Engineering Question #8904

Angel, a 16 year old female from Toronto asks on March 7, 2013,

Why are biofuels becoming so big all over the world? And how would you explain to someone what biofuels are if they don't know?

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The answer

Barry Shell answered on March 7, 2013

First please read the wikipedia entry on biofuels.

The reason people prefer biofuels is because the fuel is made from plant material that has recently grown on the surface of the earth, rather than drilling deep down into the earth to get oil, which is basically just 100 million year old plant material that with time and heat and pressure has been turned into oil.

By using surface plants we keep the amount of carbon neutral. That is: we are not adding Carbon Dioxide (CO2) into the atmosphere, which is causing global warming. Plants pull carbon out of the air as carbon dioxide. That's how plants grow in case you did not know: they take carbon that is in the air and turn it into sugar and cellulose, which form the basic structure of all plant material. If we turn plants into fuel and burn that fuel, we are just putting the same carbon back into the atmosphere as CO2 for the plants to then take up again and turn back into plant material. It's a nice cycle.

The other way, which humans have only been doing for about 100 years, is to drill down into the earth to get fuel from oil. But that just keeps ADDING CO2, and there's no "cycle". The new CO2 has no way to get back down 2 km underground and be oil again. This takes 100 million years. The other way, using biofuels, only takes about 2 or 3 years for fast growing crops like grasses, and maybe 50 years if it's trees. This is on a human scale. We should all switch to biofuels to stop the rising amount of CO2 in the atmosphere which is causing climate change and global warming.

But one caution thing about biofuels: food crops should not really be turned into fuel. It's probably not a good idea to turn food for people into fuel for cars. Biofuels should be made with non-food waste or surplus plant material.

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