Quantcast
Energy
Harvesting sugarcane in Brazil. Jonathan Wilkins / CC BY-SA

Jet Fuel From Sugarcane? It’s No Flight of Fancy

By Deepak Kumar, Stephen P. Long and Vijay Singh

The aviation industry produces two percent of global human-induced carbon dioxide emissions. This share may seem relatively small—for perspective, electricity generation and home heating account for more than 40 percent—but aviation is one of the world's fastest-growing greenhouse gas sources. Demand for air travel is projected to double in the next 20 years.

Airlines are under pressure to reduce their carbon emissions, and are highly vulnerable to global oil price fluctuations. These challenges have spurred strong interest in biomass-derived jet fuels. Bio-jet fuel can be produced from various plant materials, including oil crops, sugar crops, starchy plants and lignocellulosic biomass, through various chemical and biological routes. However, the technologies to convert oil to jet fuel are at a more advanced stage of development and yield higher energy efficiency than other sources.


We are engineering sugarcane, the most productive plant in the world, to produce oil that can be turned into bio-jet fuel. In a recent study, we found that use of this engineered sugarcane could yield more than 2,500 liters of bio-jet fuel per acre of land. In simple terms, this means that a Boeing 747 could fly for 10 hours on bio-jet fuel produced on just 54 acres of land. Compared to two competing plant sources, soybeans and jatropha, lipidcane would produce about 15 and 13 times as much jet fuel per unit of land, respectively.

Creating dual-purpose sugarcane

Bio-jet fuels derived from oil-rich feedstocks, such as camelina and algae, have been successfully tested in proof of concept flights. The American Society for Testing and Materials has approved a 50:50 blend of petroleum-based jet fuel and hydroprocessed renewable jet fuel for commercial and military flights.

However, even after significant research and commercialization efforts, current production volumes of bio-jet fuel are very small. Making these products on a larger scale will require further technology improvements and abundant low-cost feedstocks (crops used to make the fuel).

Sugarcane is a well-known biofuel source: Brazil has been fermenting sugarcane juice to make alcohol-based fuel for decades. Ethanol from sugarcane yields 25 percent more energy than the amount used during the production process, and reduces greenhouse gas emissions by 12 percent compared to fossil fuels.

We wondered whether we could increase the plant's natural oil production and use the oil to produce biodiesel, which provides even greater environmental benefits. Biodiesel yields 93 percent more energy than is required to make it and reduces emissions by 41 percent compared to fossil fuels. Ethanol and biodiesel can both be used in bio-jet fuel, but the technologies to convert plant-derived oil to jet fuel are at an advanced stage of development, yield high energy efficiency and are ready for large-scale deployment.

When we first proposed engineering sugarcane to produce more oil, some of our colleagues thought we were crazy. Sugarcane plants contain just 0.05 percent oil, which is far too little to convert to biodiesel. Many plant scientists theorized that increasing the amount of oil to one percent would be toxic to the plant, but our computer models predicted that we could increase oil production to 20 percent.

With support from the Department of Energy's Advanced Research Projects Agency-Energy, we launched a research project called Plants Engineered to Replace Oil in Sugarcane and Sorghum, or PETROSS, in 2012. Since then, through genetic engineering we've increased production of oil and fatty acids to achieve 12 percent oil in the leaves of sugarcane.

A bottle of oil produced from PETROSS lipidcaneClaire Benjamin / University of Illinois, CC BY-ND

Now we are working to achieve 20 percent oil—the theoretical limit, according to our computer models—and targeting this oil accumulation to the stem of the plant, where it is more accessible than in the leaves. Our preliminary research has shown that even as the engineered plants produce more oil, they continue to produce sugar. We call these engineered plants lipidcane.

Multiple products from lipidcane

Lipidcane offers many advantages for farmers and the environment. We calculate that growing lipidcane containing 20 percent oil would be five times more profitable per acre than soybeans, the main feedstock currently used to make biodiesel in the U.S., and twice as profitable per acre as corn.

To be sustainable, bio-jet fuel must also be economical to process and have high production yields that minimize use of arable land. We estimate that compared to soybeans, lipidcane containing five percent oil could produce four times more jet fuel per acre of land. Lipidcane with 20 percent oil could produce more than 15 times more jet fuel per acre.

And lipidcane offers other energy benefits. The plant parts left over after juice extraction, known as bagasse, can be burned to produce steam and electricity. According to our analysis, this would generate more than enough electricity to power the biorefinery, so surplus power could be sold back to the grid, displacing electricity produced from fossil fuels—a practice already used in some plants in Brazil to produce ethanol from sugarcane.

A potential U.S. bioenergy crop

Sugarcane thrives on marginal land that is not suited to many food crops. Currently it is grown mainly in Brazil, India and China. We are also engineering lipidcane to be more cold-tolerant so that it can be raised more widely, particularly in the southeastern U.S. on underutilized land.

A map of the growing region of cold-tolerant lipidcanePETROSS

If we devoted 23 million acres in the southeastern U.S. to lipidcane with 20 percent oil, we estimate that this crop could produce 65 percent of the U.S. jet fuel supply. Presently, in current dollars, that fuel would cost airlines $5.31 per gallon, which is less than bio-jet fuel produced from algae or other oil crops such as soybeans, canola or palm oil.

Lipidcane could also be grown in Brazil and other tropical areas. As we recently reported in Nature Climate Change, significantly expanding sugarcane or lipidcane production in Brazil could reduce current global carbon dioxide emissions by up to 5.6 percent. This could be accomplished without impinging on areas that the Brazilian government has designated as environmentally sensitive, such as rainforest.

In pursuit of 'energycane'

Our lipidcane research also includes genetically engineering the plant to make it photosynthesize more efficiently, which translates into more growth. In a 2016 article in Science, one of us (Stephen Long) and colleagues at other institutions demonstrated that improving the efficiency of photosynthesis in lipidcane increased its growth by 20 percent. Preliminary research and side-by-side field trials suggest that we have improved the photosynthetic efficiency of sugarcane by 20 percent, and by nearly 70 percent in cool conditions.

Normal sugarcane (left) growing beside engineered PETROSS sugarcane, which is visibly taller and bushier, in field trials at the University of FloridaFredy Altpeter / University of Florida, CC BY-ND

Now our team is beginning work to engineer a higher-yielding variety of sugarcane that we call "energycane" to achieve more oil production per acre. We have more ground to cover before it can be commercialized, but developing a viable plant with enough oil to economically produce biodiesel and bio-jet fuel is a major first step.

Reposted with permission from our media associate The Conversation.

Show Comments ()

EcoWatch Daily Newsletter

Sponsored
Food

18 Cookbooks for Building a Diverse and Just Food System

By Danielle Nierenberg and Natalie Quathamer

For a delicious end to 2018, Food Tank is highlighting 18 cookbooks that embrace a diverse global food industry. The list features chefs of color and authors that identify as LGBTQ+ working to feed a food revolution that breaks the barriers of race, gender, and sexuality. These books examine everything from building Puerto Rican flavors, conquering the art of transforming leftovers into masterpieces, and grasping what merging queer culture and international cuisine looks—and tastes—like. Whether you cook seasonally, are on a budget, or eat plant-based, there's something here to inspire every reader to diversify their diet!

Keep reading... Show less
Fracking
A protester outside the site where fracking restarted in the UK in October. OLI SCARFF / AFP / Getty Images

UK Fracking Paused Again After Largest Quake Yet

It would appear that the resurgence of fracking in the UK is on very shaky ground. A company called Cuadrilla restarted the controversial technique at a site in Lancashire, in Northwest England, just two months ago after a seven year hiatus. But it spent a month of that time doing tests with smaller volumes of water after a series of small earthquakes in October, The Guardian reported.

Keep reading... Show less
Animals
A reindeer in Sweden. Alexandre Buisse (Nattfodd) / GNU Free Documentation License

Reindeer Numbers Have Fallen by More than Half in 2 Decades

It's a sad Christmas for the world's reindeer—the antlered Arctic grazers associated with all things Santa Claus. Their numbers have fallen by more than half in the past 20 years, and climate change is likely to blame.

The latest numbers come from the National Oceanic and Atmospheric Administration's 2018 Arctic Report Card, which listed the increasing impacts of global warming on the earth's northernmost region, as EcoWatch has already reported. But the loss of Rangifer tarandus—called caribou in North America and Greenland and reindeer in Siberia and Europe—is of note because it threatens to further throw Arctic ecosystems and cultures out of whack. Reindeer are important prey for wolves and biting flies, and a key source of food and clothing for indigenous groups.

Keep reading... Show less
Energy
Mackinac Bridge from Straits of Mackinac. Gregory Varnum / Wikimedia Commons

Michigan Gov. Signs Bill to Keep Line 5 Pipeline Flowing

Michigan's outgoing Gov. Rick Snyder signed legislation on Wednesday that creates a new government authority to oversee a proposed oil tunnel in the Straits of Mackinac to effectively allow Canadian oil to keep flowing through the Great Lakes.

The controversial tunnel will encase a replacement segment for Enbridge Energy's aging Line 5 pipelines that run along the bottom of the Straits, a narrow waterway that connects Lakes Huron and Michigan.

Keep reading... Show less
Sponsored
Popular
The illegal La Pampa gold mine, seen here in 2017, has devastated the Peruvian Amazon and spread poisonous mercury. Planet Labs

Unprecedented New Map Unveils Illegal Mining Destroying Amazon

A first-of-its-kind map has unveiled widespread environmental damage and contamination of the Amazon rainforest caused by the rise illegal mining.

The survey, released Monday by the Amazon Socio-Environmental Geo-Referenced Information Project (RAISG), identifies at least 2,312 sites and 245 areas of prospecting or extraction of minerals such as gold, diamonds and coltan in six Amazonian countries—Bolivia, Brazil, Colombia, Ecuador, Peru and Venezuela. It also identified 30 rivers affected by mining and related activities.

Keep reading... Show less
Animals
Mako sharks killed at the South Jersey Shark Tournament in June 2017. Lewis Pugh

Shark Fishing Tournaments Devalue Ocean Wildlife and Harm Marine Conservation Efforts

By Rick Stafford

Just over three years ago, I was clinging to a rock in 20 meters of water, trying to stop the current from pulling me out to sea. I peered out into the gloom of the Pacific. Suddenly, three big dark shapes came into view, moving in a jerky, yet somehow smooth and majestic manner. I looked directly into the left eyes of hammerhead sharks as they swam past, maybe 10 meters from me. I could see the gill slits, the brown skin. But most of all, what struck me was just how big these animals are—far from the biggest sharks in the seas, but incredibly powerfully built and solid. These are truly magnificent creatures.

Keep reading... Show less
Sponsored
Politics
Sen. Joe Manchin and United Mine Workers of America President Cecil Roberts held a press conference on Oct. 3, 2017. Bill Clark / CQ Roll Call

Coal-Friendly Manchin Named Top Dem on Senate Energy Panel

After weeks of discord over the potential appointment, Sen. Joe Manchin, the pro-coal Democrat of West Virginia, was named the ranking member of the Senate Committee on Energy and Natural Resources, Sen. Chuck Schumer announced Tuesday.

Many Democrats and environmental groups were adamantly opposed to Manchin serving as the top Democrat on the committee that oversees policies on climate change, public lands and fossil fuel production.

Keep reading... Show less
Insights/Opinion
Hikers on the Mt. Hollywood Trail in Griffin Park, Calif. while a brush fire burned in the Angeles National Forest on Aug. 26, 2009. Mel Melcon / Los Angeles Times via Getty Images

Major Health Study Shows Benefits of Combating Climate Change

During the holiday season, people often drink toasts to health. There's something more we can do to ensure that we and others will enjoy good health now and into the future: combat climate change.

Keep reading... Show less
Sponsored

mail-copy

The best of EcoWatch, right in your inbox. Sign up for our email newsletter!