How Does the World Work?

  • See the About page for a description of the subjects of interest covered in this blog.

Series Indexes

Global Issues Blogroll

Blog powered by Typepad

Comment Policy

  • Comments
    Comments are open and welcome as long as they are not offensive or hateful. Also this site is commercial free so any comments that are offensive or promotional will be removed. Good questions are always welcome!

« Let's start with politics and governance | Main | Implications of a Sapient Governance, 5 »

September 26, 2008


Feed You can follow this conversation by subscribing to the comment feed for this post.

Paul J

Hello George

Fascinating Blog. You've been busy this last year! A question I would like to ask you in your quest to justify BTUs as an absolute? unit of economic currency:

Is a BTU a BTU always and everywhere? I can't see how anyone can attach a BTU of Coal(in pounds, given a BTU per pound heating value) as having the same economic value as an equivalent BTU value of Methane. The environmental (and infrastructural energy) costs of the use of both quantities of BTUs would be different. Even arguing from first(physical) principles there are examples where nature "devalues" her BTUs. The natural uranium reactors (Oklo mines) in Gabon are an example of nature "devaluing" the atomic BTU value of fuel through radioactive decay. Even stars "devalue" the E=MC-squared value of their fuel when their cores reach the iron? stage of burning. What I'm trying to get at is even a BTU value would be context sensitive and not absolute. We constantly revalue BTUs based on availability, cleanliness, first extractive costs, regulatory costs, etc. A BTU-based currency or cost standard would be subject to many influences that would defy the use of a stable energy standard that you seem to be desiring.


George Mobus

Good point Paul. The difference between BTU content in coal and gas, as an example is captured in the notion of useful work that can be accomplished. So it factors in downstream conversions of the energy form based on what can be used in the energy stream.

So, for example, a BTU in natural gas might actually be able to do more work than the same BTU value in coal (assuming the energy density is normalized) Gas burners might be more efficient (can get more oxygen to the fuel per unit time) and hence provide more useful work than a coal burner.

Now I have no direct experience with burner technology. Perhaps you could answer if say you can get more electrical power out of a coal plant or a gas generator for the same BTU input.

But the issue is the accomplished work per unit time, regardless of the fuel source. That is what we measure and that tells us how many USABLE BTUs are available in that particular stream.

In conclusion, it isn't the raw BTU content of a fuel that counts, but only that amount of energy that can ultimately get turned into useful work.

As for devaluation, I'm not sure what you mean.

Welcome aboard!

The comments to this entry are closed.