Biodiesel Is Not Corn Ethanol

I burn biodiesel (B20) instead of #2 heating oil in my home boiler. Recently several friends and acquaintances have questioned whether this isn't actually worse for the environment.

It's not.

We had an interesting talk here at the store this summer about this very issue.

Pretty much every study done to date has shown that corn ethanol is a bad idea. Biodiesel, on the other hand, looks much more promising. For several years people in Maine have been studying how to produce biodiesel from wood and potatoes. Recent laboratory studies have been done on producing biodiesel from algae, which could be grown in shallow pools on land which is currently not suitable for conventional agriculture (on the roof of Hannafords supermarket, for example). This would avoid all of the impacts studied in the Science article.

The basic difference between ethanol and biodiesel is that ethanol processes convert sugar to alcohol, whereas biodiesel processes convert oils to biodiesel. Corn is used as a feedstock for ethanol because corn has a high sugar content. Other feedstocks with higher oil content (soybeans, for example) are used for biodiesel.

It's important not to throw out the baby with the bathwater in the biofuel discussion. It's easy to demonstrate that subsidizing ethanol from corn the way it is currently grown is not going to solve our energy or environmental challenges. However, there do appear to be solutions available if we diversify our energy crops and begin to replace petroleum with biodiesel for space heating and other situations where liquid fuels are essential.

Many writers in the popular press don't appreciate the difference between ethanol and biodiesel and inaccurately generalize the findings about corn ethanol to all biofuels. The important thing to remember is that the biofuel that you can buy to replace #2 heating oil is not ethanol and is not made from corn.

So, why is B20 better for the environment than 100% petroleum #2 heating oil?

Three reasons:

1. B20 burns cleaner. More of the fuel is burned, leading to fewer particulate emissions.
2. B20 can be produced locally, so less energy and infrastructure is required to transport it.
3. B20 is renewable. That means we can leave the carbon that is safely sequestered in petroleum in place, and instead pull carbon from the atmosphere to grow more biodiesel. Of course, the devil is in the details with exactly how we grow the biodiesel feedstocks, but we have a lot of options--and no doubt we'll soon have more if the market for B20 continues to expand.