Is it possible to play through infamous 2 without transferring powers

No. The story progresses linearly on either path (though you can mix it up a little, it'll still head in either direction), and at some point the cutscene will always appear that forces you to make the transfer. This happens either way; good or evil. The idea is that you'd pick whichever path you plan on sticking with now (good=kuo evil=nix), since your karma meter should be maxed out either way around now (In a similar manner to to ray sphere in the original infamous). Transferring powers does not cause you to lose your old powers, but it prevents you from gaining the other character's powers. You can always switch back to your old ones from the powers menu.