I read this article a couple months ago and found it incredibly bizarre (to the point of wondering if the economist was actually real or just an invention of the author). Firstly, it spends a lot of time analyzing the consequences of exponential growth in energy usage over the next few centuries. But Google [0] will tell you that energy usage has barely moved between the beginning of their data of 1960 and the end of 2015 (and has actually been on the decline since its peak in the 70s).
Thankfully they then move on to discussing what will happen if energy usage continues not growing exponentially, when the physicist says this:
> If the flow of energy is fixed, but we posit continued economic growth, then GDP continues to grow while energy remains at a fixed scale. This means that energy—a physically-constrained resource, mind—must become arbitrarily cheap as GDP continues to grow and leave energy in the dust.
Then, to clarify, he says:
> Energy today is roughly 10% of GDP. Let’s say we cap the physical amount available each year at some level, but allow GDP to keep growing. We need to ignore inflation as a nuisance in this case: if my 10 units of energy this year costs $10,000 out of my $100,000 income; then next year that same amount of energy costs $11,000 and I make $110,000—I want to ignore such an effect as “meaningless” inflation: the GDP “growth” in this sense is not real growth, but just a re-scaling of the value of money.
No! This is not what economic growth means! No economist in the world should agree with that. It's possible that electricity will be too cheap to meter, or it's possible it won't, but some commodity increasing in price at the same rate as GDP doesn't somehow neutralize the possibility of there having been economic growth. Here's an example. Let's say widgets currently cost $2 to make and there's demand for 1000 widgets/year. If I find some innovation to save $1 on the per-widget production cost, that's $1000 of economic growth. If that innovation uses slightly more electricity (and let's assume the production of electricity is fixed), we'll bid up the price of electricity some amount and displace some less-productive use. That already happens for other finite resources like land (which in some cases leads to exorbitantly high land prices in areas like silicon valley, but that wouldn't mean there's been no growth).
[0]: https://www.google.com/search?q=us+energy+consumption&rlz=1C...