Oh great you just had to open up that can of worms. I’ll give it honorable mention but I’m sticking to switchgrass.
Why?
Centrifugal algae oil separation for biodiesel clarifications, membrane systems or the combination of both are still the preferred methods of alga-culture oil extraction processes for good reason. The process concept endeavors to recycle the cultures back to the source pond. Microwave biodiesel extraction will harvest all of what is fed into the machine and the only solid discharged will not be animal feed but ash albeit the microwave process will extract more biodiesel fuel, no cultures will remain.
The microwave process will use less energy and in the process will in itself separate catalysts, glycerin and salts through microwave clarification from the biodiesel Oil. Centrifugal algae oil separators are not cheap but neither are microwave reactors.
Algae needs a better controlled environment than switchgrass and most say with algae growing below 75 degrees F, it reduces its quality. Additionally algae needs to be fed nutrients (a consumable) while switchgrass does not and producing higher quality algae requires extra added nitrogen (another consumable).