For those who disbelieve the corollary to net oil you seem to be tripping over semantics.

I am not saying EROEI = EROEI - 1

That does not make any sence. I am talking about compond EROEI which is something I have not really defined. You must remember that these fields are finite in size. What I mean by compond EROEI really talking about a concept of Net URR where URR is Utimately Recoverable Reserves.

The formula for Net URR = (EROEI -1)/EROEI

So if well 'A' has a URR of 10,000 units of energy and EROEI is 1.9 I will still be able to recover all 10,000 units of energy. However, only 4700 units of that URR will be Net Oil. The other 5300 units of energy will be spent recovering that energy from well 'A'.

That is the corollary to Net Oil and I know it is correct. The graph from before only woks in terms Net URR which is the real heart of the Net Oil theory.

Novus,

(EROI - 1) / EROI = Amount of energy used in each iteration

Example:
(2 - 1) / 2 = 1/2 of the produced energy was used to produce it

URR is how much you can produce, regardless of how much energy investment it requires. It is an estimate based on how fast you think EROI will fall. The reason you can't produce more than the URR is because EROI is dropping to 1.

If
ER = Energy Returned/Recovered
EI = Energy Invested
ES = Energy Start (the kick start energy)

then
SUM ER = URR = Ultimate Energy Returned
SUM EI = Total Energy Invested
Net Oil = Net URR = SUM ER - [(SUM EI) - ES]

Example:

In this example we will reinvest all the energy gained in a well that loses EROI really fast (since we are really greedy and dumb).

Total Oil in Place = 1,500 barrels
Starting EROI = 1.9

1: 100 -> 'A' -> 190

EROI = 1.5

2: 190 -> 'A' -> 285

EROI = 1.1

3: 285 -> 'A' -> 313.5

On the next iteration EROI would less than or equal to 1.

SUM ER = URR = 190 + 285 + 313.5 = 788.5
SUM EI = 100 + 190 + 285 = 575
Average EROI = SUM ER / SUM EI ~1.37

To calculate Net Oil, leave out the "kick start" energy and find the difference.

Net Oil = Net URR = 788.5 - (575 - 100) = 313.5

With EROI > 1:
% of total produced = 788.5 / 1500 = 52.56%
% of URR reinvested = 475 / 788.5 = 60.24%
% of URR that is Net = 313.5 / 788.5 = 39.76%

Check out this page. They have a great interest analogy, as well as some cool graphics.

Edit: made some corrections. Forgot to take out the "kick start" energy

That's wrong!

The fraction of an oil field that can be extracted to be use by human is

Sellable Fractional Output = ( EROEI - 1 ) / EROEI

That is to say if an oil field has an EROEI of 2 then only 50% of the oil in the oil field can be extracted and sold.

The only thing I don't like about using the financial interest analogy is that it includes a time component to the equation. This tends to stump people a bit because they think in terms of compound interest and when a doubling in initial investment, for example, occurs. Nowhere does EROEI really discuss how fast things proceed. It is definitely more of a limiting kind of analysis. And more to the point, people are more likely to reinvest all their interest in comparison to oil companies, who have to continuously siphon off non-reinvested energy that an ordinary investor would typically keep compounding in an IRA, for example.

I wonder if that is what Novus is trying to get at? More precisely, what is the empirical fraction that gets siphoned off, and therefore not available for reinvestment? I'm saying empirical because it has a lot to do with profits. I would make an analogy to the tree farmer that has to resist cutting down his saplings for Christmas trees, because he can't wait for a mature stand of potential lumber.

I don't think this would be too hard to show mathematically, just take a fraction off the energy reinvested every cycle. Then, if say, half of this gets used for its intended purpose of powering NASCAR races, then Novus has a point. Which means an EROIE of 1.9 is nonsustainable, unless you have more of the patience of a tree farmer, and decide to defer gratification and not siphon off as much per cycle. Note that this only works for Novus if he assumes a value of half. I think the amount you can siphon off per cycle is <= (E-1)/E if you want to keep this sustainable.

So for large E, it is not hard to avoid oversiphoning but for smaller and smaller E, it becomes more and more difficult to resist temptation and thus decide to go for the immediate gratification, and eschew sustainability with your captive, essentially "free", source of energy.

Overall, I believe that Novus is looking at a "knee in the curve" type of analysis which provides a heuristic for a rough energy self-sustainability measure.

Basically, I am willing to hear Novus out, and try to walk myself through his thought process.

Yes, indeed. There is a huge difference between keeping a country going and keeping a well going. I posted a theory a while ago stating that how efficiently a society uses its energy dictates what EROI is sustainable. The Energy Invested could be viewed as the total energy use of the country plus the required reinvested energy. I'd guess that you'd get EROI = 1 every time though, since supply is close to demand, if not equal.

EC = Energy used by the Country

ER / (EI + EC) = 1

For EROI of 1.9: 190 / (100 + 90) = 1

If the country uses 100 units then an EROI = 2 is the minimum "sustainable" EROI for the country, not the resource. But as with oil, the price goes up when there is scarcity. So EC would fall to meet what the resource can provide, in this case.

200 / (100 + 100) = 1
190 / (100 + 90) = 1
180 / (100 + 80) = 1

Note: this is all within a "closed" system with one resource. The world uses more than one resource. But I guess you could get an average EROI for every resource and then calculate the maximum EC and minimum EROI.

Edit: meant minimum "sustainable", not maximum "sustainable", lol....it was getting late I guess.

A reminder:

What is so complicated here? Am I missing something? Is this a parallel universe? Am I from Venus?

Okay. Another thought experiment. Much like the last one without the Soccer Family

The Martians drop 1 barrel of oil on your head
You use that 1 barrel to produce 1.9 barrels.

You have 1.9 barrels of oil.
You use those 1.9 barrels to produce 3.61 barrels.

You have 3.61 barrels of oil.
You use those 3.61 barrels to produce 6.859 barrels

The Martians drag you off to a funny farm on Pluto

lol, dude...that must be where we got our kickstart energy!

I found this quote in Ethanol: Myths and Realities

Just thought it was interesting. Comments?

I would guess that of the 1.23 million BTU's, one million is the one delivered and 230 000 is consumed in the process.

You're probably right, I first read it as if you start with 2.23 mil BTUs to deliver 1 mil BTU of gasoline.

I found another web page that says 45.8 % of a barrel of oil is delivered as gasoline. (That's by volume, not BTUs) So I'm still confused.

Also, I seem to remember that the term gasoline means something different to a refinery than it does to us. I'm not sure which gasoline they're talking about in either case.

I just can't let this nonsense go unanswered.

Several people claim

100 units of energy invested in pumping yields 190 units

so far so good

190 units of energy invested in pumping produces 361 units

reality check time

The only reason you can get the 190 units out with the pump is because it flowed to the wellbore.

If you try to invest all 190 units of energy into pumping, chances are very good that soon (and absolutely certain that eventually) your pump will cavitate, or pump water or some other non energy quantity.

If you want to invest those 190 units in pumping, you need to invest a few million units into another well.

How can you possibly make such a claim when we haven't even specified the amount of energy??

Why wouldn't the chances be good that the pump would cave soon if you try to pump your first 100?

We could be talking about 100 joules for all you know. Yes, you probably can't pump any oil at all on 100 joules, but they could be part of a larger energy influx.

Since we are uncertain of quantity underground, EROI and totals,
the logic above is sound.
But to know where we are we look at two things.

Actual production
Need
Cost

we will have passed peak when price starts to climb WHILE PRODUCTION IS STILL INCREASING, because the useful oil is actually decresaisng.

BUT we must add one more factor.
If we pump 84 million gallons a day for eternity,
the increasing demand at some NEAR POINT in the future will cause an economic collapse.

this is RELATIVE PEAK OIL

In fact you could be increasing production while short supplies increase exponentially causing a collapse of the economy.

how?
Nations all increasing demand.
excluding a war, it would behave exactly as sliding down the peak.

so we should call that NET AFTER TAX oil.
in other worlds peak says we have 20 years until we are dry, dry, dry.
lets say 10 for net
I say half for net after taxes.

and before that is the new Amrican foreign policy...
First strike, accepted as new military doctrine now.

which will really decrease production quickly.

I certainly hope you guys figure it all out and yeah thanks for the initial post

I think it is more interesting looking at the "waste" side of the eroei equation.

Eroei:
20-1 = 4.7% waste
16-1 = 5.88% waste = current mideast oil Eroei
10-1 = 9% waste = current north american oil Eroei
8-1 = 11% waste
6-1 = 14% waste
5-1 = 16% waste
4-1 = 20% waste
3-1 = 25% waste
2-1 = 33% waste
1.9-1 = 34% waste
1.5-1 = 40% waste
1.0-1 = 50% waste
0.0-1 = 100% waste

Where petroleum extraction is concerned - We waste approximately 8% of our GROSS energy to get our NET energy.

Some questions:

If the U.S. currently has an Oil eroei 10-1 when did this occur and what was the Eroei 5 - 10 - 20 - 40 years ago?

That data should be charted/graphed.

The same could be done for the world, opec and all oil.
We would then have a nice curve to play with - hint hint