Ethanol is not the answer
Using ethanol as a blend stock for gasoline is not a solution to many of the problems it is purported to solve. It is however a very effective method for subsidizing the farming businesses that produce the feedstocks for ethanol production (wheat, barley, corn, etc.)
GHG Emissions
Burning ethanol in cars does NOT reduce greenhouse gas emissions. In fact, burning ethanol will increase CO2 emissions (measured on a per mile basis) because the fuel efficiency of the engine is lower. This is because the heating value (ie. energy content) of ethanol is lower than that of petroleum gasoline.
The benefit of reduced GHG emission may come from the lifecycle of producing the ethanol, but this is debatable as planting and harvesting the crops requires energy input (usually as diesel fuel), and the fermentation/distillation process requires energy input. The possible benefit is that growing the crop removes CO2 from the enviroment temporarily (whereas petroleum fuels add CO2 to the environment from geologic sources).
Nitrogen Oxides, Volatile Organics
Burning ethanol in cars may INCREASE emissions of both NOx and VOCs. While significant reductions in carbon monoxide emissions are possible with ethanol, reactive oxygen can result in increased NOx production. NOx is one of the key materials that makes smog.
Burning ethanol can decrease the quantity of volative organic species present at the tailpipe, however, it increases the emissions from filling the tank and evaporation. Also, there has been shown to be an increased amount of aldehyde emission at the tailpipe. While this could be corrected via additional catalytic conversion in the exhaust system, automobiles would need to be retrofitted.
And about the price...
The price of ethanol is related to the price of food, because the primary sources of making ethanol come from food, be it corn, barley or sugar cane. This means that fuel pricing will need to compete with food pricing. As food is more important to people than fuel, it will likely lose this war if there is situation where the price of these feedstocks is driven upwards due to demand. Food buyers will pay more than fuel buyers.
GHG Emissions
Burning ethanol in cars does NOT reduce greenhouse gas emissions. In fact, burning ethanol will increase CO2 emissions (measured on a per mile basis) because the fuel efficiency of the engine is lower. This is because the heating value (ie. energy content) of ethanol is lower than that of petroleum gasoline.
The benefit of reduced GHG emission may come from the lifecycle of producing the ethanol, but this is debatable as planting and harvesting the crops requires energy input (usually as diesel fuel), and the fermentation/distillation process requires energy input. The possible benefit is that growing the crop removes CO2 from the enviroment temporarily (whereas petroleum fuels add CO2 to the environment from geologic sources).
Nitrogen Oxides, Volatile Organics
Burning ethanol in cars may INCREASE emissions of both NOx and VOCs. While significant reductions in carbon monoxide emissions are possible with ethanol, reactive oxygen can result in increased NOx production. NOx is one of the key materials that makes smog.
Burning ethanol can decrease the quantity of volative organic species present at the tailpipe, however, it increases the emissions from filling the tank and evaporation. Also, there has been shown to be an increased amount of aldehyde emission at the tailpipe. While this could be corrected via additional catalytic conversion in the exhaust system, automobiles would need to be retrofitted.
And about the price...
The price of ethanol is related to the price of food, because the primary sources of making ethanol come from food, be it corn, barley or sugar cane. This means that fuel pricing will need to compete with food pricing. As food is more important to people than fuel, it will likely lose this war if there is situation where the price of these feedstocks is driven upwards due to demand. Food buyers will pay more than fuel buyers.
posted by Technical Bard | 10:27
7 Comments:
What about Biodiesel? Does Biodiesel suffer from the same drawbacks as ethanol, or is it a much more sensible suggestion for a petroleum alternative?
This article misses one key aspect of the oil business that makes it so polluting, the production of oil. Oil is burned under a heater and separated. This process releases as much CO2 into the atmosphere as the totality of the people driving with that fuel (heating their homes with it, etc.). So although it is true it uses more CO2 when driving it uses substantially less from extraction to burning of it.
Biodiesel is better than ethanol. It is a much better analogue to the geologic petroleum. That said, biodiesel research has shown some improvement in NOx, while all other emissions are reduced. There is minimal CO2 reduction if any. Two reasons why biodiesel is a more complex subject than ethanol are the source of the material (plant or animal fats) and how the esterification is performed and whether that has impact on the resultant properties.
The advantage over petroleum diesel is that it is a renewable resource.
Paul,
The energy input required to produce and refine petroleum is at worst about 20% of the energy value of the products. 80% of the emissions from petroleum are from the end users, not the producers. If the reverse were true, it wouldn't be an economic business.
Ethanol reduces CO2 emissions because the grain or other biomass used to make the ethanol absorbs carbon dioxide as it grows. Although emissions are produced during the conversion of the biomass to ethanol and when the ethanol is burned, the net effect is a large reduction in CO2 emissions compared to gasoline.
Thanks for the info.
I'm currently working on bio-fuel and waste fuel/ low value fuels, related projects that involve the gassification of the raw fuel to produce a cumbustible gas that is roughly equivalent of propane.
There is great potential for these technologies to be used in concert with processes that require energy in the form of heat to achieve the end product.
The advantages of this apporach are numerous, ranging from a reduction of waste to actual improvement in emissions quality overall.
Ther are currently billions of tonnes of potential fuel being wasted through inefficient processes .
We have the technology to make improvements in the big picture energy cycle by small increments which will have cumulative benefit over time.
The BIG road blocks to implementing these solutions is lack of support from governments in general. I'm not talking about tax dollars being spent. I'm talking about lack of vision, poor planning, lack of coordination, ignorance and policies that interfere with commercial adoption of new ideas.
Oh yeah and you are quite correct about the MYTH of ethanol in the current model...purely a way to subsidize grain producers.
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