Chris is still using a Yamaha GT 20 Upright live. This is a silent Piano, it has real piano action with wooden keys, whips, hammers but there are no strings and no harp inside. The hammers contact MIDI sensors hence why you can see the hammers moving inside the piano. The piano itself produces no acoustic sound, but it does allow for Chris to play various different Piano sounds with effects, synth sounds like pads and organs in songs like Fix You. Its most likely hooked up to a computer running sampled pianos, synths etc which is triggered off stage to switch sounds per song.
Yamaha no longer make the GT 20 and they are very hard to come by second hand.
Hope that helps, let me know if you have any more questions and ill do my best to answer them.
:D