The EROEI stupidity saga lives on...

Don't take offense, jeffvail, this is not personal. But I kinda hoped for more, since the posts' quality in here is pretty tremendous.

But you make a TREMENDOUS ERROR. And that's calculating energy twice. You can't do that, my friend!

Energy was invested 15 years ago in a large piece of coal mining equipment that will last for 15 years. The energy used to build it was, for the sake of example, “100 EROEI” Saudi Crude. As a result, the EROEI of the coal mined by that machine includes an input from the energy required to make that machine—we’ll say this is X. The machine is at the end of its useful life, and a new machine has been ordered. This machine is made with today’s energy, we’ll call it “50 EROEI” Saudi Crude. As a result in this halving of the EROEI of the energy used to make the machine over the past 15 years (just an example), the energy input to the same quantity of coal mined by the new machine is now 2X...

Now, who CARES with which energy was made the truck? That's not how you should math it. You should only calculate how MUCH energy it takes to manufacture the truck. EROEI is a mathematical construct defined to see if you can manage to create more energy than use in its process. Therefore, you should try to know how much energy was spent. You've get x joules. Then, you add up all the joules necessary in the process. Then, you see how many joules you got back. That's it.

No previous saudi arabia is required. That's accounting for twice the same energy, because with that, you can only learn that with previous SA oil you could build more trucks than with now's oil. You won't learn that today's trucks are twice energy expensive. Just that you can only build half as much.

And that's WAY different.

I stopped reading when I saw your error. Correct that. Then I'll read the rest. Gosh, the horror, I've said similar stuff regarding EROEI back in here. PLEASE, please, think before writing?

Please?

luisdias -

I really don't see how you can say that Jeff is counting the energy input twice.

By way of analog, say it is essential for my business that I have a certain size and type of truck, and say I pay $40,000 for it and it gives me 15 years of service before I have to replace it with a new one. And then let's say that when I go to buy a new truck, I discover that the price (in real dollars) has shot up to $60,000, largely due to increased manufacturing costs. If I state that the identical replacement truck now costs me 50 percent more than the original truck, would I be guilty of counting the cost of having a truck for my business twice?

I think what Jeff is getting at is that as the overall EROEI of a modern industrial society starts declining, it gets progressively harder to keep the whole thing going, and that if this EROEI drops fast enough, the system can degenerate into a sort of death spiral. This may or may not happen, but I think this concern is what the whole discussion is all about.

You are absolutely wrong and the original thesis is correct. EROEI is a recursive industrial life-cycle energy accounting that measures the accumulated energy required to produce primary energy. So for instance, early Spindletop petroleum pumped itself out of the ground and into a nearby refinery. Thus the Spindletop petroleum had a high eroei and required very little other energies to extract and process. In contrast today's deep water petroleum must be pumped up from the depths at a cost in additional petroleum. Yes, the fuel is in effect measured twice.

Spindletop preceded refineries closer than Pennsylvania, docks, pipelines ect and spewed out on the ground and was hastily contained by an earth dike. The first 600,000 barrels caught fire and burned up about a week after the Lucas gusher blew in.So the EROEI was negative for quite a while. Reference; "Spindletop" by James Clark & Michael Halbouty, 1953

This is an interesting history book, and could remind people of how difficult it was to start the modern fossil fuel age. The oil business didn't just start by magic, and neither will any alternative that will replace it. It was only when the British and American navies switched from coal to oil around WWI that a steady enough market was assured to make sure oil became the main fuel for the industrialisation of the world. People tend to denigrate the growth of wind and solar as not being fast enough to make a difference in the future, but they are making proportionate progress just like oil did against coal a 100 years ago or so.
Bob Ebersole

You are absolutely wrong and the original thesis is correct.

No. It is you who is absolutely wrong and the original thesis is junk. See down below.

This is no excuse for lower EROEIs, get me. People tend to think that I'm somehow escusing low EROEIS. I'm not. Of course a good EROEI is better. But you're making WRONG MATHS.

Now, who CARES with which energy was made the truck? That's not how you should math it. You should only calculate how MUCH energy it takes to manufacture the truck.

Bear with me while I try out a couple of analogies. Say the joules come in a tin. It's as if each time you open a new tin, you find the supplier has dipped into it themselves in order to bring it to you. And each day there's less. So you need more tins. The energy content has not diminished, it's just that more is being consumed before it gets to you.

Then, you see how many joules you got back.

Well you'll get back less and less. The truck collects lower-quality coal with a lesser energy payload for the thermal power station down the road, so it has to make 8 trips where 5 used to suffice in the past. And that power station is supplying the electricity to the factory that's making new trucks...

You won't learn that today's trucks are twice energy expensive. Just that you can only build half as much.

Sorry if I'm being a bit thick, but if Mr. Vail's reasoning is wrong, your argument doesn't make it clear to me as to why. It appears that what you are saying amounts to the same thing.

People just don't understand me. Listen. Less EROEI is as bad as it gets, but please, don't count it twice. A Truck that was built with a EROEI petrol of 100 will use the same energy than a truck built with a EROEI petrol of 50, 30 or 20. That's not the issue with EROEI at all. You're confusing stuff. You're saying that a truck spends the energy it requires PLUS the energy that the pumps and refineries require to function. But those are different things. The problem is how much energy does the production of ENERGY takes out of the system. If you subtract them, there's your real energy output for the society.

It appears that what you are saying amounts to the same thing.

Well it almost would if I wasn't wrong saying what I said. The thing is, a truck spends 10 energy cubes. Imagine. You have 1000 energy cubes produced. You could have built 100 trucks. But to build those energy cubes, you required 10 energy cubes (EROEI = 100), so you can only build 99 trucks with what is left (990 cubes). If EROEI = 50, then a truck won't cost you 20cubes, but still only 10. It's the energy cost that doubled. That means that for producing 1000 energy cubes, you spent 20 cubes. That leaves 980 cubes, which goes to produce 98 trucks. Like someone above said, this doesn't have much influence until it reaches values much closer to 1 (where it reaches infinity).

But get this: the truck ALWAYS costs 10 energy cubes. Not 2X it. That's different. That's WAY different.

Okay?