"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."