scholarly journals Blade Design Trade-Offs Using Low-Lift Airfoils for Stall-Regulated HAWTs

1999 ◽  
Vol 121 (4) ◽  
pp. 217-223 ◽  
Author(s):  
P. Gigue`re ◽  
M. S. Selig ◽  
J. L. Tangler
Keyword(s):  
Energy Production ◽  
Peak Power ◽  
Lift Coefficient ◽  
Minimum Cost ◽  
Blade Design ◽  
Trade Offs ◽  
Cost Of Energy ◽  
The Cost ◽  
Large Wind ◽  
Slight Advantage

A systematic blade design study was conducted to explore the trade-offs in using low-lift airfoils for a 750-kilowatt stall-regulated wind turbine. Tip-region airfoils having a maximum-lift coefficient ranging from 0.7-1.2 were considered in this study, with the main objective of identifying the practical lower limit for the maximum-lift coefficient. Blades were optimized for both maximum annual energy production and minimum cost of energy using a method that takes into account aerodynamic and structural considerations. The results indicate that the effect of the maximum-lift coefficient on the cost of energy is small with a slight advantage to the highest maximum lift coefficient case considered in this study. As a consequence, higher maximum lift coefficient airfoils for the tip-region of the blade become more desirable as machine size increases, provided the airfoils yield acceptable stall characteristics. The conclusions are applicable to large wind turbines that use passive or active stall to regulate peak power.

OIL AND THE ENVIRONMENT - CALIFORNIA CASE STUDY

1976 ◽  
Vol 16 (1) ◽  
pp. 137
Author(s):  
D. W. Barnett
Keyword(s):  
Energy Production ◽  
Social Cost ◽  
Shadow Price ◽  
Optimal Solution ◽  
Minimum Cost ◽  
Gulf Of Alaska ◽  
Outer Continental Shelf ◽  
Trade Offs ◽  
The Cost ◽  
Prudhoe Bay

USA environmentalists have tended to oppose all new energy developments. Their efforts may be counterproductive because opposition to, say, offshore oil directly leads to the continued use of other energy sources that may have a higher social cost. Rather than attempting to eliminate all pollution from energy production, which would be prohibitively expensive, one should minimize the social cost of energy production for the given demand.Linear programming is used to rank various oils (California State and Outer Continental Shelf (OCS), Gulf of Alaska, Prudhoe Bay, Athabasca tar sands, oil shale and certain foreign crudes) in terms of their social desirability. The objective is to minimize the cost of supplying the California market, subject to resource, sulphur and oil spill constraints.Social desirability is indicated by the inclusion of the oil in the optimal solution and the size of the associated shadow price. The larger the shadow price, the greater the benefits of increased production. The more negative, the greater the cost associated with forcing consumption of that fuel. The environmental shadow prices indicate the size of the trade-off between a particular environmental standard and minimum cost. The trade-offs can be surprisingly large. Any reasonable spill standard can be achieved by changing the development pattern. Generally, the further offshore, the smaller is the environmental degradation, but the more expensive is the oil. Foreign oils can be economically and environmentally inferior to domestic oils. Crude from the California OCS, San Joaquin Valley and Prudhoe Bay appears a valuable resource, while the Gulf of Alaska, synthetic and foreign crudes appear marginal to submarginal.The methodology could be readily adapted to the Australian scene.

Optimizing the Layout of Offshore Wind Energy Systems

2008 ◽  
Vol 42 (2) ◽  
pp. 19-27 ◽  
Author(s):  
Christopher N. Elkinton ◽  
James F. Manwell ◽  
Jon G. McGowan
Keyword(s):  
Wind Energy ◽  
Energy Production ◽  
Wind Farm ◽  
Offshore Wind ◽  
Offshore Wind Energy ◽  
Offshore Wind Farm ◽  
Wind Farm Layout ◽  
Trade Offs ◽  
Cost Of Energy ◽  
The Cost

Offshore wind energy technology is a reality in Europe and is poised to make a significant contribution to the U.S. energy supply in the near future as well. The layout of an offshore wind farm is a complex problem involving many trade-offs. For example, energy production increases with turbine spacing, as do electrical costs and losses. Energy production also increases with distance from shore, but so do O&M (operations and maintenance), foundation, transmission, and installation costs. Determining which of these factors dominates requires a thorough understanding of the physics behind these trade-offs, can lead to the optimal layout, and helps lower the cost of energy from these farms. This paper presents the results of a study carried out to investigate these trade-offs and to develop a method for optimizing the wind farm layout during the micrositing phase of an offshore wind energy system design. It presents a method for analyzing the cost of energy from offshore wind farms as well as a summary of the development of an offshore wind farm layout optimization tool. In addition to an initial validation of the optimization tool, an example of the use of this tool for the design of an offshore wind farm in Hull, Massachusetts, is also given.

A Techno-Economic Analysis of a Proposed 1.5 MW Wind Turbine With a Hydrostatic Drive Train

2009 ◽  
Author(s):  
James R. Browning ◽  
Jon G. McGowan ◽  
James F. Manwell
Keyword(s):  
Wind Turbine ◽  
Energy Production ◽  
Capital Cost ◽  
Performance Model ◽  
Drive Train ◽  
Cost Models ◽  
Initial Capital ◽  
Cost Of Energy ◽  
The Cost ◽  
Utility Scale

Although decreases in the cost of energy from utility scale wind turbine generators has made them competitive with conventional forms of utility power generation, further reductions can increase the presence of wind energy in the global energy mix. The cost of energy from a wind turbine can be reduced by increasing the annual energy production, reducing the initial capital cost of the turbine, or doing both. In this study, the cost of energy is estimated for a theoretical 1.5 MW wind turbine utilizing a continuously variable ratio hydrostatic drive train between the rotor and the generator. The estimated cost of energy is then compared to that of a conventional wind turbine of equivalent rated power. The annual energy production is estimated for the theoretical hydrostatic turbine using an assumed wind speed distribution and a turbine power curve resulting from a steady state performance model of the turbine. The initial capital cost of the turbine is estimated using cost models developed for various components unique to the hydrostatic turbine as well as economic parameters and models developed by the National Renewable Energy Lab (NREL) for their 2004 WindPACT advanced wind turbine drive train study. The resulting cost of energy, along with various performance characteristics of interest, are presented and compared to those of the WindPACT baseline turbine intended to represent a conventional utility scale wind turbine.

scholarly journals Trade-Offs between Speed, Accuracy, and Dissipation in tRNAIle Aminoacylation

2020 ◽  
Author(s):  
Qiwei Yu ◽  
Joel D. Mallory ◽  
Anatoly B. Kolomeisky ◽  
Jiqiang Ling ◽  
Oleg A. Igoshin
Keyword(s):  
Energy Dissipation ◽  
Trna Synthetase ◽  
Discrete State ◽  
Global Parameter ◽  
Trade Offs ◽  
Cost Of Energy ◽  
Evolutionary Force ◽  
The Cost ◽  
Kinetic Proofreading ◽  
Speed Accuracy

AbstractLiving systems maintain a high fidelity in information processing through kinetic proofreading, a mechanism to preferentially remove incorrect substrates at the cost of energy dissipation and slower speed. Proofreading mechanisms must balance their demand for higher speed, fewer errors, and lower dissipation, but it is unclear how rates of individual reaction steps are evolutionary tuned to balance these needs, especially when multiple proofreading mechanisms are present. Here, using a discrete-state stochastic model, we analyze the optimization strategies in Escherichia coli isoleucyl-tRNA synthetase. Surprisingly, this enzyme adopts an economic proofreading strategy and improves speed and dissipation as long as the error is tolerable. Through global parameter sampling, we reveal a fundamental dissipation-error relation that bounds the enzyme’s optimal performance and explains the importance of the post-transfer editing mechanism. The proximity of native system parameters to this bound demonstrates the importance of energy dissipation as an evolutionary force affecting fitness.Graphical TOC Entry

scholarly journals Potential of wind energy resources around Nasawana village in Nabouwalu, Vanua Levu, Fiji

2020 ◽  
pp. 014459872097067
Author(s):  
Krishnam Nair ◽  
Ajal Kumar
Keyword(s):  
Energy Demand ◽  
Energy Production ◽  
Fossil Fuel ◽  
Solar Pv ◽  
Cost Of Energy ◽  
Wind Analysis ◽  
The Pacific ◽  
The Cost ◽  
Wind Resource ◽  
Wind Energy Resources

Fiji is located in the South Western part of the Pacific between latitude 18° S and longitude 179° E. In 2018, Fiji has spent approximately FJD 800 million in importing fossil fuel to meet the rising energy demand in the country. In the previous year’s several solar PV and wind resource assessments has been done and results obtained indicated that there is a potential for grid connected electricity generation using recommended resources. This study was carried out in the Nasawana Village (16°55.3 S and 178°47.4 E) to determine the options to use electricity derived from the wind. Wind analysis was carried out using Wind Atlas Analysis and Application Program (WAsP) that predicted the wind speed of 6.96 ms−1 and a power density of 256 Wm−2 at 55 m a.g.l. The annual energy production predicted for a single wind turbine (Vergnet 275 kW) is approximately 631.6 MWh with a capacity factor of 26%. The cost of energy per kWh is estimated as FJD 0.10 with a payback period of 7 years.

scholarly journals Evaluation of the impact of active wake control techniques on ultimate loads for a 10 MW wind turbine

2022 ◽  
Vol 7 (1) ◽  
pp. 1-17
Author(s):  
Alessandro Croce ◽  
Stefano Cacciola ◽  
Luca Sartori
Keyword(s):  
Wind Turbine ◽  
Energy Production ◽  
Wind Farm ◽  
Control Techniques ◽  
Control Optimization ◽  
Cost Of Energy ◽  
The Individual ◽  
The Cost ◽  
Wind Statistics ◽  
The Impact

Abstract. Wind farm control is one of the solutions recently proposed to increase the overall energy production of a wind power plant. A generic wind farm control is typically synthesized so as to optimize the energy production of the entire wind farm by reducing the detrimental effects due to wake–turbine interactions. As a matter of fact, the performance of a farm control is typically measured by looking at the increase in the power production, properly weighted through the wind statistics. Sometimes, fatigue loads are also considered in the control optimization problem. However, an aspect which is rather overlooked in the literature on this subject is the evaluation of the impact that a farm control law has on the individual wind turbine in terms of maximum loads and dynamic response under extreme conditions. In this work, two promising wind farm controls, based on wake redirection (WR) and dynamic induction control (DIC) strategy, are evaluated at the level of a single front-row wind turbine. To do so, a two-pronged analysis is performed. Firstly, the control techniques are evaluated in terms of the related impact on some specific key performance indicators, with special emphasis on ultimate loads and maximum blade deflection. Secondarily, an optimal blade redesign process is performed with the goal of quantifying the modification in the structure of the blade entailed by a possible increase in ultimate values due to the presence of wind farm control. Such an analysis provides for an important piece of information for assessing the impact of the farm control on the cost-of-energy model.

scholarly journals Comparison between upwind and downwind designs of a 10 MW wind turbine rotor

2018 ◽  
Author(s):  
Pietro Bortolotti ◽  
Abinhav Kapila ◽  
Carlo L. Bottasso
Keyword(s):  
Wind Turbine ◽  
Energy Production ◽  
Turbine Rotor ◽  
Design Tool ◽  
Operating Conditions ◽  
Cost Of Energy ◽  
Potential Benefits ◽  
The Cost ◽  
Interesting Alternative ◽  
Wind Turbine Rotor

Abstract. The size of wind turbines has been steadily growing in the pursuit of a lower cost of energy by an increased wind capture. In this trend, the vast majority of wind turbine rotors has been designed based on the conventional three-bladed upwind concept. This paper aims at assessing the optimality of this configuration with respect to a three-bladed downwind design, with and without an actively controlled variable coning used to reduce the cantilever loading of the blades. A 10 MW wind turbine is used for the comparison of the various design solutions, which are obtained by an automated comprehensive aerostructural design tool. Results show that, for this turbine size, downwind rotors lead to blade mass and cost reductions of 6 % and 2 %, respectively, compared to equivalent upwind configurations. Due to a more favorable rotor attitude, the annual energy production of downwind rotors may also slightly increase in complex terrain conditions characterized by a wind upflow, leading to an overall reduction in the cost of energy. However, in more standard operating conditions, upwind rotors return the lowest cost of energy. Finally, active coning is effective in alleviating loads by reducing both blade mass and cost, but these potential benefits are negated by an increased system complexity and reduced energy production. In summary, a conventional design appears difficult to beat even at these turbine sizes, although a downwind non-aligned configuration might result in an interesting alternative.

scholarly journals Evaluation of the impact of wind farm control techniques on fatigue and ultimate loads

2020 ◽  
Author(s):  
Alessandro Croce ◽  
Stefano Cacciola ◽  
Luca Sartori ◽  
Paride De Fidelibus
Keyword(s):  
Wind Turbine ◽  
Energy Production ◽  
Wind Farm ◽  
Dynamic Responses ◽  
Control Techniques ◽  
Cost Of Energy ◽  
The Individual ◽  
The Cost ◽  
The Impact ◽  
Do So

Abstract. Wind farm control is one of the solutions recently proposed to increase the overall energy production of a wind power plant. A generic wind farm control is typically synthesized so as to optimize the energy production of the entire wind farm by reducing the detrimental effects due to wake-turbine interactions. As a matter of fact, the performance of a farm control is typically measured by looking mainly at the increase of produced power, possibly weighted with the wind Weibull and rose at a specific place, and, sometimes, by looking also at the fatigue loads. However, an aspect which is rather overlooked is the evaluation of the impact that a farm control law has on the maximum loads and on the dynamic responses under extreme conditions of the individual wind turbine. In this work, two promising wind farm controls, based respectively on Wake Redirection (WR) and Dynamic Induction Control (DIC) strategy, are evaluated at a single wind turbine level. To do so, a two-pronged analysis is performed. Firstly, the control techniques are evaluated in terms of the related impact on some specific key performance indicators (e.g. fatigue and ultimate loads, actuator duty cycle and annual energy production). Secondarily, an optimal blade redesign process, which takes into account the presence of the wind farm control, is performed with the goal of quantifying the possible modification in the structure of the blade and hence of quantifying the impact of the control on the Cost of Energy model.

scholarly journals Optimal Integration of Hydrogen-Based Energy Storage Systems in Photovoltaic Microgrids: A Techno-Economic Assessment

Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4149
Author(s):  
Fabio Serra ◽  
Marialaura Lucariello ◽  
Mario Petrollese ◽  
Giorgio Cau
Keyword(s):  
Cost Effectiveness ◽  
Energy Production ◽  
Storage Systems ◽  
Storage System ◽  
Economic Assessment ◽  
Pv System ◽  
Hydrogen Storage System ◽  
Cost Of Energy ◽  
Expected Performance ◽  
The Cost

The feasibility and cost-effectiveness of hydrogen-based microgrids in facilities, such as public buildings and small- and medium-sized enterprises, provided by photovoltaic (PV) plants and characterized by low electric demand during weekends, were investigated in this paper. Starting from the experience of the microgrid being built at the Renewable Energy Facility of Sardegna Ricerche (Italy), which, among various energy production and storage systems, includes a hydrogen storage system, a modeling of the hydrogen-based microgrid was developed. The model was used to analyze the expected performance of the microgrid considering different load profiles and equipment sizes. Finally, the microgrid cost-effectiveness was evaluated using a preliminary economic analysis. The results demonstrate that an effective design can be achieved with a PV system sized for an annual energy production 20% higher than the annual energy requested by the user and a hydrogen generator size 60% of the PV nominal power size. This configuration leads to a self-sufficiency rate of about 80% and, without public grants, a levelized cost of energy comparable with the cost of electricity in Italy can be achieved with a reduction of at least 25–40% of the current initial costs charged for the whole plant, depending on the load profile shape.

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