The turbine does the inverse of the compressor; the turbine extracts energy from the hot, high-velocity gases leaving the combustor. The compressor adds energy to entering air by increasing its velocity, and the velocity of the air is then decreased, creating a corresponding increase in pressure. The energy extracted by the turbine is converted to shaft horsepower by the rotation of the turbine. In stationary gas turbine operations, over 90% of the energy of the combustion gases will be extracted by the turbine.