What MPG Do You Want For Your Car?

[DanKegel]

I did not use the sources you claim I did.

What's your source for the threshold for minimal viable EROI?

[Ian S]

OK a different source. I did not use the sources you claim I did.

So what? Your new source (wikipedia) still says PV has an EROI of 6.8 and that data point is at least five years old.

[Sunking]

Did you or did you not want people to take your argument seriously? I took it seriously, and pointed out some actual flaws. I hoped you would return the favor, and point out some factual or logical flaw in my post.

OK a different source. I did not use the sources you claim I did.

[DanKegel]

I Knew could count on you Dan for choosing the 5 MPG car. No Thump here Dan, that noise was you heard was you passing gas. You should be smelling it by now.

Did you or did you not want people to take your argument seriously? I took it seriously, and pointed out some actual flaws. I hoped you would return the favor, and point out some factual or logical flaw in my post.

[Sunking]

I Knew could count on you Dan for choosing the 5 MPG car. No Thump here Dan, that noise was you heard was you passing gas. You should be smelling it by now.

[DanKegel]

Solar EROI is pathetic. Solar is one the lowest EROI of all the alternate sources. It is not even a fuel source. Depending on what source you want to believe as low as 2 in a residential application and as high as 7 to 8 in a commercial application in a prime location over the 25 year life expectancy. At most the best case argument you can make is an EROI of 4 or 5 overall and that is bit optimistic.

If EROI is > 1, it's a fuel source, isn't it?

IIRC you got those numbers from "Energy intensities, EROIs, and energy payback times of electricity generating power plants", http://festkoerper-kernphysik.de/Wei...I_preprint.pdf
It says EROI for poly-si is 4.0 in Germany, and 1.7 times higher (or 6.8) in southern Europe.
It also says the EROI numbers are based in part on data from 2007. We've gotten better at making solar cells since then.
http://www.mdpi.com/2076-3417/3/2/325/pdf is a review from 2013 which gives the median EROI for poly-si as 10 (judging by figure 3); presumably this is in sunny climes. So perhaps the numbers aren't as grim as you thought.

EROI of 7 is the common EROI most agree is the minimum number to be economically feasible.

That number, too, is from http://festkoerper-kernphysik.de/Wei...I_preprint.pdf. As I pointed out in http://www.solarpaneltalk.com/showth...l=1#post148441,

The paper calculated the EROI threshold as "the ratio of the GDP to the
unweighted final energy consumption" (given as 70 cents/kWh in the US in 2011)
divided by the retail price of electricity (given as 10 cents/kWh in the US in 2011).
So Cal Edison's middle-tier rates were closer to 15 cents in 2011, so EROI threshold there
might be 70 / 15 = 4.

So, by your own references, in California, the EROI threshold for viability is 4, and EROI of PV is 6.8, so PV was economically viable there at the time of those figures.

So... in sunny states like California, solar currently has a higher EROI than you claimed, the EROI threshold for viability given by your reference is lower than you claimed, and that thump you just heard was your argument falling down from lack of support.

[Sunking]

Interesting to think about of course, but Energy Invested isn't the only cost involved with any of the energy sources - but is a theoretical limit of what possible. Anything with a low EROI of course is pretty well doomed even though other costs are good.

ROI is also extremely low with Solar if it exsit at all on a commercial scale. It takes both EROI and ROI


Fuel alcohol can be quite high EROI if done right = look at Brazil's alcohol industry or read "Alcohol can be a Gas". [/QUOTE]EOI in the USA for alcohol is 1.1 to 1. Complete waste of tax payer money. You cannot use Brazil model except in Brazil. They use Sugar Cane as the feed stock and use the Bagasse to burn to generate electricity and to distill the alcohol. Sugar Cane only grows in the Sugar Belt the narrow around the earths equator. Only places to grow Sugar Cane in the USA is Hawaii and NOLA. Now there is a good idea bull doze NOLA and use the lad to grow Sugar Cane. Sure beats trying to keep the Gulf and Mississippi out of there.

[solarix]

Interesting to think about of course, but Energy Invested isn't the only cost involved with any of the energy sources - but is a theoretical limit of what possible. Anything with a low EROI of course is pretty well doomed even though other costs are good. I would imagine the EROI on the oil that came out of the Macondo oil well in the Gulf of Mexico has a pretty horrible ROI even if its EROI is high. Corn ethanol production by the way, uses a lot of energy intensive inputs. Fuel alcohol can be quite high EROI if done right = look at Brazil's alcohol industry or read "Alcohol can be a Gas".
Yes, the EROI for solar isn't the greatest, but its good enough, and it's other costs are low and its renewable and scalable. Biggest problem it has is can't be used as baseload until some form of economical storage is found (don't hold your breath).

[Sunking]

So if given the choice which car do you think you would choose to be batter for the environment, economy, and most importantly our future generations yet to be born. The one you are proud to say and want own.

One that gets 5 mpg, 8 mpg, 20 mpg, 40 mpg, 50 mpg or even 100 mpg?

Sounds like a silly question doesn’t it? Well it is, but fact is many of you chose 5 mpg unknowingly. You did so because you did not apply critical thinking and asking the tough questions. Don’t believe me? Well I can prove it. If you advocate solar energy you chose the 5 mpg model.

How can I prove this to be true you ask? Real simple you chose Solar Energy as you preferred source of electric energy. Solar EROI is pathetic. Solar is one the lowest EROI of all the alternate sources. It is not even a fuel source. Depending on what source you want to believe as low as 2 in a residential application and as high as 7 to 8 in a commercial application in a prime location over the 25 year life expectancy. At most the best case argument you can make is an EROI of 4 or 5 overall and that is bit optimistic.

Wind is a little better at an EROI of 7 to 16 depending on who’s numbers you want to use. EROI of 7 is the common EROI most agree is the minimum number to be economically feasible. Hydro is King of Renewable with EROI's of 30 to 50 depending on who’ numbers you want to use and spin. Of course the problem with hydro, at least in the USA, was all built out during WW-II era. All water ways are pretty much tapped out in the USA.

That leaves us with conventional sources of Coal, Natural Gas, and Nuclear. Again depending on who you want to believe and spin the numbers those fuel sources run as low as 30 and up to 100+ EROI’s. One of them at 100 is completely emission free if you exclude the mining and processing, and several million years of cheap fuel laying around not being used.

Which brings us to a point of asking ourselves do we really want to waste our precious resources into such a low returns? Solar panels do not fall out of the sky. They take massive amounts energy to turn silica sand into glass plus aluminum to frame them. All that energy being used to make Panels can be saved for later use, and better utilized when the power is used.Far less fuel burn and far less emissions. In other words you chose the 5 mpg car. You got so wrapped up in your passion for clean renewable energy you cannot see the forest because you focused on a single tree. So much so you failed to ask simple questions and apply critical thinking.

Something to think about