Algal Biofuels: Closer to Sustainability?

[secor77]

The article talks about trying to get the price below $5 per gasoline gallon equivalent. Given how the price of oil has been plunging lately, they may need to revise that downward. Interesting to see NASA involved though through their OMEGA project.

 

Algal Biofuels: Closer to Sustainability

 

 

[Harold Squared]

Obviously this would work in a salt water environment and something that occurred to me was that running it along with an ocean thermal power installation might be worthwhile. The cold waters of the abyss are more nutrient dense as well as more able to absorb gases such as CO2, for those who care about such things. If solar installations to date are any guide, auxiliary natural gas fired generators will be present for the inevitable shortfalls in capacity and routing the cooled exhaust through the cold water impoundment could help stimulate photosynthesis. Just a few thoughts.

[EdEarl]

Algae oil is the crown, but we will need to grow and harvest algae at very low prices for algae oil to be competitive with petroleum. I'm in favor of making an algae pellet alternative to coal. If we cannot do that, it is unlikely algae oil can ever displace petroleum. Moreover, it is simpler than making algae oil, and presumably a simpler less time consuming research project. If it works the payback is excellent, because existing coal burning power plants could convert to using algae pellets, a renewable CO2 neutral fuel.

[CaptainPanic]

Coal costs about 50 $/tonne, oil (at its current low price of 50$/barrel) costs about 50$/barrel, or 50$/159 liter. Assuming an oil density of 0.8 kg/liter, there are about 7.8 barrels in a ton of oil. Or, you could say, that oil costs about 393 $/ton. Oil is about 8 times as expensive as coal, at roughly the same energy density.

 

And that is why they try to make oil out of these algae, not coal pellets. Also, oil doesn't dissolve in water, so if you do it well, you do not have to evaporate water out of your fuel, making it an efficient process.

[EdEarl]

Coal costs about 50 $/tonne, oil (at its current low price of 50$/barrel) costs about 50$/barrel, or 50$/159 liter. Assuming an oil density of 0.8 kg/liter, there are about 7.8 barrels in a ton of oil. Or, you could say, that oil costs about 393 $/ton. Oil is about 8 times as expensive as coal, at roughly the same energy density.

 

And that is why they try to make oil out of these algae, not coal pellets. Also, oil doesn't dissolve in water, so if you do it well, you do not have to evaporate water out of your fuel, making it an efficient process.

By energy equivalent, a ton of coal is about 8,141 kilowatt hour and about 200.0 gallons [u.S.] of diesel oil.

 

7.8 barrels is about 289 gallons.

 

The energy in 7.8 barrels of oil is, I think, much higher than in a ton of coal. Thus, I think your estimate of 393 $/ton is a bit high, by energy equivalent, but still in the ball park. You make a good point.

 

It is possible to process coal into liquid fuels, but it isn't done in large amounts because petroleum is less expensive.

 

There is a considerable amount of processing and cost to turn algae into oil. I don't know how coal liquification and extracting oil from algae compare in cost. Regardless, the cost of growing and harvesting algae must be reduced significantly to make it viable as a fuel.

[Harold Squared]

Liquid fuels are more energy dense and easier to handle, which is why we no longer have "black gangs" shoveling coal into the boilers of modern vessels. The point of oil self separating from water is valid, and to make a fair comparison we should really include the energy required to dry the pellets for coal equivalent solid fuel, whatever its source. Nice comments, though.

Edited January 31, 2015 by Harold Squared

[EdEarl]

 

solarthermalmagazine.com

Rice University Study: Algae From Wastewater for Biofuels

In one of the first studies to examine the potential for using municipal wastewater as a feedstock for algae-based biofuels, Rice University scientists found they could easily grow high-value strains of oil-rich algae while simultaneously removing more than 90 percent of nitrates and more than 50 percent of phosphorous from wastewater.

 

Bhattacharjee said the algae industry’s reliance on chemical fertilizers is a double whammy for algae producers because it both reduces profit margins and puts them in competition with food producers for fertilizers. A 2012 National Research Council report found that “with current technologies, scaling up production of algal biofuels to meet even 5 percent of U.S. transportation fuel needs could create unsustainable demands for energy, water and nutrient resources.”

 

The 2012 report also pointed to wastewater-based cultivation as a potential way to make algae production sustainable. An added appeal is that the method could potentially address a looming environmental problem: nutrient pollution in U.S. waterways. According to the Environmental Protection Agency, nutrient pollution from excess nitrogen and phosphorous — the two primary components of chemical fertilizers — is “one of America’s most widespread, costly and challenging environmental problems.”

The suggestion that algae production would use fresh-water resources is absurd, since many algae strains grow in salt water, and some locations have underground salt water. Why "unsustainable demands for energy" seems incorrect, since it primarily uses solar energy to make algae-oil, which means the process creates more useful energy than it uses, especially if the energy consumed is produced from renewables.