Let's Do the Math!
This is bogus! Simple secondary school math will show how ridiculous this claim is. It's called combinations. We have, according to the report, 2 categories of items to choose from for the number of combinations. Those are energy sources and storage techniques. If there are X different possible energy sources and Y different storage techniques, then the # of combinations of the 2 items is X multiplied by Y. For those #'s to be a minimum they have to be the same, so the solution to the problem becomes a staggering 167,332 energy sources and 167,332 storage techniques. If either group is smaller then the other must be larger to maintain the product as 28 billion. I defy anyone to enumerate that many different energy sources or storage techniques.