Is algae really sequestering carbon-di-oxide?

[guru]

From what i understand, C02 sequestration means storing the carbon-di-oxide underground or under ocean and prevent it from being entering into the atmosphere. But, in algae based CO2 sequestration systems, the companies claim that they are sequestering their carbon-di-oxide emissions using algae and in turn using the algae produced for biofuel production.

Thus produced biofuels when used again releases the same amount of carbon-di-oxide consumed by the algae while growing. May be the net CO2 emission can be zero but this is not sequestration since this releases the CO2 consumed.

i appreciate your opinion on this.

regards,
GURU

[DR Johansen]

If the biofuel you make and burn replaces fossil fuel, and that amount of fossil fuel DOESN'T get pumped and used and remains underground, does that equal sequestration? Maybe it is sequestration by proxy

[dasha08]

Thank you for sharing this. I've never heard of Algae sequestering Carbon Dioxide before. Why and how do they sequester CO2 ? I think I'm learning a lot of stuff here !

[conjre]

Sequestration of CO2 involved just removing it from the atmosphere and keeping it from reentering it. So if you create a biofuel through the use of algae, you are in a sense "reusing" the CO2, even though you aren't really using the CO2 for the energy source.

If you want to use algae to sequester carbon, what you must do is grow the algae and then find a way to store the oil without destroyed the bonds between the fatty acid chains. Finding a way to do this economically however is the tricky part.

So grow algae, isolate oil, store oil. Congrats, you just sequestered carbon as well as some other elements like oxygen, hydrogen.

[ralphmcw]

@ dasha08
Algae use CO2 the same way plants do. They use energy from the sun to link carbon atoms from CO2 together to make all the carbon based molecules of the cell (including fats or ethanol that can be used as biofuels). If you can store this biomass then you are sequestering carbon. If you burn it as fuel you have a carbon neutral renewable fuel source.

[frytoy]

Has anyone considered "closing the loop" on the secondary combustion of algal fuels - i.e. co-firing it along with coal and capturing all of the resulting CO2 (from the combustion of both fuels) for further algae production? Wouldn't this be closer to true sequestration? Further, would it ever be possible to minimize (to near-zero perhaps) the continued input of fossil fuels (if CO2 capture, algal growth efficiency, waste reduction approached 100%)?

[bhaskarmv]

In oceans dead algae / phytoplankton sequester carbon by sinking to the depths.
The deeper they fall the longer the carbon is locked away -
300 meters - 10 years, 1000 meters 100 years, etc.

Fish too sequester carbon.
Fish bones are calcium carbonate.
Fish biomass too has carbon
(gross fish biomass of oceans is estimated to have declined from more than 8 billion tons 200 years ago to less than 2 billion tons)

Whale population was decimated in the 1st half of 20th century.
This has perhaps contributed to the decline in Diatom population.

[58robbo]

to answer the question, yes it is. growing algae uses carbon and burning it releases that carbon. the net result is that it's carbon neutral. i find it hilarious though that people still buy into this whole climate change nonsense and have somehow convinced people that an element, which is necessary to sustain life, is a pollutant.