[lorenzo]

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

I know a study It's called Ethanol Production Using Corn, Switchgrass, and Wood; Biodiesel Production Using Soybean and Sunflower, David Pimentel and Tad W. Patzek, Natural Resources Research, Vol. 14, No. 1, March 2005.

Kind of renders the rest of this exercise moot, doesn't it?

OMG! On the contrary, it is precisely to counter that study! Common, pstarr, don't you get it!?

Pimentel and Patzek's paper on biomass concludes by showing that solar cells are so much more efficient at converting solar energy in usable power. But that's why their study is flawed: they first dissect biofuels in all possible ways, each little factor is analysed, they're on it with a magnifying glass, trying to discredit biofuels in all possible ways. And then they compare the final result with solar cells, for which they do not make *any* analysis whatsoever.

That's *precisely* why I now want to look at the EROEI of solar cells and batteries when it comes to producing "useful power of a rotating shaft" - which is their final criterium.

Pimentel and Patzek are frauds - they use false and obsolete and old data, and they compare one technology for which they study the entire life-cycle, to another technology which they take entirely for granted.

So let's do the exercise and see whether the EROEI of solar+batteries is bigger or smaller than liquid biofuels made from sugar cane or cassava or any other useful crop (which obviously does not include corn - the worst possible crop for biofuels).

Shall we?

[lorenzo]

A good source to start the study of how much energy is required to produce NiMH batteries can be found here:

Inside the NiMH battery

Gives a basic overview of the elements needed to create such a battery. Each of those obviously requires energy during their production.


Drawing on that document, we need to find out the following:

-energy cost of producing potassium hydroxide (the electrolyte)
-energy cost of producing nickel oxide – metal hydride (electrodes)
-energy cost of producing the steel used in the casings of the batteries



:: For the Nickel oxide we can be short: nickel must be mined. So we need to look at the mining industry.

:: For the metal hydride alloys, they are produced under high vacuum. Does anyone know if this is an energy intensive process?

The metals combined in these alloys are, for the
A group: Mischmetal, La, Ce, Ti
B group: Ni, Co, Mn, Al

So we have to look at the energy used in mining and producing:

>Mischmetal: wikipedia: alloy of rare earth elements in various naturally occurring proportions. A typical composition includes approximately 50% cerium and 45% lanthanum.

>Lanthanum: see wikipedia: Monazite (Ce, La, Th, Nd, Y)PO4, and bastnasite (Ce, La, Y)CO3F, are principal ores in which lanthanum occurs in percentages up to 25 percent and 38 percent. See also category:Lanthanide minerals

>Cerium: wikipedia: found in a number of minerals including allanite (also known as orthite)—(Ca, Ce, La, Y)2(Al, Fe)3(SiO4)3(OH), monazite (Ce, La, Th, Nd, Y)PO4, bastnasite(Ce, La, Y)CO3F, hydroxylbastnasite (Ce, La, Nd)CO3(OH, F), rhabdophane (Ce, La, Nd)PO4-H2O, and synchysite Ca(Ce, La, Nd, Y)(CO3)2F. Monazite and bastnasite are presently the two most important sources of cerium.
Cerium is most often prepared via an ion exchange process that uses monazite sands as its cerium source.
Large deposits of monazite, allanite, and bastnasite will supply cerium, thorium, and other rare-earth metals for many years to come

>Titanium: wikipedia: Titanium metal is not found unbound to other elements in nature but the element is the ninth most abundant element in the Earth's crust (0.63% by mass) and is present in most igneous rocks and in sediments derived from them (as well as in living things and natural bodies of water). It is widely distributed and occurs primarily in the minerals anatase, brookite, ilmenite, perovskite, rutile, titanite (sphene), as well in many iron ores. Of these minerals, only ilmenite and rutile have significant economic importance, yet even they are difficult to find in high concentrations. Because it reacts easily with oxygen and carbon at high temperatures it is difficult to prepare pure titanium metal, crystals, or powder. Significant titanium ore deposits are in Australia, Scandinavia, North America and Malaysia.
>>the production table shows that many NiMH battery factories will have to import this metal, which means: energy used in transporting it

>Nickel: The bulk of the nickel mined comes from two types of ore deposits. The first are laterites where the principal ore minerals are nickeliferous limonite: (Fe,Ni)O(OH) and garnierite (a hydrous nickel silicate): (Ni,Mg)3Si2O5(OH). The second are magmatic sulfide deposits where the principal ore mineral is pentlandite: (Ni,Fe)9S8.
In terms of supply, the Sudbury region of Ontario, Canada, produces about 30 percent of the world's supply of nickel. The Sudbury deposit was created by a massive meteorite impact event early in the geologic history of Earth. Russia contains about 40% of the world's known resources at the massive Norilsk deposit in Siberia. Russia mines this primarily for its own domestic supply, and for export of palladium. Other deposits of nickel are found in New Caledonia, Australia, Cuba, and Indonesia.
>>this means: importing it: energy involved in transporting nickel in ships over oceans to NiMH battery factories.

>Cobalt: Cobalt is not found as a free metal and is generally found in the form of ores. Cobalt is usually not mined alone, and tends to be produced as a by-product of nickel and copper mining activities. The main ores of cobalt are cobaltite, erythrite, glaucodot, and skutterudite. The world's major producers of cobalt are the Democratic Republic of the Congo, mainland China, Zambia, Russia and Australia. It is also found in Finland, Azerbaijan, and Kazakhstan.
>>importing it: energy used in transporting Cobalt in ships over oceans to NiMH battery manufacturing plants

>Manganese: Manganese occurs principally as pyrolusite (MnO2), and to a lesser extent as rhodochrosite (MnCO3). Land-based resources are large but irregularly distributed; those of the United States are very low grade and have potentially high extraction costs. South Africa and Ukraine account for more than 80% of the world's identified resources; South Africa accounts for more than 80% of the total exclusive of China and Ukraine.
US Import Sources (1998-2001): Manganese ore: Gabon, 70%; South Africa, 10%; Australia, 9%; Mexico, 5%; and other, 6%. Ferromanganese: South Africa, 47%; France, 22%; Mexico, 8%; Australia, 8%; and other, 15%. Manganese contained in all manganese imports: South Africa, 31%; Gabon, 21%; Australia, 13%; Mexico, 8%; and other, 27%.
>>importing it: energy used in transporting Cobalt in ships over oceans to NiMH battery manufacturing plants

>Aluminium: Although aluminium is the most abundant metallic element in Earth's crust (believed to be 7.5% to 8.1%), it is very rare in its free form and was once considered a precious metal more valuable than gold.
Aluminium is a reactive metal and it is hard to extract it from its ore, aluminium oxide (Al2O3). Direct reduction, with carbon for example, is not economically viable since aluminium oxide has a melting point of about 2000 °C. Therefore, it is extracted by electrolysis — the aluminium oxide is dissolved in molten cryolite and then reduced to the pure metal. By this process, the actual operational temperature of the reduction cells is around 950 to 980 °C. Cryolite was originally found as a mineral on Greenland, but has been replaced by a synthetic cryolite. Cryolite is a mixture of aluminium, sodium, and calcium fluorides: (Na3AlF6). The aluminium oxide (a white powder) is obtained by refining bauxite, which is red since it contains 30 to 40% iron oxide. This is done using the so-called Bayer process. Previously, the Deville process was the predominant refining technology.

The electrolytic process replaced the Wöhler process, which involved the reduction of anhydrous aluminium chloride with potassium. Both of the electrodes used in the electrolysis of aluminium oxide are carbon. Once the ore is in the molten state, its ions are free to move around. The reaction at the negative cathode is

Al3+ + 3 e- → Al

Here the aluminium ion is being reduced (electrons are added). The aluminium metal then sinks to the bottom and is tapped off.

At the positive electrode (anode) oxygen gas is formed:

2 O2- → O2 + 4 e-

This carbon anode is then oxidised by the oxygen. The anodes in a reduction must therefore be replaced regularly, since they are consumed in the process:

O2 + C → CO2

Unlike the anodes, the cathodes are not consumed during the operation, since there is no oxygen present at the cathode. The carbon cathode is protected by the liquid aluminium inside the cells. Cathodes do erode, mainly due to electrochemical processes. After 5 to 10 years, depending on the current used in the electrolysis, a cell has to be reconstructed completely, because the cathodes are completely worn.
Aluminium electrolysis with the Hall-Héroult process consumes a lot of energy, but alternative processes were always found to be less viable economically and/or ecologically. The world-wide average specific energy consumption is approximately 15±0.5 kilowatt-hours per kilogram of aluminium produced (52 to 56 MJ/kg). The most modern smelters reach approximately 12.8 kW·h/kg (46.1 MJ/kg). Reduction line current for older technologies are typically 100 to 200 kA. State-of-the-art smelters operate with about 350 kA. Trials have been reported with 500 kA cells.
Electric power represents about 20 to 40% of the cost of producing aluminium, depending on the location of the aluminium smelter. Smelters tend to be located where electric power is plentiful and inexpensive, such as South Africa, the South Island of New Zealand, Australia, China, Middle-East, Russia, Iceland and Quebec in Canada.
In 2004, China was the top world producer of aluminium. Suriname depends on aluminium exports for 70% of its export earnings.[5]

>>Aluminium is very energy intensive to produce.




Obviously, the environmental costs of continuously cleaning up these mining sites are considerable and they need to be taking into account.

Mines pollute rivers, etc... just as fertilisers for energy crops do.

We will definitely take this into account.

[lorenzo]

Pstarr, please read page 72:
http://petroleum.berkeley.edu/papers/pa ... sPaper.pdf

There you see the table which shows how much solar energy is captured by different technologies.

The paper just dumps "horizontal solar cell" - and that's fine. But we are now doing the exercise to see how much energy it takes to produce that solar cell.

And then we continue, because you don't drive a realistic car on solar cells. So we also look at the energy involved in producing the batteries that are going to have to be used in an electric car.


We will then see where we stand with the final criterium Pimentel and Patzek use, which is "useful power of a rotating shaft" (there's no rotating shaft on a solar panel.[p. 71 of that same paper.] I think this is a fair challenge, don't you?

Let's continue.

[lorenzo]

Furthermore I have ripped apart your Brazilan sugar cane study. It is a cruel example of externalizing the human suffering of cane-harvestors for 1st-world gain and pleasure.

The situation is actually worse for solar+batteries. Did you know that for each kilogram of cobalt and manganese (which you need to produce NiMH batteries) on the international market, thousands of Congolese have died? The mining industry in the Congo is responsible for fuelling the worst war since WWII, killing up to 4 million people.

So how's that for human suffering?


Let's proceed.

[Caoimhan]

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

I know a study It's called Ethanol Production Using Corn, Switchgrass, and Wood; Biodiesel Production Using Soybean and Sunflower, David Pimentel and Tad W. Patzek, Natural Resources Research, Vol. 14, No. 1, March 2005.

Kind of renders the rest of this exercise moot, doesn't it?

I think pstarr IS David Pimentel or Tad Patzek, and is on this board merely to shamelessly plug his/their propagandistic "research".

Edit: I want to qualify my above statement by saying that I agree with P&P about two things. Corn sucks for ethanol, and soy sucks for biodiesel. Here's a project for them: I'd love to see a study done on the viability of hemp for ethanol and/or biodiesel... or even hemp oil being used directly as a fuel in an Elsbett style engine.

[Etalon]

Are you taking into account that solar cells, once they are made last practically for ever, producing energy with no additional energy input? For somthing like biofuel, you have constant energy input in the form of farming (feriliser, tractors ect) with solar panels, once they are made, thats it.

EROEI, energy return on energy investment, (I think). The energy return on solar cells is huge compared to the energy investment over sufficient time.

That just leaves the batteries, they dont last for ever .

[EnergySpin]

Lorenzo, no need to rediscover the wheel
The ExternE study (funded by the EU) did calculate the hidden cost of energy. Final results can be found at http://www.externe.info/

A Dutch group also looked at the BIG picture a few years ago:
http://www.chem.uu.nl/nws/www/publica/95057.htm
For something more recent, try NREL:
www.nrel.gov/ncpv/thin_film/docs/fthena ... c_2005.pdf

[lorenzo]

Are you taking into account that solar cells, once they are made last practically for ever, producing energy with no additional energy input? For somthing like biofuel, you have constant energy input in the form of farming (feriliser, tractors ect) with solar panels, once they are made, thats it.

EROEI, energy return on energy investment, (I think). The energy return on solar cells is huge compared to the energy investment over sufficient time.

That just leaves the batteries, they dont last for ever .

Of course we'll take this into account.

Let's be optimistic and take a life of 30 years for our solar cells and 10 years for our batteries.

[lorenzo]

Lorenzo, no need to rediscover the wheel
The ExternE study (funded by the EU) did calculate the hidden cost of energy. Final results can be found at http://www.externe.info/

A Dutch group also looked at the BIG picture a few years ago:
http://www.chem.uu.nl/nws/www/publica/95057.htm
For something more recent, try NREL:
www.nrel.gov/ncpv/thin_film/docs/fthena ... c_2005.pdf

Thx EnergySpin, the ExternE studies are interesting, even though there's no real detailed analysis about the energy it takes to make and recycle batteries. But it gives a great framework.

The Dutch study is good for solar cells. They give a partial "Environmental Life Cycle Assessment".


This source gives us one of the posts we were searching for: the energy required to produce a solar cell once you have all the materials ready in a factory. The study does not look at the energy involved in mining and transporting these materials. Nor in the energy involved in cleaning up the sites and the water where this material was mined, etc...


Gross energy requirement for multicrystalline silicon PV modules in kWht/m2 cell area.

Energy requirement for the cells: worst case, base case, best case
Process Energy Requirement - direct 511 244 91
Process Energy Requirement - indirect 210 46 19
Secondary input materials (glass, EVA, etc.) 89 70 50
Gross Energy Requirement for investments 160 40 20
Total Gross Energy Requirement (excl. frame) 970 400 180
Gross Energy Requirement of frame 175 120 80

Grand total for the base case: 520 Kwh/m²


Sadly, the study gives no energy requirement analysis for the following steps in the production process:

Material requirements and resource depletion

Nor for the step of cleaning up the mess that comes from the production:

Process emissions

Since for biofuels, Pimentel and Patzek look at the energy needed to remove fertilizers from waste streams, and to remove pollutants from processing the biomass, which they bring in and which reduces the overall energy balance -- we must do the same exercise for the production of solar cells. And obviously for batteries too.

[lorenzo]

Found another good paper, which does look at the energy involved in producing the raw materials.

An Empirical Perspective on the Energy Payback Time for Photovoltaic Modules

www.ecotopia.com/apollo2/knapp/PVEPBTPaper.pdf

Comes at around 5,598 Kwh/m² for a typical production.
The typical solar cell produces 1700 kWh/m²/year.

So the Energy Payback Time is around: 3.3 years. After 3.3 years, your solar cell starts to produce net energy.



Okay, we now still have to include the energy costs of cleaning up mining sites, etc...

And we can move on to the batteries.

[lorenzo]

I just come to think of an important but problematic factor.

If you use solar panels which supply the electricity to the batteries in your car, you need some way to store that electricity at night. Since most people use a car during the daytime, this means they can not be using the electricity from the solar panels during that daytime. And at night, when you re-charge your electric car, the solar panels don't work.

So we must look at batteries not only for the car, but also to store the electricity coming from the solar panels.

Batteries: two times, two packages. This is going to lower the EROEI of our solar+battery>car thing significantly.

[Caoimhan]

As for your second point, if you are willing to accept P&P's critique of corn or soy fuels then you should also respect their switchgrass numbers. And guess what? Hemp is no better, no different than switchgrass. It is just fuel-crop craze of the moment. Jah is love mahn. Hemp is for burnin

Corn sucks because it is an irrigation intensive crop, requiring a whole lot of precious water resources.

Soy isn't good for the soil. We'd be better off using rapeseed (canola), like the Europeans.

Even better... let's cut the energy-intensive deesterification process, and use straight vegetable oil in appropriately modified engines.

Edit: Just realized this was hijacking the thread, so...

Concentrated Solar Power using such cells as the Boeing-Spectralab cells seem to leverage the embodied energy in the cells to a large degree. Some CSP applications concentrate 4x the insolation onto the cells, nearly quadrupling the energy return. Assuming a similar energy investment in the manufacture as less advanced solar PV cells, it changes the EREOI calculation dramatically.

[lorenzo]

Caoimhan, thanks, that's interesting. But mind you, we're not looking at ultra-advanced solar panels. We're looking at the ordinary, mass produced ones.

Just like we don't take the exceptions when we look at biofuels. The studies never look at super crops, or ultra-high yield exceptions, nor at bioengineered varieties and experiments. They take some kind of average.

We do the same here.

[J-Rod]

Hey pstarr, did you catch the special on CNN? In particular the part where the Brazilian plant mentioned that they burn off the waste cane to power the plant, in fact they got enough to run the entire operation? Coproducts baby!

[lorenzo]

Exactly, that's the nice thing about most (tropical) energy crops: they produce so much biomass that a fraction of it suffices to power the entire operation of turning another fraction of it into a liquid biofuel.

For sugar cane this is the trash and the bagasse; for palm oil this is the palm kernel shells and the palm fruit bunch fibre; for cassava these are the woody stems, etc...

Most sugar mills in Brazil even deliver excess electricity to the grid.

[PolestaR]

Lets consider that ethanol can be produced at 10-1 . How long will ethanol allow us to grow (along with our other current liquid fuels) to the peak of liquid fuel production? Has anyone plotted both (non renewable and renewable liquid fuel) graphs, found the crossover and can give us an estimated date of shit hitting the fan from energy issues.

Obviously no one here is arguing that ethanol will keep the McMansions going forever, so how much time will it buy.

[EnergySpin]

I just come to think of an important but problematic factor.

If you use solar panels which supply the electricity to the batteries in your car, you need some way to store that electricity at night. Since most people use a car during the daytime, this means they can not be using the electricity from the solar panels during that daytime. And at night, when you re-charge your electric car, the solar panels don't work.

So we must look at batteries not only for the car, but also to store the electricity coming from the solar panels.

Batteries: two times, two packages. This is going to lower the EROEI of our solar+battery>car thing significantly.

Well there are other ways of storing electricity that do not involve double packs of batteries (1 for the car, one for storage). But the moment you invoke such solutions, you 'll find yourself out of the realm of this thought experiment. Bottom line is that ordinary PVs suck as primary means of powering the world, unless of course is stoned high in renewable fantasies.
The same thing goes for biofuel fantasies ... if , as the all data suggest, that we can get up to 30% of our current liquid fuel needs by turning to biofuels, then it becomes obvious that we need a synergistic rather than antagonistic modus operandi: hybridize the vehicles (in order to bring the liquid fuel consumption to < 3-4 l/100km) AND increase electricity production to a) power the biorefineries (not all fuels generate combastible co-products) b) allow the hybrids to operate as PHEVs.
Getting rid of most of the cars by providing personal mobility services via alternative means should be pursued relentlessly. As our urban centers retract their steps towards a new/old urbanism model, the need for cars (bf or electric powered) will/should diminish.