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285 Uppsatser om Wind Turbines - Sida 5 av 19

En studie av olika ekonomiska modeller för mångbruk baserad på vindkraft

Today produces the wind power 2,5 TWh (TWh = terawatt hours) of Sweden?s total energy input of around 620 TWh. The Parliament has adopted a national planning objective where the wind-based electricity production will increase to 30 TWh in 2020. This requires that landowners will leas there land for wind power to wind energy companies. Such land leasing means that the landowner's business is considered to be a multiple-use.

Aerodynamisk optimering av vindkraftverks rotorblad med en genetisk algoritm, BEM-teori, och XFOIL

This study presents a methodology that enables the annual average power of a wind turbine to be increased by automatically optimizing it?s airfoil, twist and chord dis- tribution. As a part of the study the software SiteOpt has been developed. This software connects the open source software XFOIL with the blade element momen- tum theory. XFOIL gives lift and drag coefficients which enable the blade element momentum theory to predict the power of a wind turbine at different wind and ro- tational speeds.

Vindkraft och landskap

The current debate about environment and climate change has contributed to more andmore investment in alternative energy sources such as wind, solar and biogas. The Swedish Parliament has set the target that wind power should supply 10 TWh in 2015.In Sweden, wind power establishment began in the early 1980s. Since then the development has gained a tremendous momentum. The purpose of this study was to find out what problems wind power brings and what power relations that exists in connection with wind power establishment and how the landscape is affected by windpower construction, focusing on some cases in Falkenberg and Varberg. This study shows that wind power establishment is a very complicated process.

Stormskador i stickvägsgallrade bestånd i sydvästra Sverige :

A storm in January 2005 felled 75 millions cubic metres of forest in South Sweden. Previous studies of wind damage in thinned stands indicated the importance of early thinnings. The risks of wind throw increased by increasing age and height of the stands. Previous studies also indicated increasing risk of wind throw along the strip roads. The aim of the present study was to investigate wind damage in Norway spruce stands in South Sweden in relation to time of the first thinning and different pattern of strip roads (width, length and direction).

Ekonomiska innovationer i den gotländska vindkraftsindustrin

Currently there is a controversial debate about that we must reduce our impact on the global warming; therefore both the Government and the local authorities have invested heavily in developing renewable energy in Sweden. The major development on the wind power market can be seen as a result of both the technological development and also on the decision that the Government took in 1996, which opened up the wind power market for private parties.This paper has aimed to examine the types of financial innovations that have arisen from the investments and financing of wind power on Gotland, and what these innovations can contribute to the future development of wind power.The problems that this thesis is based on is; what kind of financial innovations have occurred within investment and financing of wind power? How can these innovations contribute to the continued development of wind power on Gotland? The conclusion of this study shows that respondents and participants have defined a number of financial innovations that have emerged. Where some of the innovations only can be seen as incremental since they are based on continuous improvements, while others can be seen as radical as they are completely new for the context in which they operate. The study has also shown that Gotland has a great potential to produce more renewable electricity, but the development is dependent on the new power lines being built, in order to export electricity to the mainland..

Skogsbolagens syn på vindskadeförebyggande åtgärder efter stormen Dagmar

On the night of the 26th December 2011, large parts of southern Norrland were struck by the storm ?Dagmar? that caused serious damage to the forests. In the past 10 years wind damage has become a hot topic after several major storms. Forest companies own 25% of the Swedish forest and thus influenced largely by wind damage. The main purpose of this study was to examine whether forest companies attitude towards preventive wind damage actions were changed after the storm ?Dagmar?. The result was developed by doing interviews with two forestry companies.

Strömningen i och över en skog : utvärdering av en 'mixing-layer' hypotes

A new theory for predicting the windprofile over a canopy has been evaluated. The theory was first presented by Harman and Finnigan (2007). The theory relies on the forming of a mixing-layer above the canopy, due to different mean wind in and above the canopy. Characteristics from both mixing-layer and Monin Obukhov similarity theory have been used to develop the governingequations that give the wind profile. The theory has been used to calculate wind profiles for sixdifferent atmospheric stabilities.

Expansionsmaskiner istället för strypventiler - en effektivisering

In Uppsala CHP Plant, there are six pressure reducing valves to reduce the pressure from 15 to 3 bars, before six absorption heat pumps. During the process the energy is conserved but losses occur in form of exergy. The aim of this thesis is to reduce the losses of exergy. This can be done by letting turbines replace the pressure reducing valves.In this thesis an investigation has been done of the conditions today, the conditions after the change from pressure reducing valves to turbines and a comparison of three different types of turbine solutions. The three examined solutions are one turbine, several helical screw expanders and several small turbines in parallel with asynchronous generators.The six absorption heat pumps have been divided into two groups; one group of four and one group of two absorption heat pumps.

Privata markägares syn på vindskadeförebyggande åtgärder :

Wind and wind damage has become a hot subject because of the storm ?Gudrun? in January 2005. The main purpose of this study was to establish how the land owners attitude toward preventive wind damage actions was changing immediately after they had been struck by a storm. The result of the study was built on interviews. In springtime 2005 a total number of 20 private land owners were interviewed. Ten of the landowners lived in the province of Småland and ten in the province of Värmland.

Stormskador i lärk och gran : en jämförelse efter stormen Gudrun

The storm Gudrun January 8-9 2005 felled about 70 millions cubic metres forest in southern Sweden. The majority of the wind damaged forest was spruce (Picea abies). In order to decrease the risk of wind damages in the future other trees species are of interest for forestry in southern Sweden. The purpose of this master thesis was to study if larch were more wind tolerant than spruce. The method was to compare larch, Japanese larch (Larix kaempferi Lamb.), European larch (L.

Utvärdering av konsekvenserna för nätanslutning av vindkraftparker i Sverige vid införandet av nätkoden Requirements for Generators

Grid codes are becoming more demanding on power generating units due to the factthat the complexity of the power grid is increasing. The penetration of wind powerhas grown over the last years and it is clear that wind farms need to be addressedwith the same type of grid codes as conventional generation units. There is howeveran undeniable difference between the technology in conventional synchronousgeneration units, and the asynchronous generation units in wind farms.This thesis has reviewed the current grid code in Sweden and compared it to the newcode proposed by ENTSO-E, ?the Requirements for Generators?, in the aspect ofwind farms with an installed power of 30 MW or more. The comparison has beencomplemented by an analysis of how wind farms of two different technologies(Doubly fed induction generators and full power converters) can meet therequirements and technical proposals have been given on how to be able to meetcompliance with the new grid codes.The Requirements for Generators contains many non-exhaustive and optionalrequirements, because of this it has been difficult to, at this stage, exactly point outthe technical impact on the grid connection of future wind farms in Sweden.

VINDKRAFTSETABLERINGAR : EN JÄMFÖRANDE STUDIE OM NÄRBOENDES INSTÄLLNING TILL VINDKRAFT OCH VINDKRAFTSETABLERINGAR I SVERIGE OCH BRASILIEN

To achieve a sustainable development, three aspects have to take equal place in the society; environmental, economical and social. To reduce the impact on the environment and the amount of greenhouse gases supplied to the atmosphere, industrialized countries and less developed countries must start cooperating. Also the use of renewable energy sources, like solar, hydro and wind power, have to increase.Wind power has great potential as a future energy supply. It is cost efficient, quickly developed and the resource is abundant and available worldwide.Examinations made in Sweden, indicates that there are difficulties establishing wind power at the same pace as the environmental goals, set by the Swedish government, requires. Mainly because people living nearby potential areas for wind power farms, appeal against the decision.This study aims to investigate differences between how people in Sweden and Brazil look at wind power as a future energy source and at the establishing process.

Tillförlitlighet hos trafikolycksklassificering

Today?s wind power plants are only compensated for their reactive power consumption at no-load. As the wind power plants grow bigger the amount of reactive power they need also increases. This is no longer a problem that can be ignored, especially as the net owners are beginning to charge the reactive power they transport.In this thesis a couple of different methods of compensation and their prices will be discussed and evaluated. Problems, such as self-excitation, that can occur if one fully compensates the wind power plant will also be brought to surface.

Undervattensvågbrytare - En modellstudie

Today?s wind power plants are only compensated for their reactive power consumption at no-load. As the wind power plants grow bigger the amount of reactive power they need also increases. This is no longer a problem that can be ignored, especially as the net owners are beginning to charge the reactive power they transport.In this thesis a couple of different methods of compensation and their prices will be discussed and evaluated. Problems, such as self-excitation, that can occur if one fully compensates the wind power plant will also be brought to surface.

Effektivisering av energianvändningen i en förskola

This rapport contains an examination of the energy consumption of a kindergarten, which areas that have the largest impact on the energy consumption and what can be done to reduce those areas in ways that are relatively easy and profitable. It is also analyzed if it is possible to reduce the energy consumption from today?s consumption to a consumption that fulfils the demands placed on low energy houses by FEBY.The focus has been on reducing the energy consumption of the areas ventilation, heating system and hot water system, since those seemed to be the easiest ones to affect and since the building is quite recently built.There are different kinds of ventilation systems, at the moment the building have a CAV-system, which means that the ventilation is too high during large parts of the day. There are different ways to manage the ventilation system, for example presence detection, humidity sensors, CO2 sensors, temperature sensors and season adjustment. Many of those are in the end dependent on CO2 sensors to guarantee a good indoor climate, therefore the focus have been placed on this system.

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