[Doly]

I suppose this is the right place to mention the model I just got published in The Oil Drum, which takes the classic World3 "Limits to growth" model to the world of climate change, peak oil and EROEI. Hope you enjoy it:

http://europe.theoildrum.com/node/5145

[thuja]

Thanks for posting this Doly. Very interesting and detailed depiction of what is coming. I think your models don't show decline fast enough for many of the people here. But It seems evident that we are entering an age where basic resources in the form of food and energy will not meet global needs and will lead to a decrease in living standards and average age of mortality.

[Bas]

wow Doly, you must've put some real effort in there, very interesting, especially as I'm reading one of the follow ups on "limits to growth" in which they also use world3.

[Iaato]

Doly, this is fabulous work. From the graphs, it looks like you used Stella? It's great that you have incorporated EROI and specifying types of energy. I agree with your assumptions about EROI. The inclusion of carbon emissions and resulting graphs fit with my view of what will happen, too.

Your model actually predicts fairly optimistic outcomes, and I have several issues regarding your assumptions. I don't understand why you feel that non-renewable resources such as minerals can be deleted as not important?

What happens if you leave demand out of the model? Is demand essential to include? Doesn't demand follow supply, and won't we essentially use supply as fast as we can? Since there is no way to have more than matching supply and demand, why bother? Might the inclusion of demand create errors by artificially improving supply?



What causes the blip in descent of industrial output, and why is the decline so prolonged? I anticipate a much faster fall. I can understand the initial sharp peak; I view hyperinflation as causing a coming speeding up of world GDP in one big final blast of frenzied activity. But what causes the second lower peak in your model run?

Fabulous work, interesting results.

[shortonsense]

$this->bbcode_second_pass_quote('Doly', 'I') suppose this is the right place to mention the model I just got published in The Oil Drum, which takes the classic World3 "Limits to growth" model to the world of climate change, peak oil and EROEI. Hope you enjoy it:

http://europe.theoildrum.com/node/5145

[Quinny]

Excellent - thankyou

[Doly]

Of course you may ask questions! That was the point of posting here. I'm not a regular poster as I used to be (not working in a callcentre any more with plenty of five-minute gaps to fill in the day), but I still believe in discussion forums. Sorry for not replying before, I've been crazy busy lately.

$this->bbcode_second_pass_quote('Iaato', 'F')rom the graphs, it looks like you used Stella?

[shortonsense]

$this->bbcode_second_pass_quote('Doly', 'O')f course you may ask questions! That was the point of posting here. I'm not a regular poster as I used to be (not working in a callcentre any more with plenty of five-minute gaps to fill in the day), but I still believe in discussion forums.

[Doly]

$this->bbcode_second_pass_quote('shortonsense', '
')What efforts were made to test the sensitivity of your final answer on ANY of the uncertainties involved in your core assumptions?

[shortonsense]

$this->bbcode_second_pass_quote('Doly', '
')
I'm very aware that as soon as there are uncertainties in parameters, the whole model can go into question. There are even uncertainties on whether the equations used are correct. I have tested the most uncertain ones by trying a range of values on them, and got an idea of the variability on the results. The whole concept of considering different scenarios is exactly to test what happens under different assumptions and see if there are common themes emerging.

A few things that I have tested for:
1) Different ultimate reserves for nonrenewable energy sources. As you would expect, that delays the decline, but not for long, and the final result is similar.

[yesplease]

What range of EROEI values did ya use for oil Doly?

[shortonsense]

$this->bbcode_second_pass_quote('yesplease', 'W')hat range of EROEI values did ya use for oil Doly?

[yesplease]

I asked there too, but I didn't receive a reply and the comments are closed. Based on what I did see, the OP assumed oil's EROEI was at ~100:1 in the 1930s, and fell from there on, using the work of Cleveland. However, unlike Cleveland, the OP didn't preface this with the qualifier that the 100:1 figure was for discovery only, not including production costs over the life of the well, refining costs, and transportation costs. The other figures only include production costs, and also do not include refining or transportation costs. The reason this is important is that refining puts a cap on oil's EROEI of ~5:1, so at best this is what we could have been at during oil's heydays. Assuming we had tremendous FF based EROEIs and are transitioning to much lower renewable EROEIs would probably induce a relatively inaccurate model compared to using oil at an EROEI of ~5:1 or lower, and then transitioning to renewables with EROEIs in the ~10-30:1 range.

[shortonsense]

$this->bbcode_second_pass_quote('yesplease', 'I') asked there too, but I didn't receive a reply and the comments are closed. Based on what I did see, the OP assumed oil's EROEI was at ~100:1 in the 1930s, and fell from there on, using the work of Cleveland. However, unlike Cleveland, the OP didn't preface this with the qualifier that the 100:1 figure was for discovery only, not including production costs over the life of the well, refining costs, and transportation costs. The other figures only include production costs, and also do not include refining or transportation costs. The reason this is important is that refining puts a cap on oil's EROEI of ~5:1, so at best this is what we could have been at during oil's heydays. Assuming we had tremendous FF based EROEIs and are transitioning to much lower renewable EROEIs would probably induce a relatively inaccurate model compared to using oil at an EROEI of ~5:1 or lower, and then transitioning to renewables with EROEIs in the ~10-30:1 range.

[yesplease]

That's definitely a concern. For instance 5kW of solar panels plus some solar hot water would allow for all the usual stuff like AC and heating, consumer appliances, a couple efficient EVs at ~20k+ miles/year. So, on one hand, I can plunk down about $10-20k once in order to have enough energy produced for just about everything most people do for the next few decades at least, just in a more efficient way, or I can pay ~$75k ($2.5k/year for thirty years) for the same clunky inefficient FF powered stuff. In terms of value, that's a slam dunk. Granted, most consumers don't really care much about saving money, for instance many people pay off a 30 year loan over the full term, paying twice what they would have if they had simply saved aggressively and bought something, but there's plenty of value there for someone who is interested in that sort of thing.

That value represents the difference in both availability, since I can't drop an oil drill in my back yard, and EROEI, since I get more energy doing useful work via electricity from renewables than via chemical energy from FFs. For example a conventional vehicle at 25-50mpg uses about 1-2 kWh/mile of WTW FF based energy. An EV uses~150-300Wh/mile, depending on model, so we're talking about having ~6-7 times more useful energy, stuff that's doing work, be it moving a car, powering a game console, or spinning an AC compressor. Ironically, the difference in levelized cost almost mirrors the difference in useful energy, give or take.

Anyway, like I said before, a model that selectively uses extremely high EROEI figures that are only for discovery and/or extraction, and compares them to EROEI numbers for renewables over their entire life probably isn't going to be accurate. Not to mention that it ignores the difference in exergy, the amount of energy available for useful work, which is another reason why renewables are more cost effective. From 1kWh of electricity I can get ~.7kWh of useful work done in an EV, but in a conventional car 1kWh of oil will only get me ~.1-.2kWh of useful work.

[shortonsense]

$this->bbcode_second_pass_quote('yesplease', ' ')

Anyway, like I said before, a model that selectively uses extremely high EROEI figures that are only for discovery and/or extraction, and compares them to EROEI numbers for renewables over their entire life probably isn't going to be accurate. Not to mention that it ignores the difference in exergy, the amount of energy available for useful work, which is another reason why renewables are more cost effective. From 1kWh of electricity I can get ~.7kWh of useful work done in an EV, but in a conventional car 1kWh of oil will only get me ~.1-.2kWh of useful work.

[yesplease]

Based on what I've read she hasn't tested for low EROEI in terms of oil and possibly other FFs, just changed the rate of decline from the erroneous 100:1 figure and bumped up renewables a bit in order to see how those outcomes change. Assuming oil and other FFs have spectacular EROEIs when they're worse than most renewables and provide less useful energy to boot hasn't been tested so far, unless of course I've missed something.

[shortonsense]

$this->bbcode_second_pass_quote('yesplease', 'B')ased on what I've read she hasn't tested for low EROEI in terms of oil and possibly other FFs, just changed the rate of decline from the erroneous 100:1 figure and bumped up renewables a bit in order to see how those outcomes change. Assuming oil and other FFs have spectacular EROEIs when they're worse than most renewables and provide less useful energy to boot hasn't been tested so far, unless of course I've missed something.

[shortonsense]

$this->bbcode_second_pass_quote('Shannymara', 'S')he said it's based on the World3 model, which IIRC are open source and readily available. So it's not a black box, generally speaking.

[Doly]

I'll reply to the comments in an aggregated form again:

$this->bbcode_second_pass_quote('', '
')I would venture that your equation for how fast the supply of a resource is coming on line is flawed, and this flaw is correlated with and only specific to a small subset of the actual resource base available for development in the future. It is similar to the "field growth" problem in that if you make the assumption that only what you see is available for development, you massively UNDERestimate how much resource will be converted into reserves and available for use in the future. Laherrere's estimates are very much a reserve estimate rather than a resource estimate, and would lead any model directly into this particular trap. The original modelers in Limits to Growth stumbled into this issue as well, if I recall correctly.