I highly doubt that biofuel catches on, the international market for these fuels will ultimately lead to bulldozing the rain forest, as that is the lowest cost "farm" on Earth. Liquefied natural gas is the biggest cost saver of the bunch, but the tanks become gigantic bombs, that I personally would not go near. If a ramper ran a cart into an external tank, the entire airport would likely be destroyed.

However, and here is the big issue, the price of Jet A will crater once any alternative technology takes hold, resulting in sticking with Jet A. We will see fully autonomous aircraft before any of those replace Kerosene.

All of the current biofuel projects (aviation and otherwise) have dropped all feed sources which might have other environmental or social impacts. Not only do they not use foodstock, they are also avoiding plants which would utilize land which would normally (or could be) used for food.

They are focusing on plants which would grow in environments normally unsuitable for agriculture and currently not cultivated... deserts for the most part.

Another feedstock concept is algea grown in a liquid... greatly simplifies harvesting/handling of the feedstock, as the liquid can be pumped around as needed and the outside environment/soil doesn't matter as long as it's sunny.

Also waste mass (ag, industrial, garbage) is going to be a feedstock source as well.

Most of the technical challenges are resolved, I'm actually quite impressed with the progress, ten years ago I didn't think they could develop a cost effective Jet A replacement. The only thing really missing now is economy of scale. There is a big gap to bridge there, but regulatory/social pressure might dictate the use of (initially) more expensive bio fuel even if Jet A is somewhat cheaper.

It's not about cost anymore. LNG is not carbon neutral or even close to it.

It's energy density is significantly lower than Jet A, so it would require about 50% more fuel volume, and associated structural weight, which you then have to haul up to the flight levels every leg... net result even more fuel burn and carbon.

You'd need clean-sheet designs, for larger tanks and different fuel systems (turbine engines can burn anything with minor tweaks, peanut butter has been demonstrated as turbine fuel, with powerful fuel pumps of course).

But I do agree LNG is far too flammable as well, while kerosene is actually hard to light on fire unless it's atomized or vaporized.


Regulatory or social mandates/pressure will drive the need to lower carbon emissions (other emissions will still be a factor too). Bio fuel is about the only way to do that, since it's zero net carbon except for production and distribution overhead (which could also be near zero carbon if the grid is nuclear, solar, hydro).

Also huge advantage that it's a drop in replacement (at least up to 50%, probably good to 80%) for Jet A. Any other fuel/power scheme will require clean-sheet designs.

I'm aware of all that stuff, but as we have seen with the failure of the Paris Accords, you can't prevent countries from trying to game the system. Europe didn't even come close to its targets, China, forget it.

Aviation is a probably less than 3% of emissions anyway. The main reason we have climate change is the lack of available nuclear power.

Yes. But potential social pressure could circumvent regulatory requirements. Ie people choose not to fly if airlines don't cut carbon. It's already started.

True, but it's emblematic of progress, growth, and success in modern industrial society and therefore an easy target for rabid anti-establishment progressives who seem to set the tone these days.

100% agree. Freaking stupid, we could have a near-zero carbon grid which could power most passenger cars, all trains, and some trucks. Ships and most airplanes need to burn liquid fuel (could be bio fuel).

The true "green" power is nuclear. Nothing else can match the need for billions of people occupying this planet. A tennis ball sized chunk can meet a lifetime of power for a single person. Not so with wind/solar etc.
Don't think you will hear many green power advocates admitting this.

A few have started to, but not many. It's certainly not hip or woke enough for most of them... science pales in comparison to rainbows and unicorns.

The alternative energy AND the oil companies lie to them, telling them solar and wind will work, and the technology for storage is right around the corner. These industries both win, they sell their windmills and panels, and the baseload is dependent on fossil fuels, that can't be replaced by either. The ramping required to replace solar and wind when they die at different times per day, makes it physically impossible to use nuclear on the same grid.

Not in every place and situation. In a few, it makes sense. In many, the energy required to build everything, protect it, isolate the radioactive waste, outpaces the energy produced. In other words it costs more than it saves. Many cities use gas-turbines because they are over 65% efficient (thermal cycle) and are extremely reliable and scalable (can add one or two real fast as necessary). It's possible that technology could offer a cleaner nuclear or fusion solution in the future, but again, that's not where we are today.

I think we're about at a point where cheap is not a carte-blanche excuse to generate CO2.

New design nuclear (fission) plants solve every problem except waste. Waste should be considered a temporary issue, ie we're not going to use fission forever, just long enough to bridge the gap to future carbon-free sources. A single waste repository in the right place would be harmless. The only (grasping) argument against that is the danger to future primitive societies... first off, I don't think we are obligated to plan for what happens after the total collapse of civilization. Second if a future society has regressed to the point where they don't know not to play with nuclear waste, you can simply keep them out with large steel doors

Current plants are the technological equivalent of a '57 Chevy. Works fine, lasts a long time, but new plant designs are a very sharp contrast to the old ones (both systems and core physics). IMO it would be important to license only one design, for standardization purposes. First generation plants were all one-off designs, so the operators are test pilots for the life of the plant. Operators who change jobs have to spend about three years in training before they are released to "fly the line"... and then they are still test pilots.

We all understand the benefits of a fleet with one type rating...