Reactive power, revisited
The electrical technician has suggested installing a 3 phase capacitor
  bank to compensate for the “Reactive power” produced by the motors
  because if not, I may be penalized economically by the local
  electrical company.


That's all fine and dandy if you are running your appliances all together 24 7 but, in the dead of night, ask yourself, what is that bank of capacitors doing?

Answer - they are taking reactive current that they are hoping would balance the reactive current taken by the motors BUT the motors are not switched on SO, if your utility company can bill you extra for having a poor lagging power factor then they surely will bill you for having a poor leading power factor for all those hours that the laundry is shut.

Maybe the electrician has in mind some clever caps that automatically switch in and out or maybe he means installing several sets so that each only activates when their particular motors start turning? Either way, seek clarification from him and if he falls down at the first hurdle then fire him.