The price elasticity argument is a red herring. The availability of substitutes is something to consider, though to a large extent for mobile transportation fuels those simply do not exist. There are some remote possibilities that we might be able to come up with something. Electrical generation looks slightly more favourable, and would replace much coal use. The 15% or so of coal used in coking of iron for steel production, somewhat less so, though that's potentially fungible.

There's a reason I'm suggesting order-of-magnitude ranges for pricing errors rather than specific dollar amounts to any level of precision, and I'm willing to suggest a 3-8 OOM range (1,000 to 100,000,000) range based on available data.

A nonrenewable resource, economically, is one whose market price fails to account for the time costs of natural formation, such that rates of consumption exceed rates of restoration.

The relevant number from Dukes' paper, by the way, isn't strictly the biomass required, but the accumulation period of that biomass: roughly 5 million years of ancient accumulation per present year of usage (as of 1997). Another source, Reinventing Fire (Amory Lovins et al) gives the value of 17 million times higher a usage than accumulation rate.

Either way, this represents an off-books financing either in the form of debt (as many represent it) or a draw-down of capital stock or savings (as I prefer to view it), which present economic theory fails to account for.

It needn't do this, and I've been exploring how and why the present circumstance and economic mythology (to use economist Thorstein Veblen's term) emerged.

Adam Smith defines costs as the total factors of input, which would include natural factors and their factors, including formation time. David Ricardo presumed land rents (from which natural resource rents theory emerged) were based on "the original and indestructible qualities of the soil", two false premises. Boehm-Bawerk, Marshall, and Menger discussed theories of cost far more comprehensive than the minimalistic and incomplete marginal theories now dominant (and causing numerous problems throughout microeconomics). The formative papers on natural resource and exhaustive resource pricing (Gray, 1914, Hotelling, 1931) fail to cite any geological references.

At the same time that this theory (or mythology) was forming and extractive fossil-fuel industries were forming, the understanding of geological scales and processes was itself undergoing a phenomenal revolution. As of Smith's time, understanding of the age of the Earth ranged from Ussher's ~6,000 years to ... "unknowably long" (Hutton), with estimates developing over the course of the 19th century of from hundreds of thousands to hundreds of millions of years, though Lord Kelvin and other estimates ranging in the 20-40 million year range, based on understandings of thermodynamics ... and an ignorance of radioactivity. It was in this period that the legal models of property over mineral resources were established, largely Rule of Capture, with significant jurisprudence in 1804 (Post v. Priestly), the 1880s (oil & gas, W. Va. and Penn.), and 1904 (Texas). That law saw modifications in the 1930s due to advances in geological structural but not temporal understanding, and still remains largely in effect today in Texas and elsewhere (Daintith, several publications).

Chasing value manages to confound the fact that cost, price, and value are in fact three separate properties, though related. I call into question the environmental economic practice of trying to assign "use value" to various environmental factors without also taking into account the creation costs, net of environmental factors of production. I'm still thinking through full implications of this: entropy increases, so there's a net loss throughout the system, but there are more and less sustainable rates of such loss.

I stand by my point that the problem is not, as @marcgcombi's (now flagged) comment states, that renewable resources are too expensive, but that nonrenewable resources have been fantastically under-priced by market forces. The good news in my critique, though, is that this may be a problem which can be addressed through market mechanisms: a full accounting of the formation and replacement costs of fossil-fuel resources would make the extraction of them at present rates economically and financially unsustainable. A retroactive application of debits to account for the squandered resources would turn coal-, oil- and gas-extracting firms and nations into the biggest financial catastrophes ever (though nonsustainable ag processes might be another similar case).

Getting back to the price-elasticity question: if your market price fails to account for true costs of production, you are nowhere near an equilibrium point. Computations of elasticities are then the equivalent of premature optimisation in software: you've first got to get the correct outputs and functioning.

More generally: we're aware of what the long-term stable equilibrium point of human activity was prior to mass consumption of nonrenewable fossil fuel resources. Net energy throughput per capita was about 1/100th of the present value (~1/1000th for the US), and total supported population roughly 1/16th present values. We found ourselves on an over-capacity lifeboat but with an immense supplies cache. We've mistaken that supplies cache with the capacity to sustain ourselves indefinitely, a story which I suspect will end poorly.

I'm quite aware that this is not orthodox economic thinking. (It is well within the mainstream of ecology, biology, and physics, however.) I'm also aware that it's rather better supported in economics, finance, and geology, as well as legal miscarriage, than very nearly all of what is orthodoxy.