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You want to build a sustainable ethanol production plant in a rural area with great sun, water and lots of land. So, how much cellulosic biomass would you need to produce a 100 gal of ethanol? How much power used in the making?
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What kind of mileage does a 4 cyl alcohol powered vehicle get?
At present, there is no viable process to make ethanol from cellulose. All conventional ethanol plants now make it from fermented corn, sugar cane, or potatoes.
Mileage from a 4-cylinder engine car (running on ethanol) is less than that achieved with gasoline-because ethanol has only 67% of the energy content of gasoline.
A much better solution is to power vehicles with either compressed natural gas (clean, zero emissions, but you lose the trunk), or with wood alcohol (synthesis of natural gas).
I know it’s not viable in large scale yet. What does the technology usable in a small scale plant look like today? Cost?
So if a gas powered car got 30 mpg, it’d get 20 mpg on alchohol?
My questions are answered here. This is from 2005. What’s happened in the last 5 years?
http://www.harvestcleanenergy.org/enews/enews_0505/enews_0505_Cellulosic_Ethanol.htm
I recommend it. Yes, the industry is in it’s infancy BUT
So what I get from this is that our 30 mpg gas car would get 60 mpg.
If burning a gram of cellulosic ethanol produces three times more heat than burning a gram of corn ethanol, then they ain’t chemically identical. They must mean cellulose eth takes less energy to produce than corn eth- or something like that.
Yeah it’s awkwardly stated. C2H5OH works the same in your car, however they make it. I suspect the point they are trying to make concerns the production processes. Ethanol will get lower mileage than gasoline, BTW. If cellulosic ethanol works as promised, this is still acceptable.
Yeah, MPG is only really useful as a direct comparison of efficiency between similar sorts of vehicles. So what if ethanol is less dense and you only get (say) 20 mpg in your car instead of 30 mpg with gasoline? That just means you have to stop and refill the tank somewhat more often. If there was a really cheap and abundant fuel that emitted no CO2, but it had a low density, people would still flock to it even if you could only get 5 mpg in your car. You’d just have to plan on stopping at the magic-pixie-dust-gas station more frequently, and plan longer trips more carefully.
I’m thinking of converting 3 towns in a 75 mile long bioregion. Most local traffic seldom leaves it.
It may also be the best alternative for some sorts of travel, given that we eventually have to get off the oil teat, even if more expensive than CURRENT gas prices.
Part of the attractiveness of ethanol is that it is something we can make provisions for now by manufacturing flex fuel vehicles which will burn gas or E85. It’s not a really extensive design change, mostly a matter of making the fuel system out of materials that won’t be corroded by ethyl alcohol. If ethanol works out, you’re ready. If not, we haven’t wasted that much effort, and those vehicles are just burning gas like other cars.
For the last couple years, EPA has started posting E85 mileages together with gas mileages for flex-fuel vehicles. You may browse through ethanol capable vehicles here, and compare their mileages:
Click on “Cars that don’t need gasoline.”
A good rule of thumb will be that a vehicle will get about a 30% reduction in mileage over gasoline when burning E85.
Here’s a cellulosic ethanol producer who claims it can get 2,000 gallons of ethanol per acre from poplar trees. Breaking it down, I come up with 11.25 gallons per ton of biomass. However, ethanol production is usally calculated per ton of dry biomass. Amazingly, there’s actually a study that projects the dry biomass of poplar trees is 22,100 kg/ha, which works out to about 9.7 tons per acre.
So your 100 gallons of cellulosic ethanol comes from just under an acre of trees, after they’ve been dried.
I’ve seen claims that using dried corn cobs will produce a much higher yield of ethanol per ton, but of course, cobs account for only a small fraction of the biomass of a cornfield, so you’d have to harvest the cobs from many more acres.
As others have said, a gallon of ethanol produces less energy than a gallon of gasoline. Assuming the drivers in your communities are currently averaging 25 mpg in the gasoline-powered vehicles, they’d get a little less than 17 mpg if they switched to 100% ethanol. At 10,000 miles per year, each vehicle would consume about 597 gallons of ethanol – very roughly (feel free to check my math) about 6 acres of trees per car per year.
As for feedstocks, a LOT of things are possibilities for cellulosic ethanol. Switchgrass and elephant grass, for instance, which can grow on marginal lands. Not to mention waste wood like old utility poles, and the possibility of “mining” our old landfills. We currently have about thirty some million acres of land in the Conservation Reserve Program. It may be the case that something like switchgrass could be harvested off that land sustainably, with minimal ecological impact, and in considerable quantities.
Thanks for you interest. I’ll accept your math.
So, let’s imagine a community fleet of 6 vehicles used for transport and traction.
I’m thinking 3 for near-to-town transportation and transport and 3 for regional deployment (inter-town bus service, agricultural stoop labor, etc.)
Emergency calls are handled by the three local vehicles on call which pick up fire/medical trailers and do their business. No fucking sirens.
OK, 6 vehicles. On avg, each runs 50 mi per day. That would be 6 X 50 X 365 = 107,500 vehicle mi per year.
Let’s call it 6 acres X 10.8 = 65 acres per year per fleet. Around here, that’s sustainable now.
But I’m thinking several thousand acres or hemp or switchgrass would be convenient, not to mention scrap cellulose. Recycling would be big.
Well, trees need time to grow. The study I quoted harvested the trees after five years. So, in order to keep the tree crop sustainable, you’d actually have to grow five acres for each one you harvest each year.
But switchgrass, there’s another story. It grows a lot faster. Here’s an article that suggests switchgrass yields can average 11.5 tons of dry biomass per acre per year. (that’s according to Auburn University, a southern school. In the north, the growing season will be shorter, and yields will be lower.)
Running the numbers suggests both studies assume a ton of dry biomass yields roughly 100 gallons of ethanol. So switchgrass might actually produce more ethanol per acre than trees.
However, my assumption that your vehicles will get 17 mpg on ethanol goes right out the window when you indicate they’ll be hauling trailers. You’ll need trucks. The best EPA city rating I can find for a Ford F-150 is 15 mpg. Again, assume pure ethanol cuts that by 33%. Using your estimates, that works out to 10,750 gallons per year. Of course the potential higher yield of switchgrass may cancel that out.
Of course, you’ll need a production facility. There’s a small one in east Tennessee you can pick up for $250K. It’s probably going to need some fixin’ up, but at that price, it’s a bargain.
Now, someone should point out to you that even with subsidies, no cellulosic ethanol plant in the U.S. has made an operating profit, much less a long-term return on investment. But as long as you’re going for self-sufficiency you can budget your losses and plan accordingly.
Agreed. I happen to live at 8000 ft and within 15 mi of the continental divide. Plenty of poplars.
Fine with me.
Small ones at 30 mph.
Thanks for the cite.
Precisely. Thanks again.
Heck, as long as you only want a small quantity of ethanol over the course of a year, why not just get the kit?
And before you do that, try making it in a bucket.
Thanks.
Why don’t we go to an all-hydrogen economy? WE can set up big nuclear electric plants in remote locations, and use the electricity to split H2O-release the O2 and compress the hydrogen. We an then send the hrdrogen around with our existing natural gas pipelines. Hydrogen is the ultimate clean fuel-no exhaust except water vapor. Despite advances, ethanol production is not energy efficient-Brazil 9the country with the most advanced ethanol production), is looking a problems like:
-sugar can displacing food crops (driving up the price of foods)
-sugar cane requires lots of water-irrigation of the fields is depleting the ground water
Ethanol is not a good fuel in cold regions-I imagine driving a E85 car in a Minnesota winter would be a challenge
There would a few political, economic and technological problems to overcome. 
Not likely.
My understanding is that cellulosic production is quite energy efficient.
Can you give me a cite? IIRC, that aerosol Quick Start I sprayed into carburetors on frosty mornings was ethanol.
My understanding is that cellulosic production is quite energy efficient.
Yes, maybe, except there is no efficent process (yet) commercially available-all domestic ethanol is made from corn (this results in higher oil imports, but don’t tell that to the corn lobby).
Quote:
Ethanol is not a good fuel in cold regions-I imagine driving a E85 car in a Minnesota winter would be a challenge
Can you give me a cite? IIRC, that aerosol Quick Start I sprayed into carburetors on frosty mornings was ethanol.
No cite, excpet my first trip to Brazil-my BIL’s alcohol-powred Fiat was difficult to start on a cold morning ( 40 F); it them would backfire for 15 minutes (unburned alcohol in the muffler).It sounded like a small bomb till it warmed up.
If we planted every median strip, inner clover leaf, and road shoulder with switch grass, I’m betting we could provide for at least 40% of our transportation fuel without adding another acre of arable land to the equation. Of course, some inner city medians would not be big enough to use, but I can’t believe the amount of time, money, and energy wasted landscaping these huge areas of land.
Some low-rain and/or high erosion areas might only be harvested once per year, but in my area, most could be harvested 2-3 times per year.