Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE credits
Wind farms are costly projects and prior to the construction, comprehensive wind
resource assessment processes are carried out in order to predict the future energy yield
with a reliable accuracy. These estimations are made to constitute a basis for the
financial assessment of the project. However, predicting the future always
accommodates some uncertainties and sometimes these assessments might overestimate
the production. Many different factors might account for a discrepancy between the pre-construction wind resource assessment and the operational production data. This thesis
investigates an underperforming wind farm in order to ascertain the reasons of a
discrepancy case. To investigate the case, the relevant data and information along with
the actual production data of three years are shared with the author. Prior to the
construction, a wind resource assessment was carried out by an independent wind
consultancy company and the work overestimated the annual energy production (AEP)
by 19.1% based on the average production value of available three years.
An extensive literature review is performed to identify the possible contributing causes
of the discrepancy. The data provided is investigated and a new wind resource
assessment is carried out. The underestimation of the wind farm losses are studied
extensively as a potential reason of the underperformance.
For the AEP estimations, WAsP in WindPro interface and WindSim are employed. The
use of WindSim led to about 2-2.5% less AEP estimations compared to the results of
WAsP. In order to evaluate the influence of long term correlations on the AEP
estimations, the climatology datasets are created using the two different reanalysis
datasets (MERRA and CFSR-E) as long term references. WindSim results based on the
climatology data obtained using the MERRA and CFSR-E datasets as long term
references overestimated the results by 10.9% and 8.2% respectively.
2016. , 81 p.
Wind Resource Assessment, Advanced Energy Estimations, Wind Farm Underperformance, Overestimation of the Energy Yield, WindSim, WindPro, WAsP, Wind Energy, Wind & Site Engineering.