How to make biodiesel from algae?

[sweeteviljesus]

I have been reading about algae-derived biodiesel and I have a few questions. One, how is it made? Does it require the use of special algae which cannot be released into the wild? Does it require the use of special enzymes? If so, how much do they cost? Proponents claim very high yields. Why are they so high? How much does a gallon of the stuff cost? I know right now some power plants are using their flue gas to feed the algae thereby temporarily sequestering the carbon they produce (at least until the fuel is burned), but this process doesn’t yield very much fuel. What things would have to happen to make algae-derived biodiesel competitive with other biodiesels or petrodiesel?

Thanks for your help,
Rob

[Nametag]

@sweeteviljesus

I have been reading about algae-derived biodiesel and I have a few questions. One, how is it made? Does it require the use of special algae which cannot be released into the wild? Does it require the use of special enzymes? If so, how much do they cost? Proponents claim very high yields. Why are they so high? How much does a gallon of the stuff cost? I know right now some power plants are using their flue gas to feed the algae thereby temporarily sequestering the carbon they produce (at least until the fuel is burned), but this process doesn’t yield very much fuel. What things would have to happen to make algae-derived biodiesel competitive with other biodiesels or petrodiesel?

Thanks for your help,
Rob

You make biodiesel out of algae as with any other plant feedstock – you press out the oil and convert the fatty acids to esters. Yield is high because the alga used is about 50% oil; soybeans are only 20% oil, and most of the plant is waste (stalks, leaves, etc).

[sweeteviljesus]

Do promoters plan to use special algae to increase yield? Also, I have seen expected yields that are orders of magnitude higher than, say, soybeans or rapeseed. Are these accurate or are they wishful thinking? What is the cost per gallon? What breakthroughs would need to happen in order for it to be competitive with other biodiesel or petrodiesel?

Thanks,
Rob

[scm1001]

some speculative figures here suggest that using desert land it would easily be cost effective to grow the entire countries petroleum out of algae. http://www.unh.edu/p2/biodiesel/article_alge.html
Except one would need a HUGE supply of water. As the world is running out of water as fast as it is out of energy this is probably going to be the main problem. So open tanks with huge evaporation rates are out of the question. One would have to have closed glass tanks and aeration pumps. I suspect it to going to be a lot trickier than hoped. While sea water looks attractive, again one cannot put it into open tanks without evaporation and over salination

[dynamitedave]

A company in Nelson, NZ has developed a system to grow algae in sewer ponds. They trialed a setup, and it worked, and are now looking at scaling it up. The goal is two-fold; produce algae for biofuel, and to treat the sewage to a point where it can be discharged as clean

link to company website but they give no information on how, what, costs.

ABC harvests algae directly from the settling ponds of standard Effluent Management (EM) Systems and other nutrient-rich water. The process can be used in many industries that produce a waste stream, including the transport, dairy, meat and paper industries.

The two-step process firstly optimises the ponds’ productive capacity, and secondly, determines the most efficient and economic way of harvesting the pond algae. Algae are provided with full opportunity to exploit the nutrients available in the settling ponds, thereby cleaning up the water. The algae are then harvested to remove the remaining contaminant. A last stage of bio-remediation, still in development, will ensure that the water discharge from the process exceeds acceptable quality standards.

The water and sludge treatment process is an elegant clean-up and management service to councils responsible for sewerage treatment systems while also generating a low-cost feedstock for conversion to fuel.

The result is an algae-based extract that will ultimately be converted to an alternative fuel source. ABC has established that the company is likely to be able to produce, at commercial scale, a viable biofuel.