|Reformed Methanol Fuel Cell Automobile Natalie (Credit: RG)|
by Marcel F. Williams
Electric cars solely powered by lithium batteries are often promoted as the inevitable passenger vehicles of a carbon neutral future However, there are many alternate automobiles that could be compatible with a carbon neutral and even a carbon negative economy.
And even gasoline powered vehicles could be carbon neutral and even carbon negative — if the source of gasoline is from a carbon neutral or carbon negative resource.
Hydrogen fuel cell vehicles already exist that utilize compressed hydrogen as their fuel source. Hydrogen not only extends the range of a vehicle relative to a purely battery powered car but is much faster to refuel. And if the hydrogen fuel source can be derived through the electrolysis of water then carbon neutral sources of energy (nuclear, solar, wind, and hydroelectric) would also make the hydrogen carbon neutral. As a plug-in-hybrid, lithium batteries could reduce the cost of hydrogen fuel.
Methanol contains even more hydrogen per volume, further extending the range of an electric vehicle. A methanol car with a reformed methanol fuel cell would use waste heat to extract hydrogen from the methanol before its utilized by the fuel cell for the production of electricity. Methanol can be produced from the electrolysis of seawater or through electrolysis of potable water synthesized with CO2 extracted from the atmosphere. Carbon negative sources of methanol could come through the pyrolysis of urban, agricultural, and forest bio-waste. The pyrolysis of biomass can produce syngas that can be converted into methanol plus carbon rich bio-char that can be used to enhance the fertility and water retention of land areas. So sequestering the bio-char ground fertilization would be inherently carbon negative. And if the land that has been fertilized with bio-char is used to grow new forest then that creates even more carbon sequestration. So vehicles using renewable methanol derived from the pyrolysis of biomass could be considered carbon negative.
Methanol can also be conveniently converted into gasoline and utilized in existing internal combustion engine cars. A such fuel would also be ultimately carbon negative if derived from the pyrolysis of of bio-waste. However, synthetic gasoline would be even more expensive that synthetic methanol. And both fuels would be significantly more expensive than fossil fuels. So it would be more efficient to utilize relatively expensive synthetic gasoline in hybrid and plug-in-hybrid vehicles that use at least some lithium battery technology.
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