What Solar Panel Efficiency would replace Coal?

A friend sent me an article that a company called Fraunhofer has produced solar panels that can achieve 41.1% efficiency. Now taking into account the fact that solar do sent work during storms or night and greatly reduced during winters, what % do you think would be needed to supply a "majority" of our... show more A friend sent me an article that a company called Fraunhofer has produced solar panels that can achieve 41.1% efficiency.

Now taking into account the fact that solar do sent work during storms or night and greatly reduced during winters, what % do you think would be needed to supply a "majority" of our power needs as a nation?
Update: *Mispelling*
Now taking into account the fact that solar "does not" work during storms or night and greatly reduced during winters, what % do you think would be needed to supply a "majority" of our power needs as a nation?
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