Sunday, February 11, 2007

Biomass Ethanol

note: this post will be fairly boring to anyone not interested in alternative fuels. please feel free to skip over it if it's not a topic of interest to you.

I have had a lifelong interest in alternative energy, and the need for non-petroleum based fuels is clearly rising. One readily available fuel source is biomass ethanol (also called cellulosic ethanol), that is ethanol made from various organic materials including waste products. In it's most basic ethanol is merely alcohol, the same as beer, wine, vodka, etc. Alcohol is produced by fermentation, the result of yeast digesting sugars or proteins. Historically, humans have made alcohol from whatever high sugar organisms were regionally plentiful. So Southern Europe made wine from grapes, Central Europe made beer from grain, etc. The higher the sugar content, the easier the fermentation. The next step was to purify via distillation leading to the vast array of liquors available today. At it's purest, ethyl alcohol is a highly combustible liquid that is slightly more flammable that gasoline.
Despite president shrubs high rhetoric, almost all fuel ethanol made in America is made from corn. Corn makes a good feed stock due to it's high sugar/starch content. The big corporations (think ADM) found corn to be an easy, plentiful source for ethanol.
But ethanol can be made from other sources. Literally, any organic material is a potential ethanol source. All proteins, sugars, and starches that are present can be fermented and distilled. A variety of yeasts and enzymes can be used as well as some chemical acids (a technique that is NOT environmentally sound). The main barrier to producing ethanol from various low yield sources is cost. Simply put, it's harder to ferment materials that have a lower concentration of sugar. But the potential energy yield is huge. Just look around you, and total up all the organic waste around you. Here in my region, forest waste and and brush are plentiful. The problem is that processing this waste would require building a modern processing system at a substantial investment.
In our current economic and government system, it's the big corporations that have the resources to undertake large scale ethanol production The government's plan is to offer tax breaks and incentives to the big boys, who in turn look for the highest potential profits.
But there IS another way. While the original infrastructure would require a substantial investment, the potential benefits are so huge as to be almost beyond measure. Imagine a system of localized fermentation/distillation plants set up to utilize all regionally available organic waste. Think of all the waste in your own locale being made into fuel for your cars. What is needed to make the investment is a major paradigm shift from the focus on short term profits toward long term benefits. Once built, such plants can produce for many decades (in Russia, there still operating plants built during WW11 Also, localized plants will create jobs and reduce the use of landfills.
While I could say a great deal more on the subject, this post is long enough. At some point in the future, I'll post about the potential to produce electricity via ethanol fuel cells. Your thoughts?


BadTux said...

The problem with biomass is that plants are a very inefficient converter of solar energy into chemical energy. The theoretical maximum efficiency of solar energy conversion is approximately 11%. In practice, however, the magnitude of photosynthetic efficiency observed in the field, is further decreased by factors such as poor absorption of sunlight due to its reflection, respiration requirements of photosynthesis and the need for optimal solar radiation levels. The net result being an overall photosynthetic efficiency of between 3 and 6% of total solar radiation. Currently available commercial photocell panels have an efficiency of approximately 15%, and cells currently under development in the lab will convert up to 40% of solar radiation into electricity.

One argument is that production of solar cells is environmentally unfriendly, but mass production of biomass is very environmentally unfriendly too. Mass production of biomass requires clearing off low-efficiency native plants to replace them with a monoculture of a more photosynthetically efficient plant such as rapeseed, with corresponding issues of water usage, fertilization, topsoil loss, and ground water contamination. Most of the ground water of the midwest is already contaminated with nitrates due to widespread use of fertilizers, and agricultural water usage is already a major issue causing water shortages throughout the American West.

Previous cellulose-based biomass projects, such as those in the Soviet Union, relied upon the existence of waste wood products at lumber mills and lumbered-out sites. Today, however, those waste wood products are captured at the mill and at the site, and instead chipped and used for oriented strand board, or finely ground and used for particle board. Glue-based construction materials such as these are important components of today's building industry, due to the fact that we've lumbered out virtually all old growth forests and are using the new growth forest plantations primarily for studs and source materials for trusses and glulams (glued laminated structural members, which replace the large wooden structural members that were used back when we had large old-growth trees to use for structural purposes).

In short: Biomass production can be useful for recovering energy currently lost in household wastes, but due to the environmental issues, solar or even nuclear power are likely to be as or more important in the future.

-- Badtux the Energy Penguin

PS - see that little 'ABC' icon on your Blogger posting window? That's a spelling checker. Use it. It works.

--mf said...

Here in Memphis, TN, we are building a rather large ethanol facility to convert leftover cottonseed and cotton husks into fuel.

I think that this is right in line with your idea. I was quite surprised that Memphis got it right on this score.

We have MOUNTAINS of cotton waste mounded around this area, as we're a MAJOR ginning center. It seems to be a match made in heaven. Following your lines, it seems that the rule needs to be, "go with what you've got," but we can't take food away from people to put in our gas tanks... That's where folks like James Kunstler come in-- to keep the brakes on runaway happy motoring ideas, and to keep them within sane margins.

I AM worried about the ADM etal plan that takes food and Feed corn for fuel. it's already causing problems, and I fear they will only get worse.

It's getting late. I'd love to write more, but, I'm very tired.

This is an excellent article, and I'll do my best to give it more visibility.