It now seems we have a few options for sustainable jet fuel. All of this is going to take vast amounts of clean electricity. But if we Overbuild the grid to get through winter – what is all that extra power doing the non-winter months of the year? As long as the power can be diverted back to the grid in winter – we’ll have more than enough super-cheap renewable power for the options below.
Electric planes
Before we discuss jet fuel – let’s deal with electric planes. These will be small planes that fly short distances only. According to this American Chemical Society report – Feb 2020 – some of our best batteries today are at 500 Wh / kg and would only fly small regional planes of 30 to 75 people about 900 km.
IF we can invent a battery with 3 TIMES more power 1500 Wh / kg, it might carry about 300 people about 3700km. That’s not quite Sydney to Perth. But an A380 carries 500 to 800 people over 14,000 km! The experts today cannot guess how to get to those battery densities.
Hydrogen
Hydrogen takes up more cargo or passenger space. That sounds like a real problem when it cuts into their already tight profit margins. But here’s the thing. On smaller flights, fuel cells require vastly less servicing than combustion engines. The CASM (Cost for Available Seat Mile) goes down so much that even though there are less seats, the savings are so high smaller airlines might make more per passenger.
Larger flights have other challenges – but they might actually burn the hydrogen in an engine rather than use a fuel cell. There are details to work out, and it may or may not require a redesign of the whole plane back to retro looking Delta Wing aircraft. Time will tell.
Airbus have a few designs
Electrofuel
Electrofuels are similar to hydrogen in that we use up a bunch of electricity to split water for hydrogen – but then take it a step further by adding some CO2. As the wiki says:
Electrofuels, also known as e-fuels or synthetic fuels, are a type of drop-in replacement fuel. They are manufactured using captured carbon dioxide or carbon monoxide, together with hydrogen obtained from sustainable electricity sources such as wind, solar and nuclear power.
The process uses carbon dioxide in manufacturing and releases around the same amount of carbon dioxide into the air when the fuel is burned, for an overall low carbon footprint. Electrofuels are thus an option for reducing greenhouse gas emissions from transport, particularly for long-distance freight, marine, and air transport.
The US Navy has been testing it because supplying fuel to their aircraft carriers isn’t just measured in extremely expensive transported fuel – but in combat is also measured in lives! If the nuclear powered aircraft carrier can also be a mobile jet-fuel refinery, all the better.
Here is more detail from Dr John Morgan. He explains why Electrofuel from seawater makes sense given the CO2 concentration in seawater is 140 times higher than the air!
Gasification – waste to fuel
This CNBC primer is more than enough, but I also have a Gasification page that expands on how the molten slag can be useful for the building industry.
Eclipse Now 