There was a company called Wiferion that was bringing this exact product to market. They were bought by Tesla though and nothing has since come out.

There is another company called Witricity that claims to have a product ready in 2025.

At the extremes one is, as far as our technology allows, irreplaceable as a carbon neutral fuel. That being SAF. The other other viable alternatives even today. Why are you presenting a scenario where both would be needed to be created in equal measures?

So what if they can both come from the same feedstocks? There will be a day we likely don’t need diesel in any capacity. We’ll need SAF long before that. Why would we divert the valuable carbon neutral feedstocks to something like biodiesel if our goal is carbon neutrality for both?

There is a regional chain of grocery stores in my area that have level 2 and 50Kw level 3 chargers. They give you 1 free hour of level 2 charging per day (per location, I later discovered). At 9.6k charge rate, its not a huge savings, but I almost always use it when I grocery shop and its nice to come out to the car with 5% or 8% charged added.

This is extremely disappointing. Replacing existing purchased government vehicles early is neither fiscally sound nor environmental. The only group that benefits from this is petroleum companies that stand to gain back additional fuel consumption lost to EVs.

Years ago there were few public EV chargers, and even then it was common when I used one that I was the only one there. Today there are many more public EV chargers and and multi-stall chargers, its more rare that I’m the only one charging.

It doesn’t really matter whether you’re producing biodiesel or SAF; it’s a slightly different length of carbon chain coming out of the refinery.

The difference isn’t the slight variation in chemical structure of the molecule between the two products, its the drastic difference in the applicable use case of the resulting product, and the economic incentives to produce one vs the other. These are what make the SAF and biodiesel gigantically different product with hugely different economic, climate and geopolitical implications.

No amount of B5, B20 or B100 grades of biodiesel are going to enable carbon neutral air travel where SAF can. However, alternate fuels or methods of ground transportation can offset or replace diesel or biodiesel. With today’s technology only a number of small electric prop planes (certainly no commercial jets) can operate with anything close to carbon neutrality without SAF. Commercial aviation is a reality in our world and we can choose to find carbon neutral alternatives or embrace its carbon rich nature and try to make drastic carbon cuts elsewhere. I believe the latter is much less likely than the former. Alternatively we can simply turn a blind eye to our climate and reap the consequences. I’m not ready to throw in the towel and embrace that yet.

The same problem of competing with food is there because that’s where you’re sourcing carbon and hydrogen from.

Even if a portion of input feedstocks that go into producing SAF today are food or competing with food, how are you holding the position that municipal waste, used cooking oil, and agricultural waste are sources of food? I’ve posted sources that show the alternates available and possibly upcoming that would enable more non-virgin SAF. Are you holding the position that humanity will simply never achieve anything except fossil based fuel for aviation or something else I haven’t understood of your position yet?

Further yet, what is the connection you’re making a food supply with regard to hydrogen? Are you referring to fertilizer?

First, that is a great link. I don’t follow biodiesel efforts very closely and always appreciate the data from a real world execution perspective.

That said, while the article contains a number of criticisms you’re pointing out, the article is mostly focused on biodiesel and not necessarily SAF, and even less applicability to California where the majority of North American SAF is produced. The article even called this out with the distinction that biofuels (SAF in this case) from virgin feedstocks doesn’t qualify for the Low Carbon Fuel Standards (LCFS) laws in California that make SAF economically viable. Meaning there is far lower incentive to try to produce SAF from virgin feedstocks, which I believe is your primary criticism of SAF.

“Additionally, the Producer’s Tax Credit, coupled with the California LCFS, will heighten the demand for lower carbon-intensity feedstocks like tallow, UCO, and corn oil. Under the LCFS, west-coast market demand is stronger for feedstocks that provide greater carbon-emission reductions than virgin vegetable oils like canola and soybean oil. These policies will continue to pull available global feedstocks into the California renewable diesel market, and boost U.S. import demand for feedstocks that make lower carbon-intensity biofuels that generate additional credits in the California market.”

from your provided source

The other point your article highlighted was the bottleneck to using less virgin sources was the need to increase the non-virgin sources of feedstocks. As in, the market is demanding more biofuel from non-virgin feedstock than can supplied. This is important as it goes back to the work identifying and introducing further non-virgin feedstocks that I linked in my other post on this topic here.

Food. Food oils in particular.

While certainly possible technologically, for the main efforts in North America you are incorrect on the use of food (meaning something humans can eat) for SAF.

The largest producer of SAF in the USA is in California (and partially fuels LAX airport, BTW). This operation is using waste from other processes and not food that would otherwise be eaten.

source

That is a very important question. SAF is a name for a bunch of different fuels produced from sustainable sources. I posted a larger reply to the main article that details some of the input feedstocks which answers your question here.

I’ll preface this by saying that SAF by itself isn’t a silver bullet that solves all problems with carbon use in aviation. It can, however, be an important piece of a larger solution. Additionally, even in isolation without a larger plan it has a net benefit on carbon reduction which is a win in the battle against climate change.

The basic problem is that “sustainable” aviation fuels, if based on biofuels, would substantially compete with food production.

Certainly possibly, but not absolutely.

Virgin feedstocks (the stuff needed to feed in to make SAF) would support your position because the plants grown specifically for harvest to be turned into SAF would displace food crops, or possibly support destruction of other non-agricultrual land to grow net more crops. I agree with you that both of these situations would be a net negative to SAF.

However, virgin feedstocks aren’t the only nor even most desired feedstocks for SAF. There are many ways to produce the fuels that fall into the definition of SAF. Things that we would otherwise consider waste streams can be SAF feedstocks such as the following:

source

There are other pathyways being explored too such as the waste water runoff from dairy farms and beer breweries:

“To that end, the Argonne Lab scientists look to using carbon-rich wastewater from dairy farms (and breweries, for other reasons) as feedstock for SAF production. The study author at Argonne, Taemin Kim, said that the energy savings come in two ways. “Both [dairy farms’ and breweries’] wastewater streams are rich in organics, and it is carbon-intensive to treat them using traditional wastewater treatment methods. By using our technology, we are not only treating these waste streams, but [also] making low-carbon sustainable fuel for the aviation industry.””

Source

Unless we as a global society choose to simply eliminate air travel for people and cargo, we have to accept that a better approach to energy used for air travel is needed to meet reality. SAF is an important part of that in my mind.

Yes, I’m one.

Like most things, not one thing will fix a problem. SAF is one piece that measurable makes our situation better. The fact you can possibly fly on a plane today partially with SAF is an amazing achievement and the result of lots of hard work by lots of people trying to make a positive difference.

We have the excess electricity already, but I’m not yet at the legally required amount of solar panels.

At work we are investing in energy storage, both batteries and heat storage and looking for more solutions.

For any but the largest commercial solar/wind providers, batteries and heat storage (or cold storage actually too!) are the best uses of overproduction of electricity. Batteries at your location are 90%+ efficient round trip, meaning for every 1kWh you shove into the battery, even after all the conversion and storage costs, you’ll be able to get 900Wh or more out of the battery when you have a use for it. Many PV tied batteries are upwards of 97% efficient even!

Heat storage is another great use, whether in water (to mitigate need for new energy expenditure to heat water for use), or in thermal batteries for space heating. Although the biggest downside to thermal batteries are their size. If you’ve got spare space then they can be effective in a home or business.

I’m looking at hydrogen, because it’s known tech and I dream of finding a way to use it in a more stable chemical form for storage.

I did the same looking at Hydrogen, and its pretty bleak. Not only is creating hydrogen safely (from electrolysis) difficult, but storage is a nightmare. Any kind of gaseous storage is incredibly difficult because of how small a molecule H2 is, and if you’re storage is inside a building that leakage creates explosion risks.

The safest way I saw to store and consume hydrogen is absorbed into a metal hydride. The problem there is that fillers (because of pressure) are expensive $2k for the cheapest one I saw, and you need many metal hydride cylinders to store any appreciable amount of hydrogen. So they end up being large, heavy and bulky or relatively little energy storage.

For home use, a regular lithium battery is so much more efficient and safe.

What it looks like this company is building would be partially compatible with that approach.

For the Haber-Bosch process needs input H2 (plus the atmospheric Nitrogen). 33% of what this company is building is an electrolyser. Further, the Sabatier reactor they’re using (another 33% of their process) could possibly be swapped out for a Haber-Bosch reactor.

I don’t know enough about the environmental conditions needed for handling ammonia vs methane to understand if there are any “gotchas” to creating ammonia in situ.

What are the other options you see for the excess electricity that would be more feasible than this methane approach?

This has the same problem as CO2 capture technologies, that is the relatively low CO2 concentration in the air.

You’re correct that the CO2 concentration in atmospheric air is low: 0.04%. Consider the following:

• Each molecule of C02 has a single carbon atom.
• Each molecule of methane also has a single carbon atom.
• So we could say that atmospheric air has 0.04% of methane production capacity.

I would agree with you this would be a waste of time if the goal was CO2 sequestration, but it isn’t. The goal is to use otherwise 100% wasted electricity to produce something useful that can be stored long term that there is a market for, in this case methane.

The only way to make this even remotely feasible

What is your definition of “feasible” here? Economically compared to fossil based methane? Volume of production?

… are end of pipe solutions where you directly capture the exhaust of a fossile fuel combustion process. But that in turn is at best a temporary band aid.

The company agrees with you. They called out that being able to direct capture pure CO2 from an industrial application would be ideal, but as they also concluded, thats not where the excess electricity is that is really the primary economic driver of this technique.

LFP

Thank you for that.

Its odd calling LFP “new” and “a change is coming”. The first production EV to ship in the USA with an LFP was in late 2021 I think.

I would have thought this might be talking about cheaper chemistry Sodium Ion batteries, which are already on the road in small quantities in China.

I didn’t see anything in the article at all regarding speculation or futures markets of electricity with the one exception being a mention of some industrial operators signing long term contracts to buy oversupply.

Can you refer me to the section of the article you’re responding to?

I think the “swapping” may be a different use case the author is talking about. I don’t think the author was referring to an end-user executed swap to simply put in a charged battery.

This would be a service center option where a mechanic would have to take tools and removed panels and connectors to make the swap. Something done maybe only a few times, if ever, for a car during its life.

A structural battery pack is constructed to not be serviced in parts. The author calls this out with his comments on “replacing a single bad cell”. He’s right that this is a concern for structural battery packs. Here’s a Tesla structural battery pack when it was attempted to be disassembled:

There was more of that pink foam wrapping around the cells now exposed. All of that pink foam is needed for strength and its thermal properties because the battery pack is part of the structure of the vehicle carrying load forces.

Clearly replacing a bank of cells would be difficult to do if there was a cell failure, and no wear near cost effective for a consumer to have done on their car. The author is suggesting having some of THIS type of battery, but also another part of the battery in the standard hard plastic modular cases where the whole module could be removed and replaced (“swapped”)

The author is suggesting SOME of the battery be the pink foam type that is unserviceable, and SOME of the battery be behind panels in cases that a technician can swap at a service center when the module has reached the end of its life.

I had spare batteries for my smartphone for events like all-day conferences/conventions to swap batteries in the afternoon.

Sure, but how often are you going to all-day conferences. Once a year? Twice? Is it worth having the possibly 20% less battery capacity the other 363 days a year for that swapability?

Something seems missing from the description. What would make the most sense with the articles description is if there were two packs each with different chemistries. One cheap and low density, such as NA-Ion (Sodium-Ion) that could take care of 90% of EV driving needs for trips under, say, 100 miles. The second pack being a much higher density chemistry like NMC (Nickel, Manganese, Cobalt) which could add significantly more range for the same cubic cm of volume in the vehicle, but the battery would have far fewer cycles compared to other chemistries.

The idea being, beat the heck out of the Sodium Ion battery and make it easily serviceable/replaceable at the cost of range for the same volume consumed, while the NMC battery would be gently cared for and only called on in the more extreme demands of range.

If that’s what the author was trying to say, it was not clear.

This article is a bit confusing because its talking about the theoretical use cases of structural battery packs in EVs, the possible problems, and possible mitigations.

The Tesla Model Y has been using a structural battery pack for over 2 years (since 2022 model year, I think). While Hyundai/Kia may make different choices, the pros and cons from Tesla’s choices can be used as at least one path for what Hyndai/Kia want to keep or what they would want to change from Tesla’s choices.

Here’s the articles cited problems:

However, placing cells inside load-bearing components would also make them hard to replace, offsetting this practice.

In practice almost no service of the battery is done at the shop where the car is. If there is a fault anywhere in the pack, from a cell to a BMS component, the entire pack is swapped.

Most EV drivers rarely use all of their battery range; they only need it on long trips. Therefore, batteries built into load-bearing automotive components would not be needed for daily use; they could be maintained at the ideal charge level for the battery formulation and rarely used except for long trips.

This is such a strange description. This isn’t how EV batteries are used at all today, as far as I know, because it would be very inefficient in regular use. You wouldn’t want to put extra strain/stress/charge/discharge on specific cells in the battery. That would lead to unbalanced packs. Further it would be much less efficient and slower to charge the segregated pack that the article is describing. The more full a cell gets of charge, the harder/more power you need to work it to take additional charge. Also, deep discharge of cells significantly shortens their life. The author’s design description of a segregated pack would also experience much worse cold weather range reduction.

if the carmaker were to use modular battery packs, it would reduce the related cost of repairs across all of the car batteries; if they had better batteries, the need to replace them would be substantially reduced

Several automakers have tried making modular packs the way the author is describing them here. They turn out to be a bad choice because of all the extra stuff you have to do to make it flexible to accept fewer or more modules. This same thing happened to mobile phones. You used to have a removable battery, which was nice. However to make the battery removable, you had to add spring contacts, a separate tray to hold the battery, and a battery door. All of these things took space. The only time you’d ever use these, practically, would be years into the phone’s life you’d open it up to replace the battery once, maybe twice in the phone’s entire life. Manufacturers could just put a larger battery in and make it cheaper. Many phones don’t live long enough to ever kill their first battery.

The author of the article is well credentialed and has worked in the tech and automotive industry for years, so I’m very confused as to the content of this article. Its almost like it was written 3 years ago, even though it is showing a Feb 14th 2025 dateline.