raygundan

raygundan t1_j6yfaww wrote

> We need "COFFEE GOOD" or "COFFEE BAD".

The problem is that for things like this, there really isn't a black-and-white answer like that. It will be good for some things and bad for some things and then it will probably vary by person on top of it.

As a general rule of thumb, if you read an article that says something like "red wine is good for you," you can safely assume the study was really, really specific and said something like "red wine can slightly reduce blood pressure in people with mildly elevated blood pressure" and that it's the reporter who has oversimplified. It's not like the risks of alcohol consumption increasing your chance of cancer and liver damage and so on went away... it just also does this other thing they found.

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raygundan t1_j166nr8 wrote

Makes sense... the longest route in the US is less than 200 miles long, and it probably isn't even relevant since it's one of the rural routes driven by a carrier using their own vehicle.

If anything was tailor-made for EVs, it's the short-to-medium range stop-and-go of a delivery route. No idle losses, regenerative braking between the many stops, predictable distance, daily return to a central location where charging can be handled.

Edit: A little more googling says that the average route is only 24 miles, and that nearly all of them are less than 70 miles. We should have gone electric for the average postal route 30 years ago... even boring old lead-acid batteries could have managed that!

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raygundan t1_iyf9g7i wrote

> Hopefully it can find a way to solve some of the worlds problems.

Agreed on that! It's one more option in the toolkit, and just because some of the more obvious niches (cars, for example) are probably better done other ways doesn't mean we won't find good ways to put it to work.

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raygundan t1_iyf791f wrote

> far enough away that you may lose power using traditional power lines to transfer to where its needed.

Certainly possible, but even long-range power transmission has fairly low loss compared to something like producing and shipping hydrogen.

> No other way to get that energy from the Sahara Desert to my house/truck/airplane to transport it via H2 that I can see.

You're basically saying "what if we build in this difficult area" but the difficulty of building the plant and shipping infrastructure there aren't likely to be radically different than the difficulty of connecting it to the grid. One option is going to require a pipeline, road, or rail all the way to this out-of-the-way facility-- and one option is going to require a power line. You're going to have to build "a connection" one way or the other, and it seems like it would take pretty narrow conditions to make a road viable but a power line not.

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raygundan t1_iyf0zwp wrote

> Efficiency only matters in that case when you are extracting the energy to create the hydrogen from the grid and in my scenario that is not the case.

Sorta. What you've proposed might not be grid-connected-- but connecting your hypothetical geothermal power plant to the grid is still an option instead of using it to make hydrogen.

But broadly speaking, I'm with you-- if you have excess clean energy that for some combination of reasons cannot be utilized in any other more-efficient way than by shipping it out as hydrogen, go for it!

If somebody suggests to me "what if I build a power plant, don't connect it to the grid, and use that to make hydrogen" my first question is always going to be "what if we connected it to the grid instead?"

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raygundan t1_iyeyggz wrote

> For example, lets say I could drill down deep enough where I had essentially infinite geothermal energy producing hydrogen and then export it from there, would the efficiency issue even come in to play at that point as long as the transportation costs were low enough to sustain business?

All sorts of things start to make sense once you have "essentially infinite energy" from a clean source. When you get to that point, you can even do things like synthesize gasoline from scratch, burn it in hilariously inefficient 1940s race cars built from WWII aircraft engines, and then run a carbon capture system to undo the damage.

But we're not there yet. The efficiency issue still matters because our grid still gets the majority of its energy from dirty sources, so when you look at two options to do a particular job (passenger transport in this case) and one of them needs 3x the energy per mile driven... it's a hard sell. Ask me again when we're on 100% clean energy with some surplus to spare, and it may suddenly make sense despite the huge efficiency hit if somebody can build an FCEV substantially cheaper than an EV.

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raygundan t1_iyesvha wrote

There's nothing fundamentally wrong with the concept that I can see-- it just has the same chicken/egg issue. That infrastructure doesn't yet exist, but you can't sell hydrogen cars that use swappable hydrogen containers until it does.

It also doesn't help at all with the efficiency issue. Making, compressing, and transporting hydrogen ends up losing a rather substantial fraction of the energy you started with. It really doesn't want to be squeezed into tanks at high pressure-- you'll lose roughly 10% of the energy in your hydrogen just compressing it down to fit in the tank, let alone all the other losses.

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raygundan t1_iyermkg wrote

> a nicely portable fuel not subject to transmission losses

Transporting hydrogen is pretty lossy, mostly because of its bulk. Compression or liquefaction for transfer (and storage-- keeping liquid hydrogen stored requires you to either continuously input energy to refrigerate it, or continuously let some of it boil away) will eat 30-40% of the energy in the hydrogen you started with. And there's no such thing as "not subject to transmission losses" in general. Pipelines have losses just like the grid-- fluids don't just move to where you want them to go on their own. Pumping stations are required and leaks are inevitable.

Average transmission and distribution loss on the US power grid is about 5%.

That's not to say there aren't going to be some uses for hydrogen-- but as a general rule, if what you're doing can be done via the grid or another storage option, hydrogen seems like it will have a hard time competing.

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raygundan t1_iyep6cv wrote

> Why not?

Thermodynamics, mostly. A hydrogen FCEV ends up using about 3x as much energy for the same miles driven as you would if you used the same energy source to power an EV, no matter what that energy source is. A hydrogen ICE is even less efficient than that.

So there's an efficiency gap that you can't ever get over to begin with that will make hydrogen an unattractive option in any niche where an EV is workable-- so for cars, it's probably too late for hydrogen to find a niche.

But there's also a second complication with hydrogen deployment for cars. EVs were a sort of "self-starting" deployment, because you could sell them as second cars to people even before there were public charging stations. It's rare for a home not to have electricity available. Hydrogen, on the other hand, will require filling station infrastructure just to get started. There's no halfway option like there is with EVs. Sell a few EVs, market for chargers increases, build a few chargers, market for EVs increases, repeat. With hydrogen, you have to have the filling stations built before you can sell the cars at all. Saying "the only change is to fuel delivery" is true-- but that's a huge, expensive change that has to happen before you can sell your first hydrogen car.

None of this should be taken as saying hydrogen will have no uses-- just that it's very unlikely at this point to compete in the personal-vehicle niche.

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raygundan t1_iuis7j7 wrote

The link you used shows cost is for post-exposure prophylaxis, which is much more expensive than up-front vaccination.

Which is not to say there's no cost associated with vaccination, just that it's probably an order of magnitude (or two) lower than if you were giving everybody the post-exposure treatment.

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