Even double would be enough to supply our power needs the vast majority of the time, but there would occasionally be times when a bunch of cloud _and_ low winds hit simultaneously, and we ran low on power.
My thought there is, assuming that when this happened power was prioritised for hospitals and other essential infrastructure, so that there was no risk of death from a power outage, we'd just find ourselves unable to watch TV/surf the internet, how much would people be willing to put up with, in order to move entirely to renewables?
How much downtime would you be willing to put up with, per month, in exchange for purely renewable energy production
Note: Things outside the scope of this discussion include the cost of doing so, feasibility of collecting that much power in any particular place, etc. Although I will take a moment to recommend Sustainable Energy - withou the hot air, which is the only book I've seen to actually look at what's physically possible when it comes to renewables. The PDF is free too.