The numbers are here. Right now, Spanish wind power is generating ~10400 MW out of 17600 installed MW (59%, green graph). The yellow graph shows wind power as percentage of total demand (now stands at 38%). (Select "2009-11-08" as date and click "Consultar otra fecha").

Wind has been generating between 7-10 GW in Spain during the last week, check it in the other graphic (labeled as "Eólica"). "Rest. reg. especial" means other tech (biomass, solar, cogeneration), and "Intercambios int." means imports/exports (to/from France, Portugal or Morocco). When hydro turns dark blue, reversible hydro plants are pumping water.

Now, the scientific formula for deciding the positive effectiveness of this is: (customer's percieved value)/(actual retail cost)

Well, economic textbooks say economics profit equals (customer's perceived value minus actual retail cost).

Microeconomics can answer this question: monopolists engage in price discrimination in order to maximize their profits, predating the consumer surplus. http://en.wikipedia.org/wiki/Price_discrimination

Sad, but probably true. In Spain, when we switched to the Euro (2002), a lot of things that used to be sold at 100 pesetas began to be sold at 1 Euro (~166 ptas).