Biodiesel is a type of diesel created from organic components such as animal fats, virgin or used cooking oils, and many plants. Microalgae biodiesel uses a type of algae referred to as microalgae as its feedstock. This type of biodiesel presents several advantages, such as creating a sustainable form of diesel and reducing carbon emissions. There are also disadvantages, such as needing more land to create the algae and questionable efficiency.
Algae come in two distinct types: macroalgae and microalgae. The largest difference between these two comes down to size, because macroalgae is measured in inches or centimeters while microalgae is unicellular, or made up of just one cell. Despite macroalgae being larger, it is not used for biodiesel. This is because the oils that compose macroalgae are not appropriate for creating biodiesel; only microalgae have the right oils for biodiesel production.
Some of the heavy-hitter crops used to create biodiesel are jatropha, coconuts and palm oil. Jatropha creates 202 gallons (764 liters) of oil per acre (376 meters4), coconut yields 287 gallons (1.08 kiloliters) per acre, and palm oil makes 636 gallons (2.4 kiloliters) per acre. Microalgae dwarf all of these by producing from 6,283 gallons to 14,641 gallons (23.7 kiloliters to 55.4 kiloliters) per acre.
Not only does this high yield make microalgae biodiesel sustainable, but it means fewer plants will need to be grown for a sizable biodiesel yield. Microalgae can also grow almost anywhere, so there is no need for special fields or areas in which to grow the algae. The microalgae can also feed off carbon emissions, thus reducing the carbon footprint of wherever the algae are grown.
While this makes microalgae biodiesel attractive, there are some disadvantages to converting to this type of diesel. To create enough biodiesel for worldwide consumption, farm lands will need to be converted to grow microalgae and more farmland will be needed to satisfy the growing need for diesel. Microalgae also give off more nitrogen oxide than does petroleum-based diesel. As a biodiesel, microalgae biodiesel cannot be transported via pipes; it can only by carried by truck or rail, which increases the cost.
Along with this, microalgae biodiesel does not flow well at low temperatures, nor does it perform well at low temperatures because it thickens. The overall performance of microalgae biodiesel is also lower. This means fuel economy will also be affected negatively because there is less energy efficiency and, thus, more microalgae biodiesel is needed to power a motor.