I would guess due to a design flaw in the market rules (or the rules for the interaction between different national markets).
I think most large windmill turbines are designed to be able to be feathered to limit electricity production - they need some way to not fail when winds exceed generator constraints - but maybe designs use wind stalling or other dynamics to prevent that? Alternatively they could build dumping loads close to the wind power - e.g. warm some seawater with big resistors!
Edit: I love the quote "Wind farms in West Texas earlier this year were paying utilities to use their electricity on particularly gusty days because they can still earn $22 a megawatt-hour in federal tax credits." LOL.
http://www.bloomberg.com/news/2012-10-25/windmills-overload-...
I would guess due to a design flaw in the market rules (or the rules for the interaction between different national markets).
I think most large windmill turbines are designed to be able to be feathered to limit electricity production - they need some way to not fail when winds exceed generator constraints - but maybe designs use wind stalling or other dynamics to prevent that? Alternatively they could build dumping loads close to the wind power - e.g. warm some seawater with big resistors!
Edit: I love the quote "Wind farms in West Texas earlier this year were paying utilities to use their electricity on particularly gusty days because they can still earn $22 a megawatt-hour in federal tax credits." LOL.