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Every day, 45,000 planes fly across the United States, carrying some 1.7 million passengers. Aviation dominates a frequent traveler’s individual contribution to climate change, and yet it is one of the most challenging sectors to decarbonize.

The United States is the largest contributor to aviation carbon dioxide emissions in the world and is responsible for more than a quarter of all carbon dioxide emitted from flying.

But what if we could make all U.S. air travel nearly emissions free? What if we could replace carbon-intensive jet fossil fuels with a cleaner alternative: biojet fuels derived from rain-fed grass grown in the U.S.?

New research published today in the journal Nature Sustainability shows a pathway toward full decarbonization of U.S. aviation fuel use by substituting conventional jet fuel with sustainably produced biofuels.

The study, led by a team of Arizona State University researchers, found that planting the grass miscanthus on 23.2 million hectares of existing marginal agricultural lands — land that often lies fallow or is poor in soil quality — across the United States would provide enough biomass feedstock to meet the liquid fuel demands of the U.S. aviation sector fully from biofuels, an amount expected to reach 30 billion gallons per year by 2040.

In the study, the researchers used an integrated framework of land assessments, hydro-climate modeling, ecosystem modeling and economic modeling to assess where and under what conditions across the United States energy crops used for biojet fuels could be grown sustainably using criteria that evaluate both environmental and economic performance.

The criteria were extensive. The team first identified and assessed where optimal marginal agriculture lands already existed in the U.S. They then assessed whether one could grow the right energy crops on the land without using additional water.

The team then analyzed whether growing energy-crop feedstocks on these lands would have detrimental effects on the surrounding climate or soil moisture and predicted the potential productivity of yields of two different grasses — miscanthus and switchgrass — as suitable biomass-energy feedstocks. Finally, the team quantified the amount and the cost of biojet fuel that would be produced and distributed nationwide at scale. https://www.nature.com/articles/s41893-022-00990-w

Biofuels have an extremely poor record of carbon neutrality. I see Nature, so it's obviously legit, but is this concern addressed in the article?

Yeah, strip out the carbon sink and convert it to carbon, while desertifying the environment. Brilliant.

It's been proven again and again, that once you take everything into account, so called Bio-fuels are hardly providing any excess energy, while being extremely destructive in their production.

The whole idea is a product of the US farm lobby. Like sugar. Like pushing meat products.

Land lying fallow? Sounds like Trump saying water from the rivers flows uselessly into the ocean. Turns my stomach.

It hasnt been proven again and again, so quit making stuff up.

It has been proven. Ethanol burn much less efficiently and consistently. Engines run rougher, and get poorer gas mileage. Also, ethanol attracts water, which is very bad for a fuel system and engine. There is no benefit to it being in our gasoline besides juicing corn farmers.

Edit: (source and another point) The process of turning corn into fuel, and then burning it, emits more Co2 than just burning gasoline

https://www.reuters.com/business/environment/us-corn-based-ethanol-worse-climate-than-gasoline-study-finds-2022-02-14/

Read the article. This isn’t proposing use of ethanol, it’s hypothesizing that use of a kerosene-equivalent biofuel, not unlike bio-diesel, could power aviation. And while the harvesting and refinement of the fuel would no doubt pollute, and we’d still be burning the fuel’s carbon into the atmosphere, at least the continuous regrowing of the vegetation to create these fuels would reabsorb some of that carbon (which can’t be said of fossil fuels).

Far from a magic bullet, but if this is a step towards lessening carbon emissions, while retaining an affordable aviation industry (something very few are willing to voluntarily give up) then it should be considered.

Agree that the idea we would turn ALL of our accessible-but-unused farmland into bio-fuel crops is pretty depressing. A country-sized no man’s land, where nothing can survive longterm.

Yay! Nowhere for wildlife to live once all the fallow land is turned to biofuel production. Get rid of those pesky wild animals so we can all fly more.

Ok I read the article. There is no mention on how well this biofuel will perform. Which is extremely important in aviation. Their rules and regulations are insanely strict. $4.10 a gallon vs $2 for jet fuel. Plane tickets double in price? Not to mention bio fuel will get worse mpg by quite a margin. Is a $500 ticket going to be $1300? Theres so much more that needs to be answered.

All they did was identify certain unused lands in the US can grow enough grass to be made into enough biofuel that it would be equivalent to the aviation industry’s use. Whoopdie doo that solves nothing

No disagreement here—nothing solved whatsoever. But a reassurance/proposal to take biofuels more seriously, and consider that they need not cannibalize the country’s ability to grow food crops, could be a step towards a stop-gap solution that lessens carbon emissions (even if only by a margin). We need for information, more proposed solutions, and more people considering new approaches/options. Not less.

Flying short hop 100 to 300miles with electric is doable . . . International flights will HAVE TO decrease to meet realistic carbon metrics. I would favor trains/ship travel . . . Yes, it will be slower but, slow is nice, slow makes travel not like TSA and the tiny little seats 3 across with 3 ( . ) people . . .

Burning food and carbon sink just to fly.

Blimps and solar propellers. Not everything that floats is made of hydrogen.

Well yeah but we'd be bankrupt out of food

It has, biofuels is just another greenwashing money making industry.

1. Land "lies fallow" in order to replenish nutrients in the soil. If you keep planting the same field over and over again, you will wreck its productivity.
2. The poor quality soil (often the result of overprinting) cannot be used to grow biofuels unless you plan on dumping tons of fertilizers on it. Those fertilizers are often made from petroleum in the first place.

So what, exactly, are we gaining here?

Are biofuels carbon neutral?

Do you know what they call a carbon price? I understand the tCO2e part "The conversion into miscanthus delivers productive biomass, regional cooling without soil moisture loss and the lowest system greenhouse gas emissions (at US$50 tCO2e−1 carbon price). " So there is still greenhouse emissions associated but a lesser amount per $50 dollars spent per tonne of CO2 calculated emissions?

It NEEDS to lie fallow.

Money.

Big farmers gain money.

Fancy you asking...

Lets monoculture all of the wild land so to eliminate the entire ecosystem. Then we can exploit all of the land forever with zero consequences.

Hemp would be a much better source than miscanthus or switch grass for energy output (high cellulose content) and the deep root helps rejuvenate fallow soil.

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TIL that land is not scarce at all and neither is fertilizer, water for irrigation, etc.

Do people really believe this "research"?

Biofuels can eliminate only half of aviation climate harms, so they are unacceptable as solutions. We must simply fly less or not at all until electric aviation arrives.

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