Phytoplankton, specifically algae and microalgae, could turn down the heat on the morality debate over using food crops to produce energy. Microalgae produce triglycerides that can be converted into biodiesel, and they generate yields 30-50 times that of land-based crops. They do not require large tracts of agricultural land, nor do they disrupt the food chain.
While several technological stumbling blocks to producing algal biodiesel on a commercial scale remain, the obvious benefits over other renewable fuels keep investors and researchers interested. What’s more, the obstacles are well within the reach of innovators, especially when compared to the problems surrounding other biofuels, such as the financial, environmental, and social implications of using food crops for fuel.
Biodiesel has been gaining momentum recently because it is a domestically produced direct diesel replacement with low emissions and relatively high energy content. Biodiesel is relatively straightforward to produce from triglycerides, using well-established transesterification chemistry. The current U.S. biodiesel supply derives largely from soybeans, while a small percentage comes from the more difficult to process waste cooking oil.
Soy crops typically produce 48 gallons of oil per acre, require petroleum-based fertilizers and herbicides, and utilize both water and soil resources. It has been estimated that to replace just 15 percent of the jet fuel used by the domestic airline fleet would take a crop the size of Florida to sustain. Oilseed crops are more popular outside the U.S., particularly in Malaysia and Indonesia where palm oil is a biodiesel source. Palms produce a much higher crop yield of 638 gallons per acre, but the trade off is deforestation and “slash and burn” harvesting methods that release large amounts of the greenhouse gas carbon dioxide into the atmosphere.
Still, the continuing deterioration of our environment from burning fossil fuels, combined with predictions that we have reached peak oil production and estimates that China and India will soon exceed the oil consumption of the U.S., are all driving forces to finding replacements to petroleum-based fossil fuels other than food crops.
Algae and microalgae oils can be converted into biodiesel using the same methods employed for crop seed oils. Algae can be harvested every 24-48 hours, unlike land-based crops, which have much longer growing seasons. And some microalgae have an oil content upwards of 75 percent their dry weight. The added bonus is that algae uses carbon dioxide from the atmosphere in their photosynthesis of triglycerides, meaning an algae farm can be piggy-backed onto a CO2-producing smokestack to effectively eliminate up to 90 percent of the CO2 emissions.
In 1978, the U.S. Department of Energy started the Aquatic Species Program (ASP) aimed at investigating the use of aquatic plants as energy sources. The project was terminated in 1995 when diesel prices dropped to below $1 a gallon. The project made significant contributions to the understanding of algae genetics and lipid production. The ASP cataloged 3,000 strains of algae and found 300 species suitable for oil production.
Several algal farm designs are available for cultivating algae. While the design of the ASP algae production was in open algal ponds, Japan and others researched closed photobioreactor designs. Closed photobioreactors are significantly more expensive, but they eliminate the problem of contamination with unwanted native algae strains.
This past year has seen a mini-bubble in microalgae development. When GreenFuel Technology Corporation appeared on the map early 2004, microalgae biodiesel was, and still very much is, the “next big thing.” Venture capital started flowing and new start-ups began popping up seemingly overnight. Some companies jumped on board with high crop yields and low-cost scenarios, hoping to profit from the hype. While the capacity for algal biodiesel has been projected to be much larger than possible with crop seed oil, the reality is that few companies have made it past the initial demonstration stage, and no one has produced algal biodiesel on a commercially viable scale.
And with the hype often comes some shenanigans. In November of 2006 De Beers Fuel of South Africa released plans to produce feedstock for 16 billion to 24 billion liters of biofuels a year in a plant producing 144,000 liters per day of biodiesel and being run 25 days a month. It was later discovered that the large-scale plant did not exist and that the company had only 39,000 liters produced in its stocks. It has been estimated that investors lost close to $1 million each for
