I'm a sailor and I'm targeting the sailing cruiser community with it, although I recognize potential markets elsewhere. The idea is that when you are remote, in locations where supply chains and infrastructure are undeveloped, it is incredibly risky to rely on ICEs for auxiliary propulsion and electricity. You may not have access to gasoline or diesel in the quantities or narrow quality specification that ICEs require. And you certainly don't have access to fuel when you are at sea on a long passage. This system would allow you to use pretty much any conventional fuel, but it would also allow you to use biowaste, garbage paper and plastic (including ocean plastics), wood pellets, and even wet biomass like seaweed (the moisture content reduces efficiency, but is still net positive for energy generation). And it can produce energy on demand, instead of waiting around for it to decompose and produce methane.
(you must be getting this reaction a lot)
As far as the desulfurization and SOFC is concerned, we're not even close to that stage yet. Desulfurizers are pretty common, but most SOFC designs tend to be extremely large and heavy, more suitable for stationary generation. I'd like to work with NASA's Bi-Electrode Supported Cell concept, which has power densities suitable for transport applications , even better than most diesel engines. They are actively licensing the technology non-exclusively, so maybe we could get a license and produce it ourselves, but this is all bootstrapped so that is probably out of reach in the short term.
When this was banned suddenly there was a lot more food waste, and also animal feed became more expesnive, and anaerobic digestion emerged as a solution to both problems.
It's been a running theme over the past decade's various changes in Prime Ministers. A bit of a rundown https://www.afr.com/politics/federal/how-the-coalition-becam...
Edit: oh oops. I'd forgotten it had actually existed for a while
These regularly get attacked as signs of how wasteful we are (which I generally agree with) and people defend them because people with various kinds of physical impairments might find it hard to peel a fruit.
But I think if you recycle the skins/seeds/waste properly in a factory, wrap it in lightweight plastic and account for the reduced shipping weight, then you might come out ahead even if you ignore the benefits of eating more fruit.
One of the many complex decisions that a carbon fee might simplify by guiding people towards doing the right thing at every step in the process.
The Songhai Center does a full carbon cycle re-use. An interesting place to visit too!
I started researching energy storage. Creating liquid fuels from electricity would be handy for storage. There are processes, but getting CO2 and H2 to create hydrocarbons is currently very energy intensive. On the CO2 side, I think biogas can help this out. biogas is 25-50% CO2. In biogas upgrading, CO2 is considered a waste product (with purer methane the desired output). CO2 from this source looks noticeably less energy intensive than direct air capture.
I know biogas can be done on the small scale (e.g. homebiogas.com). My research focused especially on liquid fuel creation that could work in someone's backyard. I haven't found it. "High‐Selectivity Electrochemical Conversion of CO2 to Ethanol using a Copper Nanoparticle/N‐Doped Graphene Electrode"  was an exciting find, dampened after reading how well ethanol stores.
I mostly became convinced that existing oil, gas, and chemical companies will maintain dominance producing many of the same outputs, from a different (renewable) set of inputs.
You might want to check out plasma reforming. It's the path I'm currently on, although targeted for a different end product.
I mostly think I have to be doing some chemistry/math wrong, based on how not terrible the energy efficiency is. I'd love corrections or reading material, as this is not a knowledgeable area for me.
- 2 CO2 + 9 H20 + 12e- -> C2H5OH + 12 OH- = 0.084 V
- over voltage of 1.2 V is best
- 1kWh @ 1.2V yields 30 moles electrons
- 30 moles electrons has theoretical yield 2.5 moles ethanol = 0.146 L ethanol
- reduced to appx 116ml ethanol due to selectivity
- 116ml ethanol has raw energy of 778 Wh, probably 550 Wh recoverable with Combined Heat and Power
I think 55% round trip efficiency for energy-dense long term storage would be big. Of course, this isn't that (math is partially based on theoretical bests, ethanol isn't long term, CO2 capture and material movement not accounted for).
Thanks for the plasma reforming tip!
"Stockholm Vatten's sewage treatment works produce 4.1 million m³ of biogas annually, but have the capacity to double this amount." 
We looked into compression/cleaning for biogas, but both the capital requirement and ongoing operational cost was too high for the gas volume produced by the farm.
The most consistent use of compost heat has been to ensure proper pathogen reduction in certain waste materials such as wastewater byproducts. A popular example of this is called a 'dutch tunnel' (add 'composting' to that if you google it) where you have a pretty robust, loader accessible composting container which largely self-heats for pathogen reduction. I use the term 'largely self-heats' because there are aeration/mixture characteristics that are required for proper temperature development.
Searching EPA 40 CFR 503 is a good introduction to the process, because there is been a lot written about it and you can easily find guides/introductions.
(Correct me if I'm wrong, I'd love to be)
Making the biomass contribution dispatchible would be huge.
edit: fixed typo
the digestate is then spread on farm fields using similar methods/equipment used to previously spread manure.