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>Toyota says that different emissions-reducing car technologies are needed for different regions of the world. EVs are a good option for places like Europe, whe

>Toyota says that different emissions-reducing car technologies are needed for different regions of the world. EVs are a good option for places like Europe, where batteries can be charged with electricity derived largely from renewable sources, the automaker says. Other options, such as hydrogen or hybrids, may be a better fit in other regions. Obviously not all types of internal combustion engines emit carbon. Batteries are not yet 1 size fits all. And if we move toward renewable/nuclear then the source of energy for hydrogen generation will become a non-issue.

josephcsible 5y ago
Can you give some examples of internal combustion engines that don't emit carbon?
- nradov 5y ago
  Internal combustion engines have been built that run on hydrogen. But most hydrogen is produced from natural gas using a process that emits CO2.
- aurizon 5y ago
  Well, any hydrogen car that combusts the Hydrogen with atmospheric Oxygen fits this only if the Hydrogen is created by electrolysis of water. It will be very inefficient even if the Hydrogen comes from solar/wind/wave power as it will also lose efficiency due to the Carnot thermodynamic losses. https://en.wikipedia.org/wiki/Carnot_cycle https://en.wikipedia.org/wiki/Carnot_cycle If we reach a high enough order of solar/wind/wave power production we would be better served by electrolysing water to Hydrogen, which is combined with oxygen in a fuel cell in the automobile. Best practice is to steadily create electricity and store a portion in Lithium batteries - for the starting surge, using the steady fuel cell production for travelling at ~100-120 Km/hour - this reduces the size of the fuel cell needed. If you run fuel cells at high power density = low efficiency, low power can be in the 75-90% range - this is increasing steadily with research. Compressed hydrogen should be avoided as the cylinders are large and under high pressure and waste space. Crystal clathrates have the ability to reach about 50% of liquid Hydrogen density. Liquid hydrogen is also good for long haul trucks, with H2 station on interstates. Trucks can be defueled when off duty at H2 stations to deal with the Hydrogen boil-off losses.

josephcsible 5y ago

Can you give some examples of internal combustion engines that don't emit carbon?

nradov 5y ago
Internal combustion engines have been built that run on hydrogen. But most hydrogen is produced from natural gas using a process that emits CO2.
aurizon 5y ago
Well, any hydrogen car that combusts the Hydrogen with atmospheric Oxygen fits this only if the Hydrogen is created by electrolysis of water. It will be very inefficient even if the Hydrogen comes from solar/wind/wave power as it will also lose efficiency due to the Carnot thermodynamic losses. https://en.wikipedia.org/wiki/Carnot_cycle https://en.wikipedia.org/wiki/Carnot_cycle If we reach a high enough order of solar/wind/wave power production we would be better served by electrolysing water to Hydrogen, which is combined with oxygen in a fuel cell in the automobile. Best practice is to steadily create electricity and store a portion in Lithium batteries - for the starting surge, using the steady fuel cell production for travelling at ~100-120 Km/hour - this reduces the size of the fuel cell needed. If you run fuel cells at high power density = low efficiency, low power can be in the 75-90% range - this is increasing steadily with research. Compressed hydrogen should be avoided as the cylinders are large and under high pressure and waste space. Crystal clathrates have the ability to reach about 50% of liquid Hydrogen density. Liquid hydrogen is also good for long haul trucks, with H2 station on interstates. Trucks can be defueled when off duty at H2 stations to deal with the Hydrogen boil-off losses.