Ethanol Impact on Environment

[bigwaveohs]

How is ethanol currently used in California?

In California each year, 900 million gallons of ethanol are sold as a 5.7 percent blend in gasoline. Of the 900

million gallons consumed, at most, only 35 million gallons are produced in-state.2 The rest is imported, almost

all by railcar.3 In addition to the low percentage blend, a small quantity of ethanol is sold as E85, a blend of 85

percent ethanol and 15 percent gasoline.

What are the emissions tradeoffs for low blends currently used in California gasoline?

The Air Resources Board has concluded that low percentage ethanol blends reduce tailpipe emissions of certain

pollutants like carbon monoxide, but substantially increase evaporation of unburned fuel in the current fleet of

vehicles in California. A 6 percent blend, approximately the level in today's gasoline, leads to a 65 percent

increase in the evaporation of smog-forming emissions through vapors leaking through hoses and fuel tanks, a

process known as “permeation".4 Fewer conclusions can be made about the impact of the current low ethanol

percentage blend on the smog-forming pollutant nitrogen oxide (NOx) because the tests show varying effects.

The “permeation" impact occurs in both new and old vehicles although newer vehicles are designed to reduce

the effect. As the existing fleet of vehicles is replaced with newer models, the permeation impact will be less

significant. Until the fleet or the refineries are able to mitigate the impact, however, low blends could be causing

an increase in unhealthy smog. Using ethanol in high blends, such as E85 is a much better way to go for both

local air pollution and petroleum consumption.

 

[yzer]

Use of ethanol in fuels can lower emissions and improve air quality in our area, as long as the pollution caused by production of the ethanol stays out of our local air. That's one reason why California imports most of its ethanol from out of state.

As a fuel, ethanol yields less energy than is required to produce it. A gallon of ethanol has an energy value of 77,000 BTUs. Using the corn-to-ethanol method 131,000 BTUs of energy are needed to make a gallon of ethanol.

 

[westdelta]

quote:

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A 6 percent blend, approximately the level in today’s gasoline, leads to a 65 percent increase in the evaporation of smog-forming emissions through vapors leaking through hoses and fuel tanks, a process known as “permeation”.

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Vapors permeating fuel tanks? I'll entertain that talk if we're talking certain types of rubber fuel lines, but I'm skeptical about the vapors permeating the fuel tank.

 

[rommer]

quote:

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Originally posted by yzer

Use of ethanol in fuels can lower emissions and improve air quality in our area, as long as the pollution caused by production of the ethanol stays out of our local air. That's one reason why California imports most of its ethanol from out of state.

As a fuel, ethanol yields less energy than is required to produce it. A gallon of ethanol has an energy value of 77,000 BTUs. Using the corn-to-ethanol method 131,000 BTUs of energy are needed to make a gallon of ethanol.

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Thats a pretty short sighted outlook. The hell with the source as long as your air is clean?

 

[BayTrawlerGuy]

Unfortunately, looking at only narrow, regional impacts of "pollution reduction" has long been the norm in "environmental" circles. During the early parts of the clean air movement, smokestack height was a very important factor, particularly in midwest states. Why? Because if the stack was high enough, the bad stuff went up into faster moving winds and dissipated into other states. When the realities of acid rain in the Northeast became apparent, the US EPA changed things so that states no longer could just ship it over the border, but actually had to reduce it.

BTG