scientific possible? defo and to one degree or another has been worked on by many groups for a long time now.
economically Possible? unsure, while the energy and reactants are theoretically free, the temperatures involved means I would not be surprised if you are needing to replace components fairly regularly due to melt and various issues such as heat stress.
another issue is energy, while in theory it can be done with natural light the most efficient results will invariably be found in areas which is capable of sustaining long durations of high intensity sunlight, otherwise you are potentially looking at artificial sources like the one used in the experiment which then brings the cost of that energy into play, this also reduces the "green" benefits.
Also while it is possible with the available atmospheric gasses, again can you produce enough from this to be cost effective or will you need to ship in the material? again additional costs and less environmentally friendly.
Lastly what is the cost of converting to a usable fuel source?