I saw this stupid propaganda on Slashdot:
One of the most frequently raised arguments against renewable power sources is that they can only supply a low percentage of the total power because their unpredictability can destabilize the grid. Spain seems to have disproved this assertion. In the last three days, the wind power generation records with respect to the total demand were beaten twice (in special conditions: a very windy weekend, at night): 45% on November 5 and almost 54% last night (Google translation; Spanish original). There was no instability. These milestones were accomplished with the help of a control center that processes meteorologic data from the whole country and predicts, with high certainty, the wind and solar power that will be generated, allowing a stable integration of all the renewable power. You can see a graphic of the record here.
First off, by most definitions Spainish wind is only a small percentage of total electricity: 9%.
In 2008, just 27 GWh out of a total of 287 GWh generated were wind/solar/geothermal combined. The only numbers appearing the Slashdot are peak power figures - where for a few hours is wind power five times above annual average. This is what they are pointing to - November 8 2008:
(I cut off the axes because I shrunk the image and the text is too small. See the original: the y-axis range is 35 GWe, and the x-axis is a 26-hour time period).
For perspective, compare this to last week - take October 31:
(30-hour time range). Here wind power is down to 1/10th of last night's peak - the figure that actually makes it into the news. And the difference, as you'd naturally expect, is entirely made up of natural gas.