Unlike other alternative fuels, biofuels already experience substantial use in the market and are likely to remain the dominant alternative fuel for the conceivable future. With modern advances in biofuel technology coming online and with policy incentives in place to create the market for adoption, it’s important to take some time to get to know what this technology is, and where it’s headed.
So what exactly is a biofuel? While biofuels may sound like something trendy and new, they have found commercial application in automobiles since the Ford Model T. A biofuel, at its simplest, is any fuel directly derived from recently existing biological organisms (read: plants and animals). Really, that means that any fuel derived from agriculture or agricultural byproducts as opposed to from petroleum is a biofuel. Similarly, because biofuels are grown rather than mined, they are considered to be renewable in nature (renewable fuel and biofuel are often used interchangeably). The biofuel that most people are aware of is the one that’s easiest to produce: ethanol.
Ethanol, like the beer in your fridge, is traditionally produced through fermentation of simple sugars by yeast. Sugarcane and corn (think high fructose corn syrup) are the two dominant sources for these simple sugars. Similar to any high proof alcohol from your liquor store, if ethanol is at a high enough concentration, you can combust it. For biofuel purposes, ethanol is typically concentrated through several distillation processes so that it can readily be combusted in an internal combustion engine. Although ethanol is relatively easy to produce, its usage as a transportation fuel is overshadowed by cheaper and more prolific fossil fuels.
Even though we have dabbled with ethanol as a biofuel since 1826, it wasn’t until the supply shocks for oil in the 1970s that biofuel use truly became important. Brazil and the United States, the two largest producers of biofuel, have pursued development with entirely different approaches and for different reasons.
The Great Depression and World War I weakened demand for sugar, which directly impacted the value of the sugarcane market in Brazil. Through the 1930s, the price of sugar continued to decline, and as a form of agricultural policy Brazil turned to ethanol as a viable means of stabilizing sugar price. Although a slew of policies were adopted to support this goal, the subsequent economic crises ultimately caused Brazil to abandon this endeavor until the 1970s. In 1975 Brazil renewed efforts to promote ethanol production with the national alcohol program. This was enacted to reduce the threat of sharp oil price increases while counteracting the collapse of sugar prices from world overproduction and the threat of alternative sweeteners. Due to the initial groundwork from the 1930s and renewed efforts for development during the 1970s, the Brazilian ethanol program remained in place and has created strong, decade-long incentives for sugar-to-ethanol conversion. Today, Brazil is a world leader, second to only the U.S., in the production, use, and export of ethanol.
The oil price shocks of the 1970s similarly led to enactment of several U.S. policies that supported ethanol development and flex-fuel vehicles. While enacted with good intention, the U.S. incentives had limited impact in promoting ethanol production and use due to the drop in oil prices during the 1980s. While the ethanol production incentive remained in place, it wasn’t until 2005 that ethanol production became substantial. 2005 saw the adoption of the Renewable Fuel Standard (RFS), a policy that directly mandated that the production of ethanol reach 7.5 billion gallons by 2012 to aid in energy independence and security. A series of modifications to the RFS in 2007 altered production goals to 36 billion gallons of renewable fuel by 2022 (largely corn ethanol), and created provisions for other renewable fuels.
As the discussion for biofuel development has gradually shifted from that of energy independence and price stabilization to climate change, new concerns have been put forward. The first generation of biofuels, like ethanol produced from corn, have used century-old methods for production and have been effective at offsetting oil use and encouraging energy security. Modern biofuels, however, will need to do more than that.
For a modern biofuel to gain traction in society at large, it needs to not only be cost competitive with oil, but it also must aid in carbon emission reduction goals, provide price stability, be produced at scale, provide similar service characteristics to gasoline, and work with today’s infrastructure. First-generation ethanol, while easy to manufacture and produce, is unable to satisfy all of these requirements, and so the search for alternatives has begun.
Ethanol, as a molecule, remains appealing. Ethanol can be blended into conventional gasoline at levels up to 10 percent, but beyond 10 percent fuel performance characteristics change and vehicle modifications are necessary for prolonged use. While vehicle modification is relatively inexpensive, it is still a hurdle that must be overcome. Furthermore, the climate benefits of corn ethanol compared to gasoline are limited, and draughts and land scarcity have placed first generation biofuels in direct competition with food.
Modern biofuels are looking to several technology solutions to address these issues, either by moving away from ethanol toward something like diesel, or by creating processes that do not rely on food crops but can instead use agricultural wastes to produce ethanol at lower carbon intensity than today’s processes. These new processes and options, however, do not have centuries worth of development behind them, and so remain in their infancy. It remains to be determined which next-generation technologies are most viable and which will ultimately come into substantial use.
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