[davep]

David Blume of 'Alcohol can be a Gas' fame on Roadtrip:

http://www.youtube.com/watch?v=TshLDrREHk8

It gets interesting about half way through, but it is is just for the layman. It leaves many questions unanswered (that are actually answered in his book).

[JRP3]

Not so sure about this. How much energy is wasted collecting the donuts and other waste, and how much is wasted creating the ethanol? How many vehicles will the local donut shop support? How many homeless no longer get old donuts to eat? Lot of holes in the equation.

[davep]

Not so sure about this. How much energy is wasted collecting the donuts and other waste, and how much is wasted creating the ethanol? How many vehicles will the local donut shop support? How many homeless no longer get old donuts to eat? Lot of holes in the equation.

I agree. But in his book, he goes into some detail about how to integrate ethanol production into an integrated farm. This clip was far more lightweight.

[JRP3]

Big problem with ethanol is it still relies on inefficient ICE technology. I've read studies that show you get more energy if whatever biomass would be used for fuel is instead burned to generate electricity and used in EV's. I like the home cottage industry aspect of his plan but I don't see it as a large scale replacement fuel. I don't think any ICE technology is viable in the long term because of inherent efficiency problems that have not been overcome in 100 years of development. Plus all those moving parts, it's so 19th century.

[davep]

Big problem with ethanol is it still relies on inefficient ICE technology. I've read studies that show you get more energy if whatever biomass would be used for fuel is instead burned to generate electricity and used in EV's. I like the home cottage industry aspect of his plan but I don't see it as a large scale replacement fuel. I don't think any ICE technology is viable in the long term because of inherent efficiency problems that have not been overcome in 100 years of development. Plus all those moving parts, it's so 19th century.

I don't see it as a large scale replacement either. I see it more as an on-farm fuel source, with maybe a certain amount sold off.

However, as far as efficiency is concerned, you can raise the compression ratio if the engine is going to be used uniquely with ethanol. Apparently the Brazilians have an ethanol ICE test engine that is 42% efficient. I'm not sure of the figures for real-world engines though. But efficiency for an on-farm fuel is not really that important, it's more about being able to run a tractor and a chainsaw etc.

[JRP3]

I'd think that with any limited resource efficiency is important. A tractor will take X amount of energy to move regardless of the source. Using an ICE that wastes 80% of energy in the tank, (real world ICE), not to mention the energy used to make the fuel, might not be a good use of resources. If that's the only choice then that's what you do, but there may be better ways of using the biomass.

[davep]

I'd think that with any limited resource efficiency is important. A tractor will take X amount of energy to move regardless of the source. Using an ICE that wastes 80% of energy in the tank, (real world ICE), not to mention the energy used to make the fuel, might not be a good use of resources. If that's the only choice then that's what you do, but there may be better ways of using the biomass.

I don't necessarily agree about that, as a liquid fuel that can fuel a tractor is far more useful than the same amount of energy stored in plants, for example.

The system can get very efficient with reverse flow heat exchangers and suchlike, but the main point is that you still have as much protein and minerals as you had before. All that is taken out is carbohydrates that are gleaned from photosynthesis. This is important in that it doesn't in itself actually deplete the soil and the distillers grains can still be used on farm. Also, the CO2 can be used for algae to feed a fish farm, or to bump up production in greenhouses etc. I agree that there would be little point in making ethanol if it wasn't part of an integrated farm where the 'wastes' were used as inputs to other processes.

[JRP3]

I don't necessarily agree about that, as a liquid fuel that can fuel a tractor is far more useful than the same amount of energy stored in plants, for example.

My point is that you have a more efficient energy transfer if the same biomass is burned to generate electricity and run in an electric tractor than if it's distilled and burned in an ICE tractor.

The system can get very efficient with reverse flow heat exchangers and suchlike,

That stuff never happens in the real world and real vehicles...

but the main point is that you still have as much protein and minerals as you had before. All that is taken out is carbohydrates that are gleaned from photosynthesis. This is important in that it doesn't in itself actually deplete the soil

Only if you dump the stuff back onto the fields, which means more fuel being burned to spread it.

and the distillers grains can still be used on farm. Also, the CO2 can be used for algae to feed a fish farm, or to bump up production in greenhouses etc. I agree that there would be little point in making ethanol if it wasn't part of an integrated farm where the 'wastes' were used as inputs to other processes.

I suppose if you have a crop which you plant anyway to feed your livestock, and you distill it first to get the ethanol, it might make some sense, but it's really more efficient to just feed your livestock on grasses that you don't have to plant in the first place. Corn fed livestock is pretty inefficient. I just think they are trying to paint a prettier picture for ethanol than really exists when you look at all aspects of it.