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I checked out the Toyota Mirai - it does indeed use hydrogen gas cylinders from what I can tell. So this research is targeting simply the ability to transport h

by yomly 8y ago

I checked out the Toyota Mirai - it does indeed use hydrogen gas cylinders from what I can tell. So this research is targeting simply the ability to transport hydrogen. Ironically, the ships that carry all that ammonia to Asia almost certainly used fossil fuels and who knows what the carbon footprint around building the membranes for the hydrogen transfer is like

JoeAltmaier 8y ago
And shipping is the most egregiously polluting transportation in existence. Something like 10 to 30% of emissions come from 6000 ships in service. Folks claim its ok because it settles into the ocean quickly - ok for everybody but the ocean.
- metta2uall 8y ago
  This is just false - shipping contributes only 2-3% of global emissions (see e.g. http://theconversation.com/the-shipping-sector-is-finally-on-board-in-the-fight-against-climate-change-95212 http://theconversation.com/the-shipping-sector-is-finally-on...).
- marcosdumay 8y ago
  > Something like 10 to 30% of emissions come from 6000 ships in service. Some 10% to 30% of sulfur emissions come from those ships. They do that because they move in the open ocean where nobody cares about a short lived pollutant. Sulfur moves quickly into the ocean where it not only non-toxic, but also beneficial to life. (Sulfates - what it will settle down into - is widely used as fertilizer on land.)
  - manicdee 8y ago
    Just like CO2 is good for plants therefore buringnoilmis great formthe environment?
    - marcosdumay 8y ago
      Well, there is certainly some amount where the wrong kind of life takes over. It is way over what cargo ships throw around, but people have been polluting some parts of the ocean with too much sulfates.
- vpribish 8y ago
  this is from some horribly irresponsible clickbait newsy reporting a couple of years ago. It's only a very specific subtype of emissions, not 'emissions' in general.
  - JoeAltmaier 8y ago
    Nitrogen oxides and sulfur oxides. How is that irresponsible? The conversation has turned to CO2 because of global warming, but these are still damaging. And CO2 isn't strictly a pollutant at all. I stand by those statistics.
mchannon 8y ago
Here's a fun little exercise with the Toyota Mirai. Read the spec sheet, and read the wikipedia article. They claim the thing can hold 5 kg of H2, at 10,000 psi. Look into how big the tanks are. The math will show that at that pressure, taking up that much space, you can fit no more than about 3.7 kg of H2 in there. The difference between the diesel emissions and mileage scandal and the Mirai is that they actually made the math work with the former, as well as large enough scale for people to care.
- dsp1234 8y ago
  The spec sheet at [0] claims: Hydrogen storage is "Approx. 5.0 kg" 122.4L of volume (60L front, 62.4L rear) pressure is between 70 MPa and 87.5MPa Doing the math shows: density of hydrogen at 70MPa equals 36.69 g/L [1] 122.4L at 36.69 g/L equals 4.49kg [2] density of hydrogen at 87.5MPa equals 45.96 g/L [3] 122.4L at 45.96 g/L equals equals 5.63kg [4] So the amount is somewhere between 4.5kg and 5.63kg, depending upon the final pressure after filling. Which seems to line up squarely with "Approx. 5.0kg". [0] - https://pressroom.toyota.com/releases/2016+toyota+mirai+fuel+cell+product.download https://pressroom.toyota.com/releases/2016+toyota+mirai+fuel... [1] - http://www.wolframalpha.com/input/?i=density+of+hydrogen+at+70MPa http://www.wolframalpha.com/input/?i=density+of+hydrogen+at+... [2] - http://www.wolframalpha.com/input/?i=122.4L+at+36.69+grams%2Fliter http://www.wolframalpha.com/input/?i=122.4L+at+36.69+grams%2... [3] - http://www.wolframalpha.com/input/?i=density+of+hydrogen+at+87.5MPa http://www.wolframalpha.com/input/?i=density+of+hydrogen+at+... [4] - http://www.wolframalpha.com/input/?i=122.4L+at+45.96+g%2FL http://www.wolframalpha.com/input/?i=122.4L+at+45.96+g%2FL
  - amluto 8y ago
    I am highly skeptical of using Wolfram Alpha like this. It steadfastly refuses to explain how it got its answer or what sources it used. These are high pressures and large densities. Are these results of an ideal gas law calculation? Are they results from the van der Waals equation? Are they extrapolated from actual experimental data? If so, what experiment? What are the error bars? Are they talking about pure Hydrogen-1 or are they talking about the isotopic mix found in sea water? (The latter is a small correction, but it’s still something that they should explain on the site.)

by yomly 8y ago

JoeAltmaier 8y ago

And shipping is the most egregiously polluting transportation in existence. Something like 10 to 30% of emissions come from 6000 ships in service. Folks claim its ok because it settles into the ocean quickly - ok for everybody but the ocean.

metta2uall 8y ago
This is just false - shipping contributes only 2-3% of global emissions (see e.g. http://theconversation.com/the-shipping-sector-is-finally-on-board-in-the-fight-against-climate-change-95212 http://theconversation.com/the-shipping-sector-is-finally-on...).
marcosdumay 8y ago
> Something like 10 to 30% of emissions come from 6000 ships in service. Some 10% to 30% of sulfur emissions come from those ships. They do that because they move in the open ocean where nobody cares about a short lived pollutant. Sulfur moves quickly into the ocean where it not only non-toxic, but also beneficial to life. (Sulfates - what it will settle down into - is widely used as fertilizer on land.)
- manicdee 8y ago
  Just like CO2 is good for plants therefore buringnoilmis great formthe environment?
  - marcosdumay 8y ago
    Well, there is certainly some amount where the wrong kind of life takes over. It is way over what cargo ships throw around, but people have been polluting some parts of the ocean with too much sulfates.
vpribish 8y ago
this is from some horribly irresponsible clickbait newsy reporting a couple of years ago. It's only a very specific subtype of emissions, not 'emissions' in general.
- JoeAltmaier 8y ago
  Nitrogen oxides and sulfur oxides. How is that irresponsible? The conversation has turned to CO2 because of global warming, but these are still damaging. And CO2 isn't strictly a pollutant at all. I stand by those statistics.

mchannon 8y ago

Here's a fun little exercise with the Toyota Mirai. Read the spec sheet, and read the wikipedia article. They claim the thing can hold 5 kg of H2, at 10,000 psi. Look into how big the tanks are. The math will show that at that pressure, taking up that much space, you can fit no more than about 3.7 kg of H2 in there. The difference between the diesel emissions and mileage scandal and the Mirai is that they actually made the math work with the former, as well as large enough scale for people to care.

dsp1234 8y ago
The spec sheet at [0] claims: Hydrogen storage is "Approx. 5.0 kg" 122.4L of volume (60L front, 62.4L rear) pressure is between 70 MPa and 87.5MPa Doing the math shows: density of hydrogen at 70MPa equals 36.69 g/L [1] 122.4L at 36.69 g/L equals 4.49kg [2] density of hydrogen at 87.5MPa equals 45.96 g/L [3] 122.4L at 45.96 g/L equals equals 5.63kg [4] So the amount is somewhere between 4.5kg and 5.63kg, depending upon the final pressure after filling. Which seems to line up squarely with "Approx. 5.0kg". [0] - https://pressroom.toyota.com/releases/2016+toyota+mirai+fuel+cell+product.download https://pressroom.toyota.com/releases/2016+toyota+mirai+fuel... [1] - http://www.wolframalpha.com/input/?i=density+of+hydrogen+at+70MPa http://www.wolframalpha.com/input/?i=density+of+hydrogen+at+... [2] - http://www.wolframalpha.com/input/?i=122.4L+at+36.69+grams%2Fliter http://www.wolframalpha.com/input/?i=122.4L+at+36.69+grams%2... [3] - http://www.wolframalpha.com/input/?i=density+of+hydrogen+at+87.5MPa http://www.wolframalpha.com/input/?i=density+of+hydrogen+at+... [4] - http://www.wolframalpha.com/input/?i=122.4L+at+45.96+g%2FL http://www.wolframalpha.com/input/?i=122.4L+at+45.96+g%2FL
- amluto 8y ago
  I am highly skeptical of using Wolfram Alpha like this. It steadfastly refuses to explain how it got its answer or what sources it used. These are high pressures and large densities. Are these results of an ideal gas law calculation? Are they results from the van der Waals equation? Are they extrapolated from actual experimental data? If so, what experiment? What are the error bars? Are they talking about pure Hydrogen-1 or are they talking about the isotopic mix found in sea water? (The latter is a small correction, but it’s still something that they should explain on the site.)