> For a matter of convenience, we lower the energy growth rate from 2.9% to 2.3% per year ... When would we run into this limit at a 2.3% growth rate? Recall that we expand by a factor of ten every hundred years, so in 200 years, we operate at 100 times the current level, and we reach 7,000 TW in 275 years. 275 years may seem long on a single human timescale, but it really is not that long for a civilization.

His argument is that sometime in the next 275 years we have to make some change to our economic system, unless economic growth decouples from energy use growth during that time.

What he doesn't say is that it has been decoupling for decades even before he wrote that post, and, by an equally valid extrapolation argument, economic growth will become completely decoupled from energy use globally in another 50 years:

https://ourworldindata.org/grapher/energy-intensity-of-econo...

Or perhaps it isn’t, when you actually account for everything:

https://www.vice.com/en_us/article/qj4z9p/green-economic-gro...

That Vice article is talking about the difficulty of decoupling economic growth from material resource usage growth.

It's possible that our inability to recycle (in an economically efficient way) will end up putting some limit on economic growth, but this is very different from the global thermodynamic argument being made by the article that I was responding to above.

> This graph is from Tim's website and illustrates the relationship λ (lambda) between the world't total accumulated wealth (C, the integral) and our ever-accelerating energy consumption rate (a, measured in 10^21 joules per year)

It's an odd choice to use global accumulated wealth rather than the global equivalent of GDP (GWP). What are the error bars on the calculation for how much the entire planet is worth in dollars?

For reference, GWP growth rate has been between 3% - 6% in the period considered by that paper. If the net world wealth growth rate was 1.82% during that period, it would suggest that depreciation effects are significant in determining that figure.

"It's an odd choice to use global accumulated wealth rather than the global equivalent of GDP (GWP)"

No, it isn't. If you own a house that has already been build it does not influence GDP. Yet you need to finance repairs and maintenance (and therefore Energy).

The problem with most infrastructure is actually not to build it but to sustain it.

That's an interesting point. To give a sense of scale, at least in the context of the US market:

"According to US News and Freddie Mac, homebuyers should actually budget up to 4% of the property’s value in annual maintenance costs." [0]

"house price rises have averaged more than 5 percent over the last few years." [1]

[0] https://www.upnest.com/1/post/what-is-the-annual-cost-of-mai...

[1] https://www.cnbc.com/2018/06/06/us-house-prices-are-going-to...