I take issue with a statement you make in your article: “Unfortunately, burning carbon dioxide back into hydrocarbons is very, very hard.” It is only hard for human beings. Some species of algae find this task very easy. Melvin Calvin, a Nobel Prize winner from UC Berkeley, spent 25 years of his life studying plants that make hydrocarbons.
Calvin identified the genus Botryococcus as a remarkable source of hydrocarbons. He reported that the dry weight of this algae is 86 percent hydrocarbon! He identified the structures of some of the major components in the mixture. They fell into two groups: linear isoprene oligomers and cyclized steroids. Both of these products could be burned instead of coal to produce electricity and be fed to refineries in place of petroleum.
The work you wrote about requires two major investments to produce a feedstock that will replace coal or oil. The first is the solar power tower. The second is the Fischer-Tropsch unit. Neither is cheap compared to digging up coal or pumping up oil. The two investments cannot compete with skimming algae off the ocean surface and pressing out their hydrocarbons.
Too many entrepreneurs brag about how their invention will be competitive with petroleum in a few years. They are careful not to specify the price of the petroleum they are competing against. This is a real problem. The winning solution will be the one that requires the least new capital investment.
Frank Weigert [PhD ’68]
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