Renewable Fuel Sources – Biodiesel Algae
One of the most discussed renewable fuel sources in the past few years has been biofuels. With the world-wide effort to attempt to cut down on our reliance on fossil fuels, biofuels have been showing promise on being able to scale to the levels of production to affordably replace our dependence on traditional oil sources. Beyond the advantages of being renewable, biofuels have also shown that they are significantly better for the environment from the reduced levels of Carbon Dioxide released during their use. Biodiesel algae is one of the alternative fuel sources being researched for potential widespread usage.
What Makes Up a Biofuel?
Biofuels can be in various forms to include liquid, gas, or solid material. The form that the fuel is stored in depends on the method of fuel harvesting of the material. Biofuels can be made from any biological carbon-based substance, with corn and soy beans being the most popular crops used for fuel production in the early 2000’s. Using crops such as these to produce biodiesel, however, requires that land normally use to grow food that we eat is not producing edible corn or other crops any longer. As a result, industry has been investing time and energy into refining the process to extract biofuel from algae as a third generation biofuel.
Biodiesel Algae Advantages
Algae has show significant promise in being able to be the industry answer in biofuel production. Most algae will grow at 50 to 100 times a greater rate than corn or soy, and do not require freshwater or soil to be grown. Algae can be grown in non potable water in suspended containers located where the land can not be used to grow food. The traditional barriers to effective use of algae as a biodiesel have been the relative low cost of oil when compared to the cost of extracted the biofuel from algae, however, with improved technology and increased crude oil prices this gap has shrunk over the past few years. When grown in a closed system, the algae growth process can be controlled resulting in greater yields and increase biodiesel production. Another advantage of the algae growth process is that the algae pulls carbon dioxide from the air and replaces it with oxygen. This makes biodiesel algae farms more attractive to place near manufacturing plants that produce excessive amounts of carbon dioxide to help reduce pollution but also benefit the algae grower.
Biodiesel algae has the potential to make more than 100,000 gallons of algae oil per acre grown a year depending on how the algae is grown, the type of algae, and how the algae oil will be extracted. This means that if you have a 100 acre algae biodiesel farm, you could produce up to 10 million gallons of biodiesel algae in a year. It would take approximately 140 billion gallons of biodiesel algae to replace all crude oil word-wide. If algae farms can live up to their potential, then this could be done on less than 100 million acres where it would take exponentially more land to achieve the same effect with traditional biofuel crops.
How Is Oil Extracted from Algae?
Extracting the oil from algae has been the major cost barrier to the major expansion of the use of biodiesel algae in the marketplace. Once the algae are harvested, the oils are then extracted from the walls of the respective algae cells. The most rudimentary process to do this is to use an oil press which is similar to how an olive press works. The oil press has approximately a 75 percent extraction rate. Another method used to extract the oil is the hexane solvent method which first uses the oil press. Then, the leftover algae is mixed with hexane, filtered, etc so the remaining oil extracted does not have any chemicals remaining. This method results in approximately a 95 percent extraction rate of the oil from the algae. The third method used is the supercritical fluids method which can get up to 100 percent of the oil out of the algae. In this method, carbon dioxide is used to act as the supercritical fluid. The algae is pressurized and then heated to change it into a liquid and gaseous state. Then, the CO2 is mixed with the algae which turns it almost completely into oil. This method requires a significant investment in equipment and incurs significant cost. Regardless of the extraction method, once the algae oil is extracted, it is then refined using the transesterification process where sodium hydroxide is mixed with alcohol to create biodiesel fuel. After this step, glycerol is removed from the substance resulting in biodiesel algae.