I have been investigating the wonders of Algae for at least 30 years.
The beauty of algae is that it can be grown in arid areas & so as a biofuel it will not consume land which can be used for producing food.
Algae requires nutrients, sunlight & water to grow, algae thrive on saline, brackish and waste waters. Their have been proposals made where wastewater, human waste, animal waste & plant waste, along with C02 emissions from industrial process's can all be used as the nutrients in algaculture. In regards to the monoculture production of algae, wastewater, human waste, animal waste & plant waste, along with C02 emissions from industrial process's, would have to be all transported or pumped to arid area algaculture farms. After oil is extracted from the algae the algae residue is then used as a animal feedstock or as a soil fertiliser.