Some interesting info on Valcent’s system and costs, etc. can be found at this google site. It is a company release well worth a look. Second or third page.
“Valcent’s Releases Profitable Initial Production Estimates for its Vertical Vegetable Growing Systems”
More Valcent— http://www.valcent.net/s/Ecotech.asp?ReportID=182039
Sounds logical (recycles the water) but the expenditures will enormous to get these racks of algae bags out in the desert. One nasty storm would topple them all
If you want to grow algae the way to go is ponds in a hot climate where you get rain or it is humid. Not plastic bags out in the desert