Overly Simple Energy-Economy Models Give Misleading Answers

Does it make a difference if our models of energy and the economy are overly simple? I would argue that it depends on what we plan to use the models for. If all we want to do is determine approximately how many years in the future energy supplies will turn down, then a simple model is perfectly sufficient. But if we want to determine how we might change the current economy to make it hold up better against the forces it is facing, we need a more complex model that explains the economy’s real problems as we reach limits. We need a model that tells the correct shape of the curve, as well as the approximate timing. I suggest reading my recent post regarding complexity and its effects as background for this post.

The common lay interpretation of simple models is that running out of energy supplies can be expected to be our overwhelming problem in the future. A more complete model suggests that our problems as we approach limits are likely to be quite different: growing wealth disparity, inability to maintain complex infrastructure, and growing debt problems. Energy supplies that look easy to extract will not, in fact, be available because prices will not rise high enough. These problems can be expected to change the shape of the curve of future energy consumption to one with a fairly fast decline, such as the Seneca Cliff.

Figure 5. Seneca Cliff by Ugo Bardi

Figure 1. Seneca Cliff by Ugo Bardi. This curve is based on writings in the 1st century C.E. by Lucius Anneaus Seneca, “It would be of some consolation for the feebleness of our selves and our works if all things should perish as slowly as they come into being; but as it is, increases are of sluggish growth, but the way to ruin is rapid.”

It is not intuitive, but complexity-related issues create a situation in which economies need to grow, or they will collapse. See my post, The Physics of Energy and the Economy. The popular idea that we extract 50% of a resource before peak, and 50% after peak will be found not to be true–much of the second 50% will stay in the ground.

Some readers may be interested in a new article that I assisted in writing, relating to the role that price plays in the quantity of oil extracted. The article is called, “An oil production forecast for China considering economic limits.”  This article has been published by the academic journal Energy, and is available as a free download for 50 days.

A Simple Model Works If All We Are Trying to Do Is Make a Rough Estimate of the Date of the Downturn

Are we like the team that Dennis Meadows headed up in the early 1970s, simply trying to make a ballpark estimate of when natural resource limits are going to become a severe problem? (This analysis is the basis of the 1972 book, Limits to Growth.) Or are we like M. King Hubbert, back in 1956, trying to warn citizens about energy problems in the fairly distant future? In the case of Hubbert and Meadows, all that was needed was a fairly simple model, telling roughly when the problem might hit, but not necessarily in what way. Continue reading

Drilling Down: Tainter and Patzek tell the energy-complexity story

Joseph Tainter and Tadeusz Patzek are authors of a soon-to-be-released book called Drilling Down: The Gulf Oil Debacle and Our Energy Dilemma. This book is part of Charles Hall’s Briefs in Energy series with the publisher Springer. An earlier book in this series was The Limits to Growth Revisited, by Ugo Bardi.

The new book, Drilling Down, is not simply the story of the Gulf oil spill (although it does tell this story, quite well). Tainter and Patzek use the story of the Gulf oil spill as the background for discussing the energy-complexity spiral, and its relationship to this accident.

The energy-complexity spiral occurs because the availability of abundant, inexpensive energy permits increased complexity. Complexity has the advantage of allowing society to solve more problems, but it has the disadvantage of being more costly–that is requiring more energy for its creation. The need for more energy (and the fact that Energy Return on Energy Investment (EROEI) is declining) leads to a need for more complexity to obtain this additional energy, assuring that the cycle continues. With growing complexity, there is an increased risk of accidents that can be expected because of the complex nature of the system, but which are hard for participants to foresee. Continue reading

Tainter’s Law: Where is the Physics?

This is a guest post by Ugo Bardi. This post previously appeared at his English language blog, Casandra’s Legacy.

Joseph Tainter’s interpretation of the cause of the collapse of civilisations is that social structures generate negative returns when they become too complex; as shown above (fromTainter’s 1996 paper). We could call this relationship as “Tainter’s law”. But what is it exactly that generates this behavior? In this post, I’ll try to make a simple model that explains the law.

Joseph Tainter has written a fascinating interpretation of the collapse of human civilisations in his book “The Collapse of Complex Societies” (1988) (see also his 1996 paper) Collapse is a common event: it is the stuff history books are made of. The mighty empires of the past; from Sumeria to the Soviet Union, have all collapsed at some point. Yet, we don’t seem to be able to understand the reasons why collapse is so common.

In his book, Tainter examines previous studies and lists at least eleven causes (or “concauses”) of collapse that have been proposed by historians. Resource depletion, catastrophes, intruders, social conflict, and others. But is there a single cause of collapse? Or are there several? Tainter looks for a single, common root of the problem and finds it in what he calls “the decreasing returns of complexity”.

Continue reading