Running cars on ethanol made from palm oil, corn or soy is already a wide-spread reality. But the biofuel industry is still far from providing a truly sustainable and clean alternative to fossil fuels — unless it switches its gears.

The quest for alternatives to fossil fuels is not new. In fact, it’s been going on for as long as cars have existed. Originally, Henry Ford planned to fuel is famous Ford T (produced and sold from 1908 to 1927) with ethanol; other early cars were running on peanut oil. And in the years 2000, after decades of near-total hegemony of fossil fuels, the tide started to change again. A renewed enthusiasm for biofuels led the United States to implement the Renewable Fuel Standard in 2005 and the Energy Independence and Security Act in 2007, according to which the transportation industry had to adopt biofuels on a large scale, by using them as supplements to traditional fossil fuels. “The beauty of biofuels is that they suck carbon dioxide out of the air as they grow. When we burn them in our automobiles, we release carbon dioxide, but it is the same carbon that the plants absorbed while growing. Just on that basis, biofuels appear to be zero net emitters”, writes professor of thermal sciences John Abraham in The Guardian. And they have the added advantage of being a renewable resource, contrary to fossil fuels.

In Europe, biofuels have had their advocates since the middle of the 2000 decade too. For the past 15 years, the “Fuels of the Future” have had their own international conference, at the initiative of German actors of the bio-based energy sector. Since 2017, the conference includes “renewable mobility” into its main points of focus: “In incorporating this additional content, the conference organisers underline the fundamental importance of all renewable options for decarbonisation of transport. Referring to the ambitious objective of the Paris Climate Agreement, the conference organisers emphasise that decarbonisation of transport cannot be achieved by 2050 unless all these options are deployed.”

Not-so-green crops

In that spirit, the U.S. started to massively grow corn, soybeans and milo to produce ethanol, while Brazil and other tropical countries resort mainly to sugarcane. In Europe, biodiesel (a fuel usually made from palm oil) is widely available. Today, explains Smithsonian Magazine, nearly 40 percent of the U.S.’s corn production is converted to fuel. “But it turns out that the environmental problems associated with growing those crops on an industrial scale—a crop that requires highly fertile land as well as copious irrigation, tillage, and tractor fuel to produce—outweigh the environmental benefits of burning corn-based biofuel.” Because the production process often relies on coal or natural gas — at least in the U.S. –, “biofuels don’t replace as much oil as they use,” explains National Geographic. That’s not all. Some warn that the harvest of sugarcane or palm oil for biofuel could be devastating for the rainforests. And then there’s the question of food: crops (like corn) that could feed people are used to power cars; land that could be used to grow food is requisitioned for biofuel-production purposes. “Agriculture is being challenged by increasing food demand, and changes to regional climate. On top of this, most plans to combat climate change rely on the agricultural sector to increase carbon storage in soils, and to produce raw materials for the large-scale production of biofuels and power,” Dr. John Field, from Colorado State University, sums up in The Guardian.

The right crop, at the right place, in the right way

That doesn’t mean that biofuels are not the way of the future; it means that the biofuels we are producing now are not it. John Abraham recalls co-conducting a study in 2009, whose conclusions were that “if non-commercial crops were grown, you could actually end up with fuel that was significantly cleaner than petroleum. The trick was finding clean crops that don’t need a lot of fertilizer, water, and other inputs. (…) Our conclusion in 2009 was straightforward. Don’t use good cropland for biofuels. Rather, use marginal croplands, with minimal water and fertilizer, to create plants that can be converted to biofuels.” These marginal croplands can be switchgrass (which allows to produce fuel containing more than 5 times as much energy than it takes to grow and refine it) or hemp (which Ford wanted to use for the T Model, and produces nearly four times as much oil per acre as soybeans). According to Smithsonian Magazine, algae, an exotic plant called carrizo cane and a tropical shrub called jatropha are also leads worth exploring.

Of course, each of these solutions have their own specific drawbacks, and the path is not free of hurdles. Dr. John Field and a team of scientists found in a 2018 study published in Nature that marginal croplands give lower yields, which means there are “competing issues of productivity and greenhouse gas reduction,” writes John Abraham. But they also found that farmers make decisions based on the price of biofuels and the cost of greenhouse gases: “Simply put, if we put a reasonable price on carbon pollution, farmers will be able to grow switchgrass, poplars, and other species, reduce greenhouse gases, and make money. But, if there is no cost to carbon pollution, farmers will be motivated to spend more money on fertilizer and that, in the end, will lead to more emissions.” Putting a price on carbon may be the best way to make biofuels the stuff of the future.