"Energie, or Leistung"? I'm shocked, Juditta. Here I really have to intervene! O_O Horsepower is an esoteric old unit for power, not energy.
The physical terms are not interchangeable but mean very different things. In Physics, this is how the terms translate:
Kraft = Force, in Newton[N]
Energie = Arbeit(in special cases) = Joule[J] = N*s
Leistung = Power = Energy/time = Watt[W] = J/s = N*m/s