4 ms·

Yes. Hydrogenate CO2 to methanol with electrolytic hydrogen produced from clean electricity [1]. Reform methanol to hydrocarbons [2] that can burn in existing

Yes. Hydrogenate CO2 to methanol with electrolytic hydrogen produced from clean electricity [1]. Reform methanol to hydrocarbons [2] that can burn in existing engines. (Or burn methanol itself in slightly modified engines. This offers somewhat lower energy density per tankful of fuel, higher total efficiency from electricity-to-motion.) Synthetic fuel makes sense for fueling aircraft, rockets, long distance shipping, collectible historic cars, and other niches. It doesn't make sense for fueling everyday ground transportation. Too much of the original energy is lost in the chain of chemical transformations and the chemical processing requires facilities on the scale of conventional oil refineries. The total cost is lower to electrify ground transportation and supply it with clean electricity than to transform clean electricity into liquid fuels for equivalent legacy vehicles. [1] https://www.frontiersin.org/articles/10.3389/fchem.2018.00446/full https://www.frontiersin.org/articles/10.3389/fchem.2018.0044... [2] https://en.wikipedia.org/wiki/Gas_to_liquids https://en.wikipedia.org/wiki/Gas_to_liquids

JumpCrisscross 7y ago
> Synthetic fuel makes sense for fueling aircraft, rockets, long distance shipping, collectible historic cars, and other niches What's driving the emphasis on lightweight batteries for aviation over better synthesisation?
- philipkglass 7y ago
  For UAVs, battery/electric systems don't just reduce fueling costs. They deliver features unobtainable from hydrocarbon engines: - Extremely long flight endurance without refueling (in large solar/battery UAVs) - Low noise - Odorless - Simpler and cheaper manufacturing The advantages are much less obvious to me for aircraft that transport passengers or significant cargo loads. I suppose that the companies developing them are hoping to make the lifetime total cost of operation cheaper than existing aircraft serving the same niche. That seems much tougher to achieve. EDIT: Bye Aerospace, the company described in the IEEE article, says they are targeting a particular niche: https://byeaerospace.com/eflyer/ https://byeaerospace.com/eflyer/ They intend to replace trainer aircraft that burn leaded aviation gasoline. This polluting niche fuel costs significantly more than kerosene. Maybe the economics can work out for this case.
  - JumpCrisscross 7y ago
    Thank you. Incredibly clarifying.
- ajuc 7y ago
  There's no emphasis on lightweight batteries for passanger aircrafts, both batteries and biofuels are pursued and both are marginal compared to traditional fossil fuels.

JumpCrisscross 7y ago

> Synthetic fuel makes sense for fueling aircraft, rockets, long distance shipping, collectible historic cars, and other niches What's driving the emphasis on lightweight batteries for aviation over better synthesisation?

philipkglass 7y ago
For UAVs, battery/electric systems don't just reduce fueling costs. They deliver features unobtainable from hydrocarbon engines: - Extremely long flight endurance without refueling (in large solar/battery UAVs) - Low noise - Odorless - Simpler and cheaper manufacturing The advantages are much less obvious to me for aircraft that transport passengers or significant cargo loads. I suppose that the companies developing them are hoping to make the lifetime total cost of operation cheaper than existing aircraft serving the same niche. That seems much tougher to achieve. EDIT: Bye Aerospace, the company described in the IEEE article, says they are targeting a particular niche: https://byeaerospace.com/eflyer/ https://byeaerospace.com/eflyer/ They intend to replace trainer aircraft that burn leaded aviation gasoline. This polluting niche fuel costs significantly more than kerosene. Maybe the economics can work out for this case.
- JumpCrisscross 7y ago
  Thank you. Incredibly clarifying.
ajuc 7y ago
There's no emphasis on lightweight batteries for passanger aircrafts, both batteries and biofuels are pursued and both are marginal compared to traditional fossil fuels.