With storage the watts are also important because it is a measure of how much power it can replace from other power plant sources which are also measured in wat

With storage the watts are also important because it is a measure of how much power it can replace from other power plant sources which are also measured in watts. Admittedly, the time it will last is omitted, so a full energy calculation can't be done, but at least you know how many dirty peaker plants it replaces.