If I understood that correctly, no it's not the same thing.
'KI' or the 'blue bar' - The blue bar is not the same as power level. This bar represents how much energy you have to put into various techniques your character can perform. From flying to shooting beams, pretty much everything uses KI. If this bar is empty your character cannot perform any special abilities. You can recharge your KI by pressing E (by default).
'Power level' or 'PL' - The numbers on the blue bar represent your strength. The higher this is the more powerfull you will be. After a certain point, where your green 'change form' or 'CF' bar is full, you can press your 'ascend' button, Z by default, and begin a transformation. Once transformed your PL will be greater than it just was.
As I said before, blast size is directly tied to the server average PL. The higher your PL is compared to the server average, the bigger your explosions will become. The opposite is true if you are under the server average.