Abstract
Reanalyses of a case study using field measurements taken over 3½ years over rugged terrain in northern
Portugal have been carried out using contemporary calculation procedures and topographical input data.
The significance of the site ruggedness index (RIX) and the associated performance indicator (ΔRIX) are
confirmed and the consequences of applying WAsP outside its operating envelope are quantified. A loglinear
relation between WAsP prediction errors and the performance indicator ΔRIX is found to describe
the field measurements and modelling results well. The largest coefficient of determination is obtained
with a calculation radius of about 3.5 km and a critical slope of about 0.40-0.45 used in the RIX calculations.
A simple procedure is further proposed to improve wind speed and power production predictions in
terrain outside the operational envelope of the WAsP flow model. Results from the case study in northern
Portugal, employing five meteorological stations with ruggedness indices between 10 and 33%, indicate
an average improvement of WAsP power production predictions of 69%. Cross-predictions between sites
with ΔRIX values larger than 5% are improved by more than 90% on average. The procedure has further
been applied to a 23-MW wind farm sited in similar terrain and in similar climatological conditions. Here,
the prediction of the net annual energy production was improved by about 70%. The correction procedure
is empirical and requires the determination of a site-specific fitting constant.
Original language | English |
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Title of host publication | Proceedings (online) |
Number of pages | 9 |
Place of Publication | Brussels |
Publisher | European Wind Energy Association (EWEA) |
Publication date | 2006 |
Publication status | Published - 2006 |
Event | 2006 European Wind Energy Conference and Exhibition - Athens, Greece Duration: 27 Feb 2006 → 2 Mar 2006 |
Conference
Conference | 2006 European Wind Energy Conference and Exhibition |
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Country/Territory | Greece |
City | Athens |
Period | 27/02/2006 → 02/03/2006 |