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I still find it crazy that we are capturing solar energy on plants, growing them, and then burning them to get energy to move our cars… It seems so much more i

by rrlevy 3y ago

I still find it crazy that we are capturing solar energy on plants, growing them, and then burning them to get energy to move our cars… It seems so much more intuitive to just capture solar to electricity and use an electric car…

anon291 3y ago
Well we can store corn and oil and can't really store electricity.
rrlevy 3y ago
BTW, I live in Brazil where ethanol from sugarcane is widespread
- anenefan 3y ago
  Yes, I assume in regions with an ideal climate, sugar cane crops average around 50 tonnes/acre or roughly 125 t/Ha. [Note ^1 - average over all in Brazil this year is 70.5t/Ha] Using this lower average, if the yield averages around 14 ccs (roughly 1/7 sugar) the 70.5 tonnes translates to about 10 tonnes of sugar. Going the ethanol route under ideal conditions would derive around half that weight as ethanol, but ethanol is relatively easy to handle as a fuel source since the petro industry already has much of the infrastructure in place, as well as letting older engines that don't have much use remain in service. (I suspect that older pre fuel injection engines would be fine with 80% ethanol, 20% water.) However since electric cars are now not the stuff of science fiction, it maybe makes more sense to investigate and use sugar to power a fuel cell instead. [1]https://www.statista.com/statistics/742523/sugar-cane-yield-brazil/ https://www.statista.com/statistics/742523/sugar-cane-yield-...
dmbche 3y ago
It's a lot less work per Kwh to harvest the energy that plants store than what would be needed to make and maintain solar panels to make the same amount - I assume
- adgjlsfhk1 3y ago
  I doubt it. solar panels are much more efficient per volume than corn, don't require pesticide spray, aren't nearly as weather dependent, and last 20 to 40 years.
vondur 3y ago
It's indirectly solar power, and ethanol can hold more energy per volume than batteries. However all of the other inputs that go into growing ethanol cancel that advantage out. If we were using Nuclear or maybe pure solar to produce the fertilizer perhaps the math may work out.
- User23 3y ago
  Literally everything except nuclear and maybe geothermal is indirectly solar power. Nuclear is indirectly dead-star power; fossil star fuel. Unless of course the abiogenesis theory is correct, in which case oil and at least some natural gas are also dead-star fuel.
  - krisoft 3y ago
    > Unless of course the abiogenesis theory is correct, in which case oil and at least some natural gas are also dead-star fuel. I don't see how whether abiogenesis theory is correct or not matters here. The energy trapped in oil and natural gas is not from "life" but from the sun. Of course it wouldn't have accumulated without life, but that is not the source of the energy.
    - User23 3y ago
      Abiogenesis means oil and gas are primordial matter. Trapped sun energy in the form of biomass is biogenesis.
      - krisoft 3y ago
        Ah thank you for the clarification. I was not aware that it was used in that meaning too. The only meaning I did know is in the context of origin of life.
olliej 3y ago
The energy density of fuel is much much higher than electricity, which makes using fuel to transport energy to where it is needed is much easier, and it makes the effective range for gas much higher because in those cases where you need it you can always just take extra gas (even taking into account the relative engine efficiency, to the worst possible degree gas is more than 10x the miles per kg than current battery tech). Add to that speed of refueling vs. recharging, the many areas where power is not available at all, let alone super chargers (absent specialized charging hardware charging an EV takes days), etc fuel still has real value. There are vast swathes of the world where grid power is not available, so the only available power is via diesel generators, which are generally around 40% efficient. At that point using an EV is not only slower, but at that point the best case efficiency (watts/kg) is less than 34% vs a diesel car engine's 43% energy efficiency. If you have the right environment you might be able to use solar to charge the car, but I think for that you need something like 6kW of solar panels per car you want to use each day, and an additional car worth of batteries to store power during the day because you're presumably using your car at during the day. That's not a trivially portable system, so still doesn't fix the "I am driving a long distance where there aren't super chargers".
coderenegade 3y ago
Depends on the use case. I live semi rurally and an EV would be a tough sell for most people here. I do see a few of them, but these are households with multiple vehicles where the EV is a runabout, and work is done using diesel or petrol, often a 4x4 from the 80s or 90s with the better part of a million kms on the body.

by rrlevy 3y ago

anon291 3y ago

Well we can store corn and oil and can't really store electricity.

rrlevy 3y ago

BTW, I live in Brazil where ethanol from sugarcane is widespread

anenefan 3y ago
Yes, I assume in regions with an ideal climate, sugar cane crops average around 50 tonnes/acre or roughly 125 t/Ha. [Note ^1 - average over all in Brazil this year is 70.5t/Ha] Using this lower average, if the yield averages around 14 ccs (roughly 1/7 sugar) the 70.5 tonnes translates to about 10 tonnes of sugar. Going the ethanol route under ideal conditions would derive around half that weight as ethanol, but ethanol is relatively easy to handle as a fuel source since the petro industry already has much of the infrastructure in place, as well as letting older engines that don't have much use remain in service. (I suspect that older pre fuel injection engines would be fine with 80% ethanol, 20% water.) However since electric cars are now not the stuff of science fiction, it maybe makes more sense to investigate and use sugar to power a fuel cell instead. [1]https://www.statista.com/statistics/742523/sugar-cane-yield-brazil/ https://www.statista.com/statistics/742523/sugar-cane-yield-...

dmbche 3y ago

It's a lot less work per Kwh to harvest the energy that plants store than what would be needed to make and maintain solar panels to make the same amount - I assume

adgjlsfhk1 3y ago
I doubt it. solar panels are much more efficient per volume than corn, don't require pesticide spray, aren't nearly as weather dependent, and last 20 to 40 years.

vondur 3y ago

It's indirectly solar power, and ethanol can hold more energy per volume than batteries. However all of the other inputs that go into growing ethanol cancel that advantage out. If we were using Nuclear or maybe pure solar to produce the fertilizer perhaps the math may work out.

User23 3y ago
Literally everything except nuclear and maybe geothermal is indirectly solar power. Nuclear is indirectly dead-star power; fossil star fuel. Unless of course the abiogenesis theory is correct, in which case oil and at least some natural gas are also dead-star fuel.
- krisoft 3y ago
  > Unless of course the abiogenesis theory is correct, in which case oil and at least some natural gas are also dead-star fuel. I don't see how whether abiogenesis theory is correct or not matters here. The energy trapped in oil and natural gas is not from "life" but from the sun. Of course it wouldn't have accumulated without life, but that is not the source of the energy.
  - User23 3y ago
    Abiogenesis means oil and gas are primordial matter. Trapped sun energy in the form of biomass is biogenesis.
    - krisoft 3y ago
      Ah thank you for the clarification. I was not aware that it was used in that meaning too. The only meaning I did know is in the context of origin of life.

olliej 3y ago

The energy density of fuel is much much higher than electricity, which makes using fuel to transport energy to where it is needed is much easier, and it makes the effective range for gas much higher because in those cases where you need it you can always just take extra gas (even taking into account the relative engine efficiency, to the worst possible degree gas is more than 10x the miles per kg than current battery tech). Add to that speed of refueling vs. recharging, the many areas where power is not available at all, let alone super chargers (absent specialized charging hardware charging an EV takes days), etc fuel still has real value. There are vast swathes of the world where grid power is not available, so the only available power is via diesel generators, which are generally around 40% efficient. At that point using an EV is not only slower, but at that point the best case efficiency (watts/kg) is less than 34% vs a diesel car engine's 43% energy efficiency. If you have the right environment you might be able to use solar to charge the car, but I think for that you need something like 6kW of solar panels per car you want to use each day, and an additional car worth of batteries to store power during the day because you're presumably using your car at during the day. That's not a trivially portable system, so still doesn't fix the "I am driving a long distance where there aren't super chargers".

coderenegade 3y ago

Depends on the use case. I live semi rurally and an EV would be a tough sell for most people here. I do see a few of them, but these are households with multiple vehicles where the EV is a runabout, and work is done using diesel or petrol, often a 4x4 from the 80s or 90s with the better part of a million kms on the body.