done by a learner. Then at second stage, the system enables automatically transformation of ERD to relational database schema by using common rules. Thus, the learner could understand more easily how to apply the theoretical material. A detailed description of system functionalities and algorithm for the conversion are proposed. Finally, a user interface and usage aspects are exposed.展开更多
Wind-power (WP) estimation is necessary for power system in several operations, which are as the optimal power flow between conventional units and wind farms, generators scheduling, and electricity market bidding. E...Wind-power (WP) estimation is necessary for power system in several operations, which are as the optimal power flow between conventional units and wind farms, generators scheduling, and electricity market bidding. Estimating the output power of a wind energy conversion unit (WEC) mainly bases on the incident wind speed at the unit site by using the power characteristic curve. In addition, several time-series models have been using in wind speed forecasting. These models are characterized with requiring a large set of data. In order to prevent from the wind speed measurement and the need of a precise wind turbine model, an novel method basing on neural network and the grey predictor model GM (1,1) is proposed. Though the method, the estimating model can be built only by using the experimental data, which are obtained from the WP system in laboratory. The effectiveness of the estimating model is confirmed by the simulation results.展开更多
基金funded by the National Natural Science Foundation of China (41130420)the State High-Tech Development Plan of China (2012AA09A20101)
文摘Simulation and interpretation of marine controlled-source electromagnetic(CSEM) data often approximate the transmitter source as an ideal horizontal electric dipole(HED) and assume that the receivers are located on a flat seabed.Actually,however,the transmitter dipole source will be rotated,tilted and deviated from the survey profile due to ocean currents.And free-fall receivers may be also rotated to some arbitrary horizontal orientation and located on sloping seafloor.In this paper,we investigate the effects of uncertainties in the transmitter tilt,transmitter rotation and transmitter deviation from the survey profile as well as in the receiver's location and orientation on marine CSEM data.The model study shows that the uncertainties of all position and orientation parameters of both the transmitter and receivers can propagate into observed data uncertainties,but to a different extent.In interpreting marine data,field data uncertainties caused by the position and orientation uncertainties of both the transmitter and receivers need to be taken into account.
文摘The paper presents the measurement campaign of wind energy potential undertaken in Republic of Macedonia on four sites from the middle of 2006. The wind data analysis has been performed for one site, following with the assessment of energy production of simulated wind park with six wind turbine generators.
基金Project(51165019)supported by the National Natural Science Foundation of ChinaProject(1308RJYA018)supported by Gansu Provincial Natural Science Fund,ChinaProject(2013-4-110)supported by Lanzhou Technology Development Program,China
文摘The probability distributions of wind speeds and the availability of wind turbines were investigated by considering the vertical wind shear. Based on the wind speed data at the standard height observed at a wind farm, the power-law process was used to simulate the wind speeds at a hub height of 60 m. The Weibull and Rayleigh distributions were chosen to express the wind speeds at two different heights. The parameters in the model were estimated via the least square(LS) method and the maximum likelihood estimation(MLE) method, respectively. An adjusted MLE approach was also presented for parameter estimation. The main indices of wind energy characteristics were calculated based on observational wind speed data. A case study based on the data of Hexi area, Gansu Province of China was given. The results show that MLE method generally outperforms LS method for parameter estimation, and Weibull distribution is more appropriate to describe the wind speed at the hub height.
文摘A new biomass-gasification power plant, of medium-size downdraft type, is presented and discussed in its design features and performance characteristics. Its configuration and overall dimensions, initially conceived for 800 kW, were recently re-tuned, from a functional point of view and on the base of a parallel theoretical analysis, by decreasing to about 400 kW the former nominal power level. This provision, jointly with the basic design choice of adopting a long and amply dimensioned inlet-biomass thermal pretreatment section, turned out quite effective in achieving high gasification temperatures and a low-tar content in the produced gas at fuel-to-air ratios well below the usually imposed ones, to the advantage of the heat value of the product-gas. The paper discusses the numerical analysis results which helped to properly re-adjust the operational parameters of the gasifier and then presents the experimental performance data of the overall power plant including biomass consumption, gasification temperatures, gas production, composition and pollutants content, cold-gas conversion efficiency and global electric efficiency. Special care is devoted to investigating the issue of a significant production of carbon-containing particulate matter in the product gas, which turns out made up of char and fixed carbon much more than of tar species.
文摘Multi-GW renewables need multi-GW storage, or fossil fuelled power stations will be needed to balance for intermittency. For the same reason, such balancing must be able to last for an entire evening peak if renewables are not generating at the same time. Batteries and DSR (demand side response) make very useful contributions and there is a large market for both, but without large scale and long duration storage, they cannot do the job. Interconnectors also contribute to the solution, and storage will make them more profitable, but (taking a UK perspective) Ofgem identified that all our neighbours have similar generation capacity crunches and similar demand patters, so if we need the electricity when they do, we’ll have to pay through the nose for it. Last winter’s £ 1,500/MWh prices proved that―even with only 4 GW interconnection. Following exit from the single market, our neighbours will be able to say “our consumers are more important than yours at any price”. We need UK-based storage at the right scale, to store UK-generated electricity for UK use and for export―otherwise we lose security of supply. CAES (compressed air energy storage) and pumped hydro are the only technologies currently able to deliver this scale and duration of storage. Pumped hydro is cost-effective in the long term but there are few sites, and it is (location dependent) over 3x the cost of CAES. Storelectric has 2 versions of CAES: one is a comparable price to existing CAES, but much more efficient (~70% v 50%) and zero emissions (existing CAES emits 50%-60% of the gas of an equivalent sized power station). The other is retro-fittable to suitable gas power stations, is more efficient (-60% v 50%), almost halves their emissions, adds storage-related revenue streams and is much cheaper. Both are new configurations of existing and well proven technologies, supported by engineering majors.
文摘The aim of this work is double. Firstly, we want to stress out that investing in renewable energies in 2009 in Spain was a profitable activity. This question will be answered studying the possibilities of expanding "Sierra de Tineo" wind farm in the Principality of Asturias (location, wind resource, data analysis, simulation, legal standards and economic and sensitivity study of the investment), and for that, data from the year 2009 have been used. And secondly, the goal is to set the bases for a future paper where the current situation of Spain (within the renewable framework), will be compared with the 2009 scenario.
文摘The fluctuation characteristics is the inherent property of wind power.Through analysis of a large number of wind t'anns based on measured data,we find it describes the best probability distribution of wind power fluctuation for the mixed Gauss distribution of two components,and try to carry out the physical interpretation of two components.Further discussion is between the probability distribution of fluctuating wind power time difference and whole relationship.It is found that the two have basic similarity.Through comparing the different time level data quantified losses the information of wind power fluctuation,quantitative determination of the degree of impact prediction.We can summarize and understand of wind power fluctuation,constructing instance from the wind farm construction and monitoring prediction two aspect recommendations to overcome the adverse effects of wind power fluctuations on the power grid operation.
文摘This paper introduces a set of automatic dust removal device for street lamp solar panels. The device realizes the automatic dust removal for street lamp solar panels by three steps consisting of data acquisition, automatic control and mechanical dust removal. Our scheme is as follows, according to the comparison between the actual power generation and the relatively ideal condition of power generation of solar panels, we selectively conduct dust removal operation to panels. The paper demonstrates the feasibiliW of the technology based on the example of street lamp solar panels (40w). According to the calculation, the solar panels equipped with our device will greatly improve the power generation efficiency of solar panels, which means there will be 32 more degrees generated every year. Extension and application of the technique device will be beneficial for the improvement of solar panels power generation efficiency and the extension of the service life of the panels.
文摘This research seeks to evaluate the economic benefits to be gained by installing a small-scale wind turbine for a customer with a three-phase electrical supply requirement. The evidence for the claims made in this paper is obtained by using actual data obtained from the installed equipment over a three year period. The objective is to accurately appraise the financial investment using real data. There appears to be limited studies conducted into this type of research, possibly because the renewable energy sector is in the infancy stage in the host country, Ireland. There are some wind energy installations with financial appraisal techniques based on modeled data, which may, or may not, be accurate. The study concludes by claiming that the financial benefits of the wind energy turbine installation had disappointing results when compared to predicted benefits based on modeled data.
文摘In this paper, the authors present the development of a data modelling tool that visualizes the transformation process of an "Entity-Relationship" Diagram (ERD) into a relational database schema. The authors' focus is the design of a tool for educational purposes and its implementation on e-learning database course. The tool presents two stages of database design. The first stage is to draw ERD graphically and validate it. The drawing is done by a learner. Then at second stage, the system enables automatically transformation of ERD to relational database schema by using common rules. Thus, the learner could understand more easily how to apply the theoretical material. A detailed description of system functionalities and algorithm for the conversion are proposed. Finally, a user interface and usage aspects are exposed.
文摘Wind-power (WP) estimation is necessary for power system in several operations, which are as the optimal power flow between conventional units and wind farms, generators scheduling, and electricity market bidding. Estimating the output power of a wind energy conversion unit (WEC) mainly bases on the incident wind speed at the unit site by using the power characteristic curve. In addition, several time-series models have been using in wind speed forecasting. These models are characterized with requiring a large set of data. In order to prevent from the wind speed measurement and the need of a precise wind turbine model, an novel method basing on neural network and the grey predictor model GM (1,1) is proposed. Though the method, the estimating model can be built only by using the experimental data, which are obtained from the WP system in laboratory. The effectiveness of the estimating model is confirmed by the simulation results.