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Q & A: Biodiesel

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Most recent answer: 01/18/2012
Q:
What is Biodiesel????
- Anonymous
A:
Biodiesel is a new type of fuel. Regular diesel is made from the non-renewable resource, fossil oil. However, biodiesel is made from renewable resources such as vegetable oil, animal fat, and used cooking oil. Biodiesel burns cleaner than regular diesel and will run in any unmodified diesel engine.

New fuels such as biodiesel are needed in order to help protect the environment and to provide a renewable fuel so that we don't exhaust the world's supply of oil too soon.

Here's a link to the . There, you can find more information about biodiesel.


Adam

(published on 10/22/2007)

Follow-Up #1: role of biodiesel

Q:
First off Id like to say I love this site. Just recently discovered it in looking for my answer to a recent debate about light. Anyway, I was curious. You say Bio diesel is need to save our planet from depleting our fossil fuels too rapidly. Question: Doesn't it require fossil fuel to make bio fuel?
- Cleve (age 30)
Blackfoot
A:
You ask a very good question. Are biofuels just new ways of using fossil fuels or are they genuine new energy sources?

In principle, biofuels are genuine new energy sources, since the free energy to form their carbon compounds from CO2 comes from sunlight. They're essentially a chemical form of solar energy, as opposed to an electrical form.

In practice, however, many biofuels are grown using conventional farming techniques which involve very large inputs of fossil fuel energy. Corn ethanol in the U.S., for example, currently uses so much fossil fuel that the energy output only slightly exceeds the fossil energy input.

It seems that biofuels are unlikely to provide a very large fraction of total energy needs for a population as large as the earth currently has. There's a wonderful free book by David MacKay () describing the basic science of different terms in the energy budget. He focuses on  the U.K., with a high population density and relatively little sunlight, so various solar sources including biofuels would be more significant elsewhere.

Mike W.

(published on 01/18/2012)

Follow-up on this answer.