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Originally Posted by Herr_Pete
why dont we just do what brazilians do and run our cars of the sugar cane plant! which causes zero polution. Im pretty sure america and other countrys can use up the vast amounts of land to grow it! problem solved! the food prices will come down, all sorts of other prices will come down. Wae hey!  |
Well, back to the no free lunch. Current crops for ethanol generally mean taking agricultural land out of food production and using it for energy production. In South America, it also means clear cutting and burning virgin forested regions to plant ethanol crops (as the news media is just waking up to that fact). The amount of CO2 released from the burning is not trivial, and the agricultural plants cannot even begin to make up for the loss of the valuable CO2 sink that the forests provided in the first place (mid-latitude forests are the second largest source of uptake of CO2, second only to the oceans - they are also a huge source of oxygen, much more so then the agricultural or fuel crops that are replacing them).
It also takes a lot of energy to make ethanol - distillation uses nearly as much energy to make the product as you get back out of it in the end. Currently, most of the energy to make ethanol comes from natural gas, or electricity (in many areas, primarily from goal, gas or oil fired power stations).
So, while ethanol may be part of the solution, it is not THE solution, nor is it entirely environmentally friendly nor without costs. (aside: I'd also point out that it does not combust worth a dang in a cold engine, so much of the world's climate makes it necessary to still initially run the vehicle on petroleum, then switch fuels after warming up).