a)
End customers often pay more than those 10ct due to transportation losses and other overhead. So if you are connected ton the grid and have a minimum power requirement higher than the peak output of this system, the system is profitable.
b)
Coal has seen very little cost improvement over the last decades while solar is co stantly improving at 30% per year since the sixties. It is intermediate steps like this system that are likely to make solar one of the least expensive technologies around.
(BTW: A recent survey revealed that solar installation overhead costs are 3x as high in the US compared to Germany due to less efficient work organization. So if IBMs numbers are for the US there is immediate room for improvement.)