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Wind farm layout: a reliability and investment analysis
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
2008 (English)Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

Investment and maintenance costs are higher for offshore wind power compared to onshore. Also, wind turbine components offshore are subjected to higher physical stresses compared to components onshore, due to harder winds. These strong winds often lead to longer outage times of failed offshore components compared to onshore.

The reliability of the Swedish offshore wind farm Lillgrund is analysed in this report. The consequence of a component failure might be a smaller energy production than expected. This loss of energy is called expected energy not supplied (ENS) [GWh/year]. High ENS-values risks the profitability of the investment. Thus, the ENS-value of Lillgrund has been calculated with a reliability analysis and is then used as input in an investment analysis, to see how the reliability of the farm affects the investment proposal. Three alternative layouts, where the transformer is placed on land instead of on a platform offshore, are compared to the original layout.

The results show that all layouts have positive net present values (NPV), but there are not that big relative differences between the NPVs of the layouts compared to the total investment outlay. The result shows that a transformer on land is preferable when the distance from farm to the shore is 7.5 km or less, while for longer distances a platform is preferable. A sensitivity analysis shows that the NPV is most sensitive to long outage times of the turbines, compared to long outage times for cables and transformer. Results and views in the report are my own conclusions, based on the input parameters used. The views are not necessarily the views of Vattenfall. Also, it is important to notice that some data have been changed because of confidentiality. However, the qualitative results and conclusions still remain the same.

Place, publisher, year, edition, pages
2008. , 53 p.
UPTEC ES, ISSN 1650-8300 ; 08013
National Category
Engineering and Technology
URN: urn:nbn:se:uu:diva-162498OAI: diva2:460560
Educational program
Master Programme in Energy Systems Engineering
Available from: 2011-11-30 Created: 2011-11-30 Last updated: 2011-11-30Bibliographically approved

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