The Oil Drum | Climate Change and Electricity From Biomass

171 comments on Climate Change and Electricity From Biomass

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memmel on July 31, 2006 - 1:45pm

Biomass is bulky until peopel focus on use cases were the biomass is converted to and alternative form very close to where its created I don't see the sense in discussing it.

I use the scenario of the Georgia moonshiner the reason he makes moonshine from corn is its not cost effective to transport the corn from the mountian valleys to market so he converts basically onsite to a higher grade smaller format.

Biomass solutions must look at economies possible from distributed resources towards concentrated resources with minimal transport. Any other approach is relying on the existing oil/coal based factory to support production.

Consider corn.

One you need to distill so like the Georgia moon shiner you need access to some form of heat for distillation this can be solar power part of the biomass or popular or other brushy biomass used to fuel the distillation. The moonshiner used the abundant wood but in our case we could do a coupled biomass system with some optimized for burning.

Resulting ethanol can easily be moved via pipelines back to the main distribution center.

There's more but until I see someone work through conversion at the farm or better at the edge of the field to high grade
fuel using only local inputs I don't see the point.

Maybe a even better for biomass if you take a longer term view is artificial maybe salty peat bogs that are periodically drained.

I mention this because I've also researched running the oceans carbon cycle on a small scale you can readily get up conversion to krill which then form the equivalent of proto oil muck which can then be dried and refined. Salt water ponds allow the growth of wood eating bacteria and worms.

Also you can for example even look at electrical generation directly from a large muck pond via

http://news.bbc.co.uk/1/hi/sci/tech/3092754.stm

In any case managed muck ponds are very cost effective.
We routinely age wine and cheeses for years why not consider the same for biomass ?

I don't know what pisses me off not doing bio fuels or the fact that engineers are not even considering one the most basic aspects of a bio fuel system which is the initial biomass has to be converted as close to its production point as possible. This constraint drives most of the rest of the design. I find the absolute stupidity alarming. Either I'm way off base or there are a bunch of really dumb people in biofuels.

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joule on August 1, 2006 - 10:24am

memmel -

True, most biomass is quite bulky in its rough just-harvested form. But it can be made much less bulky by simple mechanical operations that can be set up at the point of harvest. The use of large tub grinders could convert the woody biomass into small chips with a far greater bulk density. Various compaction or bailing techniques could also be employed at the point of harvest.

I would venture that with proper chipping and compacting techniques, biomass could be given a bulk density perhaps a third to a half that of coal, and coal is transported tremendous distances.

I fully agree, though, that it is preferrable to have the operations as close to the biomass source as possible, but my main point is that there is still an economically favorable radius of operations for a biomass-to-energy system.

It all gets down to a big material handling problem.

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memmel on August 1, 2006 - 11:27am

Compaction takes energy we of course don't know off hand how much but I suspect its not cheap both in equipment costs and operation expenses to run this type of equipment.

After coming up with the concept of compacting biomass via a artificial muck pond or swamp I went looking for references surprisingly there seems to be no research on using pond muck as a carbon source. Now natural swamps are well know for there carbon rich deposits which burn when dried and peat is a well known source of fuel. Next with proper treatment algae blooms can be encouraged in a muck pond to add further biomass. They could be covered to collect methane also. So while the pond is filled it can act as a electric source and a methane source.

And again they can act is direct low level electric sources via bio batteries. Fresh vs Salt water muck ponds would also need investigation and those are just basic parameters that can be changed to influence the bacterial population of a muck pond you can play with oxygenation nutrients temp etc.
In colder climates composting on top of ponds covered with strong lids could be used to keep the temperature up plus using salt water ponds.

The concept would be to have a muck pond probably shaped as a long trench to allow easy access lined with clay concrete or plastic and potentially covered with plastic when not being filled. If these are done as long raised holding ponds down the lengths of a field the biomass harvester can simply deposit the biomass directly into the muck pond.

Lets estimate that it takes three years to fill the muck pond at the end of three years its drained with the rich effluent used to fertilize the field along with some of the muck. Next its allowed to dry and the concentrated carbon which is basically a cheap coal is sent to a CTL plant. And I say CTL because this process can be augmented with coal if needed. Residual ash is basically phosphate fertilizer since the biomass source is not important legumes can be rotated in to ensure nitrogen fixation and again the muck itself is incredibly rich.

Now if you want to do ethanol production also the crop can be harvested as normal and the peat can be used to close the cycle for distillation.

For energy sources we know they go oil->coal->peat so there is little or no reason to argue peat is not a valid and good energy source.

Can anyone argue against this scenario ?
Its really just a cheap bioreactor.

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joule on August 1, 2006 - 11:53am

memmel -

The energy consumption of various grinders, chippers, and balers in terms of energy per unit weight of material processed is well known. One can get that number merely by calling up any number of equipment suppliers.

If one is going to gasify the biomass or process it into ethanol, the biomass is going to have to go through at least one size-reduction step. So my point is simply: why not do that size reduction right at the point of harvest so as to also increase the bulk density of the biomass and save on transportation cost.

Harvesting pond muck is an interesting idea. As long as the concentration of organic matter is high enough and you can dewater and dry it without consuming a great deal of energy, it might have a positive energy return. It would work much better in warm rather than cool climates, particularly if you want to go with natural solar drying. Again, the economics of material handling is what can make or break such a scheme.

Building large open ponds or lagoons is relatively cheap and easy. Buidling large ponds with a transparent cover is neither cheap nor easy. Going with long narrow trenches would help ease some of theses construction difficulties.

What about harvesting water hyacinthes? These floating plants grow wild in Florida , grow incredibly fast, and tend to blanket whole ponds. They soak up nutrients like crazy, which is why there have been some demonstration projects using a water hyacinthe pond to treat domestic sewage. I happen to have a tiny koi pond by the side of my porch that is only about 5ft wide and 6 ft long. Each spring I buy two water hyacinthes for it, and by mid summer the pond is completely blanketed. In fact, I have to remove at least 2 - 3 plants each morning from mid-July through mid-September (this is in Delaware). The plants have a pretty high water content though, so dewatering and drying would be a major energy input. Just an idea.

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memmel on August 1, 2006 - 12:09pm

Lets call them muck ditches I call them ditches now simply because it makes more sense to go with a long narrow pond I think then a large one.

Also there not quite ditches since they would need to be above the land level at least at some point to allow natural drainage similar to rice farming.

For northern climates you need to simply overfill the ditches with organic matter to get a composting zone which will maintain the temperature you don't need strong covers. The temperature should stay well above freezing.

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odograph on August 1, 2006 - 12:03pm

Can anyone argue against this scenario ?
Its really just a cheap bioreactor.

At a guess, it sounds like a good idea for small scale and slow production ... but if you run the numbers for a commercial scale production plant it will start to look bad.

Can you really fill a pond over 3 years and then immediately start draining it? Or do you need to fill them, and let them stew (producing methane of course) for some number of years? How many ponds does a 100 million gallon per year plant need? If it can't do 100 million gallons, is it even a silver bb?

(in contrast, I'd expect the total cycle time for corn ethanol from grain delivery to shipment to be no more than a few weeks ... assuming they let the yeast work down to the last sugars)

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memmel on August 1, 2006 - 12:54pm

At a guess, it sounds like a good idea for small scale and slow production ... but if you run the numbers for a commercial scale production plant it will start to look bad.

I don't buy any numbers for commercial production since there based of leveraging the oil economy and will skyrocket over time. Maybe the first round of plants are feasible but what about the next round and after that ? The expense of digging a ditch can be as cheap as you want. And it can be spread of the lifetime of the ditch wich is at least decades. The only additional cost is plastic sheeting which can be itself produced from biomass so it will become fixed. In any case even when oil/natural gas becomes expensive for fuel its still a valid source for plastics for a long time esp once fuel pressure is removed.

Can you really fill a pond over 3 years and then immediately start draining it? Or do you need to fill them, and let them stew (producing methane of course) for some number of years? How many ponds does a 100 million gallon per year plant need? If it can't do 100 million gallons, is it even a silver bb?

Sure you can fill them at any rate you want it depends on the depth of the pond vs the biomass etc. That's a mechanical problem. The rate of breakdown or compaction is the issue. Take the natural setting your typical poorly maintained farm pond my experience has been that the layer of undigested organic matter is generally very low but the question is not what the fill rate is but what is the compaction rate ? I know semi dry composting takes about a year or less. A cows stomach or rumen digestion is a matter of days. A muck pond would be between these two extremes. Currently its rare to create the conditions for producing muck on purpose but in natural settings it seems to work quite well even in northern climates.

(in contrast, I'd expect the total cycle time for corn ethanol from grain delivery to shipment to be no more than a few weeks ... assuming they let the yeast work down to the last sugars)

Your thinking like and American whats the quick fix damned the costs. First everyone just about agrees the real answer is cellulose based solutions so forget about starch. My approach is a semi-managed local bio-reactor vs a monoculture solution. Considering the bacterial flora of a cow gut or termite and swamps I'd say mother nature thinks a bacterial witches brew is the best answer. Also on the chemical side you have syn-gas from the peat plus methane from the working ponds as feed stocks you can then produce whatever chemical is in demand plastics ethanol/butanol methanol FT what ever pathway. Also since you can combine the peat with methane your CO2 blow off is greatly reduced since you can boost syn gas production via C02 + CH4 -> 2C0 2H2 The methane is acting as a hydrogen source. You can do the same with coal and a natural gas source to control the C02. And that's the last point this approach works reasonable well with a tandem coal based economy till coal can be eliminated because again its really just a way to make low quality coal. And finally to address the economies of scale the peat or dried muck is already a microfine particulate so it goes right into a fluidized bed reactor or it can be moved and added as a slurry your paying the price for final drying but its like a wet coal. Potentially you could dry it and slurry with a low boiling organic solvent that's flashed off at the reactor or combine it with a natural oil like soybean oil. So it would be a carbon loaded natural oil. In the low boiling organic carrier case the carrier can be reused. In the case of a high boiling organic carries settling ponds would remove the bulk of the carrier for reuse. And to finish if you can pipeline the muck you can send it to a central plant but you can also process it locally. In any case using local muck ponds to massively increase the carbon content and break down the cellulose makes a lot more sense then exotic single species fermentation approaches for fuel.

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odograph on August 1, 2006 - 1:24pm

No, I'm thinking like an engineer ... and trying to frame this as a set of numbers.

If you don't start with a plant production number, what do you start with?

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memmel on August 1, 2006 - 2:22pm

Its not a plant production problem its a matter of determining the best way to convert bulky biomass to a usable form. I'm suggesting simple bioreactors to produce concentrated peat and methane. These would be used to produce what ever output you want if its liquid fuels then the cost is similar to CTL. Since its syn gas. I'm arguing that energy concentration at the source is a must for biofuels and natural digesters are the right thing to do. By overloading the digesters with organic material from surrounding croplands over a multi year period your replicating natural concentration steps that produced peat and thence in time coal. The approach concentrates organic material via two steps overloading from surrounding land and bacterial decomposition to reduce bulk. And its cheap and effective. The one modern magic material needed is a plastic sheet for covering that was not available to our ancestors. You can use ceramic or glass or steal coverings also so its possible without plastic but in this case a decent plastic cover makes the most sense. The ditch can be lined with clay/bricks concerete or agian plastic. My point is my argument is the number one problem with biomass is concetrating it not conversion this is a simple cheap and effective method to concentrate biomass.

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odograph on August 1, 2006 - 2:36pm

I have actually blue-sky'd about adding waste biomass to manure ponds to increase/prolong methane production. In a small (direct use, as I said above) case it might make sense.

Now, currently the output of those ponds is fertilizer, and not waste in the sense of something that must be shipped at some cost to disposal. As I understand it, it can be sold.

If you are going to propose drying and conversion to liquid fuel, that is the step ton concentrate on. For that the numbers of interest are how many tons of psuedo-peat you need, what it costs to process it, and how much liquid fuel it produces.

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memmel on August 1, 2006 - 3:05pm

Going from natural peat production See http://www.fao.org/docrep/t0512e/T0512e0b.htm

Peat The biggest problems in gasification of peat is encountered with its high moisture content and often also with its fairly high ash content. Updraught gasifiers fuelled with sod peat of approximately 30 - 40% moisture content have been installed in Finland fox district heating purposes and small downdraught gasifiers fuelled with fairly dry peat-pellets have been successfully tested in gas-engine applications (25). During the Second World War a lot of transport vehicles were converted to wood or peat gas operation, both in Finland and Sweden.

Now one approach is if the ditch is actually lined say with concrete or clay with embedded pipes and a tight cover can be fitted the entire ditch once drained and allowed to air dry can be blown with methane and in-situ gasified. Also you can introduce more dry organic material on top after draining to add fuel to finish the drying process. So in theory you need not move anything. So the final issue is how much the moisture content can be reduced during the final drying certainly methane and dry organic material can be added to finish the drying. In the case of more organic matter denser woody material such as popular thats say grown for 3-5 years beside the ditch while the ditch was being filled can be cut and used. As far as water content its known that natural peat bogs burn when drained or during droughts so obviously it drops enough for ignition and as I said before added dry organic material and methane can be used to initial and control drying and syngas production. The addition I've made is adding pipes to the bottoms and sides to inject methane if needed. Adding a final dry matter depending on moisture and creating a simple syngas reactor out of the fermenter with a fireproof covering that can be reused. If the covering is slightly wider then the ditch then it can be u shaped and simply buried to get a seal. Old time charcoal production used a similar method. I would not be surprised if you don't need to actually add water as the reaction progresses. Finally if needed or wanted the sludge could be scrapped into a smaller area before in-situ gasification. This could be done if needed by scraping several inches of the top material to a part of the ditch designed to be the gasifier as it dries. This should not be required but probably greatly hastens the drying process and its not a lot of energy.

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davet on August 1, 2006 - 12:43pm

This is interesting: what you're proposing to do is run a peat farm. IIRC the energy density of peat is not terribly high, but it might still be useful, especially as it will likely be higher than raw biomass. I think it's time to run some numbers and show us how it would really work. If you must go CTL, you have the advantage of a better C:H ratio than coal, although I don't how the engineering details work out.

Re: salt water. Usually has a lot of sulfate, at least if salt water = sea water. If you're waiting long enough to get significant methane generation you might also get significant sulfide generation, which on combustion turns back to sulfate, forming PM and acid rain. The sulfide may also have NIMBY odor issues (to be fair, H2S is also toxic). Then again, that might be trivial. Run the numbers and show us.

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memmel on August 1, 2006 - 1:20pm

Its a research problem to run the numbers I've tried to google for research on the topic but it surprisingly seems to be and area that few have considered. Sulfur is of course and issue but it can be remediated locally. I think the reason its not done is because of the smell thus in all my posts I mention the use of covered ponds or better ditches. But if you have ever been near a turkey or swine farm some things smell. I actually worked as a sulfur/boron chemist for a while since there is little work in the area once I invented synthetic cat urine and realized why sulfur chemistry is not widely pursued. The sulfur itself is a required nutrient ammonium sulfate is a fertilizer. Also note if you use a grain producing plant for at least part of the production you can combine pig/chicken farming and recycling the ammonia with the cellulose production. Also if you produce concentrated sulfuric acid it can be used for numerous industrial processes dehydration to ethers or oxidation to carbocyclic acids for example. Also I'm a chemist this is a mass transfer problem :)

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odograph on August 1, 2006 - 1:29pm

I was a chemist before I was an engineer ... and learned to run numbers in a rough quant course ... I think my old prof would want to see more than text here.

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memmel on August 1, 2006 - 2:09pm

Man numbers are hard to come by. Generally people try not to initiate anarobic digestion :)

In any case my bust guess since references are slim is to start with areobic digestion with traditional composting methods this leads to a base of organic rich material as it accumulates water is added to induce anaerobic digestion and the composting region moves up the ditch. Anaerobic digestion is hell to find but agian we can point at rumen digestion and methane digesters to show its in the few week month rang. Same with composting. So I think all organic material introduced should be reduced well within a year. Again I can't find any references outside of methane digesters for animal waster where your actually overloading the system with organic material but we can assume its about the same.

Final answer is I don't really know the rates and I don't think anyone has really tried it but they seem to be reasonable. Since its a artificial peat swap compaction is on the order of 100:1 from bulk organic material.

This google search revealed there is scientific work in the area but its all behind paywalls.

http://www.google.com/search?hl=en&rls=GGGL,GGGL:2006-18,GGGL:en&sa=X&oi=spell&resnu m=0&ct=result&cd=1&q=rate+of+organic+material+breakdown+in+anaerobic+water&spell=1

There is of course the time lag between intial filling and
final draining thats on the order of years simply to accumulate organic material for some time. I think thats
the limiting factor not the biological digestion rates.

From this
http://aggie-horticulture.tamu.edu/extension/compost/intro.html

We learn that composting reduces organic matter bulk by 80%
so my estimate of 100:1 for a mixed aerobic/anarobic digestion is reasonable.

The energy content of peat is well known plus we get the methane also.

Finally this suggestion is not a lot different from fancy bioreactors just were fine with producing methane and carbon
to make syngas instead of trying to control the products to get ethanol.

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odograph on August 1, 2006 - 2:29pm

I have a good general feeling about biogas production for direct use. That's done a lot of places in the world.

The thing I'm most concerned with here is the "to liquids" step of the BTL process. I did some surfing and it looks like pyrolysis of wood and peat is the path to a liquid biofuel (biodiesel):

Bio0il (pyrolysis oil) is a liquid fuel with medium heating value that can be used to generate electricity and heat at industrial locations such as saw mills, pulp and paper mills, wood processors, agricultural facilities and recycling facilities. Because it is derived from biomass, Bio0il is deemed to be greenhouse gas neutral. It has virtually no sulfur, low nitrous oxide emissions and very low particulates (significantly lower than diesel) when combusted. Bio0il can be used directly at the point of production. Bio0il is transportable, opening potential for small power generation plants to service installations such as hospitals, schools, universities, hotels, and other commercial and industrial facilities. On April 14, 2004, ground was broken in Vancouver, BC, Canada, on the construction site of what will be, when completed in the summer of 2004, the world's largest pyrolysis plant and the first pyrolysis oil fuelled power cogeneration facility. It will demonstrate the commercial potential in improving the efficiency of energy recovery from conversion of biomass waste to generate electric power from less fuel than traditional methods that use solid biomass combustion.
The plant is expected to process 100 tons per day of biomass and to produce 70 tons of BioOil, 20 tons of char and 10 tons of non-condensable gases. Fifty tons of BioOil per day will be utilized to fuel a gas turbine developed by Orenda to produce up to 2.5 MWE of electricity -- enough to serve 2,500 households -- to meet the power requirements of the Erie Flooring plant and also enough to export electricity to Ontario's energy grid. Surplus heat generated by the turbine will produce up to 12,000 pounds of steam per hour to provide heat for Erie Flooring's industrial operations. The remaining BioOil and char from the plant will be sold to commercial users and used for research purposes. Non-condensable gases will be used to provide heat to the process.

http://forestry.nacdnet.org/biomass/WoodBiomass.htm

Seven tons of oil from ten tons of biomass sounds pretty good ... but the question might be how pre-digesting, and then drying, to a pseudo-peat, changes that equation.

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memmel on August 1, 2006 - 3:13pm

See my above post final drying and gassification can be carried out in-situ with the right construction. Additional biomass and methane can be added to control the composition. The only real problem is how dry does a artificial peat ditch get from simple solar drying and gravity draining. I point to the fact that natural peat bogs burn under drought conditions to show it gets dry enough.

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davet on August 1, 2006 - 3:22pm

70% sounds really good, maybe too good. Wonder if you can do this with something faster growing than wood: bamboo, say, or kudzu, or water hyacinth. One concern with peat is that if it works well, we might decide to dig it up instead of make it. That would be disastrous from a CO2 perspective.

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memmel on August 1, 2006 - 4:02pm

We do dig up natural peat bogs now for fuel.

The advantage here is since were creating the peat bog we control the surroundings by two means one the bog is actually above the natural water table allowing it to be drained like a holding pond. Next we have pre-lined our bog with a impermeable material probably clay or bricks or concrete. Next we can almost certainly do in-situ gasification. We are also loading the bog way beyond natural rates by introducing biomass from the surrounding fields.

It really the artificial nature of the bog that makes it worthwhile over natural peat bogs. Of course people drain natural bogs all the time also. Generally though there far from the population and can't compete with coal at least so far.

As a finally note the ash left over from gasification is a great fertilizer and can be spread back on the adjacent fields.

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davet on August 1, 2006 - 4:41pm

We do dig up natural peat bogs now for fuel.

Well, of course. The real advantage of a peat farm (if it can be made to work) is that you only burn what you've accumulated in a year or however long it takes to make your peat, not burning tens of thousands of years of accumulated reduced carbon. The concern was that if you had a way of making peat valuable as fuel (directly, through BTL, whatever) we'll have the coal problem all over again, only we may end up destroying wetlands while we're at it.

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memmel on August 1, 2006 - 5:48pm

As long as there is coal it more cost effective to mine coal then peat.

My artifical peat ditches differ dramatically from natural peat bogs.

First there charged with organic material from the surrounding
farmland that gives you say a 100-200:1 greater accumulation ratio than a natural peat bog. So in reality your getting if you fill for 3-5 years at least 300-1000 years of natural peat production plus your capturing the methane wich is a significant part of the overall energy probably 30-50%.
If for example you have 200 units of land you would fill a
artifical bog of say 1 unit. Its a volume problem since its related to the amount of organic material and the depth of the bog I'm guessing at leat 10-20 foot depth for the bog.
Needless to say the bog itself can be located on the least valuable land. I'm guessing to some extent but you can easily take the hay from a hundred acre farm and store it on a one acre plot piling it 20 feet high I find numbers like 9-15 dry tons per acre is common for biomass.

you have numbers like this for a round bale of hay

Hay Weight. 5 ft. 5 ft. 1200 lbs/bale So its about 1 ton
per 10 sq foot.

1 acre is 1 acre = 43560 sqft
divide by ten and that's
4,356 tons per acre storage.

And assume 10 tons per acre production gives
435 acres per 1 storage acre.

Man I'm good at back of the envelope calculations :)

You don't need to tightly bail the hay but it should compact
quickly under its own wet weight in the bog.

Except that the process is the same for peat production a artifical bog as I've described has a quite different energy profile from a natural bog.

Its the above multipliers that make it a viable energy source competitive with coal. In nature as far as I know there is generally no natural situation where a bog is flooded with organic material periodically except maybe if a river overflows into the bog area and it has a lot of organic material suspended. It would be intresting if this happens naturally somewhere on the planet maybe in the Amazon ?

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davet on August 1, 2006 - 10:05pm

Bottomlands of many large rivers (Nile, Mississippi, etc) at least before the rivers were dammed and the wetlands drained. It wouldn't technically count as a bog (water inputs only by precip, no outlet) but who's counting ;)

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eric blair on August 1, 2006 - 6:10pm

Can anyone argue against this scenario ?
I can provide data against some parts. Creating a bioreactor is yet another system needing management VS the "old" (ok present) system of taking out a dollar and buying energy. It will be hard to sell VS systems that capture sunlight or wind which have less management issues.

Next its allowed to dry and the concentrated carbon which is basically a cheap coal is sent to a CTL plant. ... Residual ash is basically phosphate fertilizer
If such is true, why do the rock dust as plant growth medium people see the better growth with rock dust, if plant growth was 'just' NPK? (Examples - remineralize the earth, www.thepeacock.com, and the azioth(sp) people)

The person(s) who come up with a system that can use 40 acres of biomass and is as easy as dumping material in one part and taking out the liquid carbon-hydrogen chemical/leftovers will become very wealthy making said devices. Most of the systems being offered up have market-protection in the form of massive costs to create and to provide an economic return need to draw in material from a wide area.

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memmel on August 1, 2006 - 6:40pm

Can anyone argue against this scenario ? I can provide data against some parts. Creating a bioreactor is yet another system needing management VS the "old" (ok present) system of taking out a dollar and buying energy. It will be hard to sell VS systems that capture sunlight or wind which have less management issues.

Even in a heavily electrified society there is still a lot of places where liquid/gas organics are needed. You still need to make plastics for example paint etc etc. And fuel in some cases. I'm not saying by any means this is a route to maintian our current fuel usage I am saying that there is no reason the farm cannot be the chemical factory of the future. Boifuel/mass solves a quite different problem from wind and solar electric generation you need all three.

Next its allowed to dry and the concentrated carbon which is basically a cheap coal is sent to a CTL plant. ... Residual ash is basically phosphate fertilizer If such is true, why do the rock dust as plant growth medium people see the better growth with rock dust, if plant growth was 'just' NPK? (Examples - remineralize the earth, www.thepeacock.com, and the azioth(sp) people)

I don't quite understand this comment slash and burn agriculture has been around for thousands of years. The fertilizaiton aspects of ash are well known.

The person(s) who come up with a system that can use 40 acres of biomass and is as easy as dumping material in one part and taking out the liquid carbon-hydrogen chemical/leftovers will become very wealthy making said devices. Most of the systems being offered up have market-protection in the form of massive costs to create and to provide an economic return need to draw in material from a wide area.

I estimated 100 acres gives a good yield that's not a industrial proposition but a reasonable sized farm. And my point is some good old fashioned basic science means you don't need massive costs or industrialization to get high grade liquid fuels from biomass just knowledge. Also they can be pulling in biomass from basically fallow fields planted with legumes and grass you don't need to grow high energy row crops. So this would come from resting fields.

Burt Rutan would laugh his head off at your comment I suspect. This is not rocket science :)

And yes said farmer would become reasonably wealthy and why not ?

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eric blair on August 8, 2006 - 10:59pm

I don't quite understand this comment slash and burn agriculture has been around for thousands of years. The fertilizaiton aspects of ash are well known.

Yea, that would be the part where the arceage becomes non-productive after a few years.

Feel free to show how what I've stated is not correct.
Burt Rutan would laugh his head off at your comment I suspect.

And somehow I don't think you have a clue about what Mr. Rutan would think or not think.

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odograph on August 1, 2006 - 11:53am

Thinking of the above numbers a little bit, it's basically a ton of high quality biomass burned for every 100 gallons of ethanol distilled.

Assuming E100 cars would drive the typical 15K miles per year, at 15 mpg, that 1K gallons ... requiring 10 tons of biomass to be burned (just for the distillation step) for each and every car?

(actually, I HOPE I did that wrong)

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odograph on August 1, 2006 - 10:39am

I think it is dangerous to just say "solar or biomass" for ethanol distillation. The process requires so much energy that it becomes (a) a prohibitively expensive solar system, or (b) a rapacious consumer of biomass ... think of burning entire forests to create "clean" ethanol.

... a snippet from a recent press release:

By not drying the grains, Siouxland has reduced its natural-gas consumption to 24,000 B.T.U. per gallon of ethanol < meaning that the natural gas it uses has an energy value less than one-third that of the ethanol it makes, creating 85,000 B.T.U. a gallon when burned. (This calculation does not count the electricity the plant uses, or the diesel fuel used to haul the ethanol to a filling station.)

... one recently announced ethanol plant (near Council Bluffs, Iowa) is to produce 110 million gallons a year

my math says that requires 9.35 trillion BTU's/yr

... since a dry ton of wood fuel produces about 10.4 million Btu

my math says that you need to burn a million tons of dry wood a year?

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Robert Rapier on August 1, 2006 - 11:54am

They are exaggerating the BTUs of ethanol, though. The number they give is a high heating value, which presumes that the water is condensed after combustion so you utilize the heat of condensation. In reality, this never takes place, so the realy BTU value of burning ethanol is about 76,000 BTUs/gal. Of course the reason people exaggerate the BTU value of ethanol is to make it look like more energy was created than actually was.

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odograph on August 1, 2006 - 12:05pm

I was really just grabbing the 24K BTU for distillation ... any idea what is typical?

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Sparaxis on August 1, 2006 - 12:39pm

Check out the bottom graph on p. 37 of this link (PDF). This shows curves of the theoretical and practical minima for energy use in distillation (to 95% purity, so excludes final dehydration) depending on the starting alcohol concentration of the ethanol beer.

Assuming an initial 10% alcohol concentration, then 17,670 BTUs of steam are needed per gallon. Assuming 85.7% efficiency of natural gas combustion to steam, then total energy needs would be 20,618 BTU/gallon. The 24k noted in the article, then, is pretty close to the practical minimum.

But note that this stage alone requires at minimum 27% of the energy content of the output. In other words, if the only energy consumption in ethanol production were distillation energy, the EROI still wouldn't be higher than 3.7, which is piss-poor for any energy supply to a complex industrial society.

When I look at this, I wonder how the EROI of sugar cane ethanol can be cited at 8 or more, since sugar cane ethanol still requires this same distillation stage.

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odograph on August 1, 2006 - 12:51pm

Thanks!

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Robert Rapier on August 1, 2006 - 2:00pm

I have some numbers from an operating ethanol plant. It typically takes them 30,000-40,000 BTUs for the distillation step. The entire conversion step takes about 50,000 BTUs.

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Nick on August 1, 2006 - 6:40pm

What about using a heat exchanger to capture the heat in the distilled alcohol and transfer it to the input stock in the next cycle?

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memmel on August 1, 2006 - 6:44pm

They have to be doing that already thats pretty much a standard practice in any chemical factory. The condensor may even be directly cooled by the input to the distillation rig.

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Jack on August 1, 2006 - 9:52pm

"When I look at this, I wonder how the EROI of sugar cane ethanol can be cited at 8 or more, since sugar cane ethanol still requires this same distillation stage."

An integrated sugar and ethanol plant does not use any external energy sources such as natural gas. Steam and electricity are produced by burning sugar cane fiber waste (bagasse), which is adequate for all production of ethanol and provides excess electricity, which can be sold to the grid.

Sugar cane to ethanol processes do not avoid this distillation stage, but do not need external energy sources for it.

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Sparaxis on August 2, 2006 - 1:00am

Thanks. I was supposing that the bagasse fuel was one element in this calculation, and I now understand better why I've seen claims that the liquid-only process is 2.7 EROI compared to claims for the overall process, which most likely includes credit for energy generation as well and doesn't count the bagasse energy.

However, I think I would tend to agree more with Pimentel and not credit the process with bagasse input energy, since not returning the bagasse to the soil is in essence a non-renewable practice. Energy is energy, whatever its source.

There's a limit to the alcohol content of the ethanol beer since the alcohol is the waste product of the bacteria during fermentation, and they go inert at a certain level of waste buildup in the liquid. There shouldn't be any difference between sugarcane and corn in this regard, just between different bacteria strains.

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Jack on August 2, 2006 - 2:33am

I do think the alcohol proportion is similar. I understand in the case of sugar, it is around 10%, the same level noted for corn above.

The process of calculating EROEI from sugar cane is quite difficult. As you note, the bagasse could be returned to the ground, or used to generate electricity and sold to the grid without producing ethanol. However, the post fermentation waste is treated to produce fertilizer, so something does go back into the earth.

Also, most ethanol produced from cane is part of an intgreated sugar/ethanol plant that can produce between 60% sugar/40% ethanol and 60/40 the other way around. It is harder than it sounds to completely ascribe energy use to each portion of the process.

I am convinced that sugar cane derived ethanol has the highest EROEI of any ethanol production process and, considering inputs, a return high enough to make it viable.

There are virtually no external inputs to the refining process and the final product is a subsitute for gasoline, one of the highest value products.

Here are some links to studies with page references for EROEI calculations:

1) FO Licht presentation to METI,
http://www.meti.go.jp/report/downloadfiles/g30819b40j.pdf

EROEI Calcs: Page 20

2) IEA Automotive Fuels for the Future
http://www.iea.org/textbase/nppdf/free/1990/autofuel99.pdf

3) IEA: Biofuels for Transport
http://www.iea.org/textbase/nppdf/free/2004/biofuels2004.pdf

EROEI calcs: page 60

4) Worldwatch Institute & Government of Germany: Biofuels for Transport (Link to register - study is free)

http://www.worldwatch.org/node/4078

EROEI Calcs (for 12 fuel types): Page 17

5) Potential for Biofuels for Transport in Developing Countries

http://www-wds.worldbank.org/external/default/WDSContentServer/IW3P/IB/2006/01/05/000090341_20060105 161036/Rendered/PDF/ESM3120PAPER0Biofuels.pdf

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Sparaxis on August 2, 2006 - 1:20pm

Thank you Jack for pulling out these references. I agree that if you are going to make ethanol, sugar cane is the best starting point. Any process starting from starch is going to be inherently more inefficient. I am highly suspicious of any assertion of a solar-based silver bullet as a peak oil mitigation option (simply because the scale of our fossil fuel use already exceeds the planet's primary productivity), but biofuels will undoubtedly have some small role to play.

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Jack on August 2, 2006 - 10:35pm

Agreed. I think the future will wind up somewhere between "same as it ever was" and "the end of the world as we know it".

There are many factors involved, can we conserve? adapt? transition?

I do think biofuels can play a minor support role and could ease a transition. I am becoming convinced by Dave's post, however, that simpler localized conversion, largely to electricity may be a better long-term strategy.

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LevinK on August 1, 2006 - 10:13pm

They are burning the sugar cane stems(?) to fuel the destillation process. In addition I suppose the ethanol content in the fermented sugar cane syrop is much higher than for corn.

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Woilf on August 1, 2006 - 12:56pm

"my math says that you need to burn a million tons of dry wood a year?"

With a clearcut operation, that might be like 5 to 10 square miles of conifer (say, Douglas-fir) forest each year...

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odograph on August 1, 2006 - 1:35pm

So you multiply that buy how long it takes to grow those acres and you have the footprint needed for sustainability (of this one plant). ;-)

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Rick on August 1, 2006 - 4:17pm

Rough timing to grow commercial forests: possibly under 20 years in Chile, 27 years in New Zealand, 35-50 years USA, 75 years northern Canada, perhaps up to 100 years in Finland or Russia.

Also note the follow-on effects: the forests need planting, pruning, and harvesting, which requires workers, trucks, harvesting machinery, biomass transport, and land remediation and replanting. All of these require energy from outside the forest--so sustaining the plant's footprint requires a further footprint.

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alan on August 1, 2006 - 1:00pm

Doing a quick calculation of the collection area for a solar powered ethanaol plant I came up with 360000 square meters to replace the 300 tons of coal a day to be used at the plant in Goldfield, Iowa. Checking GoogleEarth that happens to be roughly the size of the parking lot at one of the local malls, also the size of an 18 hole golf course.

Instead of treating this as a way of reducing the fossil fuel input of ethanol how about thinking of it as a way to store solar energy.

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odograph on August 1, 2006 - 1:40pm

is that based on PV or solar concentrators to collect heat?

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alan on August 1, 2006 - 2:21pm

Solar concentrators to collect heat. I didn't include any efficieny factors or power needed for pumps as I was only interested in a rough estimate of the scale. So can we call the contribution of solar energy in my scheme Solar To Liquids?

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alan on August 1, 2006 - 3:07pm

Maybe I should be more specific about the numbers I used. 20,000,000 BTU/ton of coal. An average of 5kWhr/day/meter^2 solar energy in Iowa where the ethanol plant is located.

Obviously there needs to be a backup system for when the sun doesn't shine. They could save the coproduct and burn it when its cloudy. Burning it would probably contribute less to global warming than the methane produced if it was fed to cattle.

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eric blair on August 1, 2006 - 6:16pm

I think it is dangerous to just say "solar or biomass" for ethanol distillation. The process requires so much energy that it becomes (a) a prohibitively expensive solar system,

Here's the numbers I have from what I've got.....a 15 gal boiler likes 3-4k watts of power to get to boiling and 1kw to keep the vapor going. The system lacks good insulation (has none!) Present system operates w/o a vaccum. Any new system would use a vaccum.
Solar hot water heating - 1kw per panel, about $1000 a panel.

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odograph on August 1, 2006 - 10:42am

By the way, I grabbed the above numbers from across the internets, but here is one page that I found especailly interesting:

http://www.biomasscombustion.com/cost_comparison.html

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Woilf on August 1, 2006 - 1:02pm

Hey, that's some great information! More fun numbers to play with...

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treeman on August 2, 2006 - 12:18am

Odograph, There is something basically wrong with that link. No one sells dry fuel for less per ton than wet fuel. Leaves all the numbers suspect.

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odograph on August 2, 2006 - 9:03am

That does sound strange doesn't it? My only guess would be if one had a line on dry wood waste, it might beat the harvest of new green material ...

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