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Edited on Tue May-02-06 04:51 PM by JohnWxy
proportion that they reduce gasoline consumption (about 25% in the real world- depending upon the type of driving you do). If the Hybrid reduces gasoline consumption by 25% it reduces GHG emmissions by 25% - for that car. That's because it is still using gasolinie at 75% the rate that a non-hybrid is. Gasoline is still being consumed.
NOw, cost is an issue because you have to evaluate what you are getting for your investment. It also is a factor when not everybody goes out and buys a new car every year. In fact, surprising as this may sound to you, not everybody can buy a new car. Many people buy only used cars. so they are not too likely to go out and buy a hybrid which costs about $5,000 more than a regular new car. (okay $2,000 extra with the $3,000 tax credit - but it is still costing the country $5,000). This becomes a factor when you consider the potential of hybrids to affect GHGs to a signigficant degree.
NOw, there are about 400,000 hybrids on the road today. Against a total fleet of 211,000,000 cars and light trucks. That's a percentage of the total fleet of .19% or: .0019 as decimal fraction (411,000/211,000,000). So the reduction in GHGs for the total of all the hybrids is 25% of the .0019, or: 0.000475 or .0475%. That is the percentage GHG reduction of the GHGs produced by all the cars and light trucks due to the 411,000 hybrids. Now those hybrids cost about $5,000 extra each so the investment required to get that .000475 reduction in total GHGs produced by all cars and light trucks was: $2,055,000,000. (if you want to assume hybrids will get to 37.5% reduction in gasoline consumption, then the proportionate reduction of gas consumption and GHG for all vehicles would be 0.0007 due to hybrid vehicle use.)
Now if you want to see what it would take to reduce GHGs say 5%, then if hybrids reduce gas consumption by 25% and you want to get a 5% reduction to the total GHG emmisions (by cars and light trucks) then you would have to have the hybrids on the road equal 20% of the total of cars and light trucks on the road. Bear in mind, since not everybody goes out and buys a new car every year (more like once every 7 years - for those who buy new cars) it would take a while to achieve this. Probably at least 20 years.
Now, 20% of 211,000,000 is 42,000,000 hybrids (lets not get into how the total fleet would grow over the 20 years it would take to bulld up the hybrids to 20% of total). So if you figure the extra cost of a hybrid goes down to about $3,700 (from $5,00 now) then the cost of the 42,000,000 hybrids would be (in 2006 year dollars) $156,140,000,000.
So to get a 5% reduction in GHGs you spent $156 Billion
Now, for comparison, to get a 5% reduction in GHGs how much ethanol would be required? You would need the gasoline being used in all cars be 24% ethanol blend to get a 5% reduction in GHGs. (Well for wet-milled corn based ethanol you would need 29% of the gasoline supply to be made up of ethanol. For Dry-milled ethanol it would require 19% of the gasoline supply. The reason the process makes a difference is some GHGs are generated in making nitrogen fertilizer and in the ethanol prodution process. Wet milled ethanol produces more GHGs than dry-milled. Most of the new ethanol plants being made today are dry milled. But I just used a simple average even though as we continue building ethanol production the weighting will lean in favor of dry-milled ethanol.)
Now, how long will this take. This depends a lot on various assumptions. Will we continue to keep a tariff on Brazilian ethanol? I do not think this will continue much longer. National security and economic security factors will demand that we start importing ethanol from Brazil as we build our domestic production. Another factor is cellulosic ethanol. Most experts expect cellulosic ethanol to be commercially viable in 5 to 6 years. Once cellulosic ethanol enters the picture the GHG reduction rate really goes up. Cellulosic ethanol will reduce GHGs by 85% relative to gasoline. Since cellulosic ethanol reduces GHGs so much relative to gasoline you would only need for the total fuel supply to be made up of 5.88% of cellulosic ethanol to get a 5% reduction in GHGs. So how soon would that GHG reduction rate (per year) take place - that's a good one to try and guess. If we were to drop the tariff on Brazilian ethanol we would reach tha point much sooner. I suppose an aggressive estimate would be 10 years. But, if something like a major impact to oil supplies happened (Venezuela, Niger, Iran, another bad hurricane season - in any one of the next few years) we could see imports of ethanol from Brazil and domestic production jump up much faster and maybe 5% reduction to GHGs would be happening in 7 years.
The Oak Ridge National Laboratory has estimated we could replace (with domestic production) at least 30% of the gasoline supply with ethanol. IF that was mostly from cellulosic ethanol then you would be looking at close to 25% reduction (per year) of GHG production. NOte that there are scientists who have developed bacteria which significantly enhance the production of ethanol from cellulosic sources (one is working with Iogen in Canada). One of these scientists (from a University in Florida) expects that with the bacterium he has develeped (genetically altered to break down complex sugars) that ethanol could meet 50% of the U.S. gasoline demand.
And if I failed to mention it before, any car that runs on gas can use 10%-15% ethanol - new cars, old cars - any car that runs on gas. So you do not need to buy a new or expensive new car to heop reduce GHGs or use of imported fossil fuels. The cost issue, I'm afraid, is a factor that must be considered.
Of course in the longer run, fuel cell cars are the best hope of dramatically reducing our dependence on fossil fuels and reducing GHGs. But until they are developed, ethanol is about the most cost effective and quickest way to reduce fossil fuel use and GHGs.
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