@ 911
The links I provided are basically based on the Hill's Group study, which was a first study of oil depletion not in terms of geology and economy, but in terms of thermodynamics, namely the second law of thermodynamics (enthropy law).
The original study, made in 2013, arrived at 2031 as a date of "dead state" (defined as the situation when the entire energy you get from a barrel of oil goes into oil recovery process).
The author you are now criticizing arrived at 2022 instead of 2031 by introducing additional energy inefficiency on the site of a final consumer. But he might have some additional reasons to claim earlier date, as his page is also an advertisement for some business idea. Nevertheless he writes much more clearly for readers without background in physics and mathematics like Kunstler and his audience. But as a reader with such a background, I consider Hill's report legit in the sense that his theoretical model is sound (don't know anything about numbers he uses), even though going at the problem from the entropy perspective is like a deployment of a really big gun here. Such problems are hard to solve, he may have made mistakes. He bases his study on a kind of index values, so the entire thing depends on whether he has chosen his indexes right.
A later than 2031 year as the last one is dependent either on growing reserves of
cheap oil or growing energy efficiency of our civilization.
Well, if you like math, read the original study:
http://www.thehillsgroup.org/depletion2_002.htm
I know there was a lot of criticism directed at Hill (as you may expect, mainly centered around his understanding of enthropy), but I have found pretty ominous that both he and Duncan (of the Olduvai Theory) came to ~2030 as the last year of the industrial civilization.
However, the main argument speaking for Hill is that his model had predicted falling oil prices before they started to fall. Until then everyone had thought the prices will be always rising on scarcity.