Dragon can currently return about two tonnes of payload from orbit in a single flight. Could easily be hundreds of hearts in a flight. Still expensive, but compared to US healthcare, not as much. Also, if it's custom-grown, then you might be actually saving money on the post-transplant healthcare, compared to a donor organ. I guess the real question whether we won't ultimately accomplish this on Earth more easily. Chances are that we will.
Imagine where SpaceX would be without the taxes that paid for the know how Musk got for free from NASA.
Imagine where the US would be without the taxes that paid for the fire departments, law enforcement, transportation infrastructure etc. that Americans get for free from the government.
TELL ME WHERE WOULD ELON BE WITHOUT THE NASA CONTRACTS THAT KEEP HIM AFLOAT?
Where would ULA be without government contracts to keep them afloat? At least SpaceX has affordable commercial launches to fall back on.
Oh, sorry, a small mistake... The *volume* of the Model 3 battery pack is 360 liters, the mass is around 450 kg. So it's a 200-270 kg difference, before you add a battery into your fuel cell vehicle for recuperation. A typical hybrid car can easily have a 70 kg battery for that purpose (Prius has a 80 kg, 4 kWh battery, for example). So that shrinks it down back to 130-200 kg difference between a BEV and your FCEV.
He overestimates the energy per tank by a factor of four anyway; the page he links cites it as a tank for 1.5 kg of hydrogen. And even if he was right, a 132 kWh battery pack would still not weigh 38*75=2850 kg. That would make the 100 kWh Teslas impossible. They do NOT weigh four tonnes empty.
Around 360 kg. However, it's designed to be flat and have a low CG, so it's mostly out of the way (under your feet). Cylindrical tanks and the fuel cell stack would require some room either in the front or in the back.
We know that two of those battery packs are about the same as the 38 kg tank I linked
We know it's the other way round; you need two of those tanks with 1.5 kg hydrogen in each to store an equivalent amount of electricity that one Model 3 battery pack can store, plus a 100 kg fuel cell to power Model 3's 200 kW motors, or a 170 kg fuel cell to power the 350 kW performance model. So it's something like 180 kg or 250 kg for the hydrogen equivalent of the 360 kg battery pack. Is a 110-180 kg mass difference relevant? I suppose you could argue that it's 10% of the mass of the vehicle, but that doesn't seem prohibitive. It's also easier to "refuel" at home. Plus, your hydrogen vehicle would *still* require a battery for regenerative braking, so the difference shrinks even further.
Here's an interesting fact: the 3.7 meter Falcon 9 cores are the largest size boosters that SpaceX could get away designing to be transported on roads without making it entirely uneconomical. Here we're talking about nine meter tankage. I can't see that getting from LA to Texas in any other way than through Panama...which is both expensive and inconvenient. And slow.
Absolutely not. Two tonnes of batteries today have a power output of almost 2 MW. That requires around a 1000 kg fuel cell today. So it's at best 2x as much, and only if you completely discount the storage which might easily almost double that. So it's maybe in the 1.5x ballpark for power density.
Run the numbers yourself. A little 38kg, 52L tank [mahytec.com] holds about the same energy as 132 kWh of batteries
Well, I did. That tank is cited as containing 1.5 kg of hydrogen, which is worth around 35 kWh in your typical fuel cell, NOT 132 kWh. Your math skills suck.
There is another tank on that page, that stores 52L of hydrogen. That's about equivalent to a 132kW battery - double the typical Model 3. And the tank weighs in at 38 kg.
*That* tank is equivalent to a 35 kWh battery, HALF the typical Model 3. TWO of them would be equivalent to a Model 3. A 200 kW fuel cell stack would add another 100 kg. All three would occupy about 250 liters of volume. Model 3's battery has around 360 liters, making it 45% mode voluminous. However, it can *also* be placed more out of way, since its smallest element is less than ten centimeters long, whereas those tanks have a 33 cm diameter. It actually forms Model 3's floor.
That is not correct. Hydrogen storage, as compared to battery storage, is about 60% more efficient by volume, and around 25X more efficient by weight.
...and the tank you've linked above is comparable to a 100 kWh Tesla automotive battery, at about half the mass and twice the volume. So it's not 60% more efficient by volume, but 50% LESS, and not 25x more efficient by weight, but only 2x as much. Liar, liar, pants on fire...
And if you need 700+ kg of tank to store your hydrogen - you're doing it wrong. Here's a massive 850L tank [mahytec.com] that would be equivalent energy storage to about 4800 kg of batteries - and it weighs 215 kg. Not even close.
Are you serious? That tank is the equivalent of a 100 kWh battery. Just like the one you get in some Teslas. Are you claiming that those Teslas weigh over 4800 kg?
It's not a just a way of storing energy, it's also a valuable chemical feedstock, and its synthesis will be necessary if we want to get rid of fossil fuels in the chemical industry.
Slashdot Mirror
Dragon can currently return about two tonnes of payload from orbit in a single flight. Could easily be hundreds of hearts in a flight. Still expensive, but compared to US healthcare, not as much. Also, if it's custom-grown, then you might be actually saving money on the post-transplant healthcare, compared to a donor organ. I guess the real question whether we won't ultimately accomplish this on Earth more easily. Chances are that we will.
How big is your cell culture? Grams? Tens of grams? That's still a rounding error in a typical space station supply payload.
Imagine where SpaceX would be without the taxes that paid for the know how Musk got for free from NASA.
Imagine where the US would be without the taxes that paid for the fire departments, law enforcement, transportation infrastructure etc. that Americans get for free from the government.
TELL ME WHERE WOULD ELON BE WITHOUT THE NASA CONTRACTS THAT KEEP HIM AFLOAT?
Where would ULA be without government contracts to keep them afloat? At least SpaceX has affordable commercial launches to fall back on.
Oh, sorry, a small mistake... The *volume* of the Model 3 battery pack is 360 liters, the mass is around 450 kg. So it's a 200-270 kg difference, before you add a battery into your fuel cell vehicle for recuperation. A typical hybrid car can easily have a 70 kg battery for that purpose (Prius has a 80 kg, 4 kWh battery, for example). So that shrinks it down back to 130-200 kg difference between a BEV and your FCEV.
He overestimates the energy per tank by a factor of four anyway; the page he links cites it as a tank for 1.5 kg of hydrogen. And even if he was right, a 132 kWh battery pack would still not weigh 38*75=2850 kg. That would make the 100 kWh Teslas impossible. They do NOT weigh four tonnes empty.
How heavy is the battery pack in a Model 3?
Around 360 kg. However, it's designed to be flat and have a low CG, so it's mostly out of the way (under your feet). Cylindrical tanks and the fuel cell stack would require some room either in the front or in the back.
We know that two of those battery packs are about the same as the 38 kg tank I linked
We know it's the other way round; you need two of those tanks with 1.5 kg hydrogen in each to store an equivalent amount of electricity that one Model 3 battery pack can store, plus a 100 kg fuel cell to power Model 3's 200 kW motors, or a 170 kg fuel cell to power the 350 kW performance model. So it's something like 180 kg or 250 kg for the hydrogen equivalent of the 360 kg battery pack. Is a 110-180 kg mass difference relevant? I suppose you could argue that it's 10% of the mass of the vehicle, but that doesn't seem prohibitive. It's also easier to "refuel" at home. Plus, your hydrogen vehicle would *still* require a battery for regenerative braking, so the difference shrinks even further.
That would require a tank capable of storing 6 kg of hydrogen, but the table for that tank says 1.5 kg.
Here's an interesting fact: the 3.7 meter Falcon 9 cores are the largest size boosters that SpaceX could get away designing to be transported on roads without making it entirely uneconomical. Here we're talking about nine meter tankage. I can't see that getting from LA to Texas in any other way than through Panama...which is both expensive and inconvenient. And slow.
OK, so if the shutdown lasts A FULL YEAR it impacts NEARLY 1% of revenue?
Are you assuming that the ONLY impact of the shutdown is government travel? Isn't it kind of unwarranted?
Yea, but the cost of opening the government is $5.7 Billion.... Out of a $44~ Trillion budget.
Surely the cost of preparing a budget wasn't $5.7 Billion...until Trump screwed it up. But he owns it, so it's his problem anyway.
Yes, Cessna Citation, for example.
Well, there's for example enough lithium in sea water to make a 170 MWh battery for every person currently living on this planet. Is that enough?
Hydrogen has ~75X the power density by weight
Absolutely not. Two tonnes of batteries today have a power output of almost 2 MW. That requires around a 1000 kg fuel cell today. So it's at best 2x as much, and only if you completely discount the storage which might easily almost double that. So it's maybe in the 1.5x ballpark for power density.
Run the numbers yourself. A little 38kg, 52L tank [mahytec.com] holds about the same energy as 132 kWh of batteries
Well, I did. That tank is cited as containing 1.5 kg of hydrogen, which is worth around 35 kWh in your typical fuel cell, NOT 132 kWh. Your math skills suck.
There is another tank on that page, that stores 52L of hydrogen. That's about equivalent to a 132kW battery - double the typical Model 3. And the tank weighs in at 38 kg.
*That* tank is equivalent to a 35 kWh battery, HALF the typical Model 3. TWO of them would be equivalent to a Model 3. A 200 kW fuel cell stack would add another 100 kg. All three would occupy about 250 liters of volume. Model 3's battery has around 360 liters, making it 45% mode voluminous. However, it can *also* be placed more out of way, since its smallest element is less than ten centimeters long, whereas those tanks have a 33 cm diameter. It actually forms Model 3's floor.
That is not correct. Hydrogen storage, as compared to battery storage, is about 60% more efficient by volume, and around 25X more efficient by weight.
...and the tank you've linked above is comparable to a 100 kWh Tesla automotive battery, at about half the mass and twice the volume. So it's not 60% more efficient by volume, but 50% LESS, and not 25x more efficient by weight, but only 2x as much. Liar, liar, pants on fire...
Not really, if you pull your numbers out of your ass like you just did above.
The most recent *unsubsidized* prices of German solar are 5 Euro cents per kWh. Is that "ridiculously expensive"?
And if your capacity factor is 65%, you need half of that.
Typical capacity factor for offshore wind turbines is about 0.35.
Uh...greetings from the 21st century! How are things back then in 1999?
You sell it to hospitals and iron ore smelters?
And if you need 700+ kg of tank to store your hydrogen - you're doing it wrong. Here's a massive 850L tank [mahytec.com] that would be equivalent energy storage to about 4800 kg of batteries - and it weighs 215 kg. Not even close.
Are you serious? That tank is the equivalent of a 100 kWh battery. Just like the one you get in some Teslas. Are you claiming that those Teslas weigh over 4800 kg?
Hydrogen goes in a tank. https://en.wikipedia.org/wiki/...
At a density of 71 kg/m^3, and a temperature of 20 K.
It's not a just a way of storing energy, it's also a valuable chemical feedstock, and its synthesis will be necessary if we want to get rid of fossil fuels in the chemical industry.
It's generally not Europe that needs to catch up with these things.