Attempts to make “sustainable” jet fuel by using waste bagasse from Brazilian sugarcane

The global aviation industry hopes for over 4% growth per year, but gains in efficiency are around 1% per year. Hence the sector’s CO2 emissions will increase.  Attempts continue to be made to try and locate some sustainable sources of fuel, which could genuinely cause less carbon to be produced, over its whole life-cycle. This has so far been unsuccessful. For any fuel to be commercially viable, it has to use resources or land, which competes with human food. This is in part accounted for as ILUC (Indirect Land Use Change) effects. There are new claims that jet fuel could be made using sugarcane biomass, waste bagasse, and sugarcane could be grown on “marginal land.”  However, sugarcane would inevitably grow better on higher quality land, with more fertiliser and more water – and if that was applied, the land could be used for food. Often land termed marginal is, in reality, used by local people. The new enthusiasm for jet fuel involves using bagasse to make oils rather than ethanol. That inevitably means depletion of soil nutrients, as the plant waste is removed and not ploughed back into the soil. The team working on the sugar fuel hope their findings would ultimately be adopted by commercial fuel producers, and they have a patent on the technology.



Report by Friends of the Earth, in 2010, “Sugar cane and land use change in Brazil – Biofuel crops, indirect land use change and emissions”

The report concludes:
“6. Ethanol’s real carbon footprint

There is much controversy about the level of greenhouse gas
emissions from ethanol, even when only direct land use changes
are taken into account. The emissions caused by pesticide use,
cane straw burning, and by soil degradation, for example, mean
that emissions can increase.

When farmers move to the Amazon, trees and other vegetation are
burned or cleared to make way for pasture, reducing the capacity
to store and sequester carbon. As land is cleared, soil starts
oxidizing, releasing massive amounts of stored carbon. While
precise calculations are difficult, emissions from indirect land use
change are significant.

New research has found that emissions from indirect land-use
change (ILUC) could indeed be greater than the carbon savings from
biofuels in Brazil, “creating a carbon debt that would take about
250 years to be repaid using these biofuels instead of fossil fuels”.

Expansion into the Amazon also has wider impacts, with increased
cattle farming likely to lead to an increased likelihood of logging,
soybean planting and new illegal roads which in turn open up new
areas of forest.

Given that ILUC causes significant greenhouse gas emissions,
EU policy must take a precautionary approach.

7. Conclusion

The use of ethanol instead of petrol is clearly leading to economic,
social and environmental problems, which seriously undermine
the supposed benefits of sugar cane. Indirect land use change as
a result of expanding sugar cane plantations is leading to a
substantial increase in greenhouse gas emissions, perhaps causing
even more emissions than fossil fuels.”


Researchers find sweet source for aviation biofuel

Global emissions from aircraft are forecast to continue to grow until the middle of the century

Researchers have identified a new way to produce aviation fuel from sugarcane biomass that could deliver substantial cuts in greenhouse gas emissions.

The source crops could be grown on marginal land, avoiding displacing food production, the team observed.

They added the development of renewable liquid fuels was critical to reduce global reliance on petroleum and help mitigate climate change.

The findings appear in the Proceedings of the National Academy of Sciences.

Biofuel sweetspot

“We’ve identified a new route of chemistry with its source from sugars in sugarcane plus some of the so-called waste material called bagasse,” said co-author Alexis Bell from the University of California, Berkeley, US.

“We show in this paper how we can put these components together to make jet diesel and lubricants.”

The development of a reliable biofuel that can be scaled up to a level that be used by the world’s commercial airlines has proved somewhat elusive.

Prof Bell explained that there were a number of understandably strict requirements when it came to aviation fuel.

“The first one is that there must be no oxygen content, the reason being that any oxygen you put in decreases the energy density and as space on an aircraft is at a premium, and you’d like to pack in as much energy in the form of burnable fuel as possible,” he told BBC News.

“Second, the fuel must have the right boiling point distribution, and then it has to have properties called lubricity, which means it does not cause excessive wear of the turbine components.

“It also has to have a very low pour point, which means the temperature at which the fuel becomes gelatinous and therefore no longer flows. When you are up in the stratosphere, temperatures around the aircraft are around -40C (-40F) or -50C, so you do not want your fuel gelling up on you.”

He added: “What we have developed meets all of those criteria.”


The carbon cost of flying

  • Eight million of us fly every day and this number is increasing.
  • In 2012, 2% of all human carbon emissions were result of plane emissions.
  • If air travel continues to grow at the predicted rate, it could contribute a considerably higher proportion by 2050.

Is jet travel becoming the dirtiest way to cross the planet?


The search for aviation biofuels broke on to the public stage in the late 2000s when there were a number of test flights using a blend of conventional fuel and biofuel.

In February 2008, the first commercial flight partly powered by biofuel (derived from a mixture of babassu nuts and coconuts) took off from London’s Heathrow airport.

After a lengthy review by aircraft makers, engine manufacturers and fuel producers, biofuels were approved for commercial use in 2011.

Prof Bell said the team were hopeful that their findings would ultimately be adopted by commercial fuel producers.

“Our sponsors, BP, have encouraged us to apply for a patent, which we have, on this technology,” he revealed.

“Where they see the likely commercial interest for themselves and others is that the lubricants would be first as the profit margins are largest, next would be aviation fuel because of the growing US and European regulations requiring a ‘green’ component of aviation fuel.”

Food v fuel

In recent years, political support for biofuels has waned as concern grew that global demand for biofuels would result in a switch away from food production to biofuel production, exacerbating food security worries.

Prof Bell acknowledged that certain crops as feedstock for the sugar-derived process would be problematic: “If, for example, we were to use sugar beet instead of sugarcane then there would be a potential conflict over fuel versus food.”

But he added: “By using sugarcane, particularly in Brazil, on land that is not used for agriculture, we escape that conundrum.

“But we are talking about the Amazon basin, and one of the issues there is that if you cleared the land of scrubs and trees – whatever is growing there naturally – in order to make it available for growing sugar plantations, and you get rid of that vegetation by burning it then you are putting a big pulse of CO2 into the atmosphere.”

Prof Bell said that the process to make the aviation biofuel outlined in his team’s paper would use waste biomass to generate the energy required operate the refinery, with excess energy being put into the Brazilian grid system.