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Powering Europe - European Wind Energy Association

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<strong>Wind</strong>generationandwindfarms–theessentials<br />

fiGURE 12: PRobability DEnsity DistRibUtion of ERRoRs foR Day-ahEaD winD PowER foRECast foR noRth-wEst GER-<br />

Many; also shown aRE fittED GaUssian, GaMMa anD nakaGaMi DistRibUtions<br />

52<br />

NRMSE [15% of installed capacity]<br />

10 0<br />

10 -1<br />

10 -2<br />

10<br />

-5 -4 -3 -2 -1 0 1 2 3 4 5<br />

-3<br />

Error/<br />

the nakagami distribution shows the best fit for extreme forecast errors [tambke 2010].<br />

fiGURE 13: histoRiC DEVEloPMEnt of thE aVERaGE foRE-<br />

Cast ERRoR in thE wholE of GERMany anD in a sinGlE<br />

ContRol zonE in thE last ninE yEaRs<br />

NRMSE [% of installed capacity]<br />

10<br />

9<br />

8<br />

7<br />

6<br />

5<br />

4<br />

3<br />

2001<br />

day-ahead single control zone<br />

day-ahead Germany [4 zones]<br />

2002 2003 2004 2005<br />

Year<br />

2006 2007 2008 2009<br />

the improvements in accuracy are due to a combination<br />

of effects: better weather forecasts, increasing<br />

spatial distribution of installed capacity in Germany<br />

and advanced power forecast models, especially using<br />

combinations of nwPs and power forecast models<br />

[tambke 2010].<br />

RMSE [% of installed power]<br />

7<br />

6<br />

5<br />

4<br />

3<br />

2<br />

1<br />

0<br />

meas<br />

Nakagami<br />

Gamma<br />

Gaussian<br />

fiGURE 14: iMPRoVEMEnt of foRECast aCCURaCy by UsinG<br />

EnsEMblE PREDiCtions<br />

Model 1 Model 2 Model 3 Model 4 Combination<br />

Using a combination of models results in an error<br />

20% lower than using the most accurate of the single<br />

models [tambke, 2008].<br />

<strong>Powering</strong> <strong>Europe</strong>: wind energy and the electricity grid

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