Just another idea where the Theory may be sound and execution is whole other idea. It's just like promising ideas about Iron based batteries - they are slow to charge (24-48 hours) and discharge at a fairly acceptable rate. Either Sweden or Norway is using water to store renewable energy (haven't seen if this is an affordable technology yet. Also, CO2 scrubbers that pull in normal air to scrub out CO2 doesn't make much sense. If CO2 scrubbers don't work economically at point of origin (I.e. Natural Gas or Coal fired power plants) why would they work in attempting to scrub CO2 from regular air?