[J-Rod]

http://thefraserdomain.typepad.com/ener ... l_stu.html

$this->bbcode_second_pass_quote('', 'A') new report by UC Berkley analyzes six studies of the energy efficiency of ethanol, adjusted all of the studies to consistent system boundaries for comparison and based on the current state of ethanol production recalculated the values for corn ethanol and used a "realistic scenario" conditions to calculate the energy to produce cellulosic ethanol from switchgrass. The study found that the net energy ratio (energy out/energy in) is 1.2 for ethanol produced from corn and 8.3 for cellulosic ethanol produced from switchgrass. The net energy value (energy out-energy in) was calculated to be 4.5 MJ/liter for corn ethanol and 22.8 MJ/liter for cellulosic ethanol.

[Caoimhan]

Good news for switchgrass.

While this may seem as not so good for corn, it is still positive, and there are corn to ethanol byproducts that are valuable, so it may still be a good idea for corn growers.

[J-Rod]

Well, I read up a bit today before it was time for work, here's what I have.

Important things to note:

$this->bbcode_second_pass_quote('', 'S')ensitivity analyses with EBAMM and elsewhere show that net energy calculations are most sensitive to assumptions about coproduct allocation (17). Coproducts of ethanol have positive economic value and displace competing
products that require energy to make. Therefore, increases in corn ethanol production to meet the requirements of EPACT 2005 will lead to more coproducts that displace whole corn and soybean meal in animal feed, and the energy thereby saved will partly offset the energy required for ethanol production.

[bonjaski]

Ok,
but now lets say that steam and electricity comes from renewable energy (steam could be produced by electricity or heat)


if you get the energy needed to produce ethanol with an EROEI of 20, and this production scheme of EtOH from crom hast a EROEI of 0.5, then in summary you have a EROEI of may 10


then (considering the renewable sources) we get a positive EROEI and we have fuel forever

even with EtOH from corn

[J-Rod]

I suppose that it's dependent on how much steam was needed for the process, but sure, it's a possibility either excess heat from a nuclear plant, or solar collectors could provide that needed energy, and boost the ERoEI.

My main point is, that the main argument against the biofuels was that the ERoEI equation was never calculated with all necessary inputs in the equation, as in End Of Suburbia, where they mention the farm machinery and petrochemical inputs needed for growth. These new models appear to have taken all that data into account, and use what is essentially a high energy weed.

Is it 30-1? Of course not, but 8-1 is quite respectable, and could serve as a way to help cushion a blow from oil declines, with regard to distilled fuels.
I was hoping to get more response to this data than some crickets chirping in the background.

[mekrob]

Well, shale oil is like 2.5:1 at best, isn't it? So 8:1 is extremely good news, something we should be focusing on more than shale. Tar sands are probably beneath this energy ratio as well.

[Ludi]

Switchgrass has a number of benefits. It can grow on otherwise ruined and overgrazed land, is easy to plant, is drought and flood tolerant, can be grazed by some livestock, helps repair watersheds, reduces flooding, and can be harvested with existing haying equipment.

I'm a huge supporter of switchgrass, but not because I think it can replace our oil use. Just because it is a beautiful and useful plant.

Switchgrass growing on virtually no soil in an old quarry on our land:

[J-Rod]

$this->bbcode_second_pass_quote('pstarr', '')$this->bbcode_second_pass_quote('J-Rod', 'I') suppose that it's dependent on how much steam was needed for the process, but sure, it's a possibility either excess heat from a nuclear plant, or solar collectors could provide that needed energy, and boost the ERoEI.

[J-Rod]

You are making references to *corn* ethanol, which the Shapouri report only says is a paltry 1-1.2, even with the coproductes. Corn is obviously not an option. This thread was for discussing the 8-1 of switchgrass, which again you say is impossible, without combatting the numbers provided.

I am not saying that ethanol is a great answer, just that it might indeed provide some cushion, since much existing infrastructure exists for it's integration into the system.

My if's regarding the steam production were mainly because I have no data on how much energy it takes to make the steam to go into the process. It's a side point anyways, even with the petro input for steam, the data still shows a 8-1 ERoEI on switchgrass celluosic ethanol.

Besides, I have already invented a Perpetual Motion Device

So we can all dance and be merry.

I guess it all really comes down to a matter of scale and time. I feel that if the rest of OPEC follows suit like in the Kuwait ordeal, among many other factors, there simply won't be enough time. We are in for a major depression no matter what. (unless of course Bernake decides to go ahead and print money to create major inflation, and all the evidence points to him doing that, with the M3 being gone and all) I have my doomer days, and my anti doomer ones. But if no one ever tries anything, we might as well just pack it in now and go drink some Kool-Aid, and look for Hale-Bopp.

[J-Rod]

The whole purpose of the EBAMM was to produce a paper that used comparative data sets, from all the various studies. All these different groups calculate differently, and either account or do not account for various things like coproducts, and the energy displacements they provide. Looking at the excel data for P&P, I see plenty of data entires where there is just no cited source. Where did those numbers come from then? Why not account for those in the paper?

$this->bbcode_second_pass_quote('', 'A')s an illustration, consider the adjusted values for the Ethanol Today case: non-renewable input
energy is 20.7 MJ/L, output energy is 21.2 MJ/L, and the coproduct credit is 4.1 MJ/L. Treating
coproducts as a subtraction from input energy yields NER = (21.2)/(20.5-4.1) = 1.3, while
treating coproducts as an addition to output energy yields NER = (21.2+4.1)/(20.5) = 1.2.
Compare this small difference to what happens in the Cellulosic case; non-renewable input
energy is 3.1 MJ/L and the coproduct credit is 4.8 MJ/L, based on the primary energy displaced
by export of electricity from the cellulosic biorefinery to the grid. Treating coproducts as a
subtraction from input energy yields NER = (21.2)/(3.1-4.8 ) = -12.5, while treating coproducts as
an addition to output energy yields NER = (21.2+4.8 )/(3.1) = 8.3. Further, these calculations
ignore burning the byproduct lignin to produce electricity for use in the biorefinery, a standard
technology common in the pulp and paper industry today and in designs for celluslosic
biorefineries. This is considered “Recycled Biomass Energy” in the spreadsheet. Including this
value (26 MJ/L) as both coproduct and input, yields an NER of 1.8.

[J-Rod]

Who says they have to sell all the coproducts? From what I read there they fire the lignin to produce power from their own plants. (Which can be used to dry out the wet stock) Also, have another look at the reports in the spreadsheet model, and look at how many "source not cited" data sets there are in both Pimental and Petzak. Bash it all you want, but the bottom line is Cellulosic methodologies do indeed show some promise as a buffer for FF losses from depletion. Is that the holy grail? Of course not, there isn't one.

(Although for a good read, pick up Angels and Demons, by Dan Brown. Great style, and it involves Illuminati and anti-matter, yummy. )

[EnergySpin]

$this->bbcode_second_pass_quote('J-Rod', 'I') suppose that it's dependent on how much steam was needed for the process, but sure, it's a possibility either excess heat from a nuclear plant, or solar collectors could provide that needed energy, and boost the ERoEI.

My main point is, that the main argument against the biofuels was that the ERoEI equation was never calculated with all necessary inputs in the equation, as in End Of Suburbia, where they mention the farm machinery and petrochemical inputs needed for growth. These new models appear to have taken all that data into account, and use what is essentially a high energy weed.

Is it 30-1? Of course not, but 8-1 is quite respectable, and could serve as a way to help cushion a blow from oil declines, with regard to distilled fuels.
I was hoping to get more response to this data than some crickets chirping in the background.

[J-Rod]

Heh, yeah it's futile. But I know better than to try and convince someone totally set in his ways to accept that there's sometimes light in the DOOM tunnel. I wanted to more show others that are looking for other data that shows there are indeed ways to offset a depletion we are likely facing. In then end though, we all need to have a massive shift in the way things are done at the most basic of levels to be sustainable. Maybe we need a native American as president or something, along with an Indian congress.

I had other pics in the thread hosted, but I let my domain expire. If anyone needs to see them, I can rehost them on google pages I guess.

[J-Rod]

Heh, I know all too well about black liquor, I used to be a NDE tech, testing the inside of paper mills and power plants. Nasty stuff to say the least. My point is that it doesn't really matter they are forced to burn it or not. It's a byproduct that offsets cost they incur anyways. If they can generate electricity from byproduct, instead of burning coal or NG, shouldn't that be worked into the equation?

[lorenzo]

I want to compare the EROEI of a few energy technologies (mainly ethanol and biodiesel from useful crops), to the EROEI of a battery driven car that uses electricity from solar cells.

The EROEI for biofuels is well studied. Often, these studies conclude by showing how much of the free solar energy is actually captured by the biomass after it has been processed into a liquid fuel that is used in a 35% efficient ICengine. Because the final measure of these studies is "useful work of a rotating shaft".


Now I want to do the same detailed study for solar cells + battery > car.

It would have to be a total life-cycle study. That is: starting from the energy that's needed to create a solar cell manufacturing plant (steel production, etc...), to the energy needed to produce batteries and recycle them, etc...

We would look at "ordinary" solar panels (crystalline silicon) and "ordinary" batteries (either Lead-Acid or NiMH) for an electric car.

Anyone want to help with this?



Here's some of the things I would look at:

For the batteries:

-energy used in mining the "metal" in a NiMH battery: the most common intermetallic compounds used in NiMH batteries are AB5, where A is a rare earth mixture and/or titanium and B is nickel, cobalt, manganese, and/or aluminum. Higher-capacity "multi-component" electrodes are based on AB2 compounds, where A is titanium and/or vanadium and B is zirconium or nickel, modified with chromium, cobalt, iron, and/or manganese. (from Wikipedia).

-energy used in transporting these metals to the battery manufacturing plant

-energy used in operating the manufacturing plant

-energy used in recycling the batteries and in mitigating damaging environmental effects of those batteries once they are discarded after their useful life

For ordinary crystalline silicon solar panels:

-energy used in producing crystalline silicon ingots
-energy used in producing the solar panels (including the energy used in producing the metal frames, the glass protection layer, etc...)


Please add your own posts.

Mind you, we're not taking into account the different production (and energy) costs of an electric motor as compared to an internal combustion engine, but of course we keep the difference in efficiency of both motors (where an electric motor is obviously much more efficient than an ICE).



I wonder whether in the final analysis, the EROEI of the useful work coming out of the shaft of a solar-electric motor is going to be bigger than that of an ICE powered by liquid biofuels.

All advice from your part is welcome. If anyone knows any studies that have already looked at this, please refer to them.