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Hedging Strategy and Electricity Contract Engineering - IFOR

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ö<br />

S kã j á<br />

6.6 Power portfolio optimization with CVaR 161<br />

of flexible production units, as shown in Example 4.2. One should therefore<br />

proceed with care when aggregating periods.<br />

6.6.8. Analysis of dynamic solution<br />

As a solution from the optimization (6.53)-(6.62) we will obtain the optimal<br />

contract portfolio xú2K 1<br />

Ü<br />

á@á?á<br />

xún . We will also get the optimal weighting<br />

ë<br />

factors Ü ú<br />

1<br />

Ü õ Ü õ<br />

ë ú r Ü õ<br />

ì ú<br />

1<br />

, Ü ë<br />

õ<br />

ì ú building up the optimal dispatch strategy,<br />

i. e. the optimal exercise conditions. á@á?á<br />

In any instant within the time horizon<br />

á@áaá<br />

we<br />

can measure the state variables S, D, I a <strong>and</strong> t <strong>and</strong> with these variables as input<br />

to the exercise functions (6.51) <strong>and</strong> (6.52) get the optimal dispatch.<br />

In this dynamic dispatch strategy we are allowed to react to new information<br />

<strong>and</strong>, for example, meet unexpected high dem<strong>and</strong> by producing more or meet a<br />

price peak in a typical off-peak period. This flexibility offers an excellent way<br />

to manage these type of uncertain events, which is yet another wording for the<br />

hydro storage plant’s superb hedging capacity.<br />

An interesting question is what is this flexibility worth. One way to quantify<br />

this value would be to compare the average price of produced electricity S h<br />

given by<br />

S h 1<br />

J<br />

J<br />

jâ 1<br />

K<br />

K<br />

kâ 1 S kã j<br />

kâ 1<br />

r<br />

iâ ë õ gëiã kã<br />

ë<br />

õ gëiã kã iâ<br />

1 i j<br />

r<br />

1 i j<br />

¨1<br />

ö<br />

1 õ ì<br />

i iâ<br />

ö<br />

1 õ ì<br />

i iâ<br />

iã kã j<br />

gì<br />

gìiã kã j<br />

Ü (6.63)<br />

with the average spot price given by<br />

S<br />

1<br />

J K<br />

J K<br />

1 kâ 1 jâ<br />

(6.64)<br />

The difference between the average price of produced electricity, S h <strong>and</strong> the<br />

average spot price S actually gives us the total value of having a flexible

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