The well known LTG model lacks energy as a discrete component - it only includes "non-renewable resources", which it assumes will become increasingly difficult to extract as limits are reached. In other words, Return On Investment will decrease.
Without an explicit analysis of energy, the model is invalid, as we see in a report of an attempt to add energy as a component here; http://europe.theoildrum.com/node/5145 . It says the following: "in a world with unlimited energy, any chemical compounds useful as a raw material but not as an energy source could be easily obtained "
Energy Return on Energy Invested (EROEI) is a key, foundational element to the energy component of this new model: "The available data on EROEI is very spotty, but it’s such a crucial concept to explain what may happen in the future with energy sources that I believe a model would be inaccurate if it didn’t include it in some way."
This new model assumes that renewable EROEI is low:
"Renewables aren’t used until the end of the 21st century, due to their low EROEI: "
The new model predicts serious problems in the medium term, in large part because renewables don't start to grow in a serious way until 2075, due to their low EROEI.
Wind and solar have high EROEI*, therefore, the energy component of the model is incorrect, and so is the overall model.
*Oddly, this model also makes the unrealistic assumption that nuclear fuel will be depleted within the 21st century.
