In the depths of a swamp forest, the ferns are dying. Fanned bodies bowed together, these giant leaf-like forms topple and entangle as they bury upon one another to form a mass grave. The swamp forest becomes a murky crater of life and death, as each fern rooted in its soggy substrate ultimately lies to rest in the place of its birth. Void of oxygen and bacteria, the bottom of the forest holds millions of ferns, tree-like lycophytes, and primitive conifers. Over time, as these plants compress into the Earth, intense heat and pressure force them to refigure into dense black masses—the carbon-rich matter we now call coal.
Fast forward 300 million years. These ferns are reborn, wisps of their fronded bodies unfurling into the air as burning coal transforms water into steam to propel the churning cycle of a turbine. As the coal burns, harmful compounds that have been locked within these plants since the Carboniferous Period are released into the atmosphere, creating a noxious mix of sulfur dioxide, nitrogen oxides, and carbon dioxide. Once, these ferns served as natural air purifiers in the prehistoric landscape, releasing excessive oxygen outputs that contributed to the proliferation of giant, diverse plant and animal species. Today, in the form of coal, their corpses pollute our air, sicken vulnerable communities, and contribute to acid rain, smog, and rising global temperatures. Clicking on a light switch, we repurpose the 300 million-year-old lives of plants into electricity. Starting a car engine, we break the hydrocarbon bonds held in the plankton and algal remains in petroleum (gasoline’s crude state) and release carbon monoxide, nitrogen oxides, and particulate matter. To curb the devastating effects of coal and gasoline on the environment, the production and consumption of biofuels as an alternative source of energy began to accelerate in the United States.
In 2017, the US produced 774.6 million tons of coal, equivalent to the weight of nearly 120 million adult African bush elephants. In the same year, 29.9 percent of electricity generated in the United States came from coal, marking a nearly 20 percent drop from 2008 to 2016—a downward trend the Union of Concerned Scientists predicts will continue. Yet the use of biofuels, meaning any plant-based renewable energy, stood at a mere 11 percent in 2017. Most scientists agree that coal and other extensively-used fossil fuels, such as petroleum and natural gas, no longer serve as viable energy sources, so biofuels undoubtedly offer a better alternative. But just because an energy source is “renewable” or “bio-based” does not mean it is automatically environmentally sound or sustainable. The replacement of nonrenewable fuels with biofuels must be closely scrutinized: biofuel production and consumption in the US engender a host of issues concerning the growing competition for agricultural land use, rising global food prices, and the extent to which they actually mitigate greenhouse gas emissions.
Biofuels, which encompass all energy sources derived from living material, can be broken down into three main categories, or generations, of renewable energy. First-generation biofuels consist of fuels derived directly from food sources—namely corn, wheat, and sugar cane—while second-generation biofuels primarily derive from non-food crops or crops that can no longer be used as food sources. Cellulose-based biomass, a significant second-generation biofuel, is derived from the leaves and stems of plants. The average greenhouse gas (GHG) emissions from corn ethanol stand at 34 percent lower than gasoline, while cellulosic ethanol boasts 97 percent lower GHG emissions than gasoline. These statistics take into account the emissions caused from land use changes, or the changes associated with the conversion of land for processes such as farming or urbanization. This data demonstrates the extent to which second-generation biofuels may far exceed first-generation biofuels in mitigating GHG emissions. Lastly, third-generation biofuel encompasses energy sourced from algae—a new and promising field of study in the US.
But despite the greater environmental benefits of cellulose-based ethanol produced from non-food biomass, its commercial production remains relatively small. Ethanol produced from corn (and biodiesel produced from soybean) reigns as the primary biofuel produced and consumed in the US. Corn ethanol also represents one of the most highly-controversial biofuels in the US today in debates that pit political and economic agendas against the environment and public health. In Council Bluffs, Iowa last October, President Donald Trump announced his commitment to implement—with the “support” of the Environmental Protection Agency—the year-round sale of E15, a blended gasoline with 15 percent ethanol. Previously banned from sale during the summer months by the EPA due to its contributions to high levels of smog and its volatile nature, the sale of E15 would purportedly provide economic support to Iowa farmers. However, as the Washington Post points out, Trump’s benevolent gesture toward Iowa’s farmers ignores the grave realities of ethanol production: the accompanying rise of food prices, the use and destruction of valuable farmland for non-food products, and the immense energy expenditure necessary for corn distillation.
Corn ethanol does not constitute a suitable biofuel option largely because it does not meet the criteria for an ‘ideal energy crop’—that is, a plant that can perform high rates of photosynthesis and maintain a long growing season. These processes contribute to greater carbon dioxide capture while increasing the crop’s energy content. Additionally, an ideal energy crop yields a high harvest index, which is the percentage of above-ground matter than can be harvested as usable biomass. Many perennial grasses, which die back each year and regrow in the spring from their rootstock, meet the characteristics of an ideal energy crop. On the other hand, annual grasses such as corn must be replanted each year and typically require greater fertilizer input. Panicum sp. (switchgrass) and Miscanthus sp. (silvergrass) are two perennial grasses that could potentially serve as better biofuel sources than corn. With extensive root systems that reduce soil erosion, the uncanny ability to adapt to varying climates, and biomass yields greater than their corn equivalent, Panicum and Miscanthus could provide a more sustainable alternative to corn-based biofuels. In 2013, Purdue University scientists Qianlai Zhuang, Zhangcai Qin, and Min Chen compared the water use, land use and biomass production for corn, switchgrass, and Miscanthus to determine which crop could most efficiently produce 79 billion liters of ethanol. They found that Miscanthus required only half of the cropland and two-thirds of the water compared to corn to produce the same amount of ethanol—a result that strongly suggests its viability as a biofuel source.
Yet the use of agricultural land for fuel production and the release of carbon emissions from land use change serve as particularly complicating factors that extend beyond a potential shift to perennial grass biofuel production. On the most basic level, the use of land for biofuel production instead of crop production decreases the land available for food production. In turn, as the National Wildlife Federation predicts, this land use change could lead to greater GHG emissions, reduced biodiversity, and destruction of wetland and forest habitats. This argument, however, poses a double-edged sword: while some land use change resulting from biofuel production has indeed caused more harm than good in reducing the effects of climate change and crop production, some land being used for biofuel production is not suitable for food crop production in the first place. This dichotomy questions whether biofuel production should occur on land unsuitable for farming because any agricultural practice inevitably leads to greenhouse gas emissions. Furthermore, crops grown for biofuel—even when grown on land unsuitable for farming—replace natural carbon sinks, such as forest or prairies, that prove highly productive in capturing large amounts of carbon dioxide to clean up our atmosphere. Although some policymakers argue that biofuel crops also act as carbon sinks, the re-emission of this captured carbon dioxide through the burning of biofuels negates any claim that biofuels are “carbon-free sources.” Although potentially growing switchgrass or Miscanthus could lower GHG emissions as compared to other biofuels crops, the growth of any land-based biofuel will always require extensive space, water, and energy, while still contributing to climate change.
The impact of US biofuel production reaches far beyond national borders as biofuel production has also been attributed to higher global food prices and increased global hunger. Especially during periods of increased demand for biofuel, corn ethanol production yields greater monetary profits than corn grown for food. As more land becomes devoted to biofuel production, farmers growing corn for food must increase their prices to meet consumer demands while coping with the market’s decreased corn supply. The 2008 global food crisis marks an extreme example of the effects of biofuel production on food security and land use. Influenced in part by the Energy Independence and Security Act of 2007, which mandated a fivefold increase in the use of biofuels in the US, the global food crisis saw frightening consequences: the highest wheat prices in 28 years, tariffed imported gas and subsidized ethanol blends in the US, and a 8.4 percent decrease in overseas aid to developing countries in 2006 to 2007. Although the Energy Independence and Security Act was seemingly a step in the right direction, this legislation contributed to the astronomical increase in global food prices; some farmers struggled to meet the demands of the biofuel quotas, while others raised their food prices to compete with the market. The higher energy prices for imported fuels versus biofuels increased the demand for biofuels, which significantly influenced the United States’ production of corn ethanol.
This ramification was evident in 2008, when corn ethanol constituted 20 percent of the nation’s corn crop; today, that number stands at 25 percent of US-grown corn. During the 2008 food crisis, political leaders, economists, and Midwestern farmers claimed that biofuels contributed minimally to the drastic rise in food prices. Instead, they cited the rising frequency of droughts and the increasing global demand for protein as significant contributors to the jump in food prices. Yet a private World Bank report obtained by the Guardian says otherwise, asserting that biofuels forced global food prices up by 75 percent. Although there are many variables affecting increased food prices and global hunger, the need to reassess the United States’ role in contributing to these rising statistics through its corn ethanol production remains paramount.
Perhaps, then, a return to our roots could reinvent our fuel future. Slipping onto the scene 500 to 700 million years ago, macroalgae represents a vast array of photosynthesizing, plant-like organisms commonly referred to as seaweeds. Although microalgae have been rigorously explored as an energy source due to the high concentrations of oil found within their cells (which help keep them afloat), the study of macroalgae has recently emerged as an area of growing biofuel research. In the US today, kelp, a type of brown algae, spearheads this research because of its high photosynthetic rate and unparalleled biomass yields. Additionally, the ability to farm seaweed in open-ocean systems nearly eliminates any land use change or energy expenditures typical of land-based biofuel production. In an interview with the College Hill Independent, Dr. Lindsay Green-Gavrielidis, a seaweed ecologist and postdoctoral researcher at the University of Rhode Island, attested to the dynamic nature of macroalgae and the myriad ecological and economic benefits they offer. Considering the sustainability challenges involved in growing an organism as an alternative fuel source, Dr. Green-Gavrielidis explained how the need for water use creates competition between industries and people already vying for dwindling water supplies. Meanwhile, a competing need for space poses questions about whether the space should be left as a natural ecosystem, used for farming, or occupied by human populations. “It’s all these competing interests that make it very attractive to be able to use the ocean because you don’t have to do anything to the seaweed,” she said. “You put it in the ocean, you tend to it, you make sure nothing bad happens to it or the gear you’re using, but you’re not giving it fertilizer, there’s no need to use water—all of that is there.”
Consistent with all alternative fuel sources, however, seaweed poses its own set of drawbacks. For one, only small companies in the US currently engage in seaweed farming. The practice in the US is also relatively new, so many companies remain in the preliminary stages of their research. These two factors mean the current seaweed farming system lacks the investment and infrastructure necessary for biofuel production. This ultimately puts the US far behind many other countries that have been pursuing seaweed-based biofuels for many years. Taiwanese shrimp farmers have incorporated seaweed into their shrimp cultivation practices, leading to cleaner water and the production of seaweed biofuel; Israeli farmers have implemented multi-species farming systems, allowing for better exchange of nutrients and permitting seaweed cultivation for biofuel; Sweden has developed large-scale systems of kelp production for food, bioplastics, adhesives, and biofuels. The success of these global seaweed production systems make the rise of US seaweed biofuel research a hopeful prospect. Twenty miles off the coast of Los Angeles, a team of researchers at the Wrigley Institute of Environmental Studies are endeavoring to create a “kelp elevator” to make the large-scale production of seaweed biofuel a reality. The team first cultivates the kelp in nurseries on land, and then places a pipe containing the cultivated juvenile kelp plants 30 feet below the ocean’s surface. Ultimately, their project aims to engineer a contraption that can lower the kelp bed to obtain nutrients in the depths and raise the kelp bed to obtain sunlight. This technology would allow for full-fledged seaweed farming miles from the shore.
Despite the lack of infrastructure and investment in seaweed farming for biofuel, seaweed provides innumerable environmental benefits that make its general cultivation worthwhile. Elaborating on the services seaweed farming provides, Dr. Green-Gavrielidis explained that “in the process of photosynthesis, seaweeds take up carbon dioxide and nitrogen and phosphorous and all these things we’ve come to view as negatives because we have an excess of them in our coastal waters. Seaweeds take them out and turn them into biomass, so harvesting the seaweed effectively removes these compounds from the environment.” Although Dr. Green-Gavrielidis explained that the processing procedure for converting seaweed biomass to fuel could potentially re-emit some of these compounds into the atmosphere, she stated, “From a farming perspective and the work that I do where you end up selling the seaweed as a food, you are just removing that carbon dioxide, that nitrogen, that phosphorous from the coastal environment.” Research on macroalgae is just beginning to emerge in the US and the feasibility of seaweed for fuel is still largely unexplored. However, the affirmed positive environmental and economic benefits from seaweed farming point to promising potential for the use of macroalgae in the biofuel industry.
Biofuels are indisputably an efficient, practical technology that could potentially mitigate the effects of climate change on the environment. Yet every time we convert an area of land to the growth of corn for fuel instead of food, we must radically rethink our priorities and the grave realities of land use change and biofuel production: we may emit more greenhouse gases and we may cause more people around the globe to go hungry. As Nature posits, “The only way that biofuels could help reduce emissions is by reserving additional land not currently acting as a carbon sink to be used for biofuel production.” The use of land for food and non-food crop production is inextricably tied to GHG emissions and water consumption, and although cellulosic ethanol provides a push in the right direction, it fails to address major climate change issues: land use and conservation, water consumption, and carbon dioxide output. Even microalgae, which the United States Department of Energy claims can produce up to 60 times more oil than land-based biofuels, falls short in providing a sustainable biofuel future. It occurs largely on land, uses extensive watering systems, and oftentimes relies on artificial light. The endorsement of microalgae by oil companies such as Exxon raises questions about whether certain biofuels gain support because the infrastructure and markets for their consumption already exist—factors currently outweighing the environmental implications of their production.
In “The Place of Plants,” environmental philosopher Michael Marder writes about how the world meets plants: As sessile beings, plants remain rooted in place, incorporating their environment into their bodies and ever-adapting to the world around them. “Attentive to the places of [their] growth… plants grow in contiguity with, not against, their environmental niches.” In this sense, humanity also has to extend itself in a direction that attends to this space. In doing so, returning to parts of our environment that have been here the longest, there may be answers in algae.
SHANNON KINGSLEY B’20 doesn’t like corn.