Comments by "Engineering the weird guy" (@engineeringtheweirdguy2103) on "Donut" channel.

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  3. In physics there is an upper limit to the efficiency of anything. If you heat up a cup of coffee, you will never get 100% of the energy used back. No matter what you do. Hydrogen is made using grid energy. You are effectively storing eletricity as hydrogen. No matter what you do, to convert it back to electricity from hydrogen you will never ever get the same energy you used to begin with. So if you started with 100kwh of electricity, you will never ever be able to get 100kwh of electricity back when you convert the hydrogen back to electricity. Where you could have given that 100kWh directly to a battery electric car. It will always be inefficient. That means it will always cost more per km. If you need 3x the same grid energy per mile for a hydrogen compared to a battery vehicle, you will always be AT LEAST 3 times more expensive per km. Hydrogen fuel cells also don't output alot of power, making them very slow. That will always be the case, as the physical limitation is the surface area of the catalyst. No catalyst, no reaction. Battery electrics rely on the power output of the battery which can increase with battery size. So you will always have better performance out of a battery electric. for example the worlds fastest Hydrogen super car, the hyperion, is only just barely as fast (not faster) than the Tesla Model S plaid. The difference between the two however is that the hyperion is a purpose built performance car, no cargo space, barely any passeneger space with only 1 passenger seat and a driver seat. the rest of the car is taken up by maximising catalytic surface area and putting in batteries required to boost power output during acceleration. and even then. with all that efford the Hyperion does 0-60 mph in 2.2 seconds. Whilst the Model S plaid, which is a large 4 door 5 seat luxury family sedan with a normal trunk as well as a front truck too, does the same 0-60 in 1.99 seconds. Teslas Large family luxury SUV does this in 2.7s. All that performance without sacrificing practicality. To make hydrogen practical they need to be slow. The Toyota Mirai for example having a blistering 0-60 of 9.2 seconds. Hydrogen is also extremely explosive in the presence of atmosphere, needs to be stored at 32 times the pressure LPG is stored at, and can leak through solid metal. All of that is terrifying from a safety perspective. if you have a bad enough impact you can level a small block. ontop of that the water vapours it emits will corrode the car over time and when hydrogen leaks through solid metal, it embrittles it, making the metal increasingly delicate and liable to shatter. This means that the lifespan of hydrogen vehicles are alot less than combustion cars and even less the Battery Electrics which now have a longer lifespan the combustion cars. There simply is no way around a lot of what I just mentioned. They are physical limitations. For domestic purposes there is no way Hydrogen will be the future. Possibly for trucking and long distance freight or shipping. But not for passenger cars you and me drive. They cost more, are slower, dont last as long and are more dangerous.
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  13. It hasnt been built yet because whilst is feasible in theory, not so much in practice. what do I mean by that? well lets look at hydrogen plants operating today. One of the most modern Hydrogen plants in the world is the freshly built hydrogen plant built by Toyota in Melbourne Australia. They converted an old factory to both produce hydrogen but also be the states first hydrogen fuel station. An entire car factory, repurposed to produce hydrogen. Keep that in mind. An entire vehicle assembly line. Now it uses a 200kW, state of the art electrolyser to produce its hydrogen, it does so at a rate of 80kg every 24 hours. (which means you would need 4,800kWh of electricity to produce the hydrogen and 720kWh to compress it for storage, so a total of 5,520 kWh per 80kg of hydrogen). That would be enough to fill only 14 Toyota Mirai hydrogen vehicles. an entire factory, to produce enough fuel to only top up 14 cars per day. What i'm outlying to you is how slow and energy intensive hydrogen production is. If we scale that down to a fuel station with maybe 1/5th the size of the plant in Melbourne at best, that means you'd produce conceptually around 1/5th the hydrogen, which would be 20kg of hydrogen, or enough to top up a whopping 3 hydrogen cars per day. Which doesnt really meet demand. Then you are wanting to use on-site renewables instead of grid energy, that means you'd get maybe at best 1/3rd the energy needs over 24 hours from the space taken up by the fuel station, (you only have so much space). that means you'd only realistically be able to produce around 1 hydrogen cars worth of hydrogen per day. a whole fuel station which would have costs millions to retrofit to dispense hydrogen and more again for the hydrogen production equipment and renewables, to only fill up 1 car per day. Its not a great investment. Hence, not practically feasible.
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  42.  @TanvirNa  a company does a thing does not mean it’s any more viable. As for 6 hours? No. Super chargers do that in 5-10 minutes. But you only gotta do that for trips you might make once a year or less. For the rest of the time, you charge at home wasting 0 hours of your life getting fuel whilst hydrogen needs to waste as much as 16-17 hours per year on average getting fuel from a fuel station. As for power generation. That’s what I was getting to in my previous comment. Yes, most grids aren’t fully or even mostly green. Most still run of fossil fuels but that isn’t the home run argument you think it is. Hydrogen doesn’t occur naturally in its pure form on earth. You need to split it from things. There are generally 2 ways to do this. First is green hydrogen you split from water (sounds good right?) well not really. Seeing as you need in the order of 3-4 times more grid electricity per mile to create hydrogen than a BEV needs, from the very same electricity grid so not as green, not even close there. The other types of hydrogen production, and by far the most common, is splitting hydrogen out of hydrocarbons. And for those not in the know, hydrocarbons are fossil fuels and when you take the hydro from hydrocarbons, you’re left with just carbon. So to do that you need to burn fossil fuels releasing CO2 to split hydrogen from more fossil fuels, which releases more CO2. This process actually creates more carbon than if you had just used the fossil fuels as a direct fuel in the first place. So again. Not green. Hydrogen cars are also extremely expensive to fuel, are impractical cars, have incredibly short lifespans, slower and don’t even get me started on the fuelling issues.
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