There is at least one "large" partly commercial, partly experimental ship -
http://vikinglady.no/ and several small ones, some experimental, some operational (such as a passenger excursion vessel on the lake Alster in Hamburg)...
...but GL was a bit lagging behind some other class societies (especially DNV) in "producing" marketing gimmicks in shape of "concept ships", so they must have done something to show (or show off)
![Smiley :)](https://forum.shipspotting.com/Smileys/default/smiley.gif)
Everething "green" and "environmentally friendly" is so much trendy today... (and as every fashion - often "empty")...