In the discussion on Nuclear powered ship the question of how moder wind assisted ships handle headwind came up. Nuclear powered ships? - #206 by Jughead
Bringing the discussion to this thread, where it belongs.
There are several types of modern wind assisted propulsion available and in use and new solutions are under development.
Here is a comparison by Kongsberg of the different types presently available:
(Date of issue is not stated)
PS> The purpose of all is to reduces fuel consumption, thus GHG emission and to save money.