Aviation biofuels – in or out?

I have a potential piece of work on aviation biofuels.

It is common for me to be invited into project consortiums for pilot projects in my area. A benefit of being a small fish in a smaller pond.

Aviation biofuels has been around, talked about and planned/tested for a decade at least.

All in the family, my mother facilitated aviation biofuels in the late 2000s.

But, here we are in 2023, talking about biofuel projects.

I don’t know much about biofuels. My amateur physics brain things about the amount of energy required to be captured by plants that can be then processed into a fuel (with all the losses and other inputs) to propel 160-200 tonnes of plane into the air.

If a 170 tonne Boeing 787 travelling at 860km/hour (233 metres per second) needs about 4 tonne of jet fuel per hour during flight with jet fuel energy content of about 43,000MJ/tonne, energy requirements are 172,000MJ per hour.

Queensland experiences solar energy of about 20 MJ per square metre per day.

The implication is that the hourly energy requirement for a 787 is the solar radiation experienced by 8,600sqm (0.86 hectare).

This does not account for the range of inefficiencies in converting solar into jet fuel via plants.

If efficiency is 33%%, the area is 2.8 hectares per hour for a flight.

A long haul flight is over 14 hours = 40 hectares of daily solar potential.

Queensland has 144 million hectares under agricultural production (including cattle).

All in all, an ok solution given Queensland’s size but lots of questions about environmenta/social impacts etc.

A tentative support for my involvement.

Let’s use another metric – is aviation biofuels mentioned in the Emissions Gap work?

There are only two mentions

First mention – TRANSPORT SECTOR TRANSFORMATION

Avoid supporting technologies that are incompatible with deep decarbonization, such as natural gas in road transport and biofuels that lead to deforestation and/or compete with food production (Searchinger et al. 2019).

Emissions Gap Report 2022

Second mention – TRANSPORT SECTOR TRANSFORMATION – RECOMMENDATIONS BY ACTOR GROUP

• Regulate and incentivize zero-carbon fuels for aviation: Develop regulations and support
  fiscal policies to transition to 100 per cent low-carbon fuels for aviation and marine sectors by 2050, including advanced biofuels, green hydrogen, renewable electricity, and e-fuels generated with additional renewable electricity (Graver et al. 2022; Pavlenko and O’Malley 2022).

So the mentions are negative where biofuels lead to deforestation and competition with food but advanced (non-food competing) biofuels are in the recommendations.

On this basis, biofuels are supported with the non-food competing caveat.

That is a positive.

Another tentative support.

I go on, noting my reservations about food competition, biodiversity impacts and efficiency.