>...Algae are among the fastest growing plants in the world, and about 50 percent of their weight is oil.
*Dry* weight, and it is not 50 percent either.
>... "A pond has a limited amount of surface area for solar absorption," said Kertz.
It is not just surface area, but *solar* surface area.
Another article for the mass digestion :roll:
My guess is that they spray the plastic bags to cool down the algae a lot, so heat may not be a big issue. :? As to the ROI, it is probably not anytime in the near future.