Producing biodiesel from algae has been touted as the most efficient way to make biodiesel fuel. Algal oil processes into biodiesel as easily as oil derived from land — based crops. The difficulties in efficient biodiesel production from algae lie not in the extraction of the oil but in finding an algal strain with a high lipid content and fast growth rate that is not too difficult to harvest and a cost-effective cultivation system (i. e., type of photobioreactor) that is best suited to that strain.

Algae are the fastest growing plants in the world. Microalgae have much faster growth rates than terrestrial crops. The per-unit area yield of oil from algae is es­timated to be between 18,927 and 75,708 L/acre/year; this is 7 to 31 times greater than the next best crop, palm oil, at 2,404 L/acre/year.

Algae are very important as a biomass source. Different species of algae may be better suited for different types of fuel. Algae can be grown almost anywhere,

Table 6.7 Advantages of biodiesel from algae oil

Rapid growth rates Grows practically anywhere

A high per-acre yield (7 to 31 times greater than the next best crop, palm oil)

No need to use crops such as palms to produce oil A certain species of algae can be harvested daily Algae biofuel contains no sulfur Algae biofuel is nontoxic Algae biofuel is highly biodegradable

Algal oil extracts can be used as livestock feed and even processed into ethanol High levels of polyunsaturates in algal biodiesel are suitable for cold weather climates Can reduce carbon emissions based on where it’s grown

Table 6.8 Disadvantages of biodiesel from algal oil

Produces unstable biodiesel with many polyunsturates Biodiesel performs poorly compared to its mainstream alternative Relatively new technology

even on sewage or salt water, and does not require fertile land or food crops, and processing requires less energy than the algae provides. Algae can be a replacement for oil-based fuels, one that is more effective. Algae consume CO2 as they grow, so they could be used to capture CO2 from power stations and other industrial plant that would otherwise go into the atmosphere. Tables 6.7 and 6.8 show the advantages and disadvantages of biodiesel from algal oil.