Oregon Public Broadcasting is reporting on the efforts of a WSU researcher to turn poplar trees into transportation fuel:
[P]oplars [are] an on demand fuel source. Trees can be chopped down year round, chipped up and then fermented to create ethanol.
According to the researcher, an acre of poplar could supply about one thousand gallons of ethanol per year—which is about three times the per-acre yield of corn ethanol, with a lot less plowing and fertilizer consumption. Cool!
Of course, inveterate skeptic that I am, I had to run the numbers…
Let’s ignore, for a moment, any energy that’s used in harvesting, chipping, and fermenting the poplars. (In a proper analysis, we’d “net out” those energy inputs from the final ethanol output.) Instead, let’s just focus on the ethanol itself—and how many acres of poplars it would take to satisfy our demand for transportation fuels.
Ethanol isn’t quite as “energy dense” as gasoline. A thousand gallons of ethanol has about the same amount of energy as only 610 gallons of gas.
Here in the Northwest (British Columbia, Washington, Oregon, and Idaho inclusive) we use about 6 billion gallons of gasoline per year. So if the poplar research is close to being right, it would take about 9.2 million acres of poplar plantations to satisfy our gasoline appetite.
That’s a lot of land—it’s area about 9 times the size of Washington’s Olympic National Park, or roughly the size of New Jersey and Connecticut combined. Quite a poplar plantation, I’d say.
Scaling up to meet the total gasoline demand of the US and Canada, you’d need a poplar plantation about the size of California plus Montana, with Mississippi thrown in for good measure, to satisfy the nations’ demand for gasoline. And that doesn’t even cover diesel or airplane fuel.
Needless to say, with numbers like these, it’d take a huge national effort, and a major disruption of forest ecosystems, for poplar-based ethanol to make a serious dent in our petroleum habit.
I don’t mention all of this to throw cold water on alternative fuels. I, for one, am guardedly optimistic about cellulosic ethanol, and am delighted that WSU is doing the research. Still, it’s important to keep in mind the scale of our fuel consumption: we use so much gasoline right now that biofuels just aren’t a silver bullet. It’s going to take a lot more—everything from super-efficient vehicles, to compact neighborhoods that minimize travel, to incentives for filling empty seats—if we’re really going to create a transportation system that can last over the long haul.
Gary Durning
First off, Go Cougs! Im writing this post and looking at the wheat fields outside my dormroom window at WSU. It seems to make sense for efficency for us to plant more poplar’s and less corn. Corn based ethanol is a mixed bag becuase of the increased demand which has translated into inflation pressures on a variety of corn products. And inflation in the most basic of food sources is worrisome. An increased poplar demand wouldn’t have as many inflationary pressures as corn.
sf
From articles on “The Oil Drum,” I think the problem with cellulose ethanol is that distillation uses so much energy that it is not commercially feasible or a net energy producer. It ferments to about 1% alcohol, leaving 99% water to be distilled off by heat.
permfuel
I refer you to a new book,”Alcohol Can Be a Gas! Fueling an Ethanol Revolution for the 21st Century” Poplars are one source. We shouldn’t be focusing on just one source. What for example can be grown UNDERNEATH the poplars that can be used as energy crops? Using permaculture, what is the most efficient way to produce maximum food and energy crops in one space?The book lists around 30 sources, with water-based and desert-based crops among them. Cellulosic ethanol will be great and with the subsidies given to oil companies, it would be here now. Brazil is already making the stuff. But we can still make huge amounts of carbohydrate ethanol permaculturally WITHOUT impacting food supplies or agricultural land availability. Check out the book, see for yourself.
sf
The only reference to that title on Amazon is to a 24 year old, out of print book. http://www.theoildrum.com/story/2006/10/22/211321/89Here is an article by a chemical engineer with a recent master’s thesis on cellulose ethanol, re the problems in making it practical.
sf
In our region, I suspect that residues and thinnings from native forest trees are a bigger potential resource than poplar. And electrical generation using old fashioned steam turbine technology is probably a better way to produce energy from this resource than cellulose ethanol processes. There are currently three biomass generating plants within 70 miles of my home.
permfuel
permaculture.com for the bookLet’s just say chemical engineers aren’t biologists, and again, cellulosic ethanol is currently being made in Brazil now out of bagasse. Remember, I said water based and desert based crops. Check out book excerpts. It’s not on Amazon.. yet.
sf
I’d have to be a little skeptical. Bloomberg says they aren’t planning to produce commercial quantities until 2012. Bagasse is already used for energy by burning it. The advantage they do have with bagasse is that there are no feedstock costs because it is already there. Getting the material to the plant is typically 75%-80% of the total cost. A chemical engineer is the guy to talk to about getting from raw material to finished product.
permfuel
A chemical engineer? You mean a petroleum engineer anointed by the oil industry as the point person for ethanol? given the oil industry’s history with trying to obstruct/destroy all attempts at alternative fuel, I would vote for skepticism here as well.What are commercial quantities exactly? They presently operate a 4.6 million gallon a year pilot plant. A plant this size could be used on several average sized midwest farms right now. Will it supply the entire country? Not the point. The point is it’s being done, can be done and the only thing stopping it from being done all over is politics, a need for massive scale (hence the Iogen plant has not come online because somehow oil companies who have invested massively don’t seem to want to provide the capital to get it running. hmmmmm)Again, read the book. One can sit around on a computer and be skeptical or one can go out and do what the writer suggests. Not for armchair quarterbacks, that’s for sure.