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Cake day: June 12th, 2023

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  • I looked it up, hydrogen fuel cells can attain about 60% efficiency from the energy potential in hydrogen, when converting to electricity. So I’m not wrong, we’re talking about different numbers.

    If you are looking at the pure engine efficiency, we are now looking at >97% for most EV motors (class IE4). However, the point of the entire transition away from fossil fuels is preventing or delaying climate collapse. For this purpose lowering emissions and reducing energy use go hand in hand, hence the overall efficiency is critical.

    But we can usually also do natural gas reclamation, which is the process of removing the carbon from CH4, and producing pure hydrogen, which, I believe is a much more energy efficient process.

    Hydrogen is less strongly bound to Carbon than Oxygen, however in this process we produce more CO2 again.

    AFAIK, no real progress has gone into electrolysis for decades.

    There is a theoretical upper bound for the efficency of water electrolysis, depending on the temperature. While current electrolyzers can surely be improved, since we are already making electricity, we might as well use it directly. Some applications (aircraft, rockets, …) need the higher energy density of chemical fuels. But: Working with liquid or gaseous hydrogen is terrible: Cyrogenic liquids are not easy to handle, let alone store. Hydrogen will embrittle any metal exposed to it and when inadvertenly mixed with air forms a highly explosive gas. Even the rocket people try to avoid using hydrogen unless they really need the ISP.

    The fact is that the batteries will cause the cars life to end long before anything else wears out that could potentially cause the car to get scrapped.

    So far we have seen EV batteries not degrade a lot due to good BMS. For most cars the battery will last at least 10 years before performance is seriously impacted and even then the battery can be reused for storage (home or grid scale). Most EVs have >40kWh batteries, homes usually need 5-10kWh storage. So one chewed up EV battery could be reused for multiple stationary battery systems.

    Cycle life is the core of the battery problem.

    I do agree that current battery tech is… not great. Having less spicy cells that are easier to recycle or recondition would be a massive gain and more research needs to be a core focus. However Li-Ion and LiFePo are already good enough to work for most people most of the time. Pair this with a lot of wind and solar energy generation and you have mostly sustainable traffic. This can be done right now and it has to be done right now. I argue a lot against hydrogen because it seems like a technology that is not there yet and allows many old players in the energy market to delay a transition which is not beneficial to them.


  • One alternative is hydrogen. Hydrogen fuel cell technology isn’t perfect, with a loss of about 20-30% IIRC

    You don’t recall correctly: The efficiency of Hydrogen, from solar cell to the wheels is 26%. Electrolysis is highly inefficient and compression and chilling of hydrogen is very energy intensive. Meanwhile, EVs are at 70%.

    You are right that batteries kinda suck due to their energy density. However with EVs you can buy today you can still commute every day without noticing any major difference to an ICE car. You can also do long road trips, even in a small car, albeit slower. (Source: did both)






  • Star Trek: Picard, when the Borg wake up and the Romulans just vacuum them out. In that moment the Cube should have automatically teleported them back inside. If the teleporters were down for some reason, the remaining Drones would just happily continue working in hard vacuum and proceed to assimilate the shit out of the Romulans. What happened was an uncalled for nerf of the Borg.