what is the cost in money and energy making biodiesel compared to ethanol?

[yurbud]

A lot of the arguments about energy costs of ethanol seem like they wouldn't apply to biodiesel.

The primary difference is biodiesel doesn't create a fuel or food problem: you can squish the oil out of the plant and still have the solids for food.

And that squishing process doesn't seem that energy intensive compared to distilling alcohol.

Some guy who ran his bus on French fry oil threw in a handful of chemicals in a 55 gallon drum, cooked it overnight, and could run it in his unmodified schoolbus engine.



These school kids didn't even modify the oil, they just had to warm up the engine with conventional petroleum based diesel.

http://www.cnn.com/2003/EDUCATION/05/21/vegetable.oil.bus.ap/

[calmblueocean]

1. Actually, I just heard the other day...

that the solids actually are retained when corn is made into ethanol, and that they are sold as feed for livestock.

[LeftCoast]

2. I would love to run a hybrid bio-diesel vehicle

You'd probably get a 100 mpg+ and it would be 100% renewable.

[Strelnikov_]

3. Soy biodiesel, ~70% food value remains after processing, EROEI~3.0

Corn ethanol, wet milling, ~ 70% human food value remaining, EROEI~1.0 (1.3 w/ food co-products)
Corn ethanol, dry milling, ~ ?% 'food' value remaining, EROEI~1.0 (1.7 w/ 'food' co-products)

Soy processing coproducts are non-oil components (soy meal) suitable for human use.

Corn dry milling coproduct is DDGS, which is used as cattle feed.

Corn wet milling coproducts are corn meal, corn oil, corn germ, etc., suitable for human use. Most corn products in the supermarket today are a coproduct of the wet milling process since the starch is typically removed for production of a value added product (ethanol).

The primary problem with corn ethanol is the lack of net energy. Corn ethanol, as implemented in the great ethanol rush, using relatively cheap dry mill plants mated with fossil fuels, is a dead end, at best. A much better long term strategy would have been wet mill plants powered by wind energy, said plants designed around intermittent nature of wind. Since 67% of corn ethanol's energy inputs are at the processing plant, this approach would be a way to convert intermittent wind into an energy dense liquid fuel energy carrier.

Soy bioD does not have the large energy inputs of corn ethanol. In an integrated strategy, crop rotation (soy<->corn) would reduce external nitrogen inputs. However, the problems inherent to industrial agriculture still apply.

A viable future would be a movement back to small (160 Ac +/- in the 'corn belt') intensively managed farmsteads. These farms would be managed to maximize net food yield while minimizing external inputs. The farmers would have their corn/beans/sorghum etc. processed at local wind powered plants to yield the liquid fuels to keep the food production and distribution system going, with some left over to offset external energy inputs. I feel biofuels can at least make the production of food energy neutral.

The problem is, where do the biofuels to keep the SUVstate highways and WalMart warehouse on wheels running come from? Beats me. Particularly considering that the agriculture future above will result in decreased yield of corn/soy from that possible today with industrial agriculture monocropping.