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- Category: Articles
Portfolio Financing: An Option to Promote Wind Farms in Eastern Europe?
Investors' reduced risk perception has generated a noticeable trend in the financing of wind farms through the bond market. Project developers welcome bond financing since it provides longer term and less expensive financing than conventional loans that mature in 12-14 years. Banks are also financing projects by bundling assets from several wind farms to provide collateral for bonds.By Rosa Tarragó, Commerzbank AG, Germany
- Category: Articles
Making Wind Power Sustainable and Profitable
As the need for cleaner and safer sources of power continues to grow, wind power continues to increase in popularity. That growth, however, is limited by conventional wind technology. In this article the author describes the concept of dispatchable wind, and how it can make wind energy sustainable and profitable.
By David Marcus, CEO, General Compression, USA
- Category: Articles
A Quieter and More Efficient Solution to Harnessing Wind Energy?
Numerical and experimental results obtained from testing a new generation wind turbine indicate its ability to produce greater power output when compared to conventional horizontal axis wind turbines (HAWTs). With a three-dimensional streamlined geometry, the AXTRA turbine can produce up to three times more torque than a HAWT with the same rotor diameter. The turbine blades are sloped 45? downwind to the axis of rotation, giving an effective increase in flow contact area and making use of the additional components of velocity not present in air flowing around conventional propeller blades. Results have been obtained from experimental comparisons between 870mm diameter AXTRA and HAWT turbines and confirmed by computational fluid dynamical analysis of the flow patterns and loads on the blades. The AXTRA turbine provides new potential, particularly in the smaller end of the wind market (<100kW) where variable pitch blades are not economical and the average wind speed reaches 10m/s.By Jenny Rollo and Peter Rollo, the University of Sydney, Australia
- Category: Articles
A Monitoring and Evaluation Programme for an Offshore Wind Farm
Just offshore from the Dutch town Egmond aan Zee, a wind farm has recently become operational. As part of the project, a monitoring and evaluation programme will be carried out during the construction phase and the first years of operation. The monitoring programme includes the assessment of the effects of spills caused by ship collisions with the wind farm. But how can collisions of ships with the wind farm, and the consequences of possible oil spills resulting from these incidents, be monitored when the risk of these events is very small? Modelling the frequency and consequences of these events is the only way of making a quantitative assessment of the possible increase in risk resulting from the presence of the wind farm, and assessing its significance.By F.M. Kleissen, WL | Delft Hydraulics and C. van der Tak, MARIN, the Netherlands
- Category: Articles
Going Big by Thinking Small
The average wind speed on this planet is 5 m/s. However, as most people in the industry know, conventional wind generators are designed to achieve optimum performance at wind speeds between 12 and 25 m/s. Sites that can provide that kind of wind energy are unusual and everybody seems happy when a wind generator works at least 30 to 35% of the time. The author describes his Motorwind concept, which he thinks will overcome this discrepancy and make wind energy more efficient and more widely available.
By Lucien Gambarota, Motorwave Group, Hong Kong
- Category: Articles
Problems of a Reliable Connection between Steel Tower and Concrete Foundation
The construction of wind energy converters is normally based on an expected lifetime of 20 years. This assumption is made when designing the mechanical parts of the engine and the reinforced concrete foundation. However, in some cases defects occur much earlier and raise questions of serviceability, stability and durability. This article deals with the problems of how to connect a steel tower to a reinforced concrete foundation. It shows the possible damage that might occur and an example of reconstruction.
By Marc Gutermann, managing partner, Prof. Dr.-Ing. Steffens Ing., Germany
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The construction of wind energy converters is normally based on an expected lifetime of 20 years. This assumption is made when designing the mechanical parts of the engine and the reinforced concrete foundation. However, in some cases defects occur much earlier and raise questions of serviceability, stability and durability. This article deals with the problems of how to connect a steel tower to a reinforced concrete foundation. It shows the possible damage that might occur and an example of reconstruction.By Marc Gutermann, managing partner, Prof. Dr.-Ing. Steffens Ing., Germany
- Category: Articles
Gamesa Consolidates its own Preventive Maintenance
Among its many other activities, Gamesa is involved with predictive maintenance services and condition monitoring systems. In this article Gamesa's services and systems are described in the wider context of the needs for integrated condition monitoring, prediction and preventive maintenance for wind turbines.By Gamesa Eólica, Spain
