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Is it that hard to substantiate your claims that a 60 year amortization + 15 year construction = 75 years is reasonableWhat do you mean reasonable? It’s real. We amortise over long time horizons in project finance all the time. Also, look up residual value. (And dams.)
And yes, I’m contesting both 60 and 15; they’re 80 and 10 and could be 80 and 5 with permitting reform. And within that latter envelope, it works with conventional financing. (The same problem plagues HVDC lines, which also take 10+ years to permit.)
> Do you see the year investment time ending up in the exponent?
You may actually enjoy reading some of the foundational texts whose concepts you’re glancing across. (Principles of Economics, Mankiw, is a classic. For a more-applied text, Fabozzi’s Fixed Income.)
You’re citing real things. But you’re connecting them nonsensically. Investopedia isn’t a replacement for training, though it’s a good reference once you’ve learned the material.
(The exponent comes from compounding time preference. Its time component is orthogonal to technological progress, which embeds in the rate. That’s why it’s constant. If you want to consider obsolescence risk, you start getting into hyperbolic discounting.)