Renewable fuels have a discernible road ahead, albeit bumpy at times, in shaping the future energy industry. With the growing emphasis on climate change awareness and cleaner fuels, strengthening regulation and growing demand consistently stimulate research into new fuel sources and methods of production. One of those fuel sources often rumored to possess untapped potential has been switchgrass.
Renewable fuel is more accurately explained when breaking it down into categories that meet certain regulatory standards: Conventional Biofuel, Advanced Biofuel, Cellulosic Biofuel, and Biomass-based Diesel. The most often recognized of these is, of course, Conventional Biofuel, or more generally, corn ethanol, which makes up the majority of renewable fuels production currently.
Unfortunately, despite the vigorous support, corn ethanol production has resulted in many downsides, including adverse environmental impacts due to soil erosion, pesticide use, and land use changes, as well as many others. Corn’s growing demand as a biofuel has also had a significant upward impact to pricing, causing a ripple effect that impacts food costs. “Since the law’s passage, the price of corn has more than doubled, to an average of $4.11 per bushel in 2014 from an average of $1.96 per bushel in 2005,” the New York Times recently reported. It seems that the impact of corn ethanol production negates its use.
The hope is that a superior replacement can be found so that we can continue working toward a cleaner energy future. An alternative option to Conventional Biofuel is Cellulosic Biofuel. Like corn, it is derived from plant material. However, rather than the seeds or fruit, it is produced from non-edible plant material, such as wood chips, grasses, or corn husks. Although the abundance of potential feedstock is greater than other fuel categories, the amount of processing required to convert it into fuel creates production challenges.
Switchgrass has long been considered for its potential as a Cellulosic Biofuel feedstock because of its hardy, drought and flood tolerant nature, perennial growth, and low fertilization needs. According to results from a study performed by the Proceedings of the National Academy of Sciences, “… recent energy model analyses that used simulated biomass yields and estimated agricultural inputs indicate that switchgrass could produce >700% more output than input energy.” Additionally, that study noted the clean energy attributes switchgrass possesses. “Estimated average greenhouse gas (GHG) emissions from cellulosic ethanol derived from switchgrass were 94% lower than estimated GHG from gasoline.” That number compares to a 19-48% reduction in corn ethanol as cited in a 2012 research study by IOP Science.
However, there are many misconceptions when it comes to switchgrass. Although the plant is known to be tolerant of harsh conditions, for instance, it does not thrive without ample rainfall, warm temperatures, or deep soil. A high yield is highly dependent upon rainfall, temperature, and soil condition.
Regardless of the rumored advantages or challenges, the biggest drawback to unlocking the potential for switchgrass as a biofuel lies with production and the economic factors. According to research performed by Oklahoma State University, “The conversion process has not been tested on a large scale; thus, the economics remain unknown.” The study notes that consideration must be given to fuel prices, yield, and transportation costs.
It is clear that switchgrass possesses numerous qualities that appeal to the future biofuel industry. However, without further research, it is unknown whether switchgrass will ever have the potential to replace corn ethanol as fuel source.