"whats the point of using ethanol if its not any better for the environment."
This is a wonderful question and one that has multiple different answers. Of course finding the right ones seems to be the hard part. there are enough parts to this that we felt it needed its own page.
Warning: while this is very informative it is a very long article to digest all at once. If you want to know the final answer on ethanol emissions head here now.
Fuel spills
First lets talk about the environmental impact in the event of a fuel spill. Ethanol is actually something that we can drink (before its denatured), we use it on our hands(its the main ingredient in hand sanitizer), and it comes from natural sources such as corn, plant material and wood fibers. in the event that there is a major fuel spill ethanol actually breaks down in a fairly short amount of time. The degradation rate does depend on what the ethanol comes in contact with.
As you can see ethanol spills degrade to relatively harmless components fairly quickly. There are a couple of risks that you should be made aware of though
- Ethanol fumes are heavier than air which means it will settle in low lying areas and does pose a risk of asphyxiation. The acetaldehyde in ethanol (this is what makes alcohol smell like alcohol) is easily detectable to humans and should be an early warning sign to leave the area.
- Ethanol in groundwater is probably the biggest issue. large enough quantities of ethanol spilled in a small body of water can deplete the dissolved oxygen from the water source which would cause fish and other aquatic animals to suffocate. the likelihood of this happening is relatively low because most bodies of water that ethanol would travel across are open streams that would pose very little risk for oxygen depletion.
- while ethanol is safe enough to not cause any major environmental pollution issues there is still a denaturant added to all ethanol to make it unsafe for human consumption. The most common denaturant is low grade gasoline added to the ethanol at a 2% rate. Gasoline is made up of up many different hydrocarbons some of which are very toxic and these can cause long term environmental effects not related to the ethanol.
Now
Greenhouse Gas Emissions
Now lets talk about whats being produced when ethanol is burned in an internal combustion engine. there are a lot of ways to compare greenhouse gas emissions(GHG) between fuels and some of them don't tell the whole story. Lets start off by comparing the GHG emissions from burning a gallon of different types of fuel.
You can see in the image above that ethanol produces approximately 36% fewer Co2 emissions than gasoline per gallon of fuel burned. The problem is that we cant really stop there because ethanol has less BTU's (british thermal units is a unit of measurement of the available energy in a fuel) per gallon than ethanol so to do an apples to apples comparison we really need to look at the c02 emissions per 1million BTU's.
Now the numbers are starting to become a lot closer. With the apples to apples comparison we are finding that pure ethanol produces approximately 5% fewer emissions. Now we don't use pure ethanol, we use mostly a blend of E10 which produces roughly .5% Fewer emissions is nothing to sneeze at when you consider the amount of vehicles on the road.
We have arrived at what is known as a pump to wheel emissions calculation calculation(PTW). This tells us how many emissions are produced from our vehicle but it does nothing to find the emission created when we make the ethanol That calculation is known as the well to pump(WTP).
Next lets calculate the emissions released when we actually convert the corn to ethanol. This number will vary depending on what type of fuel is used during the ethanol production process. Our local ethanol plant uses natural gas as a fuel source to remove the water from the ethanol and the ddg's (dried distillers grains with solubles). we have to consider the emissions created from the burning of natural gas, the production of electricity used in ethanol production, and the Co2 released from the fermentation process.
Another thing that we have to figure out is how much co2 is released while producing corn. according to Iowa State University it takes the equivalent of 34 pounds of diesel energy to plant, fertilize, harvest and dry one acre of corn. if we do the math on this we will have released 761.6 pounds of co2 per acre. Now lets divide that by the number of bushels of corn produced p
research paper Fuel spills, greenhouse gas emissions, cost to produce corn, well to pump costs, well to wheel costs, costs as compared to gasoline