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Algal Biofuels Not Ready For Scale-up

Tator Tot (1324235) writes | about 2 years ago


Tator Tot writes "Using today’s technologies and knowledge, a scale-up of fledgling algal biofuel production sufficient to meet even 5% of U.S. transportation fuel demand is unsustainable, says a report released last week by the National Research Council (NRC). The report examines the efficiency of producing biofuels from microalgae and cyanobacteria with respect to energy, water, and nutrient requirements and finds that the process falls short. The energy from algal biofuel, the report finds, is less than the energy needed to make it. In terms of water, at least 32.5 billion gal would be needed to produce 10 billion gal of algae-based biofuels, the report states. The study also finds that making enough algal biofuels to replace just 5% of U.S. annual transportation fuel needs would require 44–107% of the total nitrogen and 20–51% of the total phosphorus consumed annually in the U.S."
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Leave aircraft fuel / diesel last ! (1)

macpacheco (1764378) | about 2 years ago | (#41785065)

The best approach to economically reducing our dependency on oil is to start with gasoline, leaving diesel / jet fuel for last.
The reason is simple:
    Bio Jet fuel / Bio Diesel are long carbon chains. They're produced from oils / fats.
    All organisms that produce those have low efficiency in converting sunlight into actual energy stored in those biological molecules. The most efficient crop for bio fuels is sugar cane with 7%, and that drops to less than 2% for most other crops. However sugar cane is useless for bio diesel / bio jet fuel, since it produces sugar instead of oil/fats.
    On the other hand, current solar PV panels achieve 20% efficiency in commercial products, with efficiency over 40% showed in labs, we already have an electric grid everywhere, and the electric car is already available. And solar PV can run on rooftops, so no productive land needs to be dedicated to that.
    We can convert 10% of worldwide gasoline consumption to electric fairly quickly, as long as Obama wins. The GOP has made it very clear for those who are willing to see that they don't want to directly invest in green businesses (see Gov Romney comments on Tesla, and theoretically he said so as a moderate, imagine the GOP convervatives).
    Let the US navy work on their sea water to jet fuel process, in the end that might be the most efficient process, since will have three very important advantages:
      1 - No need for any open land. This process could even be done using floating plants, since it's being developed for use aboard US Aircraft Carriers
      2 - Removes the CO2 directly from one of the places that has been absorbing most CO2 (the Sea), if we could pump enormous quantity of CO2 from sea water, more CO2 from the air would be absorbed by the sea, to keep an equilibrium, so it cleans CO2 from the atmosphere fairly efficiently, actually its more of a closed circuit, since fuel produced would be consumed, but the point is keeping oil underground instead of burning it
      3 - Uses electricity instead of the sun, so it can use any electricity source (specially nuclear, solar and wind), jet fuel plants could be installed near large electricity sources, for essentially zero transmission waste. Consider 10-20 yrs from now, with extreme solar PV adoption, baseload electricity capacity would be idle midday (specially in the summer), this might be the best way to use all their excess base load capacity any time its available

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