Welcome to Aviation Biofuels math class with Mr. Mercutio

August 30, 2016 |

BD TS 083116 aviation smIf you were reading BBC’s coverage of the aviation biofuels space yesterday, you would have seen the provocative headline:

Wood fuel plan to cut plane CO2 branded as ‘pipe dream’

Then would have looked in vain for the quoted reference to “pipe dream”…because there wasn’t one. Just the invention of a bored editor. If that gives you an instant grasp of the quality of dialogue offered by the Fourth Estate on aviation biofuels, then the BBC has rendered a service.

But, we’ll say it. Though the technology in question, Gevo, was unfairly caught in the crossfire over what are essentially airline industry goals — there are indeed pipe dream aspects in IATA’s 2050 targets. As Mercutio said to Romeo, “a plague o’ both your houses.”

The tilted playing field from solar energy to solar fuels

Let’s look at why Mr. Mercutio feels the math is skewed.

First of all, there’s the griping about double standards when it comes to solar fuels and solar energy. Anything to that? The skinny is not hard to find. In the BBC article, the closest thing you would have found to the phrase “pipe dream” was a single quote from a noted anti-biofuels activist, labeling the entire effort to make aviation jet fuels “fairytale stuff”.

The grounds? That “no one in their right minds would ever pay” 2-3X for solar aviation fuels.

Solar energy advocates must be laughing hysterically. They’ve received those kinds of deals repeatedly in their quest for scale. And good for them. They have translated those industry-building arrangements into economies of scale that have them on target to deliver cost-parity energy soon, in selected markets. These type of arrangements are a) common, b) world-changing and c) denied exclusively to solar fuels.

About those 170 biorefineries per year…

Let’s examine also the articles’s unattributed claim that the airline goal of halving the level of 2005 emissions by 2050 “would require around 170 large-scale biorefineries to be built every year between 2020 and 2050, at a cost of up to $60bn a year.”

Whoa, Nelly.

Let’s bring in some hard data.

Aviation used 71 billion gallons of fuel in 2005, globally. Even if aviation passenger levels doubled by 2050, and ALL of it was in the form of biofuels delivering a 70% reduction in CO2 compared to 2005 emissions, you’d need 2800 biorefineries.

Which would be 82 refineries per year, even if today’s rough average of 50 million gallons per jet biorefinery didn’t increase.

Let’s ask ourselves an honest question. Would an error of that magnitude normally be tolerated by the, ahem, BBC? If a news report massively mis-stated an impact of a technology in any other area of press coverage – national news, local, sports, entertainment — we could have expected a more thorough scrutiny by the sub-editors. Or a red-faced correction issued by the senior editors when the truth came to light.

But, let’s continue on a little farther down the road.

Let’s look at some actual IATA math

According to this chart, the aviation industry intends advanced jet biofuels to provide a 5% contribution to emissions reduction by 2030.


You need roughly 5 billion gallons of capacity to do so.

(Why? At 70% CO2 reduction levels, you’d generate the same emissions as 1.5 billion gallons of conventional fuel. That’s a 3.5 billion gallon reduction, or roughly 5% of 2005 convention emissions.)

How many refineries do you need? At today’s size, you need 100. So, one would have to build roughly 7 per year in the 14 years between now and 2030.

Let’s take you back to that “170 large-scale biofineries per year” claim. It’s bosh. So, there’s reason for Mr. Mercutio to wish a plague upon the house of the BBC.

Not to mention

Let’s not fail to mention that the Gevo technology highlighted in the article doesn’t require you to build any greenfield capacity.

It’s a retrofit technology. You use existing ethanol capacity. And there are more than 300 such refineries around the world today. You could retrofit your way well into the 2030s if the math was right for the owners of capacity.

Just saying.

Mercutio’s plague wished upon the other dudes.

But there’s two sides to this sorry coin.

Let’s also call BS on IATA’s 2050 emissions target, for this reason. The math doesn’t work.

The industry projects that aviation traffic will double by 2050, and that 50% of the “business as usual” increase in emissions would be taken care of via fuel efficiency. So, to fly twice as much we’d need 1.5X of the fuel.

Follow me so far? Good.

Now to use 1.5X of the fuel and emit half as much, we need to reduce the carbon intensity by 67%. As proof we reference the Nobel-winning equation:

1.5 / 3 = 0.5

Which would be fine, except that virtually every aviation fuel spec is limited to 50% biofuels content. Meaning you can cut the carbon content in half, only. Max.

(For those new to the circus, let us explain. Conventional jet engines require the use of aromatics such as benzene, toluene or xylene — not generally found in biofuels. That’s why there’s a 50% biofuels limit in most jet fuel specs.)

If you are about to email me that ARA/CLG has a 100% replacement fuel, including aromatics, passing through testing so far with flying colors, let me say this: We’re aware of that.

But let’s do the Waltz of the Maybes.

Maybe ARA’s fuel will rule the world, and every other aviation biofuel spec will crumple into powder and die.

Maybe other specs will appear allowing 100% replacement of conventional jet fuel.

Maybe future engines will allow for 100% usage of existing aviation biofuels.

Maybe there will be so much garbage piled up in 2050 that carbon-negative biofuels will be flowing from every bathtub.

Maybe all the infrastructure will be in the right place at the the right time.

Maybe the moon really is made of cheese, and Apollo 11 just happened to land on some rind.

Maybe, maybe, maybe.

So, there’s reason for Mercutio to be grumpy about the math coming from both sides of the debate.

A more sensible goal

Airlines could certainly achieve all their goals by not growing. But why not drop the carbon reduction goal to something approaching technical reality. 40%? 35%? Any bidders?

Because no one is going to write nasty things about IATA if there’s a shortfall. The world dumps on solar fuels in a manner not seen since Pia Zadora rocked the movie world.

Count on it, critics will point Mercutio’s damning words at the Advanced Bioeconomy:

True, I talk of dreams, 
Which are the children of an idle brain, 
Begot of nothing but vain fantasy, 
Which is as thin of substance as the air 

Let’s awake from the dream, and escape instead into the cool and healing air of the real dawn.


Print Friendly, PDF & Email

Tags: ,

Category: Top Stories

Thank you for visting the Digest.