5 ms·

> If we are serious about climate change, then sometime in the 2030s [1] we have to stop building new combustion engines. Or there might be a breakthrough in c

by wang_li 10y ago

> If we are serious about climate change, then sometime in the 2030s [1] we have to stop building new combustion engines. Or there might be a breakthrough in carbon capture, converting atmospheric CO2 into petroleum and we can drive combustion engines forever. CO2 capture is an area of active research and it's entirely possible that advances there will make Tesla and Solar City moot.

elihu 10y ago
Effective CO2 capture might cause governments to not mandate a certain number of electric vehicles or provide tax credits for buyers or impose a carbon tax, but if electric vehicles are better and (eventually) cheaper to manufacture than gas vehicles, then people might still prefer electric to gas even without environmental motivation.
jeff_petersen 10y ago
> CO2 capture is an area of active research and it's entirely possible that advances there will make Tesla and Solar City moot. I don't know how likely that is. Even if carbon capture comes through, the low hanging fruit of fossil fuels are gone so now we have to get more invasive in harvesting the hard-to-get ones (strip mining, fracking, etc). It's likely that even with C02 emissions taken care of that we'll want electric vehicles and renewable power in general.
- wang_li 10y ago
  I mean capture of CO2 from the air and conversion into a fuel that can be used. Something along the lines of algal farms that soak up sunlight and CO2 from the air and excrete alcohol. Combining solar and the CO2 that has already been released into a liquid fuel suitable for a variety of uses. We could cease raw material extraction entirely.
  - sxates 10y ago
    Seems inefficient. Fossil Fuels work today because you just suck them out of the ground and ta-da! free energy when you burn it. If you have to pump enormous energy into harvesting the carbon so you can burn it and re-harvest it, why not just put that energy straight into the car and cut out the carbon entirely? The battery is the thing that makes an electric car "expensive" today, but it's following a consistent downward price curve. In ~5-7 years, it will cost more to make an ICE car than an EV car, and then ICE dies. Simple as that.
    - ams6110 10y ago
      Not if the EV can't go more than 200 miles and takes half a day to refuel.
      - amatix 10y ago
        Except they already go >300 miles and take <75 mins to charge to 90%...
    - wl 10y ago
      > If you have to pump enormous energy into harvesting the carbon so you can burn it and re-harvest it, why not just put that energy straight into the car and cut out the carbon entirely? Energy density. Jet fuel has about 25x the energy per kg as the best lithium batteries. Perhaps batteries will be able to match carbon fuels some day, but it's a long way off.
  - jeff_petersen 10y ago
    Ah I see, I thought you were just talking about carbon sequestration
Certhas 10y ago
Or maybe there will be a breakthrough in battery tech and in five years we all drive Teslas. CCS + Power2Gas + synthetic fuel is unlikely to be cost competitive. It's not like climate scientists don't consider that option. In fact the only half way plausible scenarios for reaching the two degree target involve going carbon negative after 2050. And synthetic fossil fuels are probably the only way to make airtravel carbon neutral. Full de-carbonisation requires a multi-pronged approach, and cars are at a point where electric vehicles are already very close to conventional vehicles. Within a factor of two or three for range, so totally sufficient for most needs, and not much more expensive. It's one of the better options we have to de-carbonize a huge sector. Second only to the energy production sector itself. Compare to food production which looks absolutely hopeless (the two degree pathways often assume we manage to implement massive dietary changes see e.g. here http://tool.globalcalculator.org http://tool.globalcalculator.org )
- qmr 10y ago
  ... because Tesla is the only company making electric cars, right?
Robotbeat 10y ago
Even if CO2 to petroleum were 100% efficient, you're still throwing away 70+% of the energy by burning it in an ICE rather than putting it in a battery as electricity. Any likely method of CO2 to petroleum is likely to be below 50%, more like 15-30% efficient. Round-trip efficiency an entire order of magnitude worse than battery. That's why batteries are better for ground-based applications and will remain so.
- wang_li 10y ago
  I'm honestly not sure the assumptions underlying your comment. Solar cell to battery is pretty inefficient at the moment with the best solar cells converting 26% of the solar energy hitting the cell into electricity and the charge-discharge efficiency of li ion cells is 80-90%. The ultimate amount of energy delivered is less than 30%. Regardless, if any of the biological/algal methods of CO2 to fuel techniques become successful, why would we care if 5%, 50%, 100% of the solar energy received makes its way to the end product. It's basically free energy at that point. The only thing that would matter is real estate to house the facilities.
  - Robotbeat 10y ago
    Round-trip electricity efficiency is what I was referring to, assuming you'd use electricity. If you have to synthesize fuel using electricity and then burn it to produce either movement (shaft-power) or electricity, the efficiency is on the order of 10%. Whereas for batteries, the efficiency is on the order of 80-90%.
officelineback 10y ago
Isn't vegetation essentially a form of carbon capture, and it's not nearly effective enough to keep up with human CO2 emissions?

by wang_li 10y ago

elihu 10y ago

Effective CO2 capture might cause governments to not mandate a certain number of electric vehicles or provide tax credits for buyers or impose a carbon tax, but if electric vehicles are better and (eventually) cheaper to manufacture than gas vehicles, then people might still prefer electric to gas even without environmental motivation.

jeff_petersen 10y ago

> CO2 capture is an area of active research and it's entirely possible that advances there will make Tesla and Solar City moot. I don't know how likely that is. Even if carbon capture comes through, the low hanging fruit of fossil fuels are gone so now we have to get more invasive in harvesting the hard-to-get ones (strip mining, fracking, etc). It's likely that even with C02 emissions taken care of that we'll want electric vehicles and renewable power in general.

wang_li 10y ago
I mean capture of CO2 from the air and conversion into a fuel that can be used. Something along the lines of algal farms that soak up sunlight and CO2 from the air and excrete alcohol. Combining solar and the CO2 that has already been released into a liquid fuel suitable for a variety of uses. We could cease raw material extraction entirely.
- sxates 10y ago
  Seems inefficient. Fossil Fuels work today because you just suck them out of the ground and ta-da! free energy when you burn it. If you have to pump enormous energy into harvesting the carbon so you can burn it and re-harvest it, why not just put that energy straight into the car and cut out the carbon entirely? The battery is the thing that makes an electric car "expensive" today, but it's following a consistent downward price curve. In ~5-7 years, it will cost more to make an ICE car than an EV car, and then ICE dies. Simple as that.
  - ams6110 10y ago
    Not if the EV can't go more than 200 miles and takes half a day to refuel.
    - amatix 10y ago
      Except they already go >300 miles and take <75 mins to charge to 90%...
  - wl 10y ago
    > If you have to pump enormous energy into harvesting the carbon so you can burn it and re-harvest it, why not just put that energy straight into the car and cut out the carbon entirely? Energy density. Jet fuel has about 25x the energy per kg as the best lithium batteries. Perhaps batteries will be able to match carbon fuels some day, but it's a long way off.
- jeff_petersen 10y ago
  Ah I see, I thought you were just talking about carbon sequestration

Certhas 10y ago

Or maybe there will be a breakthrough in battery tech and in five years we all drive Teslas. CCS + Power2Gas + synthetic fuel is unlikely to be cost competitive. It's not like climate scientists don't consider that option. In fact the only half way plausible scenarios for reaching the two degree target involve going carbon negative after 2050. And synthetic fossil fuels are probably the only way to make airtravel carbon neutral. Full de-carbonisation requires a multi-pronged approach, and cars are at a point where electric vehicles are already very close to conventional vehicles. Within a factor of two or three for range, so totally sufficient for most needs, and not much more expensive. It's one of the better options we have to de-carbonize a huge sector. Second only to the energy production sector itself. Compare to food production which looks absolutely hopeless (the two degree pathways often assume we manage to implement massive dietary changes see e.g. here http://tool.globalcalculator.org http://tool.globalcalculator.org )

qmr 10y ago
... because Tesla is the only company making electric cars, right?

Robotbeat 10y ago

Even if CO2 to petroleum were 100% efficient, you're still throwing away 70+% of the energy by burning it in an ICE rather than putting it in a battery as electricity. Any likely method of CO2 to petroleum is likely to be below 50%, more like 15-30% efficient. Round-trip efficiency an entire order of magnitude worse than battery. That's why batteries are better for ground-based applications and will remain so.

wang_li 10y ago
I'm honestly not sure the assumptions underlying your comment. Solar cell to battery is pretty inefficient at the moment with the best solar cells converting 26% of the solar energy hitting the cell into electricity and the charge-discharge efficiency of li ion cells is 80-90%. The ultimate amount of energy delivered is less than 30%. Regardless, if any of the biological/algal methods of CO2 to fuel techniques become successful, why would we care if 5%, 50%, 100% of the solar energy received makes its way to the end product. It's basically free energy at that point. The only thing that would matter is real estate to house the facilities.
- Robotbeat 10y ago
  Round-trip electricity efficiency is what I was referring to, assuming you'd use electricity. If you have to synthesize fuel using electricity and then burn it to produce either movement (shaft-power) or electricity, the efficiency is on the order of 10%. Whereas for batteries, the efficiency is on the order of 80-90%.

officelineback 10y ago

Isn't vegetation essentially a form of carbon capture, and it's not nearly effective enough to keep up with human CO2 emissions?