6 ms·

While technically true, the conversion is inefficient. It takes a lot of power to extract H2 from H2O. You could just use that power directly. The problem with

by bdamm 5y ago

While technically true, the conversion is inefficient. It takes a lot of power to extract H2 from H2O. You could just use that power directly. The problem with electrics in -50 is keeping them plugged in when not in use. -50 is very extreme though, you’re talking far north or Edmonton.

darksaints 5y ago
The conversion using current SOEC technology isn't particularly inefficient. 88% efficient when using LHV values, 105% efficient when using HHV. http://www.helmeth.eu/index.php/technologies/high-temperature-electrolysis-cell-soec http://www.helmeth.eu/index.php/technologies/high-temperatur...
- labcomputer 5y ago
  That analysis ignores the heat used to raise the reactant (water) temperature to 800C. On its face, the claim doesn't make much sense anyway. If you could convert water to 2 H2 + O2 at zero energy cost, you could make a perpetual motion machine by taking advantage of the exothermic reaction 2 H2 + O2 -> 2 H2O.
  - darksaints 5y ago
    That's the difference between LHV and HHV. It is possible to exceed 100% efficiency when using HHV because it is an inherently more conservative convention for energy content due to practical concerns. LHV, by contrast, is bounded by the laws of physics.
    - labcomputer 5y ago
      Well, no, that's still wrong. The >100% efficiency comes from using two slights of hand: 1. Counting only the electrical energy input. But you also need to supply heat at the same time. That's the whole point of this product--use heat ~~instead of~~ (edit: in addition to) electricity to split water. Critically, they are assuming you get "free" (as in beer) waste heat at 800C... which is fairly silly. 800C heat is high-grade energy, not waste heat. Exhaust gas from a combined-cycle NG power plant, for example, is more like 250-300C. Thermal steam plants operate with a Th of ~550C (so the waste heat is much, much cooler). 2. Ignoring the fact that you need to heat the reactant (water) to 800C before you can have the discussion in #1. Now, the problem is that the heat capacity of water is much higher than an equal mass of H2 and O2. So, you can't even use the hot as-produced gas to heat the incoming water to anywhere near the operating temperature of the electrolyzer. The efficiency in a practical application is probably half to two-thirds of what they are claiming.
Black101 5y ago
But it is much faster to fill-up an hydrogen tank then it is to charge a battery.
- labcomputer 5y ago
  Really? It takes me about 5 seconds to charge my car every day, and I don't even need to leave my house to do it.
  - bdamm 5y ago
    I'm not sure why you're being downvoted. It takes me about 5 seconds too. I plug in, I walk away. When I'm ready to drive, I unplug and get in. Not complicated, adds up to about 5 seconds. All the work is being done when I'm not around. In sum, since ditching gas, I have in aggregate spent much less time tending to my car's energy needs.
  - Black101 5y ago
    It takes 5 seconds if your car was not completely empty and you don't need to go somewhere else. Hydrogen could be easily created at home too.
fouric 5y ago
> the conversion is inefficient. It takes a lot of power to extract H2 from H2O. How inefficient? That number matters. If it takes 500 kWh to make a tank that stores 100 kWh, you'd be a fool to use that energy directly, as that tank is going to store hundreds of times that much (at least) over its lifetime.
cmrdporcupine 5y ago
Apart from some freak events that happen every 50 years -50C doesn't _really_ happen anywhere settled in Canada. Even a place like Inuvik, the coldest temp ever recorded was -56.7C but only for a few minutes... in 1968. Edmonton gets a few nights where it can get below -40C every once in a while, but it's not common and again, it's not all night. Frankly it just sounds like he's confusing actual temperature with wind chill "temperature". Which unfortunately seems like something more and more Canadians do, probably on account of crappy weather reporting. I grew up in Edmonton area. People were already in the habit of plugging their (ICE) vehicles overnight on those kinds of evenings so they could start in the morning without hassle. I see no reason why an EV wouldn't be treated the same. (FWIW I live in southern Ontario now, it doesn't really get colder than -28C. But my Chevy Volt has no problem with it.)
- sandworm101 5y ago
  Fort McMurray Alberta. Not exactly the end of the earth. It is often colder than the far north because it is far from the ocean. May 19th today. There is snow on the ground. Every year there is a week or two of -40, not wind-chill, temperature. Nobody who actually lives in the north misunderstands wind-chill.
  - cmrdporcupine 5y ago
    Quite familiar with Fort Mac, have family on both sides there and spent Christmas there every couple years. It doesn't get to -50C, except as severe outlier. -40C in overnights for short periods of time in the winter. Average temps: https://images.climate-data.org/location/4623/climate-graph.png https://images.climate-data.org/location/4623/climate-graph....
  - bdamm 5y ago
    Yeah. I have been to Fort Mac many times, and lived in Prince George for 6 years. Fort Mac is kind of the end of the earth. But I know how hard it is to manage ICE cars in that kind of cold. Plug in the block heater. Leave the engine running when at the store. Carry deicer always. Fractured windshields. Ice on the inside of the windshield. Cracked dashes. Flat batteries. Hard starts due to bad fuel/air mixtures. And let's also include bad handling, because you don't really know how bad ICE cars are on actual ice until you've driven a good AWD EV like any Dual Motor Tesla. All of this is better with EVs. Yeah, you basically will end up going from plugin to plugin so that the battery doesn't freeze up hard, but in those conditions you do anyway. The level of comfort and drivability provided by a Tesla Model Y will easily exceed any gas car or truck today. Why? Because the car will always be warm and ready. The traction control is 10x better. The car can pre-melt the ice. If you're lucky enough to have a garage, well you can pre-heat while the car is inside the garage. The list goes on and on. The main problem for the Model Y is the frameless door means the window has to be defrosted before you can get in. But you will, of course, do that from the comfort of wherever you are. Frankly, Cybertruck is going to absolutely crush this. The range really meets the needs of the far north. Tesla already has a supercharger in Edmonton, and they have deployments planned for Prince George and some locations on hwy 16. This is really going to open up a lot of territory. EVs are made for the north, excepting the range. Gas cars in the north actually suck pretty bad, except that they can handle those day-long commutes. That clock is seriously ticking, and for many cases, is already up.

by bdamm 5y ago

darksaints 5y ago

The conversion using current SOEC technology isn't particularly inefficient. 88% efficient when using LHV values, 105% efficient when using HHV. http://www.helmeth.eu/index.php/technologies/high-temperature-electrolysis-cell-soec http://www.helmeth.eu/index.php/technologies/high-temperatur...

labcomputer 5y ago
That analysis ignores the heat used to raise the reactant (water) temperature to 800C. On its face, the claim doesn't make much sense anyway. If you could convert water to 2 H2 + O2 at zero energy cost, you could make a perpetual motion machine by taking advantage of the exothermic reaction 2 H2 + O2 -> 2 H2O.
- darksaints 5y ago
  That's the difference between LHV and HHV. It is possible to exceed 100% efficiency when using HHV because it is an inherently more conservative convention for energy content due to practical concerns. LHV, by contrast, is bounded by the laws of physics.
  - labcomputer 5y ago
    Well, no, that's still wrong. The >100% efficiency comes from using two slights of hand: 1. Counting only the electrical energy input. But you also need to supply heat at the same time. That's the whole point of this product--use heat ~~instead of~~ (edit: in addition to) electricity to split water. Critically, they are assuming you get "free" (as in beer) waste heat at 800C... which is fairly silly. 800C heat is high-grade energy, not waste heat. Exhaust gas from a combined-cycle NG power plant, for example, is more like 250-300C. Thermal steam plants operate with a Th of ~550C (so the waste heat is much, much cooler). 2. Ignoring the fact that you need to heat the reactant (water) to 800C before you can have the discussion in #1. Now, the problem is that the heat capacity of water is much higher than an equal mass of H2 and O2. So, you can't even use the hot as-produced gas to heat the incoming water to anywhere near the operating temperature of the electrolyzer. The efficiency in a practical application is probably half to two-thirds of what they are claiming.

Black101 5y ago

But it is much faster to fill-up an hydrogen tank then it is to charge a battery.

labcomputer 5y ago
Really? It takes me about 5 seconds to charge my car every day, and I don't even need to leave my house to do it.
- bdamm 5y ago
  I'm not sure why you're being downvoted. It takes me about 5 seconds too. I plug in, I walk away. When I'm ready to drive, I unplug and get in. Not complicated, adds up to about 5 seconds. All the work is being done when I'm not around. In sum, since ditching gas, I have in aggregate spent much less time tending to my car's energy needs.
- Black101 5y ago
  It takes 5 seconds if your car was not completely empty and you don't need to go somewhere else. Hydrogen could be easily created at home too.

fouric 5y ago

> the conversion is inefficient. It takes a lot of power to extract H2 from H2O. How inefficient? That number matters. If it takes 500 kWh to make a tank that stores 100 kWh, you'd be a fool to use that energy directly, as that tank is going to store hundreds of times that much (at least) over its lifetime.

cmrdporcupine 5y ago

Apart from some freak events that happen every 50 years -50C doesn't _really_ happen anywhere settled in Canada. Even a place like Inuvik, the coldest temp ever recorded was -56.7C but only for a few minutes... in 1968. Edmonton gets a few nights where it can get below -40C every once in a while, but it's not common and again, it's not all night. Frankly it just sounds like he's confusing actual temperature with wind chill "temperature". Which unfortunately seems like something more and more Canadians do, probably on account of crappy weather reporting. I grew up in Edmonton area. People were already in the habit of plugging their (ICE) vehicles overnight on those kinds of evenings so they could start in the morning without hassle. I see no reason why an EV wouldn't be treated the same. (FWIW I live in southern Ontario now, it doesn't really get colder than -28C. But my Chevy Volt has no problem with it.)

sandworm101 5y ago
Fort McMurray Alberta. Not exactly the end of the earth. It is often colder than the far north because it is far from the ocean. May 19th today. There is snow on the ground. Every year there is a week or two of -40, not wind-chill, temperature. Nobody who actually lives in the north misunderstands wind-chill.
- cmrdporcupine 5y ago
  Quite familiar with Fort Mac, have family on both sides there and spent Christmas there every couple years. It doesn't get to -50C, except as severe outlier. -40C in overnights for short periods of time in the winter. Average temps: https://images.climate-data.org/location/4623/climate-graph.png https://images.climate-data.org/location/4623/climate-graph....
- bdamm 5y ago
  Yeah. I have been to Fort Mac many times, and lived in Prince George for 6 years. Fort Mac is kind of the end of the earth. But I know how hard it is to manage ICE cars in that kind of cold. Plug in the block heater. Leave the engine running when at the store. Carry deicer always. Fractured windshields. Ice on the inside of the windshield. Cracked dashes. Flat batteries. Hard starts due to bad fuel/air mixtures. And let's also include bad handling, because you don't really know how bad ICE cars are on actual ice until you've driven a good AWD EV like any Dual Motor Tesla. All of this is better with EVs. Yeah, you basically will end up going from plugin to plugin so that the battery doesn't freeze up hard, but in those conditions you do anyway. The level of comfort and drivability provided by a Tesla Model Y will easily exceed any gas car or truck today. Why? Because the car will always be warm and ready. The traction control is 10x better. The car can pre-melt the ice. If you're lucky enough to have a garage, well you can pre-heat while the car is inside the garage. The list goes on and on. The main problem for the Model Y is the frameless door means the window has to be defrosted before you can get in. But you will, of course, do that from the comfort of wherever you are. Frankly, Cybertruck is going to absolutely crush this. The range really meets the needs of the far north. Tesla already has a supercharger in Edmonton, and they have deployments planned for Prince George and some locations on hwy 16. This is really going to open up a lot of territory. EVs are made for the north, excepting the range. Gas cars in the north actually suck pretty bad, except that they can handle those day-long commutes. That clock is seriously ticking, and for many cases, is already up.