There are multiple ways to win this with White, and I chose perhaps the most straightforward plan. First lure the Black king to the queenside to stop the passed a-pawn.
30.a4
Kf7
31.b4
Ke7
32.bxa5
Kd7
33.Kd2
Kc8
34.Kc2
Kb7
35.Kb3
c5
36.dxc5
c6
37.h3
Ka6
38.Kb4
Kb7
39.g4
and there's no way Black can stop my kingside majority from creating a passed pawn. 1-0