Biofuel is fuel made from either plant or animal material, and while today's generation can take credit for coining the term, humans have used biofuel in various forms for thousands of years. Recent innovations in biotechnology have taken our traditional, unprocessed primary biofuels-wood, charcoal, and animal waste-to another level by allowing us to create secondary, or processed, biofuels, including ethanol and biodiesel, the ones making headlines today.
Almost all commercially produced liquid biofuels made from sugar, starch, or oil are considered first-generation biofuels. While the specific methods of production vary according to manufacturer, ethanol is typically made through fermentation and distillation using raw materials that contain sugar, such as sugar cane or sugar beets, or a lot of starch, such as corn. Biodiesel is produced through different procedures in which animal fats or vegetable oils (such as palm, rapeseed, or soybean) are processed using alcohol and catalysts.
The sustainability of first-generation biofuels has been called into question in the last few years because land used to grow crops for fuel feedstock is taken out of food production. This has had implications for the world's food supply, and has been blamed for driving up food prices and initiating a world food crisis. Another problem is that only the sugars or oils of a plant are used to produce first-generation biofuels, thus making use of only a fraction of the total energy available, wasting the largest part of the plant, the woody mix of the chemical compounds lignin and cellulose, bound up in plant cell walls.
Second-generation biofuels addressed a number of the negative social and environmental effects of first-generation biofuels by using the woody, inedible parts of food crop plants, as well as forest harvest residues (leaves, bark, or woodchips) and non-agricultural crops grown on marginal land. Unfortunately, the process of turning woody biomass into the raw material for biofuel includes pre-treatment and fermentation with special enzymes, so it is more expensive, and more intensive, than first-generation techniques and is still not economically viable on a large scale.
As the fuel industry became disenchanted with second-generation biofuels they started to develop third-generation biofuels, using crops designed exclusively for fuel production. Many experts now believe that algae represents the "cheapest, easiest, and most environmentally friendly way to produce liquid fuel," and hundreds of millions of dollars have already been invested to develop algae as the next best source for biofuel.
The technology is disarmingly simple; certain species of algae produce bio-oils as a natural by-product of photosynthesis, and the oil can be extracted and refined. Photosynthesis only requires sunlight, water, and carbon dioxide as inputs, and given the right conditions, some species multiply quickly-doubling several times per day, even. Although the relative yield numbers vary (depending on the source of information) almost everyone agrees that the potential yield of oil produced by algae is many times greater than the next best crops of palm oil, sugar cane, corn, and soy.
Aside from higher yields, algae have other benefits over established biofuel feedstock, including their appetite for carbon dioxide (CO2). A number of algae-growing test facilities have been built next to factories and power stations to determine the potential for capturing emissions from industry. Experiments have proven that algae grow more quickly when fed additional CO2 in a photo-bioreactor; the CO2 helps the plant grow faster, while at the same time providing a way of recycling the CO2. Algae have proven tolerant of poor growing conditions and are being grown in tanks or ponds at research installations throughout the world to test production using land and water typically unsuitable for food crops. In other tests, algae are being fed waste nutrients, including polluted water produced by the oil and gas industries.
Major corporations have shown an interest in the development of algae biofuel for transportation, and a long list of companies, including ExxonMobil, Shell, and Boeing, are investing millions of dollars to study the commercial viability of large-scale production. Several airline companies have teamed up with Boeing and others to create the Algal Biomass Organization, a "trade group which aims to test and develop algae fuels for use in aeroplanes," and the group has conducted the world's first commercial airline tests using "different kinds of biofuel blends, including algae."
Investors, inventors, and speculators are lining up to push algae forward, and biofuel from algae may well be part of an overall strategy to reduce petroleum dependency, but there are still a number of issues that must be addressed. Research is trying to identify the types of algae that are most appropriate to produce biofuels, and there is still debate over whether they are best grown in open ponds or in photo-bioreactors. Researchers want to know what the best bio-reactor shape is, and even the best type of plastic to use. Others want to know where the ponds should be located and how much energy would be needed to process and transport the fuel if production is moved to remote areas. Harvesting the plants is still a problem because of their small size, and cost is an issue because specialized equipment and structures will be needed to begin growing the algae in large quantities.
Algae biofuels do show tremendous potential, but so did previous biofuels. Questions still remain about potential environmental impacts, and, although the answers are coming, it is clear that first and second-generation biofuels will continue to fill at least some of our needs for the foreseeable future. We might find that our needs are best met by a variety of fuels from a number of sources, a mixture of dedicated energy crops such as algae, enhanced recovery agricultural crop residues, and more sustainable versions of our current renewable fuels.
Original Article at greensolutionsmag
