I like that some people are trying a variety of ideas for energy generation, energy storage and CO2 capture. However, I agree that they should do some engineering and physics homework first to be sure that the ideas have some chance of success.

I actually like the concept of gravity storage, but I understand that the efficiencies are generally low. How about this one. Find a nice steep hill. Run sets of rails straight up the hill. Get some old railcars and fill them with something (sand, rocks, scrap metal, etc.). Use solar during the day to pull them up hill. Then let gravity do its thing at night.