Monday, June 05, 2006


Green Car Congress is reporting on progress toward genetically engineered bacteria that can produce ethanol directly from cellulose. Kate is warning about "head explosions" in response to this news.

Sorry, Kate. No head explosions here. This is not a breakthrough solution to our dependence on non-renewable fossil fuels. And since it isn't a breakthrough, it doesn't pose any dilemma for opponents of genetic engineering.

The cold hard truth: you still have to grow the cellulose.

There is a simple reason that fossil fuels are so valuable, and so fundamental to the explosive prosperity of society since the Industrial Revolution. Fossil fuels are a concentrated form of photosynthetically stored solar energy, concentrated from plant biomass produced over long stretches of time. By using up the bulk of the world's store of fossil fuels, industrialized society is using up millions of years' worth of biomass production in a span of only a few hundred years. There is no way to duplicate that kind of supply from annual biomass production, unless we acquire a few more planets and concentrate resources across space instead of time.

Eleutheros recently put the ethanol issue in perspective.

You want a renewable fuel for sustainable transportation? Grow something you can eat, and walk.


Ontario Wanderer said...

"Grow something you can eat and walk." What an excellent idea! When I lived in the city, I did a lot more walking. Now that I am 5 km out of the nearest village I tend to use the car more even though I could make much more use of my bicycle.

Anonymous said...

Precisely, Laura.

Cellulosic ethanol is all the rage. No one seems to realize that the amount of cellulose that has to be grown to substitute for energy-rich dwindling oil accumulated over hundreds of millions of years will demand that vast areas of wilderness be turned over to growing switchgrass or somesuch.

The paragon mentioned so often is Brazil. How nice. Brazil is cutting down uncalculable valuable tropical rainforest just to grow sugarcane for ethanol. How stupid is that? I suspect we'll find out.

If anyone thinks that cellulosic ethanol can solve all our energy problems they're deluded. If they think that a rational amount of this in combination with other things can begin an intelligent program of energy sufficiency, I'm all for it.

Saskboy said...

It's a good point that few people catch unless they think about it [or know] that almost all energy sources on earth can be traced back to the sun giving some light to a plant. Geothermal, and tidal energy excepted from that rule.

Anonymous said...

Ethanol from corn is reported to have an EROEI (Energy Return on Energy Invested) of 1.20 - 1.25. That is, if you have 1 unit of energy to invest in growing and processing corn, you can get up to one and a quarter units out.

But that's deceptive. They are counting the spent grains used for livestock feed as energy saved in not growing and processing and equivalent amount of animal feed. The only problem is that we are already in a useless surfeit of spent distillery grains, can't really use any more, so we're not really saving any energy at all by producing MORE corn ethanol.

That is, ethanol for motor fuel from corn is a net loss of energy with a EROEI of less than 1.

You hear that cellulose ethanol from corn stover and switchgrass has a much higher EROEI, but that is only if you discount the growing and gathering of the material as being nearly energy free. The logic is that you are growing the corn anyway, so the stalks and cobs didn't cost anything in terms of energy at all, did they? But once petroleum production declines, the ability to grow and gather anything that yields cellulose will get more and more expensive with a lower and lower EROEI.

If we were to derive all the motor fuel from cellulose today, it would take 10% of all the vegetation in the world for one year's supply. We can't renew it that fast.

There IS not alternative to using less energy. Time to get out the walking shoes.

CG said...

I'm using a quote from this post on my blog.

arcolaura said...

Thanks for the quote, CG. It's nothing new, and yet when I thought of it, I couldn't recall ever seeing it stated compactly.